Silvertone 1485 dual OT?

[drewl]

Cool, dual output tranny's on this amp.
Are the speaker outputs supposed to be wired in parallel or are you supposed to use 2 cabinets?
The schematic shows them as seperate, but I think the owner is plugging into only one jack and can't figure out why he's frying tubes/fuses.
Luckily the OT's are still good.

[Sweetfinger]

those were originally hardwired to a 6 X 10" cab, with three speakers per each output X-former. So use a stereo cab, or two separate cabs.

[6267]

You could also just put a shorting jack with a the proper load resistor on each channel, and hope the shorting jacks don't die too soon (use switchcraft, not ratshack !).

Depending on his style, you could also properly load and attenuate the output of amp #1 and run it into the output of channel two for that "American Woman" or "The Kinks" sound.

You can also parallel the output stages and parallel the OPTs for more power. Technically, that should work, but it's not always cut and dried. The radiotron designer's handbook gets into it, you can find that through google.

With my stereo guitar amps, I just rewire the cabs for stereo, but that may not always be an option.

[Sweetfinger]

Depending on his style, you could also properly load and attenuate the output of amp #1 and run it into the output of channel two for that "American Woman" or "The Kinks" sound.

I don't think that's an option, as the amp is not stereo. Both channels are mixed and fed to both output sections.

[Steve Conner]

I think it's probably safer to hardwire the two speaker outputs in parallel. Provided the two PIs/power sections are driven by the same signal, of course.

[drewl]

Yeah, that's what I was thinking.
It's not mine, I think the cab is long gone, and it's for sale.
They share the center tap B+ and output ground already.


marshall paralleled their first 100watters that had dual OT's.