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Posted by anthony on
04-19-2019
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Hi Romy,
Just thinking out loud here, but I have been listening to my mono DSET/Macondo for quite a while now and recently changed back to my old acoustic system so that I could poke around in the DSET innards for a little while. The old system (in stereo) seems incompetent in comparison to the mono DSET/Melquiades. In particular I've really been appreciating the YO186 tube in the midrange horn, and although I have had a 45 in there for a little while the Stalin era Russian tube is really something special. I remember reading on this site about your thoughts of getting some of the YO186 tubes traits as low in frequency as the Upperbass Channel, and from what I have heard I would tend to agree, or at least I think it may be worth trying.
Also on my agenda is to build a valve based LCR phono and for the past few days I have been thinking about possibly going the whole hog and incorporating a valve preamplifier as well. My current sources do not have the voltage output to directly drive my DSET/Macondo to satisfying volume so I am going to need some kind of preamplification, preferably with about x3 or maybe x4 amplification...the Placette will not work as a linestage alone. Although not yet measured, the DSET will probably prove a complex and relatively low impedance load for a preamplifier so the pre will need a low output impedance, preferably 20R or less. Difficult with valves but not impossible, especially if using an output transformer.
Which brings me to my current thought bubble...a low gain pre-amp with perhaps a YO186 as output tube, or even an interchangeable arrangement with both 2.5V and 4V tubes as is currently in the DSET, which would allow using perhaps a 45 in the pre and the YO186 in the DSET or vice versa. There are certainly concerns about having too much of a good thing and messing with what the DSET is able to achieve in combination with Macondo, but perhaps this may be a way of getting the YO186 traits into the entire frequency range, not just the upper mids.
I also have some memory about reading on here about you experimenting with valve preamplification in the early or pre-Melquiades days but being unable to find satisfaction. Technically, I like the idea of good SS circuitry to handle the pre-amplification duties, and it seems as though Guy Hammels recent introduction of gain to your Placette Linestage has been successful, so that is an option also for my unit. Shortly I will have a very good Class A SS Pre finished that has some gain and will use a high quality volume control, so perhaps it will make the Placette redundant. But it would be nice to do it all with valves..
Regards,
Anthony
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Posted by Romy the Cat on
04-20-2019
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Anthony, I know what you
feel but I am no sure that I might be too useful for you quest. Let me to explain
first the points you made.
I do not know why Placette
does not work in your situation. You do not have enough volume? If it is the
case then you might have too low gains in your front end. All my front ends
have very high gain: Bidat, Lavry, my phonostage, Passific use have it. The
only in Video mode what I drive the things from Oppo then I have no volume and
that brought me to new high gain active Placette modules. I do not know what
frond end you have; it might be easy to add some gain you your current front
end. If it is not discreet circuit in you front-end and has some kind of chip
then my lowering a feedback you can always get 6-12db more. If it is not volume
but you do not like the Placette sound then I would like to hear more details:
what specific you do not like in it. I think I know very well this unit and I might
be able to debug the problems.
Now about the bigger fish to
fry: to make another pream. Here is I feel a bit out of depth. I spent a LOT of
time to look for great preamp and what I found Placette I did not try anything else.
There is absolutely no reasons to say that Placette was the only one good
preamp during my “active” period of my looking. I just reported among what I experienced
but it was understandably limited. During the last 15 year that I had not been looking
for any preams there was zillion other preams made and I have no idea what they
are. Still for the configuration of a pram driving passive filters you need a current
source with as low output impedance as possible. There is not a lot preamps out
there that drive a lot of current with sub 20R impedance. Many contemporary oops
preams will do but they not necessary sound acceptable. So, here we go… the
game is open…
If I do play the game of looking for an alternative to Placette preamps then I would look still for discreet
SS units like Blowtorch and alike. The active Placette with gain is a controversial
inot in my estimation. It is very good but I do feel a difference between the no
gain Placette and the gain Placette. It is hard to explain the difference as it
is not in realm of sound but rather is a realm of “efforts”. I have not happy with any tube preams I have
heard.
Now we enter the realm of DIY:
the idea of making you own preamp. I know absolutely nothing bout SS designs. I
made one that was designed for me by a very strong person and it was an honorable
nightmare sonically. My tube line stages also were not good but it means
nothing, you can me luckier. I would certainly not consider YO186. It is a spectacular
tube but very colored, particular in the under-power mode as it is being used in
Milq. In the Milq specific application, driving S2 and operating in a very
limited range I feel I get the best from YO186 and use the YO186 colorations creatively.
I however feel that it is no way a wide range tube and any type 45 tube is WAY
more accurate sounding.
How to get low output impedance
of out tubes. Yes, the OPT might help. Paralleling tube and trying the OTL mode
might help. To use some low R rube like 6C33C as preamp out tube might be a
very interesting direction to go. Another alternative would be to have a
voltage gain with tube and to have output no gain SS buffer. There is many
options out there but too little time to try all of it… I am not sure why I
feel you need a tube preamp. It sounds to me that you need gain not a tube
preamp. If you formulate your objective that you need a tube preamp then try to
formulate for your why you feel you need tube preamp. The point I make is that
any progression in audio navigation should start with formulating a proper question
to yourself:
http://www.goodsoundclub.com/Forums/ShowPost.aspx?PostID=432
That is in my view helps to focus on what you need instead of
what is possible out there.
This is very interesting thread I would like to see where it take you.
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Posted by anthony on
04-20-2019
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 Romy the Cat wrote: |
I do not know why Placette
does not work in your situation. You do not have enough volume? If it is the
case then you might have too low gains in your front end. All my front ends
have very high gain: Bidat, Lavry, my phonostage, Passific use have it. The
only in Video mode what I drive the things from Oppo then I have no volume and
that brought me to new high gain active Placette modules. I do not know what
frond end you have; it might be easy to add some gain you your current front
end. If it is not discreet circuit in you front-end and has some kind of chip
then my lowering a feedback you can always get 6-12db more. If it is not volume
but you do not like the Placette sound then I would like to hear more details:
what specific you do not like in it. I think I know very well this unit and I might
be able to debug the problems.
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Exactly that, my sources do not play loud enough through the Melquiades or DSET. Like your OPPO, they only put out about 2V RMS which seems to be the modern standard and I need more. Can you remember what input voltage DSET needs for maximum volume? I can measure this, but just need some time. Some sources these days have less than the nominal 2VRMS output, and my favourite source (which is my dac) I believe will only give a little over 1VRMS (which I need to measure).
