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08-07-2020 Post does not mapped to Knowledge Tree
anthony
Posts 338
Joined on 08-18-2014
Post #: 41
Post ID: 25908
Reply to: 25907
Listening to the 10y
Last night and this morning I have been comparing my favourite SS preamp with gain and the breadboarded 10y.  I've been using my dac with its low 1.125Vrms voltage output as the source because I know what it is capable of and know its (lack of) sound well.  Early on in my Macondo/Melquiades journey I measured listening SPLs and was surprised how much louder things were with the loudspeakers that sidestep sounding compressed.  This listening had peaks circa 105dBa with crescendos sitting a consistent 100dBa+ at the listening chair.   This is 10dB louder than with previous speakers.  Calms were still registering 70dBa.

The 10y plays in another league.   Imaging and layering were almost like comparing a finger painting to a Monet.  Both were good,  but the 10y brings such clarity to Macondo, separation between notes,  guitar strings almost rendered individually with their own attack/ sustain/ decay.  Sound was neither darker nor brighter,  just more clear,  revealing,  rich. 

Plus there is loads of gain.   Even at those listening levels with my quietest source attenuation was 10dB. This equates to a Zout of 12r.  At the lower end of my listening windowwith 20dB attenuation Zout is about 1r.  I should measure this to confirm,  but both those numbers are lower than the Placette.

Speaking of the Placette, I will have to pull it out of the cupboard to compare it to the 10y with matched volumes.   I also have another SS pre just arrived with has been measurebated into existence with measured spec's difficult to confirm with the best measuring equipment getting about.

Also,  I plan to reconfigure things a little and put YO186 into the preamp.   It will be interesting to hear.  
08-08-2020 Post does not mapped to Knowledge Tree
rowuk


Germany
Posts 454
Joined on 07-05-2012
Post #: 42
Post ID: 25909
Reply to: 25908
Congratulations on your next step!
I am always a bit hesitant to buy into "listening descriptions". I am a musician and am confronted every day with Sound bias - attraction to what we are accustomed to, expectations being confirmed. We are creatures of habit and modifying old habits is a very big deal.
As long as what we are comparing are in a similar league, we need weeks if not months to really sort out what is happening. Certainly there is no measureable parameter for "neutral color". There has to be a reason for the 10Y being in another league. The rest of your equipment is too good for that to happen - unless the 10Y is adding something special.
I am very happy that the breadboarded preamp is fulfilling your dreams. Your project has been in a state of "wanting to get done" for a long time. I can imagine the joy of being this far. Gain cannot be underestimated. With a very high quality source material, I find a need for a "plausible" playback volume. If we can't quite get there, we know that we are missing something.
I will be following this closely to see how it unfolds. Have a great weekend!

Whenever I feel blue, I start breathing again.
08-08-2020 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,166
Joined on 05-28-2004
Post #: 43
Post ID: 25910
Reply to: 25908
My view of the situation.
Anthony, I am afraid I do not agree with your assessment of the situation. Let look at what is going on together.
 
The 10Y preamp is not another league but juts a proper architectural solution for your system configuration. You have a power amp with very complex input, and you need a very current-able preamp to push it through. Most of the preamps are either not powerful enough or juts sonically not good. I have the same power amp and I very much know how it sound what I dive it from frond end. Note that I have more or less powerful front-ends that can push some current, not at the level of a good preamp of cause. When I use to do it, I used between the front-ends and Milq my T-bridge attenuators that maintain constant load impedance but variable output impedance. I do not like how my playback sound with it because with each volume setting it sound very different. Also, it sounds different from source to source. A good preamp stabilizes all of it and a good preamp should make it to sound better, pretty much along the lines that you describe. So, I feel your reaction is just a presents of a good preamp vs driving you playback directly from front ends. At least it is my version of interpreting what you say.
 
Now, about your 10Y preamp specifically. I am not familiar with the sound of that configuration + you have the autoformer in play. However, I know that all elements at the top of their class performance sound identical: what we note are not the benefits of an element of the chain but the discrepancies the element creates. Your 10Y preamp might be a good and transparent component that rectify the disability of you front end to drive Milq. This is very easy to test. Take an ordinary conventional loudspeaker with an ordinary conventional power amp and drive it from your frond end and from 10Y. You will not see the “another league” situation. The 10Y will be most likely much better but it would be in different way than what you described in case 10Y drives Milq.
 
I would be very interesting to see your 10Y vs Placette evaluation at the same volume level (this is very critical). I am still a bit skeptical that you have properly functioning Placette as your description of it performance is very much different with what I experience. In my view an active Placette (the older version) operates very much atop of what is possible with preamps. If 10Y is a good pream then it should be very close to what Placette does. It should be different but very close and should not be “another league”. I might be wrong of cause…
 
About the YO186 in the 10Y preamp. Most likely you will have better and softer bass, in my language “softer bass” is a positive thing. I do not think that YO186 will be able to beat 10Y. It would be very interesting battle but do not forget that 10Y and YO186 have own character of how they react to operation points, power supplies, type of bias and zillion other things. Good lack to spend next year of your life to investigate all of it, I mean nothing negative, I just mean that it all takes time to discover methodologically honestly.
 

