Power Tranny Hum?

[Guarnera]

I just finished the Power supply chassis for my TSE 300B amp. I used two brds. And made two chassis. One with just the power supply section, and one with the amp section. I'm waiting on some heat sinks to package up the amp section. Anyway, I'm getting a little buzzing from my power supply transformer. Not through the amplifier. But when no music is playing, and I get close to the power supply, I can hear a little buzzing. The transformer is bolted down tight to a 1/4" aluminum plate on a wooden chassis, with 10-32 Screws and nuts, and lock and flat washers. Should I loosen up the nuts a little? Put some neoprene under the transformer? What should I try? Thank you all very much?

 

[wdecho]

I think it is normal for most PS transformers like the ones for this amp to buzz some. I notice my SSE amp Edcor transformer has a little hum. I have 4 other tube amps using Hammond and Edcors that are quite. Unless it is very intrusive I would just turn the music louder.

 

[Evenharmonics]

My TSE with Hammond PT did that too. Then I switched to toroidal PT and no more buzzing. I wrote about it here.

 

[wdecho]

My TSE with Hammond PT did that too. Then I switched to toroidal PT and no more buzzing. I wrote about it here.

I do not see the schematic you used for the toroid transformer. I know one is supposed to have a center tap on the high voltage transformer that the toroids do not have. I would like to see how this is done. I have an idea of what to do but I would like to see how you did it.

 

[jan.didden]

I just finished the Power supply chassis for my TSE 300B amp. I used two brds. And made two chassis. One with just the power supply section, and one with the amp section. I'm waiting on some heat sinks to package up the amp section. Anyway, I'm getting a little buzzing from my power supply transformer. Not through the amplifier. But when no music is playing, and I get close to the power supply, I can hear a little buzzing. The transformer is bolted down tight to a 1/4" aluminum plate on a wooden chassis, with 10-32 Screws and nuts, and lock and flat washers. Should I loosen up the nuts a little? Put some neoprene under the transformer? What should I try? Thank you all very much?

If this is mechanical noise as you seem to suggest, you have made a nice sounding board what with the alu and wood snugly attached to the transformer. ;-)

Loosen the transformer from the rest of the construction, and if the mech noise gets less, that's the cure.
Neoprene or other washers would help.

Jan

 

[Evenharmonics]

I do not see the schematic you used for the toroid transformer. I know one is supposed to have a center tap on the high voltage transformer that the toroids do not have. I would like to see how this is done. I have an idea of what to do but I would like to see how you did it.

Something happened to the image link on that thread. Here is the image posted.

 

[cbutterworth]

On my SSE, I noticed that the hum disappeared when I swapped some of the transformer wiring. For example, the secondaries can be wired either way (AC isn't polarized in the wiring diagrams.).

For me the hum went away when I swapped the secondaries. I suppose that one of the transformer's primaries is wired to ground at the circuit box.

Anyway, I can't explain it, but swapping transformer wires stopped the buzzing transformer.

Charlie