3e Audio TPA3255 Rev. B PFFB

[Rakharo]

I recently assembled and amp around the 3e Audio EAUMT-0260-2-B board. It sounds awesome, but the voices/higher frequencies are popping out a bit too much, probably some feedback could change this.

I was wondering if anyone had the drawings/PFFB modification instructions of the Rev. B board, since on the website of 3e Audio I can find only the instructions/manual of Rev. A

Emailed them and the answer i got was:
"the manual on our website is refer to B version.
did you check that?"


...which is not true

any clue?

 

[stuartlew]

Oh, I might have to buy one then. I have age related hearing loss, and often have to boost those high freq so I can understand the words.

 

[ernperkins]

I'd first try switching op-amps since they're on DIP sockets. Much less work!

 

[Rakharo]

I bought some OPA1656s and ordered the components for the PFFB upgrade

3e Audio replied to my mails telling me that they would upload the Rev. B schematics soon... let's hope

Soldering will be fun!

 

[johoya]

Would you mind to share the detail (eg. soldering pictures and components, or video) after success ? I don't understand the circuit diagram but would like to take a trial step by step.

 

[Rakharo]

Sure!
Since there is no info about this available at all, this could end being useful.

 

[wealas]

You could use the schematic from the Rev A instructions and a multimeter to figure out what goes where, start with the resistors above the opamps and follow the traces.

 

[Rakharo]

True, but schematics would be nice anyway!

 

[e_fortier]

See attached PDF

It’s not from 3e Audio but it’s going to help in ordering the few needed components

 

[3eaudio]

latest PFFB instructions

 

[angchuck]

Hi,

Do i need to short any of the jumpers to get the board to work? i am running 24v, and the red led powers up but no sound

 

[mamocel]

2 different mod for input on this board and 3 wire on connector!
what's you signal input?

 

[Rakharo]

Hi,

Do i need to short any of the jumpers to get the board to work? i am running 24v, and the red led powers up but no sound

if you look at the bottom side of the board, where the jumpers are soldered, you can see "SE" and "DIF"

If you use balanced (differential) signal (3 input cables per channel) then you have to put the jumper on DIF

If you use unbalanced signal (2 input cables per channel) then put your jumper on SE

 

[3eaudio]

Hi,



Do i need to short any of the jumpers to get the board to work? i am running 24v, and the red led powers up but no sound

did you try higher 24V? like 28,30 or higher.

 

[mamocel]

asymetrique signal, find the good .
put a finger on wire ....if you ear a buzz. it's good !: hphones:

 

[angchuck]

Ok I suspected undervoltage. Will try 36v in the weekend

did you try higher 24V? like 28,30 or higher.

 

[carmol]

Any luck with higher frequencies ?
I am experiencing the same harshness
but PFFB didnt help too much

 

[adejacko]

I have the 3e 3250 amp. Love the sound except for the upper mids. Can changing an op amp tone down those frequencies? BTW 3e Audio use the more expensive OPA1602, rather than the cheaper recommended upgrade of LM4562 (for measurements not for sound)
See 3e Audio SY-DAP2002 Review (DSP Amplifier) | Audio Science Review (ASR) Forum
So what is a better op amp than the OPA1602?

 

[carmol]

I dont believe too much in op upgrading,
NE5532 is used in many hi end equipment,
unless... the provided one's are bad fake.
Is there a way to discover such fake ?
Advices for easily available op-amp for substitution ?
Something quickly available on Amazon..
Must be DIP-8 type

 

[bucks bunny]

Here I have some fakes of NE5532. I discovered these while doing noise measurements using ARTA producing noise levels by 20~30dB higher compared to prime parts. Furthermore DC power consumption was a fraction of the originals. This fits nicely into a re-labelled LM358 - the cheapest crap globally available.