TPA3255 - all about DIY, Discussion, Design etc

[Fsatsil]

A full bridge class D amplifier (3e runs the 3255 in BTL mode) does not suffer from bus pumping, at least not to extent to warrant a huge bank cap. Typically bus pumping is caused at low frequencies for half bridge designs, if this is really a concern I'd suggest measuring the supply with a sub-100Hz say a 60Hz tone audio signal. You got me puzzled so I'll measure as well the supply on my 3e amps be puzzled!

Please don’t be puzzled. I probably don’t need the capacitor but I have a lot of them and I paid about $1/ea so I use them in all my projects lol.

 

[audiomovil]

I like both the OPA1656 and OPA1612, they sound even better in my opinion if you put a 0.1uF poly cap across the power and ground pins (4 and 8 in the case of a dual opamp).

do you have a picture of it, i'am very interested

 

[Fsatsil]

you just solder a capacitor from the power pin to ground pin on the opamp.

 

[audiomovil]

you just solder a capacitor from the power pin to ground pin on the opamp.
View attachment 1079101

Thank you, I will do it!

 

[Milo]

I just finished wiring up my 3e Audio/Meanwell build and I’m pretty happy with the results.
View attachment 1076477

Hi Fsatsil, from which manufacturer did you buy the TPA3255 board? From your words, I realize it works very well! Thanks!

 

[audiomovil]

Hi Fsatsil, from which manufacturer did you buy the TPA3255 board? From your words, I realize it works very well! Thanks!

IFAIK 3e audio has no stock of TPA 3255 2 ch. I saw in a YouTube video they are working in a new and better model.

 

[Fsatsil]

Hopefully the new 3e Audio amp with pffb will be available soon! Can’t wait to try it
https://www.3e-audio.com/amplifier-kits/tpa32xx-with-pffb/

 

[GiAnt1961]

Bad news from my new DIY class D 10 channels amp. After some testing days, the reset led of the TPA3255 from 3e audio lit up. When I connect the speakers also the fault led switch on. Is it dead?

 

[julbo]

Bad news from my new DIY class D 10 channels amp. After some testing days, the reset led of the TPA3255 from 3e audio lit up. When I connect the speakers also the fault led switch on. Is it dead?

Thermal warning, is the heatsink hot? If heatsink not hot, maybe the heatsink is not correctly coupled to the chip. If bad thermal coupling chip gets hot and faults into OTW, heatsink is cold leaving the false impression that all is dandy

 

[GiAnt1961]

Thermal warning, is the heatsink hot? If heatsink not hot, maybe the heatsink is not correctly coupled to the chip. If bad thermal coupling chip gets hot and faults into OTW, heatsink is cold leaving the false impression that all is dandy

Dear julbo, I don't think this is the problem as it happens instantaneously when turned on

 

[julbo]

Hmm, assuming the chip is ok because it’s a hard bugger to kill, might be a power supply droop due to bad contact or faulty cap.
Similar thread might help :
https://e2e.ti.com/support/audio-group/audio/f/audio-forum/673710/tpa3255-tpa3255_otw-issue

 

[vitopro]

you just solder a capacitor from the power pin to ground pin on the opamp.
View attachment 1079101

I have tried with an amtrams 0.1 uf but the sound has deteriorated significantly

 

[Fsatsil]

I have tried with an amtrams 0.1 uf but the sound has deteriorated significantly

The last time I actually used a cap across the power pins of an opamp was probably 15+ years ago when modding a Marantz cd63. Very fast video opamps were a popular “upgrade” and many would oscillate without a cap across the power pins. Are you sure you soldered the cap to the correct pins? It shouldn’t deteriorate the sound at all.

 

[angchuck]

Dear julbo, I don't think this is the problem as it happens instantaneously when turned on

I bought 4 and 3 were faulty. One is as u mentioned. Tough to debug. I assume swapping the chip will be easier or just get another module

 

[dreamth]

Where the hell do you buy these kits guys?

 

[vitopro]

The last time I actually used a cap across the power pins of an opamp was probably 15+ years ago when modding a Marantz cd63. Very fast video opamps were a popular “upgrade” and many would oscillate without a cap across the power pins. Are you sure you soldered the cap to the correct pins? It shouldn’t deteriorate the sound at all.

Yes, checked many times pin 4 and 8, but no way.

 

[zek]

If the caps are polarized, have you checked how they are attached?

 

[vitopro]

If the caps are polarized, have you checked how they are attached?

It is a not polarized cap. It is a poly film cap 0.1uf 630v

 

[audiomovil]

Where the hell do you buy these kits guys?

AliExpress

 

[bloqhed]

Aliexpress for 3e kits, I run boards from JLesterP https://www.jlelectronicsph.com/products , xrk971 also has boards available at his Etsy store.