These are 500VA each I have one below deck too... 😀 (~170mm dia. x 80 mm H each)
The caps are 80V, 10,000uF
Daniel, to avoid the transfer of mechanical vibrations to the chassis you could even consider placing the plate supporting the transformers on four rubber feet, the ones with screw mounts on both sides. I did that for a tube amplifier once. It doesn't prevent air-transmitted humming, but it does avoid your chassis humming along with the transformers.
Hi Kokkie,
Thanks, I will keep this in mind ordinarily I use a rubber disc under the transformer.
For what it is worth I loaded these to full capacity and the mechanical noise was extremely hard to hear with my ear next to the transformer.
- Dan
I see that you got your transformers from Poland. Are you happy with these toroids? Could you tell how much you paid for these and how much shipping to Australia cost? It's expensive to get heavy items from China and Poland is much further away.
Thank you,
cheers,
ok... the input grounds are tied together and then with a small cap connected to the backplane of the chassis. The anodized backplane is screwed to the chassis rails. The question is whether or not I need to assure the connection between the backplane and the metal chassis plate to which I connect the mains earth?
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The capacitor from shield to ground is just an EMI ground. You may or may not need it. The mains ground should be a real safety ground. The aluminum panel fastening screws are probably adequate for the safety purpose. You can try measuring the resistance with a meter that will do 4-wire ohm measurements in the milliohm range. If there is too much resistance (>50 milliohms maybe) try scraping or sanding the anodization off at the mechanical connection points. You could also try external star washers between the panel and the frame. If you are really paranoid, you could use a small amount of Noalox, which is used in aluminum to copper connections in house wiring (note that aluminum wiring is generally prohibited in many jurisdictions after starting numerous fires due to improper connections).