The desire for a valve preamp comes solely from one direction: I am going to build one or two valve phonos to see how they compare to my SS phonos, and if successful it would be nice to box up the phono and preamp into the one chassis (separate power supply of course)...so one box on the shelf rather than one phono box and one preamplifier box. Of course the valve preamp has to earn its place and in general I am happy with the Placette but it does not have any gain. It is unlikely that any future sources that I end up with will have high voltage output so it makes sense to me to add a little voltage gain in the preamp rather than fiddling with my sources. The SS pre that I almost have finished may or may not have enough gain and it may or may not be a successful challenger to the Placette, but only time will tell. Of course slapping a SS pre in the same box as a valve or SS phono is not a real issue...it can be done.
| Romy the Cat wrote: |
Still for the configuration of a pram driving passive filters you need a current source with as low output impedance as possible. There is not a lot preamps out there that drive a lot of current with sub 20R impedance. Many contemporary oops preams will do but they not necessary sound acceptable. So, here we go… the game is open…
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The SS pre that I am building fits these parameters...and sounds very good in other systems...but the DSET is a very specific load to master and it will be interesting to see how it performs against the Placette. Like all my audio projects, it has taken a long time to finish and at the time all I wanted was a unity gain linestage and I almost did not start the project because of the 4x (from memory) gain but thought if it did not work out that I could task it as a headphone amplifier.
| Romy the Cat wrote: |
If I do play the game of looking for an alternative to Placette preamps then I would look still for discreet SS units like Blowtorch and alike. The active Placette with gain is a controversial inot in my estimation. It is very good but I do feel a difference between the no gain Placette and the gain Placette. It is hard to explain the difference as it is not in realm of sound but rather is a realm of “efforts”. I have not happy with any tube preams I have heard.
Now we enter the realm of DIY: the idea of making you own preamp. I know absolutely nothing bout SS designs. I made one that was designed for me by a very strong person and it was an honorable nightmare sonically. My tube line stages also were not good but it means nothing, you can me luckier. I would certainly not consider YO186. It is a spectacular tube but very colored, particular in the under-power mode as it is being used in Milq. In the Milq specific application, driving S2 and operating in a very limited range I feel I get the best from YO186 and use the YO186 colorations creatively. I however feel that it is no way a wide range tube and any type 45 tube is WAY more accurate sounding.
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Point taken about the YO186 colourations, but I still would like to be able to try it. The twin output socket arrangement on the DSET is great and can be easily duplicated.
| Romy the Cat wrote: |
How to get low output impedance of out tubes. Yes, the OPT might help. Paralleling tube and trying the OTL mode might help. To use some low R rube like 6C33C as preamp out tube might be a very interesting direction to go. Another alternative would be to have a voltage gain with tube and to have output no gain SS buffer. There is many options out there but too little time to try all of it… |
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The 6C33C could certainly drive current, and I have spare OPT's here that I could use to experiment. If I went with tubes I would like to go DHT in this situation for a few reasons which I will outline in the next paragraph.
| Romy the Cat wrote: | I am not sure why I feel you need a tube preamp. It sounds to me that you need gain not a tube preamp. If you formulate your objective that you need a tube preamp then try to formulate for your why you feel you need tube preamp. The point I make is that any progression in audio navigation should start with formulating a proper question to yourself:
http://www.goodsoundclub.com/Forums/ShowPost.aspx?PostID=432
That is in my view helps to focus on what you need instead of what is possible out there.
This is very interesting thread I would like to see where it take you. |
|
Motivations! Yes, the murky world of why we do what we do. The further I have progressed in this DSET/Macondo project the more personal meaning it has accumulated. Some people have a mid-life crisis and buy a Porsche or a yacht, some guys quit their high paying desk job to go and build a house in the scrub or the beach or use their hands on some large and introspective projects that bring an ongoing associated sense of relief or calm or achievement. Well, I have the satisfying professional work plus I am still lucky enough to be hands-on at the farm so I am not suffering so much the urge to quit either nor do I need a tree change to balance my life's ambitions...everything is calm and plain sailing at the moment and has been for some time.
What started out as a project to "get good sound" and "learn new stuff" has morphed into a little of a meaningless semi-philosophical tangent. To me, DSET/Macondo is about many things including shunning the modern axioms of convenience and instant gratification and taking the path well trodden. I am very proud of myself that the first DSET was powered up and is in operation without electrocuting myself or letting out any smoke (other than one potentiometer that went off the end of its track and stuck) and that I got the grounding scheme right first time. The gear is huge and heavy and imposing and much of it is older than I am and it all uses amplifier topology that went out of fashion before my father was born but at the same time it is also relatively unique and of course "I made it". To say that "I made it" is not some small factor influencing my thoughts about the valve preamp would be an untruth.
Plus, the valve pre would fit into the general vintage styling of the entire system and of course would be heavy, hot, large, difficult and all the things I have come to love about this project.
But, the sonic reasons remain the same as when I started this project, I want good sound. At the moment I have a partially finished acoustic system and I am trying to pick the best path forward. I definitely need more gain but am resolved not to alter the output of my sources but instead to put some gain into the preamplifier. That is the first hurdle: loudness. I would love to build it myself and if possible do it with tubes but if SS is necessary then SS will be used. If I end up sending my Placette over to Guy to get beefed up like yours Romy then that is what it will be. At the moment, however, I will need more volume to make meaningful judgments about what I hear. And of course I need to finish building the horns!
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Posted by Paul S on
04-21-2019
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Anthony
Do I remember that a big part of Romy's choice for a pre-amp was based on the specific needs of his DSET Milq, with it's inter-stage X/Os? And do I remember the Placette Active Pre-amp has consistent, fully buffered 10R out? The phono stage might be tubes or SS (or hybrid...), but surely you want it well isolated from the DSET? Anyway, it sounds like a situation where a SS (or discreet) buffer would have some electrical advantages, at least if you want to keep the combined size and weight less than an upright grand piano. How much net phono gain (excluding RIAA losses) do you want? If you need greater than typical MM gain, good luck doing that with all tubes and then running it straight into that DSET.
