This one's for you @restorer-john !
I recently bought a very well priced 4-channel TPA3255 module from AliExpress (see measurements here), and though I'd take the opportunity to try out some very cheap 36V SMPS modules at the same time. They were this one, nominally 36V/5A for less than 5 US dollars, and this one, nominally 36V/7A for 20 US dollars, of which I bought 2 samples.
Let's get the super-cheap one out of the way first. On a first inspection it's not terribly built, but one of the negative output terminals doesn't seem to be connected. I detest screw terminals for anything that's going to have to sit in a case for a long time, but at this price that's what you get. On powering up it does generate 36V across the terminals that are connected, but appears not to have any ability to output current. Essentially dead on arrival, and therefore I have no measurements of amp performance with it. It did not blow up or make any magic smoke, it just didn't do its job.
Moving on to the "expensive" $20 modules, things got a bit more interesting. Build quality again showed no obvious issues. In the first round of stepped sine testing, both samples produced a very healthy 80W into 1 channel before going above 80dB SINAD. However sample 2 had an odd anomaly just under 1W, and was making buzzing noises at higher powers:
So I thought OK, let's see whether sample 1 reaches its rated power, and I plugged it directly into my 4R7 dummy load. It produced 7.3A, and I was very impressed until there was a small pop after 4 seconds and it stopped functioning. Now 36^2/4.7=275W which is a bit above its rated capacity of 36*7=250W. I gave it some recovery time but it's dead as a dodo. There are no blown fuses or exploded components, it's just not working, so I guess the output mosfets died?
I then retested sample 2 (the one with the glitch), and somehow it's now only capable of driving the TPA3255 module to 25W:
So that was fun and I need to order a higher quality 36V power supply, probably from Connex, which I have used with great success in many projects
I recently bought a very well priced 4-channel TPA3255 module from AliExpress (see measurements here), and though I'd take the opportunity to try out some very cheap 36V SMPS modules at the same time. They were this one, nominally 36V/5A for less than 5 US dollars, and this one, nominally 36V/7A for 20 US dollars, of which I bought 2 samples.
Let's get the super-cheap one out of the way first. On a first inspection it's not terribly built, but one of the negative output terminals doesn't seem to be connected. I detest screw terminals for anything that's going to have to sit in a case for a long time, but at this price that's what you get. On powering up it does generate 36V across the terminals that are connected, but appears not to have any ability to output current. Essentially dead on arrival, and therefore I have no measurements of amp performance with it. It did not blow up or make any magic smoke, it just didn't do its job.
Moving on to the "expensive" $20 modules, things got a bit more interesting. Build quality again showed no obvious issues. In the first round of stepped sine testing, both samples produced a very healthy 80W into 1 channel before going above 80dB SINAD. However sample 2 had an odd anomaly just under 1W, and was making buzzing noises at higher powers:
So I thought OK, let's see whether sample 1 reaches its rated power, and I plugged it directly into my 4R7 dummy load. It produced 7.3A, and I was very impressed until there was a small pop after 4 seconds and it stopped functioning. Now 36^2/4.7=275W which is a bit above its rated capacity of 36*7=250W. I gave it some recovery time but it's dead as a dodo. There are no blown fuses or exploded components, it's just not working, so I guess the output mosfets died?
I then retested sample 2 (the one with the glitch), and somehow it's now only capable of driving the TPA3255 module to 25W:
So that was fun and I need to order a higher quality 36V power supply, probably from Connex, which I have used with great success in many projects
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