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Amplifier Modules and PCBs For Sale

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Deleted member 148505

Tested OPA1692IDR in my IRCore350M, it tamed the highs (vs OPA1656) and the vocals are better. Overall smoother, nice opamp.
 

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Deleted member 148505

AlexScan said:
Good Lester, keep it for the IRCore and test it on the TPA !
Click to expand...

Of course :D, I also tested it on my TPA3255.

Initial impressions, very detailed opamp for TPA3255, airy, has 'bloom' sound, smoother and less harsh than OPA1656.

But I like the OPA1692 better on my IRS2092.

I think I will go back with the LME49720 on my TPA3255 V1.1

I will test OPA1692 and OPA1656 again when my TPA3255 PFFB arrives. I did a better HF bypass there in the opamp section.
 

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Deleted member 148505

Tried NJM4580 on my TPA3255, the sound is 'dry' and midrange to highs are forward sounding. NE5532 is better.

Problem with NE5532 is the not so good 'CHhh' sound, and the instruments are synthetic sounding. Maybe someone can relate haha :spin:
 
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Deleted member 148505

AlexScan said:
Exactly the medium is the best i can hear with LME49860... the LT1364 is my other favorite for mid and musicality.

No need to order LM4562... you are already LME49720... try OPA1612 maybe
Click to expand...

I might make the LM4562 DIP version the "default" chip for my PFFB (LM4562 is cheaper and some find it more airy and open VS LME49720) . I'll also try OPA1612.

Attached PFFB implementation on the bottom PCB. It is not 'hardwired', can be reversed to non-pffb by removing jumpers and RF1-RF4 and of course by changing back the parts.

PCB can handle 1D17A, 1D23A and VER2923 inductors.
 

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Deleted member 148505

dudaindc said:
JLester,
Do you mind sharing details about this mod?
Thanks!
Click to expand...

Changed R442 to 35.7K ohms 0805 SMT

Credits to Piersma <link here>

Will use boost converter to get 12V that will power the chinese subwoofer filter kit that I've bought from shopee.ph

Aside from aux supplies, the output also requires small load current to operate correctly so if you will use it for TPA3255, you should put a resistor load on -V and ground.
 
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Deleted member 148505

Yes, it will be available before November.

Unfortunately when we measured the gross weight of the build with Coilcraft, it exceeded 500g which will double the shipping amount, so we only provided 3 options that weighs less than 500g.

Attached some pics.

Loopback THD+N of my QA400 setup is around 0.002% only, so with high-end measuring equipment, the result might be better.
 

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AlexScan

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Joined 2011
JLesterP said:
Currently breaking-in my new TPA3255 module, after 2 hours of music playing the sound is getting more amazing. I can say that putting PFFB is worth it :)
Click to expand...

Good to hear that Lester... in wich way ? more warm ? more smooth ? more natural ? more detailed ?

Wwith 16dB of gain you know how many volt the preamp need to output for reach maximum power ?
 
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