Best regards,
Paul S
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Posted by rowuk on
04-21-2019
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How many sources do you currently have? If you are building a phono corrector, make it for 4 volts output. If you have a PC for digital playback, there are good DACs with more than 2V output. That would leave a tuner to pimp - certainly less risky than a new preamp.
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Posted by Romy the Cat on
04-21-2019
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| anthony wrote: | | Exactly that, my sources do
not play loud enough through the Melquiades or DSET. Like your OPPO, they
only put out about 2V RMS which seems to be the modern standard and I need
more. Can you remember what input voltage DSET needs for maximum volume?
I can measure this, but just need some time. Some sources these days have
less than the nominal 2VRMS output, and my favourite source (which is my dac) I
believe will only give a little over 1VRMS |
|
Oh, good, why did not you tall it before. How the hell can
you listen if it you DAC outputs 1V?! No wonder you have no volume. Also if you
have no voluble you do not “get” one of the most advanced feature of multi-amp topology
multiplied with one of the most advanced feature of Milq design: an ability to absolutely
effortlessly to walk over dynamic contracts, particularly at high volumes. Most
of the amps out there change sound as volume rise, not multy-amped Milq. This
is all together a big subject that requires a separate explanation. Anyhow,
with 1V from your front end you are nowhere. My front ends have 3.1V at 0dB
digital. Many of Milq’s ideas were very much formed around the input Milq tube that
ruin with 4.5V bias and that can naturally (with no feedback injected into cathode
as Lamm does for instance running 12AX7) can handle the whole input voltage
swing. My phonostage pushed over 4.5V and it will drive the Mil on A2 but it
will be at the volume where the wind will be flying out on my listening room. With
3-4V at input we still at the perfect window where the driver tube not stressed
by input voltage and the output tube is still not clipped by power:
http://www.GoodSoundClub.com/TreeItem.aspx?PostID=6057
I do not know what your fav DAC is but if it is operational
amplifier basedDAC then you can easily get more gains out of it by lowering the
op-amp feedback.
| anthony wrote: | | The SS pre that I am building fits these
parameters...and sounds very good in other systems...but the DSET is a very
specific load to master and it will be interesting to see how it performs
against the Placette. Like all my audio projects, it has taken a long
time to finish and at the time all I wanted was a unity gain linestage and I
almost did not start the project because of the 4x (from memory) gain but
thought if it did not work out that I could task it as a headphone amplifier. |
|
DSET has no specific load demands the input passive filters
are. All that you do in the preamp you make, from the Milq perspective, make
sure that it has as low output impedance as possible but to be stable at the
same time.
| anthony wrote: | Motivations! Yes, the murky world of why
we do what we do. The further I have progressed in this DSET/Macondo
project the more personal meaning it has accumulated. Some people have a
mid-life crisis and buy a Porsche or a yacht, some guys quit their high paying
desk job to go and build a house in the scrub or the beach or use their hands
on some large and introspective projects that bring an ongoing associated sense
of relief or calm or achievement. Well, I have the satisfying
professional work plus I am still lucky enough to be hands-on at the farm so I
am not suffering so much the urge to quit either nor do I need a tree change to
balance my life's ambitions...everything is calm and plain sailing at the
moment and has been for some time.
What started out as a project to "get good sound" and "learn new
stuff" has morphed into a little of a meaningless semi-philosophical
tangent. To me, DSET/Macondo is about many things including shunning the
modern axioms of convenience and instant gratification and taking the path well
trodden. I am very proud of myself that the first DSET was powered
up and is in operation without electrocuting myself or letting out any smoke
(other than one potentiometer that went off the end of its track and stuck) and
that I got the grounding scheme right first time. The gear is huge and
heavy and imposing and much of it is older than I am and it all uses amplifier
topology that went out of fashion before my father was born but at the same
time it is also relatively unique and of course "I made it". To
say that "I made it" is not some small factor influencing my thoughts
about the valve preamp would be an untruth.
Plus, the valve pre would fit into the general vintage styling of the entire
system and of course would be heavy, hot, large, difficult and all the things I
have come to love about this project.
But, the sonic reasons remain the same as when I started this project, I want
good sound. At the moment I have a partially finished acoustic system and
I am trying to pick the best path forward. I definitely need more gain
but am resolved not to alter the output of my sources but instead to put some
gain into the preamplifier. That is the first hurdle:
loudness. I would love to build it myself and if possible do it with tubes
but if SS is necessary then SS will be used. If I end up sending my
Placette over to Guy to get beefed up like yours Romy then that is what it will
be. At the moment, however, I will need more volume to make meaningful
judgments about what I hear. And of course I need to finish building the
horns! |
|
Anthony, I do understand all of it but the sentient you
expressed has, in my view, a self-defeating and self-limiting fallacy. A desire
to have “good sound” is abstract and never fulfilling. It is not different from
the famous emperor’s comment that Mozart’s music has too many notes. Your parley
in audio as a substitution for mid-life crisis is not something that I have problem
with. I do have a problem that very frequently in audio people get taken by
ability render differences (by building or buying) and do
not recognize that they keep moving irrelatively- latitudinal or lateral. A
true progress in audio and better audio come with observation of system owner longitudinal
or amplitude progress. I do not see in anything you say, at least publicly, any
factoring of any listening objective and this is a bit concern you. Not that I
worry about you too much, you do not need my worry, but I also know a lot about machine-
humans interaction, in this case machine are audio methods. I do not want to bother you with all of it
but I juts share you with my presupposition that you might take under
consideration or might discard it as a stupid nuisance. If after a period of
time listening you playback you detect that you move in your listening preference
from whatever you are listening to Bach, Beethoven and perhaps Brahms then your
playback “works” probably and you are getting “good sound”. If during you practicing
audio your listening inclination do not move altimetry toward to Bach then you need
to start changing tubes, voltages, cartridges, cable elevators etc….
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Posted by anthony on
04-21-2019
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| rowuk wrote: | | How many sources do you currently have? If you are building a phono corrector, make it for 4 volts output. If you have a PC for digital playback, there are good DACs with more than 2V output. That would leave a tuner to pimp - certainly less risky than a new preamp. |
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Yes, Rowuk, it is important to specify this:
Dac: My dac outputs about 2VRMS but it never sounds its best unless attenuated slightly. I always run it at -6dB into the Placette and use the Placettes volume control, which is why I said the dac outputs 1WRMS. At the moment I do not listen to this dac and have just been streaming from my computer through a soundcard which only outputs 2VRMS, and if I want loads of volume I add a SUT. I can talk with the manufacturer about increasing the output of this dac. It has zero feedback in the IV stage but I think the stages can be "stacked" to give more voltage.
