stereo to mono conversion

[dscottguitars]

Hi, I want to connect my stereo outputs into one speaker. Is it as simple as using a higher power speaker at a higher impedence? Two 8 ohm outputs at 10 volts would add to 16 ohms and 20 volts, yes?

Or could I connect the outputs together inside the amp before they go through the transformers and then connect an appropriate transformer? I feel this would be best.

I have a stereo tube amp, 6aq5's and would like to make it one output.

Thanks...

[pdf64]

You could set it up as a bridged system, see
Bridged and paralleled amplifiers - Wikipedia, the free encyclopedia

[dscottguitars]

I don't understand the schematic having only one wire out of each amp.

[jmaf]

I don't understand the schematic having only one wire out of each amp.

There's a common wire, which is ground. If you pull a tap out of common for each of the hot wires out of the amp, you'll have 2 x 2 wire channels as expected.

I've never experimented with bridging the output of 2 transformers, but there's some theory you need to get right. You can't just bridge the 2 channels unless you take care that they're exactly in phase, for which you'll need a 2 channel oscilloscope and input a sine wave through a generator.

If there's a phase shift between channels and you still bridge them, one will be consuming power supplied by the other, essentially they'll just be a mutual load and depending on how bad the phase shift is, you can even damage them.

At 180 degrees it's a complete short circuit, so if you get the leads backwards that's what you'll be looking at: a mushroom cloud.

[pdf64]

The bridged system requires one amplifier to non-inverting, the other to be inverting, ie they do need to be 180 degrees out of phase. There's no short circuit, because the load is between the amp outputs.

[Steve Conner]

I think jmaf says "bridge" above when he means "parallel".

Bridge is more like connecting in series.

Paralleling tube amps is fairly easy. The high output impedance makes them share current naturally, as opposed to SS amps.

[dscottguitars]

It sounds as if there is too much controversy over how to bridge the two channels after the output transformers.

What about bypassing the transformers. I have two wires for each, red-common and blue-tube output. Can I connect the two output-blue wires and the common-red wires and feed that through an output transformer?

[dscottguitars]

stereo to mono wiring

Hi, I have a 6AQ5 stereo amp with 6AU6 preamp tubes. I want to make this a mono amp for a guitar.

Can I combine the two output wires that go from the 6AQ5 tubes to the output transformers, and the two wires that come from the rectifier (6X4) going to the other side of the output transformers; then put those two wires in a bigger output transformer?

Thanks,

Daniel

[dscottguitars]

Nice forum, love all the responses. Adios!!