The TPA3255 can indeed sound very good and the Aiyima is a good starting point, but well-designed class A amps are a completely different animal. It’s difficult to go back to class D from class A. That’s been my experience. I have both running in my house daily, but the main system has been class A since I first powered up the Vfet SE lottery amp. I then built an F5. LuFo is next in line.
Thanks Guys.
I had build an AKSA 55 Nirvana some moons back but my modded TPA3116 did sound better as did my EL84 Tube Amp. The magic with the 3116 happened when I bypassed all the garbage and fed the chip directly balanced via a transformer from my AK4493 dac. I also bypassed the output stage from the dac. That is what's called synergy I guess.
But audio nervosa has kicked in again and I want to see if the bar has been raised in the diy amp Camp.
I had build an AKSA 55 Nirvana some moons back but my modded TPA3116 did sound better as did my EL84 Tube Amp. The magic with the 3116 happened when I bypassed all the garbage and fed the chip directly balanced via a transformer from my AK4493 dac. I also bypassed the output stage from the dac. That is what's called synergy I guess.
But audio nervosa has kicked in again and I want to see if the bar has been raised in the diy amp Camp.
It accepts the standard Yarra/M2X daughter boards. The Melbourne, WBA18, and ACP+ are probably the most practical candidates to generate the required output swing. They are is discrete amps so less susceptible to supply chain for single part bottlenecks. The ACP+ has an optoisolator that might be tough to get. I have the OPA454 HV opamp versions available and need to make them available in the shop. However, they use a DCDC converter that is really hard to get with the supply chain issues.
I totally forgot that JPS64 made an Aksa Lender front end for the Yarra/M2X format with a built in HV DCDC PSU - this would be ideal for the LuFo actually. PM me if you want to be the verification builder for it.
It uses the LT8357 DCDC converter and an external MOSFET for the step up. Schematic attached.
It uses the LT8357 DCDC converter and an external MOSFET for the step up. Schematic attached.
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@von Ah - re: cap bank boards. Randy has some that he modified a bit from Chuck's PCB design for the Singing Bush. I think he has a listing in the swap meet. rhthatcher
If he doesn't have any, then I may have a few of Chuck's original design laying around.
I'm sure there are tons more out there, but that's what comes immediately to mind.
I have (4) MD803 for $80 including free shipping to continental US, or please make an offer.
Attachments
You can run a sweep with a DATS to see which has the most linear impedance vs frequency.
My two MOTs measure 87mH/2.2R and 66mH/1.7R with DATS. So I think getting 4 more will help me select two similar ones.
Naturally, they measure differently with different methods:
Naturally, they measure differently with different methods:
- DATSv3: 87mh/2.2R; 66mH/1.7R
- TrTester: 115mH/2.1R; 88mH/1.0R
- DMM: 1.2R; 1.2R