Tuner: TU-X1 which puts out plenty of voltage from memory, certainly it was a lot louder than all my other sources. Unfortunately the cockatoos have ruined the cable on the FM antenna and I need to get on the roof to rewire and better protect it from birds. I am reasonably sure this source will put out 4VRMS.
TT: One of the valves I am looking at using in a valve phono is a cascoded 6S3P which should give about 56dB of gain from two stages after RC RIAA filter losses. 30pF-50pF input capacitance. Add a SUT before and I may have as much as 32dB more gain which would give a total of 88dB which should squeak 4V from my 0.2mV MC cartridge. The SS phonos that I have here will give 76dB (1.3VRMS output including 32dB SUT) and 63dB (0.25VRMS without SUT - not sure if I can run a SUT before this phonostage, but if I can that is 95dB gain). One complication here is that I would like to run balanced from cartridge to phono which would reduce those total gains by 16dB at the SUT: 72dB for the valve phono; 60dB for the first SS; 79dB from the second SS). 86dB total gain is 4VRMS. Then if I go for an LCR RIAA filter I may lose more gain...not sure how much.
Bluray/DVD: I've been hoarding some DVD's of various orchestral performances with intention of adding visual capability to my listening room after everything else is up and running. Every decent disc player with modern video these days only outputs 2VRMS and I do not know of any that output more.
Computer: Streaming youTube or Tidal from my PC via a sound card such as Focusrite Scarlet 2i2 or RTX-6001 Audio Analyser only gives the equivalent volume of about 2VRMS output. Note that my computer streaming is different to using my Dac (above). The Dac has its own dedicated and optimised computer whereas streaming, as we are talking about here, happens from my work PC through a random soundcard.
Hence my case for a pre-amp with some gain, ideally about 12dB or 4x.
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Posted by anthony on
04-21-2019
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| Paul S wrote: |
Anthony
Do I remember that a big part of Romy's choice for a pre-amp was based on the specific needs of his DSET Milq, with it's inter-stage X/Os? And do I remember the Placette Active Pre-amp has consistent, fully buffered 10R out? The phono stage might be tubes or SS (or hybrid...), but surely you want it well isolated from the DSET? Anyway, it sounds like a situation where a SS (or discreet) buffer would have some electrical advantages, at least if you want to keep the combined size and weight less than an upright grand piano. How much net phono gain (excluding RIAA losses) do you want? If you need greater than typical MM gain, good luck doing that with all tubes and then running it straight into that DSET.
Best regards,
Paul S |
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Yes, I would only consider running a preamp into the DSET. The convenience of remote source and volume control is just too hard to give up once you have it...at least for me it is.
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Posted by anthony on
04-21-2019
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| Romy the Cat wrote: |
Oh, good, why did not you tall it before. How the hell can
you listen if it you DAC outputs 1V?! No wonder you have no volume. Also if you
have no voluble you do not “get” one of the most advanced feature of multi-amp topology
multiplied with one of the most advanced feature of Milq design: an ability to absolutely
effortlessly to walk over dynamic contracts, particularly at high volumes. Most
of the amps out there change sound as volume rise, not multy-amped Milq. This
is all together a big subject that requires a separate explanation. Anyhow,
with 1V from your front end you are nowhere. My front ends have 3.1V at 0dB
digital. Many of Milq’s ideas were very much formed around the input Milq tube that
ruin with 4.5V bias and that can naturally (with no feedback injected into cathode
as Lamm does for instance running 12AX7) can handle the whole input voltage
swing. My phonostage pushed over 4.5V and it will drive the Mil on A2 but it
will be at the volume where the wind will be flying out on my listening room. With
3-4V at input we still at the perfect window where the driver tube not stressed
by input voltage and the output tube is still not clipped by power:
http://www.GoodSoundClub.com/TreeItem.aspx?PostID=6057
I do not know what your fav DAC is but if it is operational
amplifier basedDAC then you can easily get more gains out of it by lowering the
op-amp feedback.
|
|
With DSET, I do not bother to listen with that dac and I stream approximately 2VRMS from a soundcard (Focusrite Scarlett 2i2) attached to my work computer. It is better. When I really want some volume I add a SUT but of course this is not an optimal solution. As I mentioned in my earlier post to Rowuk, my main dac has has zero feedback at output but the IV stage can be "stacked" for more output: I am tempted to try this. The output stage will drive loads of current and the manufacturer thinks I am mad running it through a preamp.
Thanks for this information Romy. 3V-4V output is what I need: I'll aim for 4V.
Oh, and believe me that in my Macondo's current state I hear the Milq absolutely walking over dynamic contrasts even at the volume I am able to muster with the SUT, it is extraordinary, and will only improve with the UB horn.
| Romy the Cat wrote: |
Anthony, I do understand all of it but the sentient you expressed has, in my view, a self-defeating and self-limiting fallacy. A desire to have “good sound” is abstract and never fulfilling. It is not different from the famous emperor’s comment that Mozart’s music has too many notes. Your parley in audio as a substitution for mid-life crisis is not something that I have problem with. I do have a problem that very frequently in audio people get taken by ability render differences (by building or buying) and do not recognize that they keep moving irrelatively- latitudinal or lateral. A true progress in audio and better audio come with observation of system owner longitudinal or amplitude progress. I do not see in anything you say, at least publicly, any factoring of any listening objective and this is a bit concern you. Not that I worry about you too much, you do not need my worry, but I also know a lot about machine- humans interaction, in this case machine are audio methods. I do not want to bother you with all of it but I juts share you with my presupposition that you might take under consideration or might discard it as a stupid nuisance. If after a period of time listening you playback you detect that you move in your listening preference from whatever you are listening to Bach, Beethoven and perhaps Brahms then your playback “works” probably and you are getting “good sound”. If during you practicing audio your listening inclination do not move altimetry toward to Bach then you need to start changing tubes, voltages, cartridges, cable elevators etc….
