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08-26-2018 Post does not mapped to Knowledge Tree
wolfy
Posts 7
Joined on 07-16-2016
Post #: 1
Post ID: 25058
Reply to: 25058
Paul McGowan. tubes in preamp
Paul McGowan is a regular poster on youtube.  I have to take his presentations with a grain of salt as they always conform to sales pitch for PS Audio products, but they are interesting.  Recently, he asserts that tubes in preamp stage will provide higher resolution.  Ok, great, but if that is the case I would like to better understand why.  Romy asserts that tubes belong in the power amplifier and not in preamp section.  Ok, great too, and that makes more sense to me.

Really, tubes are more transparent that solid state?  It's my understanding that tubes are inherently producing more distortion of the signal, so how is resolution or transparency going to be better with tubes?  

https://www.youtube.com/watch?v=AlyJVhUykug

W.
08-26-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,166
Joined on 05-28-2004
Post #: 2
Post ID: 25060
Reply to: 25058
The Mr. McGowan's type of question...
Wolfy, first of all your question is based upon wrong supposition. I never asserted that tubes belong in the power amplifier and not in preamp section. I never remember made this comment and why I know it is because it is never was a part of my believe system. I generally do not think that SS circuitry can much in term of quality to a properly implements tube circuitry but this thinking has a LOT of contingents. I am not circuit specialist and I am rather a brutal end user and I can only judge form the examples that I witnesses.  I have seen remarkable SS and tubes amps but generally I feel that tube amplifiers as class are more cables then SS amps. The mistaken supposition that you took was probably because I use SS preamp in my own playback. First of all what I use for my playback is not coupled with my believe system. Second, I use it mostly because for the topology of the playback I use I need an ultra-low output impedance in my preamp. The third is because I did not have a preamp that would beat my active Placette in term of transparency and dynamics. I do not claim that they do not exists, they might, I just do not have it. 
 
Regarding, the Paul McGowan: it tend do not watch his films as some kind of intellectual challenge. I have seen a few of his films, it was entertaining and his is a very comfortable with himself man. He still in his wisdom, in my estimation, do not rise to the level of demands that I impose to Sound.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-27-2018 Post does not mapped to Knowledge Tree
wolfy
Posts 7
Joined on 07-16-2016
Post #: 3
Post ID: 25063
Reply to: 25060
Thanks Romy.
  I had in mind a few comments made on your forum which I had in mind when I listened to Mr. McGowan:

"Vacuum Tubes the Vacuum Tubes must not be used in line level outputs.  In audio Vacuum Tubes meant for power amplifiers, preferably for out stages, that where they do job."


"14) A preamplifier shall not use vacuum tubes as output devises. Come on, get real! No one yet built an absolutely transparent tubes buffer. The output stages of an Ultimate preamplifier shall be DC-coupled SS devise."

I must have misunderstood your points.
Still, I do think Mcgowan's assertion is interesting.  Maybe it does not matter whether tube or solid state, but more so how they are implemented.
W.



08-27-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,166
Joined on 05-28-2004
Post #: 4
Post ID: 25066
Reply to: 25063
Conflicts resolution. :-)
Well, the conflict you pointed might sound reasonable but not completely. The First quote is taken from a thread “Disregard Digital with Vacuum Tube output”. In there I advocated do not look into D/A converters with tube output stages. In was in 2005 and at that time there were tones of DACs with tube output stage that did the DAC’s “humanization”. I very much did not like it then and do not like it now. Again, not because it is topologically impossible but because any single DAC that I had/heard at that time was not good in my estimation and the best DACs I have heard used SS outputs. So, in context of the thread the comment was appropriate in my view.


The second comment is from 2009, the “The 15 Commandments of Ultimate Preamp” thread. It said exactly what read: “No one yet built an absolutely transparent tubes buffer”. I do stand with the observation that up to the time I very actively was monitoring what the best was done out there I did not see any tube preamp that I find to be transparent. I built a few my one transparent tube buffers and I commissioned some people who I have high respect to build buffers for me, not one was able to do it transparent enough. That lead to my choses but I do not deny that it is possible to have a very transparent buffer, there is nothing in tubes that theoretically limits it.