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-09-2020 Post does not mapped to Knowledge Tree
anthony
Posts 338
Joined on 08-18-2014
Post #: 44
Post ID: 25911
Reply to: 25909
Me too...
 rowuk wrote:
I am always a bit hesitant to buy into "listening descriptions". I am a musician and am confronted every day with Sound bias - attraction to what we are accustomed to, expectations being confirmed. We are creatures of habit and modifying old habits is a very big deal.


Me too.  I have attempted to "reset" my expectations in regards to this preamp several times now.  Truth is that I was not expecting it to be so successful so early.

Today has been a day away from audio on the farm.  Two hours drive each way and a whole day chasing cattle has been invaluable time to think about the situation.  I have been trying to think of ways in which the sound was deficient yesterday with the 10y in play.  You see I had some friends visit yesterday afternoon, and my family were away last night so we spent a lot of time listening to music and talking about it and catching up with a few beers and single malts.  It was a wonderful night and the sound was magnificent.  

The breadboarded amp is not perfectly laid out, some of the wire loops near the tube are too large, power transformers could be a little too close together, nothing is shielded, the B+ power supply is not my ideal choice being regulated but was selected because it was very easy to adjust the output voltage and has very low noise and output impedance, I've not experimented with any capacitors, haven't even matched the 10y pair in use.  There are probably a number of other things wrong with the setup.  You see, this was the first step...sounding to see if something good could come of the venture...but it has already achieved more than I expected.  

One of the things that I wonder is whether I would be so enthused about it in a different system than DSET\Macondo?  Kind of a moot point really, because that is the sole purpose of this preamp with special considerations to make it especially suitable, but really, would it work so well elsewhere?   At one stage we wanted some music from Tidal and streamed it on another lesser dac, it was quite disappointing, so I think the situation may be less the 10y adding some kind of special sauce but simply the 10y competently driving the DSET and allowing my best dac to shine.       


 Romy the Cat wrote:
  The 10Y preamp is not another league but juts a proper architectural solution for your system configuration.


^^^ this.  After yesterday and last night I am more likely to concur.  The 10y might add a little special sauce, but in this situation it may not prove to be much at all, and if it does then it is working for me at the moment.

My understanding of the Bartola hybrid mu-follower boards is that the DHT does the amplification, a SS mu-follower provides an almost ideal anode load, and that the output is pseudo push-pull from the mu-out of the SS mu-follower with output impedance set by the chip in the said follower.  The mu-follower has quite a high PSRR and I am currently using what sounds like quite a competent B+ regulated supply with a lower output impedance than is likely to be possible with tube rectifiers or non-regulated supplies.  The system sounds like it has boundless energy when required and good resolution all the way from the lowest bass notes up past the midrange.

At the moment it all sounds so 'right'...no obvious deficiencies or inadequacies...and that may be because I am still in the honeymoon period and have been caught a little by surprise at how much more enjoyable the music has suddenly become.  Time is required to properly understand what I am hearing and apart from trying a few more simple things as discussed earlier in the thread, am considering boxing up the preamp and perhaps returning to it once Macondo is complete and tuned into the room, and once I am able to digest where and how I would like things to improve.

 Romy the Cat wrote:

About the YO186 in the 10Y preamp. Most likely you will have better and softer bass, in my language “softer bass” is a positive thing. I do not think that YO186 will be able to beat 10Y. It would be very interesting battle but do not forget that 10Y and YO186 have own character of how they react to operation points, power supplies, type of bias and zillion other things. Good lack to spend next year of your life to investigate all of it, I mean nothing negative, I just mean that it all takes time to discover methodologically honestly.
 


Bass is deliciously soft at the moment with the 10Y, particularly at night when the power is better.  Still though, the YO186 will be an interesting test.
08-10-2020 Post does not mapped to Knowledge Tree
anthony
Posts 338
Joined on 08-18-2014
Post #: 45
Post ID: 25912
Reply to: 25908
Transparency
 anthony wrote:
I also have another SS pre just arrived with has been measurebated into existence with measured spec's difficult to confirm with the best measuring equipment getting about.


I've been listening to the new buffer with imd/thd/snr/blah blah blah all claimed to be state of the art.  Huge PSRR and CMRR, gain up to 20dB, super low output impedance, able to source 50mA or thereabouts, and able to drive quite a capacitive and low input impedance load (300r claimed).  The buffer has been configured for 12dB gain and plugged directly between my favourite dac and the DSET's...no analog volume control nor input selector in use.

It sounds nice...better than the previous SS preamp I have been using.  Imaging is clearer, sound is neither lighter nor darker and the buffer is more enjoyable to listen with than the previous SS pre.  More clarity, more definition.  Volume matched with the 10y though, even with its input selector and analogue volume control vs a cleaner signal path with the buffer, the DHT is more moist, more three dimensional with its imaging, more flesh on things such as vocals, strings and noticeably the left hand of the piano.  More emotive.  The valves still seem to draw a more detailed, higher resolution picture but the gap is no longer an order of magnitude as it was before with the previous SS pre.

Perhaps, with a lesser source or lesser speakers, some people may prefer the buffer to the DHT pre because it does paint a less detailed picture, maybe a smoother picture in some circumstances with less capable loudspeakers, but Macondo is able to deliver the clarity and detail at significant listening volumes and with the buffer I feel as though I am missing out on a little bit of something the 10y is able to provide.  Based on the excellent measurements and drive capabilities of the buffer, you could make the assumption that either the 10y is better at driving DSET or it would appear that the 10y is adding something not entirely inaudible, which is not unexpected.  If it is adding something, it is not adding much but it is engaging and I like it right now.  