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I've not explored Bach too much yet. Am still exploring several others whose works have piqued my interest when heard on the radio and elsewhere. Not having any classical music in the house during my childhood has limited my field of view in this regard but interest is ever expanding...I am sure Bach is not going anywhere and I will get to him when the time is right. Hearing something I enjoy and then finding the individual performances that tickle my sensibilities and then realising that some performances of the same work (from the group of performances that I admire) are more suitable depending on my particular state of mind is so much more rigorous and complicated than blindly sticking on some rock or pop that still sounds exactly the same from the day it was released because it is only ever really performed by the one group. I find that with classical music that due to numerous interpretations of any given piece there is more work to be done by the listener and more to be learned and gained thinking and exploring what interests you. I'm certainly still learning...
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Posted by anthony on
04-25-2019
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So, I have been looking into suitable valves to base a preamplifer around that are suitable for driving the DSET's. The pre must have a broad bandwidth, low output impedance, some current drive, and not be prone too easily to microphony. Oh, and preferably DHT...but that one is not set in stone. I have also decided that I would like to chase 6x or more gain in the preamp. Simple!
Ale Bartolas site has been particularly useful. He has spent an inordinate amount of time refining designs over time and openly shares his experience. Initially I was attracted by the 71a and 45 because of their relatively low plate resistance but at 3x and 3.5x gain I would need two stages and I don't want two stages. DHT's such as 26, 01a, 10y are around that 8x gain or a little more so are suitable from the gain perspective, but they vary a lot in plate resistance and therefore output impedance. Driven with Ale's "Hybrid Mu-Follower" aka gyrator load, these DHT's should have the following output impedances:
- 71a Zo = 13R
- 45 Zo = 14R
- 26 Zo = 503R
- 01a Zo = 270R
- 10Y/801a/VT25 Zo = 42R *26R with more anode current
- 2P29L Zo = 29R *pentode connected in triode
So, if I knock out those valves with insufficient gain and unsuitable output impedance the only DHT that I am left is 10Y/VTA25/801a. Or the excellent Russian pentode. Apparently the 2P29L is just not microphonic at all and the 10Y is manageable, similar again. Both tubes have high transconductance and can push more current than usual for triodes; both have a bandwidth out to near MHz range; both use a similar B+. 7.5V filament vs 2.2V heater.
So there are two. Nothing in between them regarding my initial design brief. One is DHT though...the other is just not microphonic.
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Posted by Romy the Cat on
04-26-2019
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Anthony, I am not so thrill
that you are unlashing your into this direction. Not that it is my business and
you can do whatever you want. Still, I feel that methodologically it is not right
way to build a playback. What I mean is that to evaluate a quality of preamp is
very hard job if you do not have a well performing playback to the sound of
which you well accustomed. If I was you I would make $5 op-based gain stage, of
buy/borrow a cheap preamp driving it into Placette and then I would finish the entire sound in my room.
As everything is done and calibrated THEN, ONLY THEN, I would go for good gain
stage.
As everything is done you
will have a few options. Again, I do not know what frond end you use. Some of
the frond-ends have powerful output stages and can drive line level transformer
against Placette. Some of the frond-ends have output stages that might be easily
tweaked to get extra dozen dBs. I you do insist to have a separate gain stage
then you need to decide if you will be driving it into Placette or you will substitute
the Placette. If you will be driving the gain stage into Placette then you do
not have any concern with output impedance and the array of the available topologies
is wide open, this is the direction that I would go. If you are willing
to make a preamp that will replace Placette then I feel it will be VERY hard
to. Regarding the tubes if you insist to do it on tubes. I love the 10Y but I
have no idea how it doe as preamp and with the transformer that you will be using
(wish in my view will be the definitive element of you preamp). The tripod strapped
2P29L might be interesting, you can even drop the impedance with cross
screen feedback. I never heard 2P29L, they are from the family of tube that
Germans made for Russians after WW2 and the tubes were mostly military
targeted. There was many of them with odd voltage, the 4P1L might be the one
that you also might consider. There is a cult in Russia of those tube follower but
those people do not impress me with other then audio- soldering skill,
so I have no ideas what to think about those type of tubes.
Anthony, I am serious, do not west
you energy on fighting the gain stage war. Make you playback to sound well as
is. Buy for $50 on eBay a CD played that can swing 3.5V and focus on the rest
of you system. You will return to your gain problems after you finished. I wonder
why you demonstrate so much loyalty to your frond-end. You know, it is much
ease to find a good front-end then to fine a good line level buffer.
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Posted by anthony on
04-27-2019
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| Romy the Cat wrote: | | Still, I feel that methodologically it is not right
way to build a playback. |
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No disagreement from me on this point. This is all just a thought bubble for now. Even if I wanted to press go on this project based on past experience it would be about a year before the parts were wound and assembled...at least a year. There are DSET's and horns to finish, a room to treat, other fish to fry.
I like to try and think several steps ahead and incorporate those ideas into current actions. Instead of getting Macondo tuned and then going "time to build a valve preamp to improve xxx or yyy", I will have researched the subject and will be able to say time to build a 10Y or 2P29L preamp starting with this particular circuit that I like. And because this is potentially on the horizon I will leave enough room on the equipment rack to fit the boxes. Anyhow, I should make it clear that a valve pre is not an imminent project until I start to build my LCR phonostage, which is not going to happen until I get Macondo up and running in full.
So please think of this thread as trying to investigate which direction I could go regarding valve preamplification. To date I have identified 6x gain, low output impedance, broad bandwidth, some current capability, manageable microphonics. Let's see what can be found.
| Romy the Cat wrote: |
Again, I do not know what frond end you use. |
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My preferred source is a Phasure NOS1a G3 dac. The thing has no discernible sound of it's own. It outputs 1.25VRMS SE and I run it at -6dB because it needs a little attenuation to sound its best which means 0.625VRMS. I don't know if it is the IV stage of the dac or if it is the software that affects SQ...I suspect the software. It can push a lot of current. The Placette dims the NOS1a a bit....whitens some of its colours...cramps a little dynamics. I can live with this because the Placette also brings remote source switching and volume control.
| Romy the Cat wrote: | | Some of the frond-ends have output stages that might be easily tweaked to get extra dozen dBs. I you do insist to have a separate gain stage then you need to decide if you will be driving it into Placette or you will substitute the Placette. If you will be driving the gain stage into Placette then you do not have any concern with output impedance and the array of the available topologies is wide open, this is the direction that I would go. If you are willing to make a preamp that will replace Placette then I feel it will be VERY hard to. |
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I was thinking about replacing the Placette, but to be honest had not considered a separate gain stage just for the dac...perhaps that is doable.
| Romy the Cat wrote: | | I love the 10Y but I have no idea how it doe as preamp and with the transformer that you will be using (wish in my view will be the definitive element of you preamp). |
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Ale Bartolas Hybrid Mu Follower eliminates the output transformer. The output impedances I quoted earlier in this thread were using that topology, so a 10Y without output transformer has 8x gain and circa 30R output impedance.
