Purifi Class D

[John Hughes]

So, I thought I'd chime in to this discussion.  Been in the audiophile industry in the digital realm.  Been a stone cold analog fanatic. Lived with at least 6 different digital or SMPS amp designs as well as many of the classic Solid State including Levinson, Spectral, First Watt (J2 being my last amp).  Several of the most extreme tube systems including Audio Note, and for a period of fortunate time an entire analog Shindo tube setup including turntable. Have 'showed' with many other amp designs at RMAF, CES etc.   I've been out of audio for a while, but have been getting re-acquainted with it.  After a lot of research I got the VTV Purifi amp with the Sparkos input buffer. I'm running a Holo May Dac into it and I have a pair of speakers of my own design: 15" open baffle, single driver speakers with a Raven super-tweeter (100db efficient).  

 

I will say upfront that a system is a sum total of all its components, and put a component into it that is not sympatico won't work.  If you have worked hard to get the best tube sound and you plunk a digital amp into the mix, you are probably not going to be wowed.  For me, I am supremely happy with the VTV, with Sparkos.  But it was actually my discussions with VTV that prompted him push for the design of the tube input buffer, though I haven't tried it myself yet.  

 

You might think that using a 400 watt amp with 100db efficient speakers is a mistake, but that amp has to control a 15" open air driver.  And at least for me, the match has been exquisite.  The noise level with Purifi is vanishing low on this highly efficient system, I don't think a tube amp could match it!  The VTV punches way above its price level with the right care and attention.

 

I get more spine tingling realism, more subtlety, realistic dynamics, clear and smooth treble, bass in the upper 20's, transparency and lack of coloration.  The best system by far, I've assembled. Overall better than tubes, easily better than A/B solid state.

 

I just wanted to counter the experience that Gutb has posted here, as some others have done.  I do have the benefit of almost 30 years experience designing and installing systems. And I have an army of ancillary products, cables, tweaks and voodoo to get what I want out of a system :)  But a good digital amp today (I wouldn't have said this 10 year ago) IMHO is as good as other amplification in the context of intelligent system design.  

 

All that said, I will say that I am super interested in the Orchard Audio GaN amps!  And I'll love the hear the Mola Mola products too sometime. 

[John Hughes]

41 minutes ago, Rexp said:

I haven't had the chance to test a class D amp with a high-end all analog front end (source and source material). Have you done this, any conclusions? Thanks! 

Not with this current generation.

[John Hughes]

13 minutes ago, jaytor said:

I listen to my system about eight hours a day since I've been working at home for the past year and my desk/computer are at the back end of my listening room. I've been quite pleased with my Purifi based amps. I also have a number of class A and A/B amps that I've compared them to including a couple older amps (Krell KAV-250a, Bryston 4B-ST), a Parasound JC5,  DIY FirstWatt F5 turbo monoblocks, and Neurochrome Mod-286 monoblocks. The Purifi amps compare favorably to all these. 

 

For the last couple weeks, I've been listening to the Purifi amps with VTV buffers that utilize a 6922 dual-triode feeding a pair of Weiss discrete op-amps. At first, I was disappointed with the sound compared to the Neurochrome buffers, but I'm starting to enjoy the sound. I'm not sure if I'm just getting used to them, or if they are still breaking in. I have around 100 hours on them now. Unfortunately, it's a pain to switch back and forth since they use different connectors. After I put another 100 or so hours on them, I may switch back to give the Neurochrome buffers another try. 

 

Unless the VTV buffers continue to improve a fair amount more, I'd have to say that the Neurochrome buffers are a much better value. But I'm also considering trying a different set of tubes to see how much difference that makes. 

Well tubes can make a huge difference, but I do trust VTV to have selected some that match well (he's been in the tube business for decades).

[John Hughes]

Rexp I don't think your opinion is an absolutist statement.  I've had top end vinyl systems (5 figures and up, I still have one, just not setup currently), and tape systems, and top digital systems.  I have also done a fair amount of ADC of tape masters and vinyl. What music sounds better on what system has a lot more to do with the mastering and physical medium.  For sure a first pressing of say Miles Davis from 1960 in great condition will probably blow away any digital version, because the master tapes today have degraded significantly (and the tape player is probably not ideal or adjusted/tuned correctly either in most case).  But a digitally recorded work on vinyl is usually inferior to a quality digital copy to my ears.  Its a bit elitist IMO to hold everything to the golden age of analog recording when 95% of the music today is in fact digital. And I simply don't understand the clamor for modern vinyl when most is not analog (and the companies releasing it aren't forthcoming). Or rather I get the sentiment and non-audio part of the experience, but not the audio portion.    