To date, I've only listened with my favourite dac.  The Phasure NOS1a/10y partnership is something I am enjoying.  Perhaps at a later date I will not be loving the DHT pre with some other source/s and it would be nice to include something like this buffer into the preamp and be able to switch between SS and DHT gain stages.  Something to think about.
08-11-2020 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,166
Joined on 05-28-2004
Post #: 46
Post ID: 25913
Reply to: 25912
An important note
Anthony, I do not know what you new buffer is. A few notes. The difference between sub 10R and 300R of output impedance is significant for the load you have (Milq) between your new buffer and your 10Y preamp. The type of the description you provided, however, is not something he I feel might be attributed to impedance difference.
 
Now the important note. Beside the acknowledgment of the sonic differences (which is semi-important) you might look at the overall musical capacity. When you get a grip of the overall musical capacity then the cataloging and recognizing the sonic differences begin to have slightly different twist for you as you have a context under which the sonic differences are observed. The “imaging is clearer”. What is it mean? I do not mean to be cynical at all. It is a legitimate question. How much imaging clarity we need and how much other problems we will tolerate to have “imaging clearer”? We certainly do not have “imaging” during our live events.  Just think about it. I know, it is an annoying part of me and my wife goes crazy whan she tells me that she loves me and I ask her “what does it mean?”
 
Ok, let me give you a tip in this direction. I would make a statement that many people would not understand but trust me, I know what I am taking about. Imaging is super important byproduct of playback as it is a very objectively depicts timing of everything. The ultimate objective in playback is however is not to get best imaging but take it to next step: to make system to present music with no imaging at all. According to my experience it happens only in DPoLS configuration. The DPoLS playback also has imaging but it has absolutely nothing to do with imagine that a playback has outside of DPoLS. Saying that, do I feel that we need to have “imaging clearer” outside of DPoLS? Yes, we do. We, however, always should ask ourselves what does it mean in connect of a larger picture.
 

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-11-2020 Post does not mapped to Knowledge Tree
anthony
Posts 338
Joined on 08-18-2014
Post #: 47
Post ID: 25915
Reply to: 25913
Clarification
 Romy the Cat wrote:
Anthony, I do not know what you new buffer is. A few notes. The difference between sub 10R and 300R of output impedance is significant for the load you have (Milq) between your new buffer and your 10Y preamp. The type of the description you provided, however, is not something he I feel might be attributed to impedance difference.

 


Nice pick Romy.  The output impedance of the buffer is < 0.1R.  One of the chips it uses is spec'd for 600r loads and it will drive 300r satidfactorily...apparently.

 Romy the Cat wrote:
Now the important note. Beside the acknowledgment of the sonic differences (which is semi-important) you might look at the overall musical capacity. When you get a grip of the overall musical capacity then the cataloging and recognizing the sonic differences begin to have slightly different twist for you as you have a context under which the sonic differences are observed. The “imaging is clearer”. What is it mean? I do not mean to be cynical at all. It is a legitimate question. How much imaging clarity we need and how much other problems we will tolerate to have “imaging clearer”? We certainly do not have “imaging” during our live events.  Just think about it. I know, it is an annoying part of me and my wife goes crazy whan she tells me that she loves me and I ask her “what does it mean?”
 


When listening to the various preamps/buffers thus far there has been a direct correlation between 'clarity' of the image and how realistic I perceive the sounds on the individual instruments to be.  When in the sweet spot, Macondo throws a spectacular soundstage with images locked in place.  A piano that is a little to the left of centre seems to be more coherently "put together" in the soundstage when the sounds that it is making seem more "real".  It is not something that I recall noticing with other speakers.  A pair of good 2-way standmounts can image wonderfully when setup correctly, but they do not image in the same way that Macondo seems to be imaging.  With the point source speakers the image is there and you can move around the room and it does not really fall apart or move but with Macondo in nearfield you move far from the sweet spot and the soundstage collapses.  However, the show that Macondo gives you from that sweet spot surpasses anything that I have ever experienced elsewhere, and the more "right" instruments sound the clearer they seem to image within that soundstage.

I think the 'clarity' is related to how well DSET is responding to the preamplifier.  The reason I say that is that I have brought the Placette Active Linestage back into the room.

First, I rewired the Placettes dual-primary power transformers for 230v operation rather than the default 115v.  Guy advised just to run a step down transformer and I had been using a variac, but now there are no compromises.  Secondly, I made up a 5v linear power supply that runs the relays and volume control to replace the failed supply.  Then I brought it into the room and matched the volume between it and the 10y using sine waves from a number of frequencies...I'm sure I have a pink noise file somewhere for this but it has disappeared.  The 10y has 18dB of gain on paper and to match the Placette it is being run at -19dB, so pretty close.

More volume would be nice, but it is what it is.  Previous experience suggests that the Placette gets better with time, so other than the initial listen immediately after matching the volumes, I will continue to listen to the Placette for a day or two to reorient myself with the sound and then compare it formally to the 10y.
 Romy the Cat wrote:
Ok, let me give you a tip in this direction. I would make a statement that many people would not understand but trust me, I know what I am taking about. Imaging is super important byproduct of playback as it is a very objectively depicts timing of everything. The ultimate objective in playback is however is not to get best imaging but take it to next step: to make system to present music with no imaging at all. According to my experience it happens only in DPoLS configuration. The DPoLS playback also has imaging but it has absolutely nothing to do with imagine that a playback has outside of DPoLS. Saying that, do I feel that we need to have “imaging clearer” outside of DPoLS? Yes, we do. We, however, always should ask ourselves what does it mean in connect of a larger picture.
 