The first SS pre with 3x or 4x gain (that I started two or three years ago for another project) will be in operation soon. I will play with tweaking it a bit and compare it to the Placette to see what I have got. It should be enough gain for all of my sources apart from my dac. Yes I am loyal to that dac. I did the hard yards comparing it to several other contenders and it came up trumps so I would need convincing to seriously consider moving it along.
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Posted by Romy the Cat on
04-27-2019
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| anthony wrote: | | My preferred source is a Phasure NOS1a G3 dac.
The thing has no discernible sound of it's own. It outputs 1.25VRMS SE
and I run it at -6dB because it needs a little attenuation to sound its best
which means 0.625VRMS. I don't know if it is the IV stage of the dac or
if it is the software that affects SQ...I suspect the software. It can
push a lot of current. The Placette dims the NOS1a a bit....whitens some
of its colours...cramps a little dynamics. I can live with this because
the Placette also brings remote source switching and volume
control. |
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Anthony, thank. This is very interesting reply and we have a lot of talk about
it. First thing first: if your Placette clips dynamic and whitens some of its colors
then you should get rid this preamp because it does because it does not do its
duty. I never experienced this behavior before and my initial sentiment suggested
that you were wrong in your assessment.
I am not familiar with Phasure NOS1a G3, so naturally I was
looking what it is. I found an article that give me some point of reference. It
was Phasure NOS1 vs. Pacific Microsonics Model Two
https://audiophilestyle.com/forums/topic/6287-phasure-nos1-vs-pacific-microsonics-model-two/
“The
NOS1 is like taking an x-ray of the music. It’s so crystal clear and pure. And
yet it’s so easy to listen to. It’s exciting and yet relaxing at the same time.
….In contrast, the Model Two is more full-bodied. It gives the impression of
richer harmonic content. It retains some of the NOS1’s detail but loses its
super clarity – it’s simply no match for the NOS1 in this respect. The bottom
end is more pronounced and weightier – but then perhaps a little less tuneful
for it. It is an incredibly musically engaging DAC though”
I
know Pacific very well so, what I am reading here? It sounds like Phasure
has what I call “expedited” sound. I can testify that Pacific has absolutely perfect
what they call harmonic content or in other language a balance between transients
and decay. The “expedited” sound
shorten a bit the decay time/volume and makes transients more prevailing. This
is what very commonly audio people feel as “quality” but I degree with it. You
will be able to experiment with it
By changing the transformer
ration at you SETs. The more idle an output tube is running the “faster”, more
details, higher contrast and more “x-ray” sound become. It
will also hale via striping of some harmonics. People frequently go in audio
for that “expedited”, high resolution sound and I can give you many examples
of it. I feel that this direction is not fruitful. I was there and I very much
rolled myself back from that quantitative perception of quality. Playing with
that OPT load change you will eventually find a golden middle that will be not
the most “x-ray” setting. I am NOT insisting that what people comment positive
regarding the Phasure DAC is what I described above but it might play some role.
As I said above it was my INITIAL sentiment
that you wrong in your assessment and rather felt that Placette juts do not do that “expedited”, “less-harmonics” pushing
that makes you to feel that it “cramps a little
dynamics”. The initial part is gone as there is absolutely nothing that might explain
your comment: “whitens some colours”. if your preamp does it then it is not a
good preams. Since I do not feel it is possible I preams there are 3 factors that
might be in pay.
1)
Your Placette is
misfunctioning
2)
Your admiration with “expedited” sound somehow
find a pass in your mind to this decolorization
3)
I am clueless
with my assessment and somehow Phasure found a new “golden middle” at
the level I am not familiar.
All of the options above sound reasonable to me.
With 0.6V you get out of your Phasure you are nowhere. The
guys online say the Phasure is being supported very well. Why don’t you ask the
Phasure designer to help you with higher output for Phasure. He can experiment
on you and you will be acting like a beta-tester for him. If his DAC pushed 0.6V at it’s best then the Phasure
owner know that it is the problem. I think it might be a good collaboration
between him and you to and in the end you both will be benefited.
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Posted by rowuk on
04-27-2019
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There seems to be a standard 2.7V option for you:http://www.phasure.com/index.php?PHPSESSID=rdq01o6tv8ed20nii15hjqnjb0&topic=1560.0
"Output level for Single Ended Mode (RCA) is 1.5VRMS (-3dBFS relative to normal Full Scale). Output level for Differential Mode (XLR) is 2.7VRMS (+3dBFS relative to normal Full Scale)."
The differential mode would require a transformer to make it single ended - or you need a balanced input on the Placette. Both should be an option. In any case, I am sure that Peter from Phasure could accomodate you also with more gain if you need it.
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Posted by anthony on
04-27-2019
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Romy, I will attempt to fill you in on some backstory.
My Placette was purchased from a guy in France. My dac is made in the Netherlands. To an Australian that is just like next door. I have a good and strong relationship with Peter Stordiau who makes the Phasure stuff and at the time he was looking at releasing a SS preamplifer himself. Maybe. Peter has a strong set against preamps because they "ruin the sound" and I thought that this would be a good opportunity for Peter to play with the Placette so I had the Frenchman send it to Phasure instead of to me. The first thing that Peter did before listening was measure the linestage and its volume control in various positions and it does measure very, very well. But as we all know THD does not count for much of the listening experience and he put it in his system and really did not like it..."just like all preamps the Placette also ruins the sound" and then "you should send it back". Peter is a busy guy and I did not want him to lose too much time with this project but I did ask him to pull off the lid and see if there was anything obviously wrong and perhaps to give his opinion on how to modify the buffer. Well, everything is glued down inside and it is difficult to get a look underneath the circuit boards but all the caps and wires looked fine, the unit measured well and operated properly in its own idiosyncratic way.