In my case I did not possible it as I was needed an ultra-low output impedance whish in case tube preamps means an extra state … not good in my books… 
 
Again, regarding McGowan. I kind of discard those talks because he was taking about “resolution” and I have no idea what it is. Well, unfortunately I know what he and his audiences mean and I do not care about this characteristic at all as they do not talk about “proper” resolution but rather about transients contrasts – a bogues distinguishing of Audio confusion.
 
PS: With all it said, I agree that I have to be less “resolute” in my judgment. I think nowadays I am possessing slightly softer judgment then 10 years back. I know that nowadays I would not spend another $100K and 4 year of my life to chaise an ultimate tube buffer. I do applaud the people who would and I would like to use it if it was discovered. I feel that a proper SS buffer can do what make person do not want to look for tube buffer as the ultimate tube of SS buffers would produce unethical results. The tube implementation would be MUCH more expressive and exotic.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-13-2018 Post does not mapped to Knowledge Tree
gordan
Posts 16
Joined on 01-29-2009
Post #: 5
Post ID: 25153
Reply to: 25058
DHT preamps
in the last years there was lots of development in field of DHT preamps. new circuits, or old circuits becoming practical and useful - especially related to hum inducing DHT heating issues that used to affect the sound. now you can basically have a superior full-DHT layout throughout amplification (both pre and output) much easier than before.
This YT video is strange. This topic can't be summed in 5 minutes talk, unless it's a sale pitch type, stating PS Audio knows the best. Sorry.
11-13-2018 Post does not mapped to Knowledge Tree
Amir
Iran Tehran
Posts 355
Joined on 02-11-2009
Post #: 6
Post ID: 25154
Reply to: 25153
AMR DP-777 Bit Perfect I
I have listened to AMR DP-777 DAC (SE versio and upgraded nos tubes) many times.in my idea the best sound of AMR dac come from "Bit-Perfect I" filter if you listen to good records. if i put bad records then there is no difference between filters and even i may prefer other filters.


https://www.stereophile.com/content/abbingdon-music-research-dp-777-da-processor-measurements



Bit-Perfect I filter means there is no filter in signal path (no digital and no analog filter).the time domain response of this mode has no overshoot and the time domain response is perfect.
Audionote UK removed Brickwall low pass analog filter after 2003 and all new AN dacs have no digital no analog filters in signal path. I have Audio Note DAC 5 Special.

these NOS tube DACs may have problem in low frequency extension (in a bass extended system) and processing complex music like classical orchestra (these DACs could not drive low impedance pre-Amplifiers) but in my two way system they are better than other DACs.
I have listened to many many expensive solidstate DACs (dcs scarlatti , CEC da0 3.0 , accuphase 100/101 and ...) but non of them give me the true sound.all of those ss dacs use digital and analog filters.

www.amiraudio.com, www.hifi.ir
11-13-2018 Post does not mapped to Knowledge Tree
Amir
Iran Tehran
Posts 355
Joined on 02-11-2009
Post #: 7
Post ID: 25155
Reply to: 25154
Can we use DACs with more than 2channel?
In loudspeaker and amplifier design we could use more channels to have better result (like 12 channel DSet concept) but i never seen any DAC/Pre to have more channels.It seems i am speaking about moronic idea but it is interesting to me think about that.For example designing 6 stereo channel DAC/Pre  for a 6 channel of loudspeaker . It means we will have 6 separated stereo dac/pre.Crossover filters are not in digital domain.

www.amiraudio.com, www.hifi.ir
11-14-2018 Post does not mapped to Knowledge Tree
gordan
Posts 16
Joined on 01-29-2009
Post #: 8
Post ID: 25156
Reply to: 25155
DSP/multi channel DAC/Preamp
 Amir wrote:
In loudspeaker and amplifier design we could use more channels to have better result (like 12 channel DSet concept) but i never seen any DAC/Pre to have more channels.It seems i am speaking about moronic idea but it is interesting to me think about that.For example designing 6 stereo channel DAC/Pre  for a 6 channel of loudspeaker . It means we will have 6 separated stereo dac/pre.Crossover filters are not in digital domain.

