Anyone investigate a 36watt (4 PWR Tube) version.

[HeeBGB]

I had a friend play my 18watt 2x12 and he thought it was great but not loud enough for him. I was thinking about looking for a set of transformers that would accomodate the 18watt circuit with 4 EL84's.
Has anyone investigated this before? Any thoughts as to the specs of the tranny's.

[zaphod_phil]

Not often you hear of someone complaining of an 18watter not being loud enough! Vox AC30 transformers hsould be ideal for the job, and fairly easy to get hold of....

[dboul]

You just have to calculate the extra juice needed for the two extra power tubes and get PT that can produce that and the OT has to be rated high enough for the new output.

Every tranny company makes AC30 sets that would do the job, as Phil noted, but just look at the values needed to run the tubes and how many watts you need to produce and you'll get it.

My personal favorites are Mercury Magnetics, I have a Radiospares OT clone that they made for my AC30TB that sounds spectacular. Much much better than the factory Vox replacement unit.

Good luck! Post a circuit layout if you build it!

[Plexi]

Heyboer sells a great AC30 set.. I've built a dual 6v6 version, a dual EL34 version.. I do have a 4 EL84 version here built out of an old PA amp,but its not finished yet. I still like the sound of those EL84 bottles.

Richie

[dboul]

Hey Richie,

Do you have a layout of the 4 tube version? My buddy wants me to build him a hotter version at well, with enough power to push a 4x12 a little harder than the 18 watt does.

Maybe off 18 watt topic here sorry . . .

Yeah, I forgot to mention that Mercury is a big West Coast company and the Easterners love the Heyboers . . . both are excellent!

[Wannatone]

Think a Marshall or other 2x EL34 OT should work, too.
AC30 iron would be my choice, though.

[Plexi]

Dan, not much to add.. i'd use the choke in place of the 1k5 then added screen grid resistors. ,and also if you cathode bias the amp..you'll need to change that,maybe add one for each tube..or one for a set of tubes . The rest is just adding the wireing to the extra tubes.
Richie