TPA3255 - all about DIY, Discussion, Design etc

[454Casull]

Yeah, Class D Audio unfortunately doesn't have any measurements, or even real specs, on their website for this. Too bad.

 

[daniboun]

I know this is Class D Audio ) Just asked if someone has tested it )
Thanks anyway

The only measure we have :

0.006% THD+N at 1 W into 4 Ω > this is not the best we saw.

 

[Solve]

It's this one.
TI-3255 Balanced Class D Amplifier Class D Audio

 

[454Casull]

I know this is Class D Audio ) Just asked if someone has tested it )
Thanks anyway

The only measure we have :

0.006% THD+N at 1 W into 4 Ω > this is not the best we saw.

That's from the TI datasheet.

 

[turion64]

bushellj: let me tell you what I’ve done with 3e-Audio amp which I think has enhanced its sound dramatically.

Realistically it was pretty good right out of the box but once I was in possession of a drMordor tpa3255 amp I wanted to see if I could make the 3e board sound a little more pleasing. I drive the amp with the 36V SMPS from 3e-audio. I swapped the output main caps with Panasonic FC 1500uF 50V. I by-passed them with WIMA 1uF MKS caps (I had them laying around; 2.2 uF probably would have been a better choice as would using MKPs if they weren’t too big). I tested many op-amps and finally decided to use OPA1656. Someone suggested the use of a Elna SILMIC II 10uF 25-35V cap soldered to pins 4 & 8 (of the DIP opamp mounting pins) under the board. I also changed out the 1) pre-opamp caps with WIMA 2.2uF MKS caps, 2) the pre-3255 caps with 1uF Nichicon UES bi-polars and 3) finally the caps used in the LC portion to .68uF EPCOS/TDK caps.

If you go to the "Aiyima TPA3251 Modification Build Thread !" and look at the synopsis on Post #144 by ClaudeG as to what he did on the tpa3251
amp if you want to challenge yourself. I’m going to try a few bypasses using his 7XR & C0G cap ideas to see if they improve my 3e board any further.

Regards,

Pete


(B32529C1684J)

I have a 3e-Audio EAUMT-0260-2-B Rev1 two channel TAP3255 board (this is the latest released board as far as I know).

Has anyone looked at the options to add bypass capacitors to the main Power Supply Capacitors ? Should be quite easy to add them under the board.

I don't know if you would have access to the AVVD Supply on the TPA3255 to add any additional Capacitors at this point.

As the Op-Amps are on DIL adapters it should be quite easy to add some dedicated capacitors to the Op-Amp's power supply pins.

Any opinions as to whether this would improve the amplifier ??

 

[nerddude]

I have two micro audio 600w 44v smps that would work with tpa3255..I no longer need them since I changed amp modules.looking to get $65 shipped

 

[daniboun]

bushellj: let me tell you what I’ve done with 3e-Audio amp which I think has enhanced its sound dramatically.

Realistically it was pretty good right out of the box but once I was in possession of a drMordor tpa3255

I also own both 3E Audio RTR modules + Finished amp and many Drmordor boards. Would be interesting to get your opinion about the updated 3E Audio module (with mods) vs Drmordor TPA3255 ?

 

[ElliJ]

I am interested in a modified 3e 3255 vs DrMordor too. Hopefully soon I will be able to compare the two. My 3e has Panasonic caps and bypassed op amps.

 

[bushellj]

bushellj: let me tell you what I’ve done with 3e-Audio amp which I think has enhanced its sound dramatically.

Realistically it was pretty good right out of the box but once I was in possession of a drMordor tpa3255 amp I wanted to see if I could make the 3e board sound a little more pleasing. I drive the amp with the 36V SMPS from 3e-audio. I swapped the output main caps with Panasonic FC 1500uF 50V. I by-passed them with WIMA 1uF MKS caps (I had them laying around; 2.2 uF probably would have been a better choice as would using MKPs if they weren’t too big). I tested many op-amps and finally decided to use OPA1656. Someone suggested the use of a Elna SILMIC II 10uF 25-35V cap soldered to pins 4 & 8 (of the DIP opamp mounting pins) under the board. I also changed out the 1) pre-opamp caps with WIMA 2.2uF MKS caps, 2) the pre-3255 caps with 1uF Nichicon UES bi-polars and 3) finally the caps used in the LC portion to .68uF EPCOS/TDK caps.

If you go to the "Aiyima TPA3251 Modification Build Thread !" and look at the synopsis on Post #144 by ClaudeG as to what he did on the tpa3251
amp if you want to challenge yourself. I’m going to try a few bypasses using his 7XR & C0G cap ideas to see if they improve my 3e board any further.

Regards,

Pete


(B32529C1684J)

Hi Pete.

Thank you for your comments on the 3e-Audio module. Do you have any photos you could post to show the modifications.

I also have a couple of the Aiyima (Tilear) amplifiers and I have also been following the "Aiyima TPA3251 Modification Build Thread". It was this thread that made me start to think what could be improved on the 3e-Audio board !!

I already use the OPA1656 Op Amps as my default choice and was also looking at adding Caps to these as suggested in the above thread as it would seem quite easy given the plug in DIL modules without damaging the main PCB and the SQ returns seem quite good. I am sure this would work for any amplifier with DIL sockets for the Op-Amps.

I was also looking at suitable options for bypassing the Chengx main Caps - Whether these would benefit of being replaced or just bypassed I guess time will tell as people experiment.

It seems that providing clean power to the Analogue side of these amplifiers provides the most SQ benefit. Other than the main Caps there is not much room (physical space) for any significant additions !!