 
DPoLS sounds like such work.  Yet to be experienced. 
08-13-2020 Post does not mapped to Knowledge Tree
anthony
Posts 338
Joined on 08-18-2014
Post #: 48
Post ID: 25916
Reply to: 25915
Polarity?
 anthony wrote:

I have brought the Placette Active Linestage back into the room.



This comparison is proving more difficult than anticipated.  Inconsistent results between subject tracks have given me some doubt on just what I have been hearing so I have had to go back to first principles in an attempt to explain it.

Often, the 10y sounds flat out better than the Placette:  more resolution, better transients, more energy.  However, with some other tracks the difference is not so noticeable and there is really very little separating the two preamps.  It has not happened yet where the Placette is clearly preferred, but the two are occasionally quite difficult to differentiate.  

Thinking about why this may be happening this morning led me to think about absolute polarity.  As far as I am aware the 10y inverts phase and the Placette is non-inverting (not 100% sure).  Could the preference for the 10y be coming down to using more recordings where absolute polarity should be reversed?  I don't know and never before has absolute polarity been a concern of mine...but perhaps it should be.  

The buffer that I previously tested was also very good and although it is able to be set to inverting or non-inverting output it had been set to non-inverting.  To get more volume in-room I had also been experimenting with using this buffer to add 12dB of gain before the Placette.  So at lunch I set the buffer to invert the output so it is the same polarity as the 10y preamp and have gone back to some of the recordings where the 10y was ahead.

This is a fairer fight now!  Regardless of how it turns out, there will be some way to set the buffer up to be able to switch absolute polarity on the fly possibly even using the remote.
    
08-14-2020 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,166
Joined on 05-28-2004
Post #: 49
Post ID: 25917
Reply to: 25916
You are getting somewhere...
This is very interesting, Anthony. I do think that absolute polarity has own role to play. Also, do check the DC that might be sent out of your preamps, certainly with Placette and with your 10Y before the transformer. Chas it with disconnected Milq and positive bios will kill any DC offset from preamp. You might also try to measure the AC voltage on your Milq’s input with and without connected preamp.

Another a very valid thing to try is to see of the same difference with the same recordings happens with different DACs, preamps the you will take care of the absolute phase. You see, different DACs topology have different post DAC filters and they send different amount and different type of UHF into the upstream chain. Your 10Y is UHF limited and in a way acts as low pass filter, which is not necessarily a bad thing. Placette is wide open monster in UHF, in fact it might run a video signal with is very good for it but not necessarily good for music.  I in a past observe a phenomenon that Placette was very much picky to what I used in DAC output filters. I have some CDs that if I play them with Bidat vs. Lavry Gold DACs they sound like very much different recordings and the difference is VERY different than a typical delta between Bidat vs. Lavry. If do the same experiment with a different preamp then the difference will be between the DACs but in completely different way. In most of the cases TLO-Lavry Gold with Placette has too much “resolution” and too ferocious dynamics that is superbly impressive to thrill audiophiles but not so musical and I tend do not use this combination.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-16-2020 Post does not mapped to Knowledge Tree
anthony
Posts 338
Joined on 08-18-2014
Post #: 50
Post ID: 25918
Reply to: 25917
DHT's tested
Have put all my DHT's on the curve tracer to see if pairs can be matched for preamp duties.  

My stash of 10y/VT25/801a/VT62 are generally all very new or NOS specs with mu and plate resistance varying a little, but generally close to nominal specifications.  The VT25's in particular were very even and I have put a pair of them in the breadboarded preamp with pretty much identical specs at the operating point.  The VT62's all had higher plate resistances and lower plate current than the VT25's.

The YO186 were all over the shop...which you could guess by the margins offered in the spec sheet I suppose.  The glass bottle shape and size varies with the year.  Dates range from 1938 to 1956.  A pair of April 1956 YO186 test almost identically and likewise a pair of 1938/1956 that I am running in the DSETs.  Mu varied from 3.1 to 4.1, which is quite substantial, the low mu sourcing loads of current, up to 65mA where the spec sheet says 38ma, and the high mu source about 24mA at that same point.  In between the mu3.7 tubes have the correct current and plate resistance.  So, two closely matched pairs that sit right on the specification sheet parameters (one pair in the DSET's, one pair to try in the preamp), a pair of low mu/high current which I am not sure are particularly useful, and two pair of high mu/low current which may also be good in the preamp...they may actually be preferable there.

The CX371a pair tested 85% and NOS, which is nice.  One 45 ST was more or less dead after the abuse it suffered breathing life into two DSET amplifiers while its mate tests perfectly.  The four UX245 globes that tested NOS on a TV7 and AVo MK3 show up as about 70% emmission in the eTracer.  Shame...they are really beautiful tubes.

After all that, I have identified three matched pairs of YO186 to trial in the preamp and gained a better understanding of the voltage gain they are able to offer.  The low current sourcing pairs are more or less the same gain as a 45 but with a lower plate resistance, not that the plate resistance matters when using a mu-follower but it does if using an output transfomer.  Both the 45 and YO186 are therefore borderline candidates for the preamp because they offer 12dB of gain which would barely be enough with the mu-follower, and they are unsuitable in my situation for use with an output transformer because gain would be lost.