Of course there are, for example this is a very specialized product in this field - Najda DSP: http://www.waf-audio.com/products.php?pos=1&lang=en
8 analogue channel outputs with volume control so you can feed for example 4 x 2 channels of multi way horns.
i dont have any experience so someone else need to write how good and useful it is.
for sure there are other products like this today.
11-14-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,166
Joined on 05-28-2004
Post #: 9
Post ID: 25157
Reply to: 25156
I do not think anybody does it commercially.
Gordan, this is slightly different concept. The presence of multiple outputs with volume control does not assure that each of the channel has own time delay circuitry. Plus it look like Najda does volume at digital level, which is not so good. I personally do not know any GOOD DACs that would incorporate multiple output buffers with individual time delays made properly at digital level. Ironically a lot of very cheap pro audio equipment have this option but I did not see in High-End audio anybody went to it. There was a guy, I think it was in Moscow or in Poland who has two identical DACs running and one of them run time delay. If you use only digital playing then it is good direction to go to time synchronize the base horns with the rest of the channels.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-14-2018 Post does not mapped to Knowledge Tree
gordan
Posts 16
Joined on 01-29-2009
Post #: 10
Post ID: 25158
Reply to: 25157
Pro audio solutions
 Romy the Cat wrote:
Gordan, this is slightly different concept. The presence of multiple outputs with volume control does not assure that each of the channel has own time delay circuitry. Plus it look like Najda does volume at digital level, which is not so good. I personally do not know any GOOD DACs that would incorporate multiple output buffers with individual time delays made properly at digital level. Ironically a lot of very cheap pro audio equipment have this option but I did not see in High-End audio anybody went to it. There was a guy, I think it was in Moscow or in Poland who has two identical DACs running and one of them run time delay. If you use only digital playing then it is good direction to go to time synchronize the base horns with the rest of the channels.

Najda volume control is analogue in each channel. The rest I don't know, especially I don't know how DSP is implemented and if individual time delays are possible. But if you are able to physically time align your setup, I think this is very useful.
You are right about pro audio, I've been at few demos aimed to pros and was shocked with options that exist today. Actually if you want full control on what is happening in your room, you can go with smallest setups from L Acoustics, d&B, Nexo, or similar. They are far ahead of home audio and totally reasonable with prices in comparison...
11-14-2018 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,664
Joined on 10-12-2006
Post #: 11
Post ID: 25159
Reply to: 25158
Far Ahead?
Well, so far, this has been the problem, that someone "solves" an audio problem in a way that takes the life and deeper meaning from the sound of evolved Music.  What Romy said about digital sound processing was put kindly,  but only because he was looking at the problem simplistically, in the context in which it was presented.  For sure, if ever recorded sound can yield  evolved results through multi-layered DSP, including during playback, then many of us will be rushing to implement these solutions!  I hope anyone who thinks they have found a viable solution will share examples!


Best regards,
Paul S
11-15-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,166
Joined on 05-28-2004
Post #: 12
Post ID: 25160
Reply to: 25158
I beg differ...
 gordan wrote:
Najda volume control is analogue in each channel. The rest I don't know, especially I don't know how DSP is implemented and if individual time delays are possible. But if you are able to physically time align your setup, I think this is very useful.

 
Do not want to derail the thread about the magnificent Paul McGowan, and it is despite that Amir has fucked it up, but I would disagree with you, gordan. About Najda. It is good for them that they went with analog out, if they did but in context of multichannel output it is wasteful and an indication that they have one extra and completely necessary buffer stage. A volume control should be at input but at output, otherwise you would need an active stage to drive the cable after the volume control. A good analog output stage is expensive and to waste it for not used channels is very expensive. So, if they go with analog output stage for each channel then it is a very simple and cheap adjusting a feedback in opamp or in some kind of integrated chip where the functionality has built-in. So, I would vote for no volume controls in DAC outputs, would it be a single channel or multichannel…

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-26-2018 Post does not mapped to Knowledge Tree
gordan
Posts 16
Joined on 01-29-2009
Post #: 13
Post ID: 25171
Reply to: 25160
No go
Frankly I don't need this explanation about Najda, I know it all - only wanted to point at its existence which can not be denied. For some people it will work. For us snobs loyal to our PLLXO solution, this device can be used for some basic experiments to check options on the fly, not as a final solution. What we need can only be DIY-ed so far.
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