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Any Point In Upgrading Purifi Based Amp with Sparkos Opamps?

dmusgr

Member
Is upgrading the Opamps in a Purifi based amp snake oil or does it yield an audible benefit?
 

DVDdoug

Major Contributor
It's unlikely to make any difference. Purifi has a good reputation and I assume their amps are already better than human hearing.

I don't know anything about the Purify circuitry but most op-amps used in audio are used in non-critical, low gain, circuits unless we're talking about a microphone preamp or a phono preamp.

One of the wonderful things about op-amps is that their high open-loop gain allows for negative feedback (corrective feedback) which makes the op-amp characteristics less critical.

...That's also the same reason you can usually swap-in another random preamp without fouling anything up.
 

NTK

Major Contributor
Forum Donor
Snake oil.

The Purifi evaluation kits, which are supposed to showcase their performance, use TI OPA1612 opamps. If you think Purifi doesn't know how to pick opamps, then why do you want to trust them with the rest of their amplifier design?
 

Matias

Master Contributor
Forum Donor
Snake oil.

The Purifi evaluation kits, which are supposed to showcase their performance, use TI OPA1612 opamps. If you think Purifi doesn't know how to pick opamps, then why do you want to trust them with the rest of their amplifier design?
Actually Bruno recommends OPA1656, so not sure why they chose the OPA1612 for the EVAL1...
 
OP
dmusgr

dmusgr

Member

NTK

Major Contributor
Forum Donor
Actually Bruno recommends OPA1656, so not sure why they chose the OPA1612 for the EVAL1...
Perhaps Bruno is cheap and he knows the difference is undetectable.

OPA1612.png

OPA1656.png
 

Jim Taylor

Active Member
Forum Donor
Is upgrading the Opamps in a Purifi based amp snake oil or does it yield an audible benefit?

Let's start with a known quantity: Purify-based amps work, and work at (or close to) the cutting edge of amplifier performance. AFAIK, their distortion profile is completely below the threshold of human hearing. This means that the characteristics are completely inaudible. See here, for example:


Therefore ... any change that would be audible to a human being means that the performance of the amp has been degraded, and that is of absolutely no benefit.

Jim
 
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MaxwellsEq

Major Contributor
Forum Donor
You are in luck. Amir managed to do some op amp comparison measurements here:
 
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