I will try them with a hybrid mu-follower though.
08-16-2020 Post does not mapped to Knowledge Tree
anthony
Posts 338
Joined on 08-18-2014
Post #: 51
Post ID: 25919
Reply to: 25917
Three preamps compared
Now that all three are on the same absolute polarity and have been listened to quite a bit I thought it time to write down my impressions.  From least preferable to most:

(3) Neurochrome Universal Buffer set to invert polarity and with 12dB gain.  No volume control and no input selector:  Dac >> Buffer >> DSET's.  A really high performer given the low price with a lot of good things going for it, including its tremendous flexibility.  Unfortunately, although it does drive the DSET better than pretty much every other preamp and buffer I have tried and trialled, it is not as capable in this task as the next two preamps.  There is a whiteness introduced to the mids that is noticeable on vocals and some strings which may have to do with the capacitive load of some of the filters at the input to the amplifiers.  An easier load and I am quite sure this whiteness will disappear and what is left is nothing but neutral.   Very good soundstaging, excellent clarity, loads of frequency extension at both ends.

(2) Placette Active Linestage. 12dB gain added with Neurochrome Universal Buffer.  Dac >> Buffer >> Placette >> DSET's.  This is better.  Whiteness is gone (probably thanks to the 18kR resistive load of the Placette) and a softness or delicacy has found its way to the presentation, more like real instruments.  Even though input selection and volume control are added to the signal path, this is a more complete, balanced, enjoyable experience.  There does not appear to be anything missing.  Vocals are lovely, strings better, more definition and clarity in all instruments and softness in the bass.

(1)  10y breadboard preamplifier.  Dac >> 10y >> DSET's.  I am trying so hard to overcome my obvious biases here, and for a while today I almost convinced myself that the Placette was marginally better in this role with the DSET's, but in the end I cannot deny that the 10y plays with a little more delicacy, or consideration, tenderness, or however I am failing to describe it.  Think of the difference as how two musicians can play the same notes but sound slightly different, a softer touch here, a little more firmness there, seemingly more time between the notes, a slight calmness...that is what the 10y is doing compared to the Placette.  There is just a little more variation in the notes that makes things just a little more dimensional and less flat.  It is quite close though.  Both reveal very fine nuances and sounds but the Placette is not quite able to articulate things quite as well as the valve pre.  The soundstage feels very wide and expansive with all three preamps with the Placette more three dimensional than the Buffer but the 10y is a little different.  I cannot decide if the Placette stage is noisier or more noisless than the 10y.  With the Placette it feels like things are presented on a huge screen about 5m wide and 2m high, but with the 10y I do not have the illusion of a screen, where you think there is glass or something see-through where there is no apparent sound appearing.  The 10y just puts the images in the same places as the Placette, with a little more 3d or little more depth (they pop), but the illusion of the "screen" is not there rather just sounds appearing in their place with nothing below or above them.  It is strange, and I have not decided which, if any, I prefer.

Dinner is on the table.  I will add some more comments later.

08-16-2020 Post does not mapped to Knowledge Tree
anthony
Posts 338
Joined on 08-18-2014
Post #: 52
Post ID: 25920
Reply to: 25917
More thoughts...
 Romy the Cat wrote:


Another a very valid thing to try is to see of the same difference with the same recordings happens with different DACs, preamps the you will take care of the absolute phase.


To date, my listening has been with my favourite dac, the Phasure NOS1a.  The other dacs here don't really compare, and if listening with digital I will always go Phasure otherwise for background I might stream Tidal from my work computer via a Focusrite Scarlett 2i2, which is quite befuddled compared to the more expensive dac.

 Romy the Cat wrote:


You see, different DACs topology have different post DAC filters and they send different amount and different type of UHF into the upstream chain. Your 10Y is UHF limited and in a way acts as low pass filter, which is not necessarily a bad thing. Placette is wide open monster in UHF, in fact it might run a video signal with is very good for it but not necessarily good for music.  I in a past observe a phenomenon that Placette was very much picky to what I used in DAC output filters. I have some CDs that if I play them with Bidat vs. Lavry Gold DACs they sound like very much different recordings and the difference is VERY different than a typical delta between Bidat vs. Lavry. If do the same experiment with a different preamp then the difference will be between the DACs but in completely different way. In most of the cases TLO-Lavry Gold with Placette has too much “resolution” and too ferocious dynamics that is superbly impressive to thrill audiophiles but not so musical and I tend do not use this combination.


The Phasure dac is completely filterless...nothing, nada, zip.  The digital filter is applied in the computer software and sent to the dac in 32/768 which just plays the file NOS without additional filtering at all.  As such the Phasure dac is wide open frequency wise.  Plus the BNC cables I use are video spec and have something like 1dB attenuation over 100m at 6GHz and they are not filtering any UHF either.
"Ferocious dynamics" is not something that I am associating with the sound that I am getting here from this dac, and sometimes I might correlate that sort of sound to washed out or white mids with an emphasis on highs, but the sound here seems very well balanced.
08-16-2020 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,166
Joined on 05-28-2004
Post #: 53
Post ID: 25921
Reply to: 25920
The last paragrapher worth to read a few times...
 anthony wrote:
Have put all my DHT's on the curve tracer to see if pairs can be matched for preamp duties.  

