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VTV Purifi Amplifier Review with Weiss Buffer

peng

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Too bad for me, if VTV offers the option of using the Purifi input buffer on the regular model, or use high quality standard binding posts on the Eigentakt (Eval1) model then it would have been an easy decision for me. Or I just mod it myself but if I go that route I would want to find out if VTV void the warranty on mod units (even such minor mod), then would I be able to get warranty replacement directly from Purifi, in the event that any of the modules failed. I am sort of fixated on VTV's because their price are low enough to preclude and sort of DIY build.
 

Billy Budapest

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Too bad for me, if VTV offers the option of using the Purifi input buffer on the regular model, or use high quality standard binding posts on the Eigentakt (Eval1) model then it would have been an easy decision for me. Or I just mod it myself but if I go that route I would want to find out if VTV void the warranty on mod units (even such minor mod), then would I be able to get warranty replacement directly from Purifi, in the event that any of the modules failed. I am sort of fixated on VTV's because their price are low enough to preclude and sort of DIY build.
Did you see the banana-to-five way post adapters I linked?
 

goryu

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Actually, the VTV to buy is the one based on the EVAL1 board in the Ghent case. Just ask VTV to make it with a standard fused IEC inlet rather than the Delta filter. For U.S. customers, it is the least expensive Purifi amp I’ve seen sold by anybody. It is essentially the reference design, minus a control cable used for the reference design’s push button on/off switch and LED.

They won't do it. I asked.
 

peng

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They won't do it. I asked.

I really don't see an issue with those Delta, it says Y-cap is optional but the schematic does show both. Even if it has both, it shouldn't be an issue but I need to think it over in case it does. Regardless, based on Bruno's post, if you plug everything into the same outlet you won't have the potential issue he talked about with the Y cap type.
 

Billy Budapest

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Yes, thank you for that, will keep that in mind for sure.
The additional resistance introduced by the adapters could affect measurements in a small way. Can someone else confirm?
 

peng

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The additional resistance introduced by the adapters could affect measurements in a small way. Can someone else confirm?

Not really an issue for me anyway, I may just use banana plugs, but it is good to know there are options. Resistance can be easily measured and it does not need a Wheatstone bridge, Ductor or Biddle tester for the accuracy required. If I get one of those adapter I will take some measurements, just for curiosity, not that I worry about it.
 
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dOSs

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"In my mind this changes the amplification game completely. Outstanding."

New(?) subjective review of the VTV in which the Weiss opamp measures best according to some human ears.

I'd love a chance to professionally evaluate the Purifi opamps subjectively. Lots of unfounded claims around of hugely different sound qualities.

Whether they sound 'better/worse' to one side: these people must be hearing something different, surely?

"Personal preference and ancillary gear will help determine which is right for you, but I am plagued by the question of which version is truer to the original signal. But once I switched to the Dynaudios the answer was different - the Eigentakt was clearly better at longer and more distinct decay of the treble strings, without a hint of harshness. The Sparkos version was just slightly less so, to the extent that you can only notice in direct comparison.

The later arrival of the Weiss op-amps settled the score. The Weiss was at least as detailed as the Eigentakt, but yet beautifully balanced. The best of both other versions, and the weaknesses of neither."


 
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peng

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"In my mind this changes the amplification game completely. Outstanding."

New(?) subjective review of the VTV in which the Weiss opamp measures best according to some human ears.

I'd love a chance to professionally evaluate the Purifi opamps subjectively. Lots of unfounded claims around of hugely different sound qualities.

Whether they sound 'better/worse' to one side: these people must be hearing something different, surely?

"Personal preference and ancillary gear will help determine which is right for you, but I am plagued by the question of which version is truer to the original signal. But once I switched to the Dynaudios the answer was different - the Eigentakt was clearly better at longer and more distinct decay of the treble strings, without a hint of harshness. The Sparkos version was just slightly less so, to the extent that you can only notice in direct comparison.

The later arrival of the Weiss op-amps settled the score. The Weiss was at least as detailed as the Eigentakt, but yet beautifully balanced. The best of both other versions, and the weaknesses of neither."



