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ElliJ, your wiring is correct - except that you left the postive legs of the blocking caps attached to the board. This means there is still continuity back to the opamps, and I have been told by forum member dubai2000 that you will not get the full strength signal of your input.
I cannot confirm this, myself, because for my setup I completely removed the blocking caps, then added my own outboard caps.
I cannot confirm this, myself, because for my setup I completely removed the blocking caps, then added my own outboard caps.
I see an interesting variance in opinion regarding certain aspects of the TPA325x amps;
And regarding PFFB, in the early days of trying TPA325x amps on this forum, conventional wisdom was that PFFB was an insignificant feature ...
now it seems to be de rigueur!
Myself, and forum members dubai2000, chips666, bisouxxx, vitopro, and Peterwitkin have found otherwise - there is a big difference in bypassing the opamps.
And regarding PFFB, in the early days of trying TPA325x amps on this forum, conventional wisdom was that PFFB was an insignificant feature ...
now it seems to be de rigueur!
Hi linuxfan,
I think we must consider the performance of the TPA3255 as a whole, let me explain: a TPA3255 with quality inductors (ex : Wurth flat wires, Ferrocore etc) and high quality caps (Wurth, Epcos, Nichicon etc), Genuine opamps (OPA1612 / 1656 Genuine 5532 etc) and LLC PSU + PFFB in addition = TOP end TPA3255/51 amplifier.
PFFB with poor components makes no sense
Bypass OP Amp with poor other components makes also no sense
This is the reason why XRK / DrMordor / 360 CUstoms board remain unmatched
No compromise on quality and options. 🙂 the higher price is therefore justified
I think we must consider the performance of the TPA3255 as a whole, let me explain: a TPA3255 with quality inductors (ex : Wurth flat wires, Ferrocore etc) and high quality caps (Wurth, Epcos, Nichicon etc), Genuine opamps (OPA1612 / 1656 Genuine 5532 etc) and LLC PSU + PFFB in addition = TOP end TPA3255/51 amplifier.
PFFB with poor components makes no sense
Bypass OP Amp with poor other components makes also no sense
This is the reason why XRK / DrMordor / 360 CUstoms board remain unmatched
No compromise on quality and options. 🙂 the higher price is therefore justified
I can see the logic of bypassing the opamps with a balanced input as you would have 2 opamps in series. Obviously they are needed with SE for BTL. I’m pleased my wiring is correct, the info was spread out a bit over the forum and I double checked the ti circuit. I guess if you had a multimeter you could check the resistance between the opamp and - blocking cap. I did want the wires running under the board as I wrongly assumed the blocking caps were through hole and that would have been very easy.
I think the TI PFFB write-up mentioned that it was actually a good way to improve performance with cheaper inductors?
Indeed: if you can't fix it with a hammer, you have an electrical problem! 😀
(not from me I confess
)I agree. By the same logic we should consider the entire signal chain from source to amp - which will vary significantly between individual audio setups ...
It sounds like you have a good system match and good synergy between your source device and those particular opamps. But this recipe may not apply to everyone.
The 3e-audio boards are not considered in this league?
Forum member doctormord (360customs developer) seems to agree with Rallyfinnen -
So the 360customs devloper is not a big fan of PFFB ... but this was back in 2018, and as I said (or implied) fashions change.
I warn you against such technical elitism. This high pedestal of superiorty is based on ill-informed and ill-considered foundations (that if it can't be measured, it can't be heard). It may find a comfortable home over on the audiosciencereview forum, not here.
Indeed, you are right, seems that my Double AK4497 DAC is working really well with my TPA3251/55. As I probably said before, this DAC is equiped with 4 OP Amps : 2 OPA1656 + 2 OPA1611. Itseems it combines well in the chain (DAC > OPA1656 / 1611 > Amp > OPA1656.)
The 3E Audio Board is excellent, I also own it. But I do prefer the DrMordor one. ( I mean in this new version powered with main voltage + aux voltage)
I don't have the same feeling when listening. Better sound stage, more precise bass than the 3E Audio (once more : it is my feeling). Just a bad point about the DrMordor board > a little pop when switching ON.
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Did you try the 3e audio with Opamps bypassed? I can tell you results are a lot better in this way.