Upgrade from 18w to 36w Marshall Clone

[Zarrir]

Hello there! I recently posted about chopping a tube amp project in order to obtain a power amp only layout. Now i´m curious to know what is the experts approach on how to extend a very well known project (like the Hoffman Stout bellow) by adding two more EL84s to double the wattage while keeping the basic tone. Anyone?

[kagliostro]

I think you must consider a different PT and OT

the tone, to me, if you add one other pair of the same tubes will stay near the same

Franco

[Zarrir]

Yep, definitely a AC30 type of transformers. But how about the schematics? Should i simply add the two new tubes in series with the other two? This is where my beginner´s fears start.

[sluckey]

The output tubes will be parallel, not series. Look at Hoffman's AC-30 and just copy his schematic for the four output tubes. You will need a PT and OT suitable for the AC-30.

[Zarrir]

Awesome tip as usual Sluckey! Going there right now!

[MakerDP]

There are also 36-watt variants to be found on the 18watt.com forums.

[labb]

http://mhuss.com/18watt/schematics/36wTMB5.gif    Give this a go.

[Zarrir]

Super!! Is this one tested and confirmed, Labb?

[labb]

should be. here is mhuss's site        http://mhuss.com/18watt/