Voice of music 160 voltage question

[dub136]

Hello:
  I have posted before about a 1953 Voice of music 6v6 push-pull amp and have  completed some of the mods you  suggested. Sounds real good--thank you all.
      Here is my question:
      I put a grounded plug on this amp; the hot black to the on-off/tone control pot
                                             the neutral white to the original 2-prong receptacle-this is also the connection for the power transformer                                                the green ground to the chassis with a star washer;
 When I connect a meter (set to DCvoltage) to the cap can terminals and  to the ground  receptacle at the wall I can bleed the voltage off the cap can... but if I plug the amp in(with the  on-off/tone control pot in the off position) , the voltage rises at the cap can.
 I wonder if the voltage is coming through the neutral wire and powering the power transformer?
Please tell me what You think.
  thanks for sharing your knowledge,
  Dub

[HotBluePlates]

Do you have a schematic for your amp?

[dub136]

yes  have schematic but it just show  ac coming into original ac  receptacle and then to  power trans.

[HotBluePlates]

Hmmm....

You don't have a power switch anywhere? Do you really need the courtesy outlets on the amp?

The only way to get power into the amp is to have a complete continuous loop from the power cord black wire, through the PT to the power cord white wire.

The exception is that if you have a power switch in the circuit (and proper wiring in your wall outlet, power cord, plug), the black wire will still show wall voltage with the amp plugged in and the power switch in the "Off" position. That's because this wire is live all the time, and the neutral white wire should be bonded to the green ground wire back at your circuit breaker panel.

It almost sounds as though your On/Off switch is just a Standby switch, killing B+ power to the amp, but not disconnecting the power at the PT, rectifier, filter cap. In this case, your voltage would rise at the cap, because with the amp disconnected from the B+, no current is being drawn and the voltage un-sags.

[PRR]

"Voltage rises..." to what?? 300V? 3V?

Right-away, or *after* the rectifier warms-up?

> When I connect a meter (set to DCvoltage) to the cap can terminals and  to the ground  receptacle at the wall

That's a strange way to measure. Why not just across the cap?

[dub136]

Thanks for your replies
  Added a fuse because It didnt have one .
The black A/C comes in to the chassis and goes to the fuse and then to the factory on-off/tone control then to the factory 2-prong recptacle then the PT
The white neutral goes to the factory 2-prong recptacleand then to the PT
      DC   Voltage rises instantly 9vdc
DC voltage is small but does increase when amp is plugged  in
 I was draining voltage through my meter when I noticed this . I may have crossed  the PT wires leaving the factory 2-prong recptacle .
Thanks again,
  Dub

[HotBluePlates]

How is your cap can attached to any wiring on the primary side of the PT?

If the cap wasn't attached to the primary (even indirectly), then the voltage on the can couldn't rise when you plug in the amp with the power switch off.

I suppose that means there could be some leakage through the power switch. If there is any opening, you might try some contact cleaner in it, and work the switch back-n-forth to clean off the contacts.