Purifi Class D: Junk?

But it's not 2.2kohm. That's the OEM amp module without a buffer board.

I bought it without the custom input board. It uses the standard Purifi board's input and buffer, which apparently isn't bad. I didn't bother spending a bunch on custom input boards and buffers because I figured this will at least give me a fundamental grasp of the sound. Custom buffers shouldn't make or break the sound, should they?

My Audio Research sp-16 has 240 ohm output impedance into Bel Canto ref1000m amps. These have 100kohm input impedance with the BC input stage versus 10k ohm for the stock Icepower module used solo on the ref1000 model. That is to provide good performance with most any preamp including higher output impedance tube preamps. So yes special input stages are done for a reason and do provide significant better performance in many cases.

No, you are reading the spec of the amp without a buffer. The stock Hypex generic buffer board that is sold by VTV has 47K to ground on each phase. This is in the buffer added mode. If you configure the board so the buffer is not in the circuit.....then you would have 14db less gain and have the 2.2K input impedance. I am pretty dang sure VTV supplies the input board configured with the on board buffer.....so the input impedance is 47K. Please contact VTV for more info. Why would you ask anyone else? I never understand why people ask on Audiogon about things before contacting the manufacturer.

I mod the crap out of VTV Purifi based amps. Sounds nothing like stock. All stock modules by all manufacturers need heavy mods to sound great. The implementation of every single thing makes a sonic difference....fuses, jacks, wires, input stages, shortening the signal path, bypass caps, mods to input stages and regulators, changing output coils to air core, etc, etc. etc. There are so many levels of sound that can be achieved. BTW.....the stock Hypex buffer using 4562 op amps and ordinary regulators is nothing like having the custom input board using Sparko labs regulators and Sparko or better input op amp.....but that board needs a lot of mods as well. I modifiy the Sparko labs regulators, the Sparko labs op amps (seriously better with mods), change all the parts in the input circuit to better ones, use better bypass caps on the output of the regulators, hardwire much better input wire directly to the input stage bypassing the connector on the board, hardwire the output of the input buffer directly to the Purifi modules bypassing the edge connector, etc. etc. etc. The sum of all my mods is a completely different amp.....All implementations of Purifi modules will sound completely different. You really need to get that the input buffer and implementation is just one thing. There are tons of ways to make the sound better.....including modding the input buffer itself. The generic stock sound of the stock Purifi module is just that....a generic sound.......there is so much more to experience.

Shortly, I will have a fully modded amp that I will be sending out on tour.....then you can try without buying......then you will know what is possible with Purifi......stay tuned.

By the way, the standard input buffer sold by VTV for use in their amps is from Hypex....not Purifi. You have to buy the Purifi input board directly from Purifi.....and it is not a mono module. It is a stereo module and uses different op amps and different regulators than the stock generic Hypex boards sold by VTV.

This thread reads so much like Ghost Hunters it’s making me nostalgic.


https://www.imdb.com/title/tt0426697/