Champ Rectifier

[angelodp]

can i sub another type of rectifier other than the 5Y3 on my silver face champ ?? Its a cathode bias amp.... would i have to reset bias with other than 5Y3 ??

ange

[CaseyJones]

If it's a real silverface Champ not a clone the short answer is "No".

There's only 2 amps on the 5 volt filament. The silverface transformer is the weakest link, it runs hot to begin with and the B+ is higher than it should be.

In theory a 5AR4 has a 2 amp filament and should work in a Champ. In practice it cranks the B+ higher and blows fuses, not what you want IMHO.

If you're talking a clone with an aftermarket PT it's a different story.

[angelodp]

Thanks my man...... I'll go get the 5Y3..... its a real one..... and sweet sounding.

best ange

[rfgordon]

You could also run a 5V4 and get a B+ between that of a 5Y3 and a 5AR4. Also, for whatever reason, indirectly heated cathode rectos, i.e., 5AR4, will make some champ-style amps noisier.

I'd also strongly advise you to drill the hole and put a standby switch on the back panel.

[angelodp]

Can you share a schematic or layout for the standby please,

best A

[rfgordon]

Creating a Standby switch, where one is not already present, is easy.

1. Locate the B+ wire coming off pin 8 of the rectifier. (Remember, the pins are numbered clockwise when looking down at the wire connectors on the socket.)
2. Unsolder that wire.
3. After drilling the 1/2" hole and mounting a switch (Carling switches are fine), connect one switch terminal to pin 8 of the rectifier.
4. Connect the wire you took off the rectifier to the other terminal of the switch.

That's all there is to it.

[angelodp]

Nice...... will do

Ange

[jjman]

Drilling a hole will permanently reduce the value of the amp. A tube rectified amp's PS voltages come up gradually as the rectifier warms up. I don't see any significant advantage from a standby on one.

Use an NOS 5y3 (not a Sovtek) to avoid some increased PS voltages.