 

[bushellj]

I am interested in a modified 3e 3255 vs DrMordor too. Hopefully soon I will be able to compare the two. My 3e has Panasonic caps and bypassed op amps.

Can you post some photos and provide details of the components you used ?

 

[Brad Pitt]

Hi all,
i got a TPA3255 amp from Jle.
I am going to suppress the input stage ( two OpAmp inverser with gain =1) because i ordered a differential DAC with high level (SMSL SU-9). Any objections ? Is anybody did same ?
In this way, i expect to suppress also the AC coupling caps (Nichicon UES bi-polars). If the DAC does not send DC voltage ... Too dangerous ?? Is yes, any idea to other model of caps ? The problem is the low space to put MKT, even small. Or with 1uF only (Wima MKS2).

 

[turion64]

I also own both 3E Audio RTR modules + Finished amp and many Drmordor boards. Would be interesting to get your opinion about the updated 3E Audio module (with mods) vs Drmordor TPA3255 ?

daniboun: you know I’m a fan of the drMordor’s board from previous posts. It’s not that it’s the "richest" sounding amp (mine came with 5532s mounted) but maybe the change to 1656s might really warm it a bit. Having said that,and as I’ve posted before, the sound from his stock board is just so effortless, so even, one can listen for hours and one’s ears find nothing displeasing. For the cost, it is a magnificently designed Class D amp...with it’s own PS built in!!! I also noticed that unlike the other builders you mention he chose not to use output caps bigger than 1000uF which is probably why the sound is so clean?

My goal, for the 3e board, was to get it as clean sounding as drMordor’s. I still want to try a few of ClaudeG’s bypass mods just for fun. I’ll update when I get the parts.

Cheers and Merry Christmas to ya!

Pete

 

[ElliJ]

My mod

This is the mod I made. I lifted the 1 leg on each op amp to remove their power. I wired the source sockets to the SMT caps, this was very tricky and tested my soldering skills (these caps can also be bypassed by soldering the wires to the other side of those caps). I will post the Panasonic caps I used later, I need to look it up. I did not try out the balanced DAC I used before I made the changes which means I can’t make any decent comparisons. However the DAC was a Scarlett Solo which is good but not expensive. The overall improvement was really impressive. It sounds less bright with much better midrange and bass without sounding boomy.

 

[ElliJ]

Panasonic 1500μF Electrolytic Capacitor 50V dc, Through Hole - EEUFC1H152L

 

[denbret]

Hi ElliJ,

I want to make this change.

I am using the PCB in SE mode and unbalanced, is the bypass correct in SE mode?

Denis

 

[turion64]

Can you post some photos and provide details of the components you used ?

Here’s my mods..again, SE input..big cap bypasses are 1uF WIMA MKS right now but will try 4.4 uF once parts arise.

Merry Xmas

Pete

 

[turion64]

This is the mod I made. I lifted the 1 leg on each op amp to remove their power. I wired the source sockets to the SMT caps, this was very tricky and tested my soldering skills (these caps can also be bypassed by soldering the wires to the other side of those caps). I will post the Panasonic caps I used later, I need to look it up. I did not try out the balanced DAC I used before I made the changes which means I can’t make any decent comparisons. However the DAC was a Scarlett Solo which is good but not expensive. The overall improvement was really impressive. It sounds less bright with much better midrange and bass without sounding boomy.

Nice job with the older, trickier board! It wasn’t clear to me..SE or Balanced input? The newer version board makes everything a lot easier.

Pete

 

[Deleted member 148505]

Hi all,
i got a TPA3255 amp from Jle.
I am going to suppress the input stage ( two OpAmp inverser with gain =1) because i ordered a differential DAC with high level (SMSL SU-9). Any objections ? Is anybody did same ?
In this way, i expect to suppress also the AC coupling caps (Nichicon UES bi-polars). If the DAC does not send DC voltage ... Too dangerous ?? Is yes, any idea to other model of caps ? The problem is the low space to put MKT, even small. Or with 1uF only (Wima MKS2).

You can copy ElliJ's bypass-opamp mod. It will also bypass the DC-Blocking caps for the opamps.

For JLE board:

• Remove SE/BAL solder jumpers
• Remove opamps from sockets
  
• Connect J1-1 to socket A pin 1
• Connect J1-3 to socket A pin 7
  
• Connect J2-1 to socket B pin 1
• Connect J2-3 to socket B pin 7

Electro caps encircled in red in below pic have a 2.5mm Lead Spacing, which means you can replace them with 2.5mm 22-23-2021 molex connectors, then connect each to 2.2uF MKT caps (use short twisted wirings, they are included in PFFB circuit!)

 

[Majotzen]

aymia tpa3255 put in PBTL

For future reference and in case anybody wants a nice 2.1 amplifier, I managed to put one of the chips into PBTL mode on the following board.



It was clear that the board had been designed to allow of changing of modes, but I was not able to get my hands on any documentation.
So I might have done it the wrong way, but the amplifier is working great now in PBTL/mono mode. I basically just had to ground one input and change the Mode2-pin of the chip.

You can see below here how I have managed to do it. Red are components which must be removed. Green are added shorts (solder).

Hi there,
thanks for the contribution, exactly what i was looking for.
I have the same board and want to also implement it.
Do I understand correctly that the signal comes via input 3 and output is bridged via 3 and 4?
do jumpers have to be moved from SE to DIFF?

 

[ElliJ]

Hi ElliJ,

I want to make this change.

I am using the PCB in SE mode and unbalanced, is the bypass correct in SE mode?

Denis

It can only work in balanced. When in SE it creates a balanced/differential signal with the 2 dual op amps. I am a mechanical engineer not electrical, someone else here can confirm.