Class D Amp Photo Gallery

Thanks for the kind words guys.

@Chermann yes that’s exactly the cases I used, I found the fit and finish really good, plus it came with lots of extra screws. They were pricey at £96 for the pair including shipping but after much searching it seemed like a reasonable price and I like the look of the rounded corners.
 
Considering DIY Audio is such a great resource and I'm grateful for all the information provided this is my somewhat limited attempt to give back. Having read a lot, I decided to build some DIY mono block amps, to the intiated this build is simple, however as someone new to this field it took me a while to research and complete.

The build is consists of connex electronics SMPS300RS and 3E Audio TPA3255-1CH-480W amplifier modules and some eBay cases sourced from China found on eBay. Overall I'm really impressed with the cost vs performance ratio. Im using a PI4 feeding a S.M.S.L Sanskrit 10th DAC into KEF LS50's. With an ear pressed to the speakers there is a feint hum, I recommend the combination.

Congratulations on your build. It looks professional, my builds don’t look nearly as tidy. Where is the hum coming from? The amps or the DAC?

Just noticed you have power leads going to both power terminals on either side of the amp. I don’t think this is needed, there are two just so you can choose the best one for routing.
 
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Thanks Elli,

Currently the amps are jumpered for SE but I have an RCA to XLR coming from the DAC to the power amps. The XLR is jumpered at the XLR connector in the wire side housing, GND being tied to something else (I can’t remember off the top of my head what it’s tied too), it’s a cheap eBay job, I think the connectors were £4 or something and I was dubious of the design of them, however my knowledge is limited in this area. I suspect the hum is being introduced here at the XLR, the aim is to have a balanced DAC at some point and then to correctly ground the XLR’s based on Bruno Putzey’s “The “G” word” paper.

The DAC tested very well on Audio Science Review, so I doubt the DAC is to blame, I need to do some testing with other equipment I guess to rule out a defect.

Regarding the dual power feed to the amps I queried this myself but XRK explained its best practice to have both rails feed so I followed this advice. Granted if not needed and considering the proximity to the amp input wire it would be good to remove it if possible.

Have you had any hun issues with your amps? Do you 3e Audio modules in your builds?
 
It seems pin 1 & 3 are tied together, so I’m not sure if this is the issue..
 

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New take on a DIY class-D amplifier. This is the prototype, just finished...

The amplifier is based on a 5th order modulator for optimum performance.

Features:
  • 400 watt @ 4 ohm
  • Peak current limited to 30A
  • Distortion levels of below 0,0005% at 1dB below rated power.
  • Output noise level 33uV
  • Output impedance approx 50uΩ
  • Fully differential input
  • Gain 30dB
  • Input impedance 10kΩ
  • IRF DirectFET output devices
  • Onboard gatedrive regulator
  • PSU requirements: +/- 60VDC (35-65VDC) and +/- 12VDC. All rails are monitored.
  • Board size 50mmx80mm (thats smaller than your credit card)

The board includes a full protection circuit:
  • +/- 60VDC to low (<35VDC)
  • +/- 60VDC to hig (>70VDC) bus pumping
  • +/- 12VDC to low (<10VDC)
  • Short circuit (Current limited to 30A)
  • Large HF signals at output
  • Overtemperature (60 degress celcius) - Not likely to happen 🙂

Next updates version will also include protection against output MOSFET failure.

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3d-5.jpg


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An externally hosted image should be here but it was not working when we last tested it.