DIY 4 Phase Sinewave Generator for Turntable Motor Drive

Also small update from my side, I have acquired a new set of transformers, and switched out the one from the phase that was overheating. Now the amp remains cool, and the motor seems to work correctly.
What is concerning me is that the one odd amp overheats to maybe 40°C (warm to touch but not hot). Might this be due to the fact that it is smaller than the others (18va vs 25va), or could this point to some other problem?
 
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Hi, I'm new here. I have a question regarding assembly. I understand the capacitors in this design are non-polar from what I've been able to find online. However, I noticed the schematic indicates there is a preferred orientation for each capacitor. Is the orientation of the capacitors of any consequence? Thanks!
 
Initially posted under audio Power Amps; I'm posting here for additional views: If someone would let me know if they own an iteration of the model of class d amp specified in Pyramid's original SG4-assisted motor controller design that they'd be willing to part with, or have a recommendation for an alternative inexpensive amp (even a kit would suffice) easily found online that would work for this project, I would appreciate it. Thank you all so much for all of the help thus far, and thanks Pyramid for the project!
 
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Hello, Enby2,
I have used this one, its been running for over two years now without any problems.
 

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Hi Enby2, my build was to power a Linn Sondek motor. The amplifier is used without modification, but I use resistors between the SG4 and the amplifiers to lower the final voltage down to 100 v ac. I will find the values of the resistors and draw a small diagram. The value of the resistors will depend on value of the step up transformers.
 
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