If you don't take such subjective reviews seriously you wouldn't be alone.:)
Even @Kal Rubinson couldn't hear much of a difference between the NAD Purifi amp and the AHB2 (if I understood him right in the Stereophile review of the M33 in which he did use the term "seemed" and "subtle" more than once, to describe differences heard) and I am confident that may not have the so called golden ears, but for sure he has the training and experience to tell even minor/subtle differences between amps, is such differences can be heard in properly done DBTs. I believe the claimed difference between input buffers that measured with similarly low THD+N would either result in very subtle difference and/or disappear in a blind test except for those with exceptionally good and discerning hearing capability.
 

mocenigo

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"In my mind this changes the amplification game completely. Outstanding."

New(?) subjective review of the VTV in which the Weiss opamp measures best according to some human ears.

I'd love a chance to professionally evaluate the Purifi opamps subjectively. Lots of unfounded claims around of hugely different sound qualities.

Whether they sound 'better/worse' to one side: these people must be hearing something different, surely?

"Personal preference and ancillary gear will help determine which is right for you, but I am plagued by the question of which version is truer to the original signal. But once I switched to the Dynaudios the answer was different - the Eigentakt was clearly better at longer and more distinct decay of the treble strings, without a hint of harshness. The Sparkos version was just slightly less so, to the extent that you can only notice in direct comparison.

The later arrival of the Weiss op-amps settled the score. The Weiss was at least as detailed as the Eigentakt, but yet beautifully balanced. The best of both other versions, and the weaknesses of neither."



I think the quoted sentence refers to Eigentakt amplifiers in general.
So there are three implementations here

1. Using the EVAL buffer (what this guy calls "Eigentakt")
2. Using a custom buffer with the Sparkos opamps
3. Using the Weiss opamp

The Sparkos definitely color the sound, as I have experienced. No, it was not a controlled test, but there was a warmth and an extra layer of smoothing that were quite annoying to my ears, or brain.

I am not surprised that the Weiss sounded "at least as detailed but beautifully balanced". The stock EVAL buffer sounds a bit lacking in dynamics in my opinion. Moving to the Neurochrome buffer, which is a composite amplifier and not a simple single ended opamp like the EVAL buffer, seemed to make the sound subjectively more lively, whereas it sounded a bit constrained at low listening volumes with the EVAL buffer.

Now, the Weiss seems to be the only discrete op-amp actually measuring better than any discrete opamp on the market and even better than the Neurochrome circuit (we are talking about THD at -150Db). However, the Neurochrome is already crazy precise.

I believe that I could hear the difference between Sparkos and stock buffer/Neurochrome (and I guess the Weiss), in controlled tests as well; less secure about distinguishing stock buffer and the Neurochrome (or Weiss), I doubt one could distinguish between the last two. Of course I would not bet money on this! This is all subjective + a good dollop of hand waving on top.
 

dOSs

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I believe that I could hear the difference between Sparkos and stock buffer/Neurochrome (and I guess the Weiss), in controlled tests as well; less secure about distinguishing stock buffer and the Neurochrome (or Weiss), I doubt one could distinguish between the last two. Of course I would not bet money on this! This is all subjective + a good dollop of hand waving on top.
I'm awaiting a 1612 Opamp version (March). If it's too detailed and fatiguing I'll insert foam plugs in my earports.
 

dOSs

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If you don't take such subjective reviews seriously you wouldn't be alone.:)
Even @Kal Rubinson couldn't hear much of a difference between the NAD Purifi amp and the AHB2 (if I understood him right in the Stereophile review of the M33 in which he did use the term "seemed" and "subtle" more than once, to describe differences heard) and I am confident that may not have the so called golden ears, but for sure he has the training and experience to tell even minor/subtle differences between amps, is such differences can be heard in properly done DBTs. I believe the claimed difference between input buffers that measured with similarly low THD+N would either result in very subtle difference and/or disappear in a blind test except for those with exceptionally good and discerning hearing capability.
Oh I completely agree, I'd just like the opportunity to do a fully scientific AB with all of them to personally experience what it is folk seem to think they're hearing.
 

peng

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Oh I completely agree, I'd just like the opportunity to do a fully scientific AB with all of them to personally experience what it is folk seem to think they're hearing.

