• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

300b Chinese Ebay board

Can the covers of the OPT's be shielded by electrically grounding to chassis? Maybe they already are- Might check for continuity.
They are very close to PT and could be picking up noise from PT. Overall construction looks very nice for hobbyist builder, tho.
Jim
 
Hi Jim, yeah the chassis came with the holes vertically. I wanted to space the transformers initialy. I dont know what you mean by electrically grounding the chassis. I did ground the ctr tap of the transformer but it seem to give me more noise. the schematic for this board is kinda crappy and my knowledge for electronics isnt great either. I am just wondering were it gets its ground from?.......Frank
 
OPT shells look like crinkle coat over aluminum in detail pic. Assembly pic looks like they are secured by black anodized allen head set screws.
Might run wires soldered onto one allen set screw of each cover to gnd lug (pic). Have to file off anodize coating to solder. That should ensure shielding for opts, as long as allen screws engage metal cover(s)
 

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