How to mod a 18w to 36w?

[PinkPanther]

Hi there!
I was wondering if anyone could help me with my question.
How can I mod my 18w to 36 w?
I know I should double the output section, but how..?
Any schematics or so?

Thanks!
Niko

[Geek]

Hi,

First two questions you have to answer to yourself before thinking of such, is 1) can the power supply handle it and 2) can the output transformer handle it?

Cheers!

[PinkPanther]

Yeah I know,of course I would change the PT and OT to something that fits, I just forgot to mention that!

Niko

[martinw]

Change the PT and OT.
Add two valve sockets.
Add another cathode R and C.
Add another Screen grid R.
Add 2 extra grid resistors.

In simple terms that's it. (I think.)

There are schematics around in the Downloads section, study them and note the essential differences in the output section. You'll see it's pretty simple.
There are of course options to disable/limit the two extra valves, but they're not an essential ingredient.

[keith]

As a side note, might want to make sure your speaker can handle the additonal wattage. Between the PT, OT and the speaker, the conversion can be a bit expensive.
Keith

[clyde]

This is not a mod, it's a rebuild, possibly it would be easier to start from sctatch, definitely if your chassis is too cramped to handle the extra tubes. Best of luck.

[mnrsmith]

I've wondered if it possible to add the two extra el84 with another 18w OT with the secondaries of the two OT in parallel ? (or perhaps just driving a different speaker)

[rickdog]

I've built 3 18 watters and two 36's. It would be best to just build the 36 watt as an amp in it's own right. It will take a lot to rebuild the 18 into the 36 properlyand it'll probably look like doggy dung by the time you're done modding everything in.