 

With today's top digital gear which now costing about what a quality vinyl rig does, IMHO parity has finally been achieved between the formats just in the last couple of years.  However, I also believe that a system put together to serve vinyl will usually not bring out the best in a digital rig, and vice versa.  And just as physical isolation is critical to great analog, electrical isolation and filtration is required to get the best out of digital. 

 

I have some high resolution digital conversions I made of2nd and 3rd generation master tapes and my favorite vinyl taken when my analog rig was at peak performance.  I have been comparing them with high resolution digital versions that I have for the same albums.  With my carefully built and tuned digital rig, I find I prefer the high resolution remasters to the vinyl rips I have.  The qualities of the vinyl may be a bit more open in the midrange, but the high rez remasters are clearly superior in bass and treble and detail. 

 

The VTV Purifi amp I have shows these differences clearer than any other amp I have used with amazing transparency and fidelity BTW.  

 

I am also excited by the evolution of professional digital restorations which I think are getting to the level of improving on what comes off the master tape and restoring some of the magic that has been lost with age in a convincing way. 

[John Hughes]

4 minutes ago, Iving said:

 

 

I've heard more valve era records than I could afford to buy as I have traded commercially for some years. It's a particular kind of experience playing these discs inc. DECCA wb sxl etc even on mediocre decks (the ones I use for cleaning records - you can easily hear the difference). I can't say I've done systematic comparisons with digital equivalents. But many congruent digital non-classical issues sound dire - Loudness if nothing else. So bad that it's easy to attribute to the master not the digital system. What I'm really saying tho' is that no matter what I say - the market has an opinion of its own. To acquire a respectable collection of these records now, and buy the deck fitting for their enjoyment,  you'd have to be pretty seriously wealthy. Probably there's also a longevity argument in play for long term investment. 

Yes, I have hundreds of irreplaceable records pressed in that era.  Ribbon mics, judicious use of tube compressors, tube recording gear, and engineers that actually understood music :)  Those are the gems, and too few people have heard what analog performance was capable of and what those records can do. But that's the past.   RCA original Dynagroove, Mercury Living Presence, CBS Six Eyes :) Sigh. 

[John Hughes]

8 hours ago, barrows said:

So here, what you are actually saying is that you like the sound of lots of distortion/noise added to the music: tube gear of that era certainly added lots of distortion, same with ribbon mics, etc.  There is nothing wrong with that per se, but it is not actually high fidelity to the music.  And yes, I have heard many vinyl records from the late 50s and 60s.  In fact it is very likely that a clever digital recording engineer, today, could emulate that sound for you in their recordings using DSP.

I disagree.  Today and back in the 'golden age' the recording and editing process is a series of decisions and compromises as to what distortions and EQ the engineer has to navigate to serve the musical intent.   The result of that process guided by the recording engineers of the time working within the limitations of their equipment made decisions that I think resulted in some of the best representations of music I've heard.  Quite a lot of that was a very heavy hand in editing, including compression used in the service of the music.  The solid state equipment that followed the tube equipment really sucked in the 70s (IMHO) and recording engineers changed their vision of how music should sound according to the limitations that presented. Some of that was the odd order harmonics that gear added to the sound. It took decades for the technology to catch up.  And early digital recordings were mostly dreadful too. Today we are finally in a different world, where I believe that the technology used in the studio stewarded by the best engineers can serve the music as well.  But finding recordings of major artists that get to that level remains a challenge :)

[John Hughes]

So I got an email today that My Starkrimson has shipped!  Coming cross country, First Class mail so it might take a while to get here though.  I'll be comparing this GaN amp to my VTV Purifi amp. 

[John Hughes]

@Barrows. This is a smart answer!  My speakers are super efficient so these differences won't be audible.  But I'd bet the higher power modules would make a difference in speakers at 4ohms and less than 88db efficiency.

[John Hughes]

Wow! that some impressive specs improvements!  I don't doubt that it will be an improvement!

[John Hughes]

I think Orchard Audio uses their modules?

[John Hughes]

9 minutes ago, 57gold said:

The Orchard Audio amps are lower output/current designs.

Yes, and they use the GAN boards that correspond to that. 

 

GaN Systems and Orchard Audio Deliver “Near Perfect” Fidelity

[John Hughes]

1 hour ago, PYP said:

These kind of amps take a very long time to break in.  

Yes, I agree with that. Also, you need to be careful with ancillaries like power cords.