Me too, as I said before, I would not mind paying $100 entrance fee to participate in such comparison listening tests, together with both preconceived, believers and non believers. I am quite sure the believers won't score better than me, I mean not enough for them to really tell the differences they heard in sighted test but I still want to see it first hand, instead of just reading studies. My belief is mainly based on logic and my to some extent, knowledge/understanding in EE theories, mathematics and amplifier designs.

Obviously I would only pay for entrance if I know what's being compared and how will the tests be done lol..
 

mocenigo

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I'm awaiting a 1612 Opamp version (March). If it's too detailed and fatiguing I'll insert foam plugs in my earports.
For all purposes that’s a definite amplifier unless you need more power or something that handles 1 Ohm or less with aplomb.

Since I design my own speakers and make sure that they have high sensitivity, with impedance always above 6 ohm and with very limited maxima and argument, well, for me it is the best type of amp on the market regardless of price.
 

dOSs

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Me too, as I said before, I would not mind paying $100 entrance fee to participate in such comparison listening tests, together with both preconceived, believers and non believers. I am quite sure the believers won't score better than me, I mean not enough for them to really tell the differences they heard in sighted test but I still want to see it first hand, instead of just reading studies. My belief is mainly based on logic and my to some extent, knowledge/understanding in EE theories, mathematics and amplifier designs.

Obviously I would only pay for entrance if I know what's being compared and how will the tests be done lol..
Ditto. My interest isn't in shaming folk or anything of the like, I'd just like to go through the full process and understand what it is that these people are hearing so that I can gain something from the likes of the review I posted.

I'm not digging out said reviewer. I'm just genuinely curious as to what these perceived differences are.

I know the standard view on here is DID YOU BLIND TEST? WHAT CONDITIONS? and very rightly so. But let's face it, that's a bollocks stance. As objective as i am I can't afford a full test scenario let alone the cost of several amps to test therein.

But to witness what they're hearing and to then try and explain what they're hearing scientifically would be far more beneficial to me than a billion WAS IT ABX BLIND? WAS IT? rebuttals
 

peng

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Ditto. My interest isn't in shaming folk or anything of the like, I'd just like to go through the full process and understand what it is that these people are hearing so that I can gain something from the likes of the review I posted.

I'm not digging out said reviewer. I'm just genuinely curious as to what these perceived differences are.

I know the standard view on here is DID YOU BLIND TEST? WHAT CONDITIONS? and very rightly so. But let's face it, that's a bollocks stance. As objective as i am I can't afford a full test scenario let alone the cost of several amps to test therein.

But to witness what they're hearing and to then try and explain what they're hearing scientifically would be far more beneficial to me than a billion WAS IT ABX BLIND? WAS IT? rebuttals

I don't disagree with you either for the most part, except the last part. By the way, you are probably aware that ASR has more than one tests that people can do online, and sort of done DBT too using music clips done for such tests. I do not recall anyone scoring well in those tests. Should we expect people to be able to tell the difference between amps that are designed for accuracy and have specs and measurements that would understandably make them hard to tell apart? And if not done in ABX blind, do we just accept whatever the testers tell us as facts regardless of what the experts told based on their experience, often in studies.

To me, it would be far more beneficial to try and find the reason why sample A would sounds different, or better than sample B only if the listening tests were done in ABX blind with reliable support data. If we know the reasons for the differences heard, then we may be able to develop a way to pick the best performed amp based on accuracy/transparency/neutrality, without having to hear multiple amps in our own setups and done in ABX blind tests that we all know are difficult to do.

By the way, here's one example of how useful (not not) it can be for people comparing avrs without following a protcol, you only have to read the first page to see that it is all over the map:


There is also logic here, if hearing is believing, then we need to hear whether the amp designers/engineers actually do listening test and tweak their design (circuitry, parts etc..) by conducting all sorts of listening tests, or they just use best practice in the design and be not influenced by their own listening tests. If it is the former, then should we not expect such amps would not measure well, at least by Amir's standard bar? And either way, are we willing to buy amps that are tuned by the designer's ears even if it resulted in subpar measurements, again by Amir's standard?

Lastly, you may be interested in reading Peter Walker's (a brilliant and highly regarded engineer) comment on listening tests, if you haven't yet. I found what he said interesting, but logical, and hope you would too.


The original interview article:

 
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