 
It was very interesting to read about all of it. If you have a socket for YO186 then you can accommodate all 4V tubes and I site like them If you do have a chance, try the a pre-WW2 RE604. This is a day of all 4V stube, and I do like it for full range applications. It is expensive nowadays however. In Milq you do not use then in full range however.
 
 anthony wrote:
Now that all three are on the same absolute polarity and have been listened to quite a bit I thought it time to write down my impressions.  From least preferable to most: 
….
Dinner is on the table.  I will add some more comments later. 


 
Again, it was very interesting, but… Let agree that methodologically you did not try Placette as it performance was masked out by you need to use your Neurochrome buffer to get gain. Your chain will sound as the worst element is and in case of 10Y you have the worst element removed. I do have high high probability that if you were able to run Placette and 10Y directly then they will sound identical as the same volumes. I think it is simple to test. I do not know what output in your Phasure DAC. Get any DAC with a op-amp in output stage, most of them are. Find where a feedback provided to the output op-amp and reduces it to gain10-12dB more gain from the DAC. If Phasure DAC has no op-amp in output stage, then get any other DAC. The quality of the DAC is not import you need it purely foe prove the methodological concept. Then repeat the experiment. I think that you will find then Placette will hold his own.
 
 
 anthony wrote:
The Phasure dac is completely filterless...nothing, nada, zip.  The digital filter is applied in the computer software and sent to the dac in 32/768 which just plays the file NOS without additional filtering at all.  As such the Phasure dac is wide open frequency wise.  Plus the BNC cables I use are video spec and have something like 1dB attenuation over 100m at 6GHz and they are not filtering any UHF either.
"Ferocious dynamics" is not something that I am associating with the sound that I am getting here from this dac, and sometimes I might correlate that sort of sound to washed out or white mids with an emphasis on highs, but the sound here seems very well balanced.

 
Anthony, this exactly answer all questions then. You need to reinterpret at the result of your experiments in context of what I will be writing now. You see, there is school of thinking that if a DAC operate at very high sampling rate then the post DAC filter is not necessary, or a file might be very shallow as all post DAC nastiness  will be at very high frequency that is very far from auditable range, It is very legitime way of think and indeed some of the systems do sound spectacular wit DACs like this. I did a LOT of looking into it. The excessive HF that is sent by DAC works out ONLY if later one in the chain you have some kind of lowpass filter the strips that HF component. I your case use you 10Y buffer you have via the auto-former that is bandwidth limited. Placette is the worst in your case as Placette has a huge bandwidth, as I told it runs video signal. So, in case of Phasure + Placette you have the whole HF nastiness HF from DAC sent directly to Milq. A reasonable question would be why Power Amps filters do not act as the power is frequency limited as well. The legitimate question to ask but unfortunately it does not work in this way. I have written about it years back. My theory was that audio components get “poisoned” by excessive HF and they have a memory of that poisoning.  Do not ask me to explain it, I do not know how, I am just a practitioner and the depth of electronics design is not a feld that I am interested in. Anyhow. What I say is very easy to test it. Wake your phono stage and disengage your RAAI filter. Play music for an hour. It will be a horrible HF only sound, but you do need to play it laud. Then put the phono filter back and play it normally. It will be sound horribly because you power amp is “poisoned” by HF. It will take a good day of a normal operation to recover good sound from your amp until the HF “poison” will de dissolved.
 
So, I do think that in your case, considering the DAC you are using in case you use too HF transparent preamps you “poison” you power amp with HF. You can put a simple first order low pass subtraction filter before Placette and you will have better sound.
 
So, where it lives you. Obviously if you have frond-end with more output then I am very convinced that Placette will fulfill all your expectations, I am not kidding it is very hard to beat it. However, if you had this arrangement then you most likely would not like you DAC as much as via Placette it would sound not too gentle enough. If you willing to use your DAC then keep your 10Y preamp as it acts a great low pass filter for your system. If you would like to use Placette then you need a DAC with a post conversion filtration (preferably analog) and more output voltage.  
 
What is very important to understand that in case you have both of the scenarios implemented then you should have identical result the end. Another very important message you might consider is that in case of your 10Y the main beneficiary to sound is not the quality of tube or your auto-former but a presence of preamp that acts and post-DAC low pass filter.
 

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-16-2020 Post does not mapped to Knowledge Tree
anthony
Posts 338
Joined on 08-18-2014
Post #: 54
Post ID: 25922
Reply to: 25921
All sources
 Romy the Cat wrote:

Again, it was very interesting, but… Let agree that methodologically you did not try Placette as it performance was masked out by you need to use your Neurochrome buffer to get gain. Your chain will sound as the worst element is and in case of 10Y you have the worst element removed. I do have high high probability that if you were able to run Placette and 10Y directly then they will sound identical as the same volumes. I think it is simple to test. I do not know what output in your Phasure DAC. Get any DAC with a op-amp in output stage, most of them are. Find where a feedback provided to the output op-amp and reduces it to gain10-12dB more gain from the DAC. If Phasure DAC has no op-amp in output stage, then get any other DAC. The quality of the DAC is not import you need it purely foe prove the methodological concept. Then repeat the experiment. I think that you will find then Placette will hold his own.
 


