New Dual TPA3255 Module + PFFB / Fully differential / OP amps DIP8 @ Great price

[john61ct]

water is wet

 

[frabor]

Would be good to see it measured.

150w/8 300w/4 and 600w/2 ohm. Can it actually produce this?

If we add more cooling the unit should be available to produce more. If the OP specs are correct, and I think they are, the module is a dual TP3255 operating in dual mono, so each chip should be able to produce 600 W at 53V when fed 2 V. Those are the limits of the chip, so in theory, if properly implemented, the board could be able to 600W x2, therefore the claims of 300W, depending on cooling and power, are feasible.

 

[Mark185]

I have purchased and tested 4 different TPA3255 boards as well as finished amps from 3E Audio, Fosi, and Aiyima. No TPA3255 amp will live long at 48-53 volts without really good heat sink design and forced air cooling. These suckers get hot enough to cook on at high voltage. Think I mentioned this earlier - I am a EE. When we want to test for reliability and rapidly age a circuit like this, we subject it to many, many stressful thermal cycles. Run a 3255 hot all the time and you will shorten its life. There is derating data for many electronic parts that predict life based on thermal operating environment. I am sure TI has this for their chips although I have not checked their data sheet for it.

Long story short, those power ratings listed above for 1% and 10% THD are not realistic. No one that wants their equipment to be reliable will operate at those levels with 48-53 volts power supply. More realistic number is ~200-250 watts per channel into 2-4 ohms which is still damn good. The power output Amir has measured on 3E Fosi and Aiyima 3255 amps is very indicative of what is safe and prudent. 300-600 watts per channel is pure marketing BS.

 

[pma]

Agreed. And good thermal management is a key - which almost never happens.

 

[Mark185]

The other aspect rarely mentioned is if one lowers the supply voltage to 36-40 volt range, the operating temperature drops significantly and so does measured THD and SNR. You may be limited to 80-125 watts per channel depending on speaker impedance and power supply voltage but the amp will be much cleaner in terms of distortion and probably will not need forced air cooling.

 

[pma]

Yes. But you would not hear any improvement. If you think you will, then please provide us with files for a DBT.

 

[Mark185]

Yes. But you would not hear any improvement. If you think you will, then please provide us with files for a DBT.

I accept that it would not be an audible improvement. Lower operating temps are good enough for me. To each his own.

I do not believe files for DBT from me would prove anything. I would be using a Behringer microphone and Focusrite audio interface which would introduce their own coloring on the sound.

 

[mocenigo]

I mesured this module with E-MU 0404, on the photo is simple SE-BAL converter and module is after some mods but measurements are made without converter and both before and after mods. Direct balanced signal from E-MU, PSU TDK-Lambda 39V, dummy load 6,8Ohm, power approx. 6W.
View attachment 541756
Sorry for the mess.
Oryginal module, 6W load, 39V supply:
View attachment 541757
Moded. Replaced opamps with OPA1656, green Nichicon caps with sandwich C0G(NP0), power caps with low esr Nichicon, inductors with Sagami 7g17a-100:
View attachment 541758

It seems that the second configuration is worse, despite the "better" components. Is it the OPA 1656 working outside its optimal conditions, or what else could be the reason? If the reason is not the OPA, this means that "better" components may actually be detrimental?

 

[eric00886]

I mesured this module with E-MU 0404, on the photo is simple SE-BAL converter and module is after some mods but measurements are made without converter and both before and after mods. Direct balanced signal from E-MU, PSU TDK-Lambda 39V, dummy load 6,8Ohm, power approx. 6W.
View attachment 541756
Sorry for the mess.
Oryginal module, 6W load, 39V supply:
View attachment 541757
Moded. Replaced opamps with OPA1656, green Nichicon caps with sandwich C0G(NP0), power caps with low esr Nichicon, inductors with Sagami 7g17a-100:
View attachment 541758

How do you like this one? There are so many TPA3255 modules out there these days. I recently picked up this exact one along with its single-ended-to-balanced module. I’m really keen to try out the OPA1656 with it, but my usual buying channels are just flooded with fakes.

 

[frobek]

It seems that the second configuration is worse, despite the "better" components. Is it the OPA 1656 working out of optimal conditions, or what else could be the reason?

I think it was caused by the adapter SOIC-DIP8 and inadequate decoupling. Finally I installed OPA2134 in DIP8 package, but I didn't measure it.

How do you like this one?

Nowadays it's the main amplifier in my 2-way active system. I doubt that as cheap part as OPA1656 could be faked, but everything is possible.

 

[eric00886]

I think it was caused by the adapter SOIC-DIP8 and inadequate decoupling. Finally I installed OPA2134 in DIP8 package, but I didn't measure it.



Nowadays it's the main amplifier in my 2-way active system. I doubt that as cheap part as OPA1656 could be faked, but everything is possible.

I picked this module specifically because it has dual TPA3255s with PFFB. The seller recommended adding a preamp, since implementing PFFB lowers the overall gain. As for the volume, I haven't really noticed any issues so far—probably because I always listen at lower volumes anyway.

There are no local retail distributors for the OPA1656 in my country, so I'm pretty much forced to buy them off Taobao.

 

[Thomi]

I am looking for reliable high quality ADAU1452 DSP based boards, ideally lots of I/O channels

ADAU1445/ ADAU1466/ ADAU1467 even better if FIR required

With enclosure available would be nice.

I don't mind the amp chips being built in, but must be preamp-out as well if some channels need moar Watts.

3e Audio? Tinysine?

Actual purchase links would be appreciated

What about the York DSP 2x4 Link?

 

[john61ct]

What about the York DSP 2x4 Link?

Thanks. With only 4 outputs I think I'd need BNC clocking to avoid clock drift messing with phase alignment.

Maybe one unit for each L/C/R "stack" would work, but I think maybe RPi5 would be easier and cheaper?

 

[AyrtonRe]

Speaking of PSU, I made a great discovery at a rather reasonable price. (68€]

Check here (48V / 40A 2000W Single Rail version)

Nice PSU, built using an LLC resonant circuit design with high-quality components. Excellent circuit design. Compact, modern (pfc + llc). On the secondary side, A synchronous rectifier with 4 mosfets (150 v) instead of diodes. On the primary side, 2 transistors from magnachip: mdr60r037jf (37 mω, 70–80 a). The brain of the system is the kpe2592bsg chip—a specialized “2-in-1” combined controller that integrates control of the pfc (power factor corrector) and llc (resonant converter). The voltage range of 39–59.5 v is great.


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Hi! I saw you disassembled this power supply.

I'm trying to implement a low-voltage remote ON/OFF control for the 48V output without using a massive AC contactor or DC SSR. Since the main controller (KPE2592BSG) doesn't seem to have a public datasheet, did you happen to figure out a way to safely disable the LLC stage? I was wondering if pulling a specific pin high/low or intervening one of the optocouplers could work as a standby/enable switch.

Any insight on the PCB logic would be really helpful. Thanks!