TPA3255 Power Supply Select

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Joseph1

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Joined 2012
#1
I owned a TPA3255 based 2.1 Amplifier.
https://www.yuan-jing.com/tpa3255-c...0w-x-2-sub-woofer-325w-audio-tuning-bluetooth

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I checked it with a 19V/4.5A power supply & feels like it has very low performance specially no BASS at all with 4 ohms JBL 10" subwoofer.

What is the recommended power supply to check it to have more BASS?

Thanks
 
#7
A 19V 4.5A PSU (~around 85W, not even factoring in efficiency) is severely underpowered even for a normal 2.0 TPA3255.
My suggestion is to get at least 36V 5A, do check the power cap's voltage rating before you upgrade.
After a quick look at this amp's gut, I fear that even a 48V PSU won't be able to give you the bass you need...
 
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#9
In my experience, bass performance depends on the speaker at least as much as the TPA chip amp. If you have an inefficient speaker in a lossy box, it's gonna need a lot of speaker beating power to get things shaking. I've run multiple different TPA amps, with different power supplies, into different speakers and I can tell you these 3255 boards will belt out the thump. I'm running two different rigs right now.

The first rig is the Bluetooth frankenspeaker. It's running one channel of a 3255 stereo (BTL) board to a 12" Peavey black widow (4 ohm) and an rx22 (8 ohm) compression driver. Source is a cheapo Bluetooth speaker preamp module. It does 120+db down to about 50 Hz, mainly because the black widow is a woofer, not a subwoofer. Power supply is a 36v, 6a amazon special. I tried it with 48v, but it was just too ******* loud!

Rig two is the man cave subwoofer. It's a aiyima monoblock (pbtl) being fed by the LFE RCA output of my home theater receiver. Wired to an old school JL audio 12w3v1 in a big coffin tuned to 26 Hz. Same story: I rigged up a high v power supply and downgraded (I think that one is 35v) because it was knocking pictures off walls upstairs. While connected to 48v, I think I actually made the thing hiccup while belting out the earthquake, just for a fraction of a second. don't know if it was thermal or over current, but the little aiyima wasn't distorting.
 
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#10
@Joseph1
There're a few reasons as to why I made that observation. Please forgive me if I am a little naive, as I have only observed 2.0 models using the TPA3255.
1. This amp in particular has a very small heatsink. Would it be able to provide the power necessary for the subwoofer before temp safety limits kick in?
2. I've seen 2.0 amps with more impressive power caps than this. Is there enough power stored to ensure strong bass reproduction, while at the same time feeding both R/L speakers?
 
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#11
Oh wait, you made sure the sub is plugged into the "subwoofer out", yes?
It just came to me that if you use the R/L out, the amp might cut off the bass frequency entirely (from 100Hz downwards for example), leaving you with no bass whatsoever 🙂
 
#12
Here's my 2 cents worth. The 3255 chips will take 50vdc just fine. It's the supporting hardware that may or may not like it. Some of the boards use a power management chip (step down buck converter) that will fry if it sees too much DC input. Some of them don't. You gotta be diligent doing research before you pull the trigger on prospects. I did this research before buying anything.

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Here's the board I'm using in the frankenspeaker. Shui yuan middle model. It handles 48v just fine. They have a cheap one, same board but populated with generic parts. Top model is a different board, mainly because it has a larger heat sink and more power supply capacitors.
 
#13
Joseph1 said:
... with 4 ohms JBL 10" subwoofer.
Click to expand...
From other posts on this forum I understand you have the subwoofer component of a JBL Bar 3.1 system - which only accepts bluetooth input from a separate unit, which you have lost.
So I'm guessing you have disconnected the subwoofer unit's digital amplifier from the speaker, and are running speaker wires directly to the speaker terminals, correct?
 
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#18
I would avoid it.
  • direct import from China, it does bear the CE logo but safety signs are in chinese and primary voltage is listed as 220V so it is not meant for export. RF filtering may be less effective.
  • input is not universal, it requires a manual 110/220 switch. It may be indicative of old design with low efficiency: the fan will spin faster and be noisy.
  • no temperature derating graph is provided. You can assume that 480W is specified at 25C with infinite heatsink: available power on real application is realistically 50-60% of the rated value
 
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