Yes, true.  A few more observations about the listening:

Having one preamp playing for extended periods always gave me the best sound, whether that was the Placette with the Buffer or the 10y.  When the 10y was in for extended periods I thought it worked better than when swapping them in an out to do relatively quick comparitive listening.  Likewise, when the Placette was in for extended periods I thought it sounded better than when swapping it in an out for quick comparitive listening.  Psychoacoustics?  Probably.  There are guys here that buy into the whole cable settling theory but I do not know...all I know is that when swapping things in and out that the sound was not quite as good as when things were left in place for hours or longer...perhaps it was my mood at having to change all those cables.

The quick comparitive listening was a little confounding.  When in for the long run I thought the 10y held a larger advantage than when doing the quick comparitive listening.  Swapping things in and out more quickly the sounds became more or less the same and I was really struggling to hear the 10y as being any better than the Placette at all.  I used my observations from the longer term listening as a starting point in the short term stuff and they just were not observable to the same degree.  As I reported, there was not much in it.  Perhaps it is the dac HF issue and DSET poisoning you mentioned earlier.  Sounds like it.  Maybe there is just very little between the two, which is an excellent outcome for me.

I the past few weeks I have purcased a Pioneer UDP LX-500 universal disc player so that I can listen and watch my Bruckner and other DVD's and Blu Rays.  Well, like pretty much everything these days it is 2Vrms output and needs some gain to get loud enough.  I played that Gogol Suite CD you mentioned earlier in the thread (to scope out how much gain I might really need) and used pretty much the entire 18dB the 10y had to offer...through the Placette without any gain it was like trying to listen to whispers.  Anyway, point here is that I need gain from my dac, disc spinner, phono stages, even from the little dac I use to stream Tidal because none of them give more than 2Vrms output.  That is my issue.

To my ears there is very little separating the Placette and the 10y.  I think I may be able to improve the 10y once it is boxed up with a more ideal layout and perhaps also with an unregulated power supply.  The Placette could possibly be improved by using a different dac and by using one of Guys buffers for gain which in essence is exactly the same concept as the Buffer I am using.  Guy has made it clear that nothing more is going in the case of my Placette and that if I need gain there will be another box for his buffer.  How that works for multiple sources I have not yet figured out.

In the end I have breadboarded a preamp with gain that at least runs in the same league with the Placette.  Two things about this were certainly not expected:  firstly, I did not expect to be able to get the Placette working as well as it does now, but sorting out the power supplies has really helped as has the polarity thing with much of the digital music I listen to; secondly, I did not expect the valve preamp to be so immediately successful.  Sure, it is a proven design with SS output and I did my reading between the lines to choose a valve that drew enough current, was not microphonic, and gave a sound that was not overtly sweet or warm, but I only gave the project a 50% chance of success and even then after much, much more effort than has gone in thus far.  That a DHT is so neutral and transparent and can compare to modern engineering such as the Placette is extraordinary.

 Romy the Cat wrote:
 
So, where it lives you. Obviously if you have frond-end with more output then I am very convinced that Placette will fulfill all your expectations, I am not kidding it is very hard to beat it. 
 
 

Three weeks ago I would not have agreed with this statement, but now I do.  The Placette is very hard to beat.  If both systems were optimised, I am not sure the 10y will beat it, but they will be more or less equivalent.

 Romy the Cat wrote:
What is very important to understand that in case you have both of the scenarios implemented then you should have identical result the end. Another very important message you might consider is that in case of your 10Y the main beneficiary to sound is not the quality of tube or your auto-former but a presence of preamp that acts and post-DAC low pass filter.
 


I am certainly not ruling that out, and will mull over consequences and actions in relation to HF and dacs, but I do need gain from all my sources.
08-16-2020 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,166
Joined on 05-28-2004
Post #: 55
Post ID: 25923
Reply to: 25922
I think you are done then
Well, you can’t use Gogol Suite as some kind of reference in term of gain. The Gogol Suite was record by Pope Music at very high dynamic range they have very little compression. It feels like very soft volume recording as a result.

Architecturally for your system, considering that you have low voltage souses the 10Y sounds as a better solution. If you were able to make your 10Y to sound comparable to Placette then your preamp is operating very close to how preamps should sound and you do not need to look any further. Make sure that the fain you have from your preamp does not flood your input stage and does not max out your output stage. Is your AC voltage at input is under the DC voltage of your bias at 0dB digital level then you are all set. It is important do not drive the driver tube to A2 operation. The same goes with output tube, make sure that it does not go for A2 operation and it will clip very hard. 

Another aspect. You know now what are the loads of your channels and they are fixed impedance. Now you need to assure that your amp is properly set power-vice. Drive your power amp at 0dB digital and max out your preamp. Let pretend that you are not clipping, add another preamp and make sure your power amp just beginning to clip. It is very easy to with a generator BTW. Now make sure that when your sinusoid gets clipped then it happens symmetrically atop and at bottom. Probably it will be the most applicable for your LF channel. Idle the LF channel as much as your power permits you (those drivers will sound better with less loading) and set if at symmetrical clipping. You can slightly adjust voltage and current of the output tube operation in order to moderate the top and bottom clipping. If happens the you have not enough power for your room  drive the Milq LF in Pure Class A then you have a problem. Let me know if it’s the case. I predict that in your room and with the amount of you LF drivers you would be able to use Milq;s LF with no problems.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-25-2020 Post does not mapped to Knowledge Tree
anthony
Posts 338
Joined on 08-18-2014
Post #: 56
Post ID: 25927
Reply to: 25923
All for nought?
Well, I decided it was time to start using some  "proper" interconnects between the preamp and DSET's, ordered them and had them delivered.  To date I had been using cheap interconnects from the local electronic shop (literally $6) which should be ok...afterall they are just wire and how easy is it to attach some coax to rca sockets?  All my good cables were either too short or too long for the job so the $6 fellows became the interim solution.  Have been happy with the sound I am getting, was able to dial in a decent sound quite easily using just the l-pads for the upper channels to get a reasonably flat measured response at the listening position.

