What is wrong with TPA3255?

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SanjeevM

Member
Joined 2017
Well, thats what is my view. I havent tried out a linear PS on a switching amp yet.

I did feed the RPi + Boss with a buck convertor. The sound quality took a nosedive. When I restored the Allo adapter, which is switching but presumably generates lesser noise, SQ got restored.

Sent from my ASUS_Z00AD using Tapatalk
 
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irribeo

Member
Joined 2013
Your 3116 ampboard has no decoupling/high frequency filtering, it is switching 400kHz, you feed it with switching psu and you like it and you said everybody that hears your setup likes it. All that amp ripple/noise and your smps ripple/noise added, unfiltered, and you like it. You may not like the filtered tpa3255, curious to read your eval post when you have listened to that better filtered one.
 
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SanjeevM

Member
Joined 2017
irribeo said:
Your 3116 ampboard has no decoupling/high frequency filtering, it is switching 400kHz, you feed it with switching psu and you like it and you said everybody that hears your setup likes it. All that amp ripple/noise and your smps ripple/noise added, unfiltered, and you like it. You may not like the filtered tpa3255, curious to read your eval post when you have listened to that better filtered one.
Click to expand...

Yes, what you say is indeed true. I have a Volt+ amp too, which has supply filtering built on board with a 3118 chip. Curiously, the 3116d2 Chinese XH board plays better!! I can't explain why, but that's the swap-out listening test result!!

I am waiting for the trafo, after which I will report again on the result after using a linear supply.
 
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diytoon

Member
Joined 2005
users.pandora.be/tony.de.lobelle/toon/
bass lift

after a few weeks running in...

very good sounding amplifier.
the best sound so far, but I keep having problems with de bass SPL.

to correct it I using my Roon equalizer by lifting the bass with 6 dB from 120Hz downwards...

Strange, all my other amps do not have that gap in the bass region...
source is always the same, speakers are always the same as is the PSU...

3e has received my mail and will get back on this, to see what is causing this.

any one else using this board? would love to hear what others think of this amp...

Tony
 
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diytoon

Member
Joined 2005
users.pandora.be/tony.de.lobelle/toon/
3e-audio feedback

Got a mail from 3e-audio (good service!)...

36 vdc might not be enough...I should try 48 vdc smps...
Ordered this one:
400W 48V 8.3A Single Output Switching power supply AC to DC SMPS | eBay

May take a while to get here...so back to dual monos tpa3118 on pure battery power...not so bad... :)
Mini TPA3118 Diagital Audio Signal Channel 60W Amplifier Board Module

I really hope the 48vdc will solve the bass problem, but I am not convinced...hope I am wrong... :)

I will post the result her if any interest...
 
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irribeo

Member
Joined 2013
Low inputimpedance might, but 6dB at 120Hz ???? There are some settings, ampboard and chip, maybe sollution is in that. Powerinput decoupling can have bass diminishing effect, but again 6dB at 120Hz ??? If Toon only has very low dampingfactor amps, no feedback class A, tubeamps, and speakers have impedancepeak around 100Hz, then other amps might have a 6dB peak and this "better" amp would have no peak. That would be lower outputimpedance than other amps Toon owns.
 
doctormord

doctormord

Member
Joined 2007
360customs.de
Upgrading from 36V -> 48V may give a bit more "precision/attack" to the lower frequencies but wont change the frequency response at all. This also would only apply if your power-supply is hard dropping at high output levels. If the clip-led never came on while testing, this isn't related.

Have you measured the audio bandwidth of the amp?

diytoon said:
Got a mail from 3e-audio (good service!)...
36 vdc might not be enough...I should try 48 vdc smps...
Ordered this one:
400W 48V 8.3A Single Output Switching power supply AC to DC SMPS | eBay
Click to expand...

Nice death-trap-. Why not spending some more bucks into a MeanWell supply for additional safety? :)
 
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