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PSUs for TPA3255 amps when max power desired

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john61ct

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Please post purchase links to reasonably priced units, for non-US sources, specify whether US tariffs are an issue.

Context:
www.audiosciencereview.com

Ampapa D1 Stereo Amplifier Review

@ Amirm: do you think that a 36V/8A PSU, or even a 24V/10A could be suitable with this amplifier, whether for 4 or 8 Ohms loaded per channel, based on your measurement results ? (This follows my reflection just before regarding the 'heating' of the amplifier in IDLE)
www.audiosciencereview.com www.audiosciencereview.com

If you have constructive feedback on the back & forth there, please post it here not there.

Obviously the stock 48V non-adjustable bricks, most people will be fine with 5A, others are willing to shell out more for 10A if their speakers are hard to drive and they occasionally want max-safe SPL.


Both true for me, so looking at 3e's A7 units and (equivalent power?) DIY boards

I'm interested in ADJUSTABLE PSU's

to get up to 51V

and interested in SPL testing to see what the right current input is to get there.

I am NOT recommending this unit

JUNTEK DPM8624 60V 24A Programmable DC Power Supply Adjustable Step Down Voltage Buck Converter 485 Wireless Communication

just giving an example of the features I'm after

Its output might be noisy, obviously clean & quiet is a paramount requirement.

some Mean Wells can be adjusted, and certain lines are known to be so, more to follow on that.
 
Yes LRS have a clean rep.

Note that 350W is ~7A

RSP or HEP also good apparently, iirc they adjust up to 52V
 
Usable 166W vs 144W in 8 ohm seems 'worthwhile' but the difference between 51.5V and 48V results in only 0.6dB more headroom !
Max. supply voltage (not recommended) = 53.5V (180W).
The difference in max output power between 53.5V and 48V supply voltage is only 0.9dB.
 
In the 48V 10A class I see the usual suspects from Fosi and Ampapa on amazon DE. And the 3e audio one on audiophonics.fr - they all cost about the same <100 €.

I recognize the case of the Creadvent. I think I had some 12V 10A bricks from Ali in that case. Low quality, but worked. Just to try it out and to replace it later I would get one of these for cheap.

An adjustable PSU f.e. 10-60V 2xA is pro equipment. They can be found in the lab section, but are usually very expensive. 30V and less is more common and much cheaper in the lab category, but not what was asked.
 
john61ct said:
Please post purchase links to reasonably priced units, for non-US sources, specify whether US tariffs are an issue.

Context:
www.audiosciencereview.com

Ampapa D1 Stereo Amplifier Review

@ Amirm: do you think that a 36V/8A PSU, or even a 24V/10A could be suitable with this amplifier, whether for 4 or 8 Ohms loaded per channel, based on your measurement results ? (This follows my reflection just before regarding the 'heating' of the amplifier in IDLE)
www.audiosciencereview.com www.audiosciencereview.com

If you have constructive feedback on the back & forth there, please post it here not there.

Obviously the stock 48V non-adjustable bricks, most people will be fine with 5A, others are willing to shell out more for 10A if their speakers are hard to drive and they occasionally want max-safe SPL.


Both true for me, so looking at 3e's A7 units and (equivalent power?) DIY boards

I'm interested in ADJUSTABLE PSU's

to get up to 51V

and interested in SPL testing to see what the right current input is to get there.

I am NOT recommending this unit

JUNTEK DPM8624 60V 24A Programmable DC Power Supply Adjustable Step Down Voltage Buck Converter 485 Wireless Communication

just giving an example of the features I'm after

Its output might be noisy, obviously clean & quiet is a paramount requirement.

some Mean Wells can be adjusted, and certain lines are known to be so, more to follow on that.
Click to expand...
Among the best power supplies for audio applications with single-rail voltage are the Mean Well HRP power supplies, especially the newer N3 series.
These power supplies are designed to quickly meet high and rapidly changing current demands, such as those found in CNC machining centers. Even control boards/computers can be powered simultaneously without any issues.

The HRP N3 series delivers 350% of its rated power for 5 seconds. This means the 48-volt power supply with 300 watts and a peak power of 24A for five seconds would be more than sufficient. At 51 volts, it would still deliver 22.5A.

I also have a good impression of Micro Audio power supplies.
 
Is anything special needed to run multiple 3e A7 off a single PSU? Assume plenty of headroom, rating 10A per box...

Or is it safer to avoid that?

@3eaudio
 
Last edited:
You might prevent ground loops when each one has its own power supply.
 
john61ct said:
Is anything special needed to run multiple 3e A7 off a single PSU? Assume plenty of headroom, rating 10A per box...

Or is it safer to avoid that?
Click to expand...
I would avoid y-cabling in this area of power consumption. Unless you find cables and connectors that bring the proper rating. Possible, but questionable with these standard plugs. Some screwable coupler would be better.
 
I meant in general not with any particular PSU types

and yes proper wiring for a given current level is very important. At each A7 input, the connection will only see only the actual ampacity being pulled by that individual unit
 
solderdude said:
You might prevent ground loops when each one has its own power supply.
Click to expand...
Interesting. I thought those were more often caused by system components being fed by varied power circuits at differing ground references?
 
ground and - of the power supply are the same.
Thus the audio grounds are all connected and the - of all amps are connected to a different ground point.

When using separate power supplies only all audio grounds are connected together.
 
john61ct said:
Is anything special needed to run multiple 3e A7 off a single PSU? Assume plenty of headroom, rating 10A per box...

Or is it safer to avoid that?

@3eaudio
Click to expand...
Don't do it. TPA3255 amps do not want to have multiple units run from a single supply. Really - don't do it.


Nothing to do with the grounding, just don't do it.

The problem is in how class-D amps work. Class-D amps essentially connect the PSU to the output of the amp in short pulses at 500-600 khz. When this happens the PSU voltage fluctuates. That is OK for single chip devices because the TPA3255 chip aligns the pulses between the left and right channels. For multi-chip devices like the 3e A7, there is a pin between the two TPA3255 which connect the two separate chips and allows them to negotiate to align the signal pulses. When you have multiple TPA3255 on a single PSU, the pulses won't align and when one chip is outputting power and another chip suddenly comes online out of phase with it, then an issue occurs. Fosi tried to solve it by making a filter in the power line when feeding two Fosi v3 Mono, but even v3 Mono uses sometime run into trouble.
 
Last edited:
Thanks, excellent detailed response, glad to get that clarified and I accept that recommendation
 
TDK-Lambda SWS600L-48

output voltage range of 38.4V to 56.0V, so be careful use your DMM before hooking up !

rated output current max of 13A, can set to wherever you like below 10A if you like

Or to save money if you don't need to eke out every last bit, get TDK-Lambda SWS300A-48 (or the older SWS300-48), which provides 48V at 6.7A
 
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