Put in the new interconnects and the sound is harsh..not nice.  Bass is gone, sound is bleached and irritating even listening at lower levels.  It has been a long time since I've had new cables but I never recalled such a change in sound so I turned down the volume and let them play in the background for a few days.  No change.  Put in the old $6 wires and good sound was back.

This really had me scratching my head so I grabbed the LCR meter and measured both sets of cables.  The cheapies measured 0.4ohm DCR and 0.4ohm AC resistance (100Hz - 100kHz) whilst the new cables an excellent 0.03ohm DCR and 0.018ohm AC resistance along with a quarter of the inductance, although both cables have inductance and capacitance under control.  The only real difference I could find that may or not influence the sound is the resistance of the wires.

So, with the new interconnects I have had to attenuate the midrange/fundamentals/HF channels and the good sound seems to be back.  Early impressions at least.  This tuning has only been done by ear, but about 5dB more attenuation has been necessary in the upper channels, give or take, and I will have to find some time to pull out the microphone and measure the frequency response once more.

It seems as though the $6 interconnects really were broken, or at least they acted as a high pass filter for the sound, which means that I should re-visit the preamplifier comparisons to be fair to all contenders with the new interconnects.  What a pain.
08-25-2020 Post does not mapped to Knowledge Tree
rowuk


Germany
Posts 454
Joined on 07-05-2012
Post #: 57
Post ID: 25928
Reply to: 25927
Your enviable situation
Just think back a couple of years where you read about claims of difference in the sound of cables and wondered if it could be true. Well, in many cases it isn't and those posting document the BS by making claims that simply do not describe what cables do!
Just think about how you wanted a system of such resolution that the cables became "important". Now you can make decisions.
It may be a pain, but I consider you to be one of the lucky ones!
There is no decision more gratifying than one without compromise!

Whenever I feel blue, I start breathing again.
08-26-2020 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,166
Joined on 05-28-2004
Post #: 58
Post ID: 25929
Reply to: 25927
Do not ask me how I know it.
I do not know how about 5dB attenuation via cable but for sure cables sound very different. Hey you are talking to a person who have a small fortune spent for wiring my entire system with vintage Dominos and I never felt that it was waste of money. There is so much talk about cables that I do not want to pollute this thread with this subject. I do feel that it is a bit to early for you to worry about cable and you need to setup the major game strategy and then wary about the dribbling. BTW, be advised that the configuration of your system permits you to do some very interesting things in term of cabling. You for instance might DC bias the cables with DC voltage that is very positive impact some of the cables. All you need to do is juts to shut down the positive bios supply and do not set 0VDC at impute.  As the preamp is connected the ultra-low Zout of the preamp will ground the negative bios voltage to ground via the 400K grid-bias resistor. This will generate the proper negative bias for the driver tube and the DC voltage will be flowing over your interconnect to preamps output. Very cook configuration. Do not disconnect your interconnects in this configuration while your amp is work as you will be baying need drivers for your speakers and new windows for you house. Do not ask me how I know it.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-27-2020 Post does not mapped to Knowledge Tree
anthony
Posts 338
Joined on 08-18-2014
Post #: 59
Post ID: 25930
Reply to: 25929
No questions asked
 Romy the Cat wrote:
I do not know how about 5dB attenuation via cable but for sure cables sound very different. Hey you are talking to a person who have a small fortune spent for wiring my entire system with vintage Dominos and I never felt that it was waste of money. There is so much talk about cables that I do not want to pollute this thread with this subject. I do feel that it is a bit to early for you to worry about cable and you need to setup the major game strategy and then wary about the dribbling.


The circa 5dB attenuation is strange.  All that I can think is that the $6 cables were somehow broken.  I've never heard such a difference with cables before and hope I do not have to again with this project.  I just need some cable of the correct final length so I could keep things tidy and went with something I am familiar with.

 Romy the Cat wrote:
Do not ask me how I know it.
 

You paint quite the picture there Romy...


 rowuk wrote:
There is no decision more gratifying than one without compromise!


Yes.  What a nice way to phrase the concept.
04-23-2022 Post does not mapped to Knowledge Tree
N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006
Post #: 60
Post ID: 26763
Reply to: 25901
Preamp details
Hi Anthony,
Nice piece, congrats! I'm in need of a good preamp and was thinking of making the same as I have 801A's. If I may,

1. Has the 801A pre stayed in your system? How do you feel about it after the time? 

2. What is the OP of 801A, Ale's 200V/20mA/-6V?
3. I understand Slagle's autoformer is at the output, do you decouple it from 801A with a cap? If so how big and what brand.

4. What kind of bias do you use? Resistor, SiC or sth else?
Thanks, Jarek


Cheers,
Jarek
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