I'm hoping someone will chime in re: the overall imbalance. However, what you might do in the interim is to take the schematic and note voltages at various key points as comparisons between left and right channels. It may not be the best or most direct way to get to the root cause, but it'll get you started.
I did have one other question though. When you said "blowing the 3A fuse on the neutral side", I got a little uneasy.
It looks like you have an IEC and switch combo with dual fuse holders built in; one fuse for the hot and one fuse for the neutral. If so, I think you really want a higher rated fuse on the neutral line than the hot. You want the hot to blow in the case of an overcurrent or fault situation. If the neutral blows, and the hot does not; you still have a live hot line inside your amplifier. I use a 10A on the neutral and vary the rating for the hot based on the amp.
Caveat - I had hoped someone would also chime in on that also... I'm not an expert, and you should never take electrical safety advice from me. I build with 90% pattern recognition and 10% actual knowledge. Per my usual fraidy-cattedness... wait for a confirmation or someone saying that I'm crazy.
I did have one other question though. When you said "blowing the 3A fuse on the neutral side", I got a little uneasy.
It looks like you have an IEC and switch combo with dual fuse holders built in; one fuse for the hot and one fuse for the neutral. If so, I think you really want a higher rated fuse on the neutral line than the hot. You want the hot to blow in the case of an overcurrent or fault situation. If the neutral blows, and the hot does not; you still have a live hot line inside your amplifier. I use a 10A on the neutral and vary the rating for the hot based on the amp.
Caveat - I had hoped someone would also chime in on that also... I'm not an expert, and you should never take electrical safety advice from me. I build with 90% pattern recognition and 10% actual knowledge. Per my usual fraidy-cattedness... wait for a confirmation or someone saying that I'm crazy.
I recall a discussion about fusing neutral here. I don't think it's done in the US. I thought I was supposed to have a lower value fuse on it.I'm hoping someone will chime in re: the overall imbalance. However, what you might do in the interim is to take the schematic and note voltages at various key points as comparisons between left and right channels. It may not be the best or most direct way to get to the root cause, but it'll get you started.
I did have one other question though. When you said "blowing the 3A fuse on the neutral side", I got a little uneasy.
It looks like you have an IEC and switch combo with dual fuse holders built in; one fuse for the hot and one fuse for the neutral. If so, I think you really want a higher rated fuse on the neutral line than the hot. You want the hot to blow in the case of an overcurrent or fault situation. If the neutral blows, and the hot does not; you still have a live hot line inside your amplifier. I use a 10A on the neutral and vary the rating for the hot based on the amp.
Caveat - I had hoped someone would also chime in on that also... I'm not an expert, and you should never take electrical safety advice from me. I build with 90% pattern recognition and 10% actual knowledge. Per my usual fraidy-cattedness... wait for a confirmation or someone saying that I'm crazy.
Anyway, I'm going to replace the JFETs and the smoked MOSFET and bias it up again. I was actually able to listen to it for a short time, and I have to say the sound was authoritative.
I moved it to the main system, powered it on (without speakers connected) and it smoked. Getting a bit tired of this.
well that stinks. I would certainly get some taller standoffs.
https://www.amazon.com/gp/product/B08KXTW9PH/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
I like having this kit handy. Kind of expensive for a what amounts to a cheap item per project but after having it around, I wouldn't hesitate to reorder it again when some of the sizes run out. Having it has saved a lot of time on projects. I also use the insulators that you are using.
edit* I just realized this thread is old. Sorry...
https://www.amazon.com/gp/product/B08KXTW9PH/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
I like having this kit handy. Kind of expensive for a what amounts to a cheap item per project but after having it around, I wouldn't hesitate to reorder it again when some of the sizes run out. Having it has saved a lot of time on projects. I also use the insulators that you are using.
edit* I just realized this thread is old. Sorry...
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Mark - How is your F5 project coming along? I'm not sure if you've finished things have been enjoying your amp, or if you gave up for a little while... Sometimes it's best to walk away for a little while and come back "fresh."
If you are still having trouble, I would recommend checking the back of your PCB for leads that might be grounding to your heatsink. Your standoffs do look rather short, thus increasing the likelihood that something is poking from the back of the board. I did this trick with an ACA build some time ago, took a while to track it down because everything else looked great.
Have you verified that the power supply is functioning properly for the channel that is giving your trouble?
If you are still having trouble, I would recommend checking the back of your PCB for leads that might be grounding to your heatsink. Your standoffs do look rather short, thus increasing the likelihood that something is poking from the back of the board. I did this trick with an ACA build some time ago, took a while to track it down because everything else looked great.
Have you verified that the power supply is functioning properly for the channel that is giving your trouble?