When I received the unit in Australia I put it straight into play and was immediately disappointed. Of course I had more time to experiment than Peter so I raised the mains voltage to 120V which helped things a little and then eventually I tried -6dB attenuation through the dac (Peter and I had been running zero attenuation...why attenuate at both in software and the linestage?) which for some reason improved things a lot. And so it has been running ever since. I have not experimented with different attenuations but on my previous system I have experimented with putting the Placette between the NOS1a G3 and without, and there was still an audible but subtle degradation.
Since getting Macondo hobbling along I have not repeated the experiments but I should. After listening to Macondo my old system sounds compressed and incompetent and it may be possible that the effect of the Phasure/Placette on Macondo could be amplified, but alas that is something that I will try down the track when I have Macondo up and running in full.
Peter never released a Phasure preamp. I don't think he ever strongly felt the need for one in the Phasure community and perhaps he was never really satisfied with his attempts.
I have recently talked to Peter about beefing up the output stage of the NOS1a and I know that during development of the latest IV stage (the G3 in NOS1a G3) that Peter was experimenting with stacking the modules for more voltage output but Peters seems to think that I would be best off getting a preamp with some amplification so that it can push 4V from modern low output sources. He has no suggestions...does not like preamps, haha.
So the modern standard is 2VRMS output which pretty much everything these days adheres to. Peter chose less output (1.25VRMS) for a number of reasons including "it sounds better" (was able to eliminate one regulation stage in the dac) and because most modern amps have too much gain and thus less source output equals better overall gain structure. It harms me especially because I run at -6dB into the Placette which is half the rated output (0.6VRMS).
Hopefully that explains which I run things as I do right now.
| Romy the Cat wrote: |
Since I do not feel it is possible I preams there are 3 factors that
might be in pay.
1)
Your Placette is
misfunctioning
2)
Your admiration with “expedited” sound somehow
find a pass in your mind to this decolorization
3)
I am clueless
with my assessment and somehow Phasure found a new “golden middle” at
the level I am not familiar.
All of the options above sound reasonable to me.
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I am pretty sure my Placette is functioning correctly. At least there were no THD remnants when Peter looked at the unit in the Netherlands. It did come halfway around the world to me afterwards, but I am currently operating on the premise that it is fully functioning.
So, Mani's comments of the NOS1/PM2 in 2011 are before my time: I purchased my NOS1a (notice the "a") in 2013. Phasure's business model is not really a business model per se, more an enthusiasts model. Peter is forever experimenting in software, connections or hardware and when he finds something with sonic merit he releases it to the group as an upgrade rather than as a new dac. So that NOS1 of Mani's in 2011 has had three major upgrades since then for it to become the NOS1a G3, the G3 being the new current amplification output stage (1.25VRMS), the "a" was new power supplies and somewhere along the way there was a new improved USB interface. Along with changes in the software that drives the dac, the current NOS1a G3 is a higher functioning, better sounding dac than the early model that Mani had to compare to the PM2. I've never seen a PM2 so cannot comment on its harmonic content et cetera, but I have directly head-to-headed it in my home system with some very good dacs (MSB/Playback Designs/Killerdac/AMR/Weiss) to name a few, so I can comment on what the Phasure dac brings when compared to those dacs and what it gives away.
The biggest surprise to me as far as performance goes was a dac produced by the local cult of the Killerdac. It is a simple redbook only, TDA1741a dac with a valve output stage. In its home environment, listening to simple music (girl and guitar, Frank Sinatra, Ella Fitzgerald) this dac slays everything, even the Phasure dac with its harmonic content and pure engagement. It is beautiful to listen to. But as soon as there is any sort of complexity to the music, think rock or heavens forbid orchestral, it just falls in a congealed heap and is beaten by pretty much every dac out there. A one trick pony.
I had a top level MSB Analog dac here for several weeks and I can say that this is a good example of "expedited sound", or should I say what I think you mean by that phrase. Some would call it clinical, but I would call it bleach white and dry. By contrast the NOS1a (it was 2013, so not the modern incarnation of the Phasure dac) had more body and flesh, definitely more sustain and more engagement.
One dac that I listened to that I liked was the Playback Designs MDP-8 (not the MPD-5, that was ordinary). In direct comparison in a better system than mine both the Phasure NOS1a (not current version) and MPD-8 were reasonably similar in many ways with similar dynamic swings and harmonic tails. They were more similar than dissimilar. Where the Phasure stood out was not at the beginning or end of the strokes, the attack and release, but in the middle of the note, the decay and sustain. This is I think where the "clarity" as Mani's calls it really comes from with the Phasure...the in-between. There is a resolution here, particularly noticeable with male voice and with piano, where the Phasure just has more texture. I love it. As soon as I realised that extra resolution is there I listen more carefully to it in other sources.
Other dacs that I have compared to the Phasure dac have all been different in various ways, but I seem to notice a few "constants" of the Phasure dac that other dacs I have tried have not been able to replicate.- the Phasure seems to sort out the rubble of complex music better than anything else I have tried. At loud and soft volumes, with a large orchestral piece with voice (some Mahler for example) the Phasure dac retains composure and "individual sounds" better than anything else I have compared it to. It stays composed, moves nicely between phrases and does not seem stressed. It took me a while to realise this as an important trait for me. Interestingly, this seems to be a tradeoff with a lot of the modified dacs that I have heard, they tend to fail at complex music.
- it is really difficult to pick a signature sound of the Phasure dac. It sounds different on all material. I can detect in my Placette, even on the old system, that there are some elements of "sameness" from different sources.
- as mentioned by Mani in 2011 and by me earlier, the "clarity", "resolution" or "unclutterdness" of the Phasure is tough to live without.
I can see how some people may be underwhelmed by the Phasure dac when they listen to it for the first time. There are no "oh wow" sound effects and everything just seems normal and balanced and capable. There is the obvious "clarity" that Mani talks about, but I would call that something else..."uncluttered". The harmonic decay is all there, the resolution is all there, tone is probably a little darker than most dacs because of its uncommon resolution in the bass frequencies. After using it for a while many get to appreciate what it does not do: stumble, exaggerate, clutter, colour. I think that it is a great source for a SET amp...apart from the dismal voltage output.
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Posted by anthony on
04-27-2019
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| Romy the Cat wrote: | The “expedited” sound
shorten a bit the decay time/volume and makes transients more prevailing. This
is what very commonly audio people feel as “quality” but I degree with it.
