A Rockster Variant Mutant Donster Monster

[matt h]

(deleted)

[Rick]

I've had a case or two where the fil V was a tad too high. Preamp filaments were opening up prematurely. Keep it as close to 6.3V as is feasible. I may have even paralleled some ceramic 1 ohm resistors and put a pair on each leg. It's been a while, memory ain't what it used to be. Another trick to lower voltage where a bigger drop is needed is to use a pair of 1N4007 diodes. That should drop about .7V. I might be wrong, but I don't think NOS tubes handle high fil. V well. If you can read "The Hobbit" by the light of your preamp tubes, they might not last too long.

[Littlewyan]

Are you using 2 x 100R Resistors for the Artificial Centre Tap? I know you're not using the full rated current for the heater winding but on one of my PTs the heater winding is rated at 8A and I'm only using 3.9A yet its at 6.3V exactly.

[donzoid]

Thanks Matt...that's good news! I'm just paranoid about checking it because I have been using so much old iron, that its typical to have to compensate for it there.

[donzoid]

Wyan, thanks - no I didn't create an artificial CT for the heaters, this one already has a CT on the 6.3 section.

[donzoid]

LOL, just saw Rick's post- yeah I was looking at this from "all" those angles, (except the reading by heater light).

I have a few sub-ohm resistors on hand for old iron (pre 1970-ish) but want to make sure this can handle old stock tubes for sure, the newer prod. ones probably won't have issues, but (ahem) they don't sound as good either.

[RJ Guitars]

Very cool, thanks for posting this build, I was suspect that you'd like the way the octals worked out... like a Rocket but with a little more of everything?

[matt h]

Finally had a chance to listen to the clip-- sounds great!

[donzoid]

Thanks for all the help to everyone. I hope this thread will help anyone looking to venture out from the norm...it can be a scary place for a noob like me, but so far this beast is roaring.

RJ, it's a beast and as you know well, not the same as the el84 flavor at all, plus here we are using some "Ghetto UL" designs...I have been a/b'ing it with my 18watt and am pretty stoked to try a stereo setup with a rocket/express. I think its gonna be just "awful"...



I'll post pix as soon as I get the reverb thing installed. Pretty sure I have found a suitable reverb driver out of the cache of old hammond organ parts!
Paint is drying on the headbox so she'll be ready for action by the next gig!