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Romy, in my previous response I did not address this ^^^ head-on, rather from all other directions in terms of experiences with other dacs.
Thinking more about "expedited" sound and how you describe it, I think that I do understand what you are trying to convey. At the other end of the spectrum there is also "lazy" sound, which to me is a SET amp being used fullrange into completely inappropriate loudspeakers. Wet, slow, transients lacking especially in the lower frequencies...all colour and no content. Not even the right type of colour, the wrong type, audible distortion. The worst of this I have heard is some diy open baffle speakers powered by SET amps...wow that sounded horrible but the diyer LOVED it...
The "expedited" sound is just as abhorrent to me as the "lazy" sound and for more or less the same reasons. Just as "lazy" is all colour and no content, "expedited" is no colour and no content. Both lack suitable texture, or resolution or what we individually call it in our own minds.
I would not characterise the Phasure dac as "expedited" sound, quite far from it...although that diyer I mentioned with the SET powered open baffles may call it cold and colourless...haha.
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Posted by Romy the Cat on
04-28-2019
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Ok, thanks for explaining. I
few things I would like to note.
If your preamp, being
incorporated between you front-end and you power amps degrades sound in any way
or does not make sound better then it is not a good preamp. Period, there is no
way look at the things differently. I personally
did not experience the situation when Placette failed in term of
transparency but it does not mean it might happen out there. I feel in a way challenged
and a bit stumbled and I have no idea why Placette would not be transparent. If Phasure has
some kind of new definition of transients then Placette is so fast that
it runs video signal (!), it should be able to accommodate whatever is pushed
to it at audio level. So, I minorly doubt your and Peter conclusions but I also
live a room for me being wrong. I might live some room to challenge your judgments
about the “details” you feel Phasure outputs. I
have seen it before and was tripped a few times myself. However, you comment
about decolorization of sound by Placette and whitening out what Phasure outputs is very serious charge that has no room
for any interpretation or challenge. Hypothetically I would like to try
your Phasure to confirm that it can stress Placette.
I do not need a DAC and I will not make efforts to try it but if Phasure will be walking next to me then I might.
My experience with finding a transparent
preamp, very much as Phasure’s Peter experience as you can see are very alike:
most of the preamps ruin sound. So, entering your idea to build you own you will
have a very difficult challenge. I am not kidding but I am estimate that it
will be more difficult then to build Milq/Macondo as you will be walking to unexplored
territory. If I were in your shoe and if I have no confidence in the Placette performance then I would most certainly work with your Peter asking his with a solution make his DAC output
at least 3 Volts. Peter should be consistent and reasonable in his hate. If he
hates preamps so much then he should not advocate DACs that outputs 0.6V. No power
amps will be happy with 0.6V!
I need to say that I am not exactly
understand the Phasure ecosystems. It is DAC that works only from software
player and if it so then why no one talk about the sources of the material that
is being played. There is a huge difference between ripped CD and raw digital
files, how the files were ripped and many other subjects. I do not understand
the notion of volume control at software and DAC level and many other things. Not
that I need to but I would certainly would like any attention at digital level
to be wide open. It sounds to me that Phasure has SS chip in the output and
this is where you can experiment. There are new op amps out there that reportedly
good you can play with them; I so feel that the absolute transparency you will
find at SS level not at tube level.
Rgs,
Romy the Cat
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Posted by Paul S on
04-28-2019
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While I've hardly gone out of my way to learn more about streaming digital, the reason for that is the consistently mediocre results in my experience. Really, how does one rate and build on streaming digital in musical terms? So far, results I've heard are a "second system" level, at best. Of course, this means I am altogether unqualified to talk about the fine points and differences of streaming sound delivery, apart from what I hear, and I certainly do not have a "corresponding" understanding of the hardware and software effects here.
All the above said and considered, isn't Burson in Australia? They are quite the darling in small studios now, and for streaming/headphone enthusiasts.
Best regards,
Paul S
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Posted by anthony on
04-28-2019
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| Paul S wrote: | While I've hardly gone out of my way to learn more about streaming digital, the reason for that is the consistently mediocre results in my experience. Really, how does one rate and build on streaming digital in musical terms? So far, results I've heard are a "second system" level, at best. Of course, this means I am altogether unqualified to talk about the fine points and differences of streaming sound delivery, apart from what I hear, and I certainly do not have a "corresponding" understanding of the hardware and software effects here.
All the above said and considered, isn't Burson in Australia? They are quite the darling in small studios now, and for streaming/headphone enthusiasts.
Best regards,
Paul S |
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Yes, streaming is a step backwards in terms of sound quality, no question. But that is how I get enough volume at the moment...it has to change. In the Phasure ecosystem, streaming is a little different. The albums are downloaded first, stored on the local drive, and then played as if it is a local file. In this way the streamed music sounds just like the rest of your digital music collection, but it is not really streaming most people would recognise it, given the download stage.
Yes, Burson are Aus, but knowing Peter everything will be SMD or SMT so the Burson stuff will not fit.
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Posted by Romy the Cat on
04-28-2019
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Again, I have advocated this subject again
and again. Streaming is not a second-class source. It is all depends of what
you are streaming. If you stream a source of unknown origin (which is 99.9% of
the files that you do now own) then it is wild west and you deal with absolutely
unpredictable quality. A single and simple rate conversion, volume change or
any other DSP processing on the side of the file owner will lead sonic
degradation much greater then use of a few shifty line-level preamps sequentially
connected. So, when I am taking about streaming and if we presume a conversation
have any sense then we are talking about streaming our own files, known to use quality
from our own drives. “the albums are downloaded first” in most of case are
very bad. The houses that sell music files has no sound quality working culture;
this has been proven zillion times. You basically have mp3 leave crap that being
unsampled to the format of your choice.
Even if you have a production CD that might act
as a common reference of some kind of quality then there is a great variation how
the CD was pressed, who did it and what vintage of the pressing. Not the last
factor is how the CD was ripped. There are great differences and have seen some
stanning examples that quality of ripped made huge difference. So, streaming
might mean absolutely different things. The best streaming that I have seen were
raw digital master-copies sold to me non-commercially with an assurance that
there was no processing on the files performed or my own digital files made
from my own conversion of some of my LPs.
Again, most of the crap out there is garbage on term of
sound quality unless you know (trust)
the source personally and can control the whole chain.
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