ac100 (Rocket 100) build suggestions

[Roe]

I'm planning an AC100 build and needs some suggestions. Specifically,
- should I use the original floating paraphase phase inverter or rather a standard long tail pair (like ac30s and the early ac50s and TW rockets)?
-Alternatively, I might use an ac30 style driver into an 12au7 driver for more punch (cf. Park 150 and Marshall Major)
- What should I do with the unused triode in the preamp - either bias tremolo or an extra gainstage perhaps?
- which choke would you recommend? Originals were 10H-19H, the latter had a high resistance that lowered the screens voltage and curre

[Stevem]

I think most of what your asking comes under the heading of personal preference, but the extra gain stage idea by means of using that unused triode way down there at the PI section will likley just get you a oscillating monster of a amp!

[pompeiisneaks]

I don't have tons to input here, but I did build an AC100/2 once and really liked it for the short period I had it. It took me forever to figure out the problem was a bad PT where one of the windings was shorting and causing catastrophic issues with tubes and the like. I rebuild that as my Sluckey's Dual Marshall and got a new PT from jelle for it. There is a video series out in my long past history of maybe 2 years ago of that build

It was my second amp and pretty bad though lol.

~Phil

[Kagliostro]

I don't remember well but, as far as I can remember, the AC100 had (seriously ?) problems to the Bias circuit

IMHO worth doing research on the subject, may be you can plan a mod to that part of the circuit before to have problems, if you decide to go for a clone

BTW, if you are interested I've a bit of good documentation useful to clone the AC50 that I can share if you are interested, unfortunately no about the AC100

About the AC100 I've this, but don't remember if it is joined with the intention to solve the Bias problems or only to achieve a better bias set for each tube



K

[Roe]

Amp works well and sounds good after some tweaking. the mains voltage sags from 459 to 408v at full power, whereas the screens sag from 449v to 343v at full power. Filtering is 110uf, 100uf, 47uf, 32uf, 22uf, 10uf. choke is 15 henry, 256 ohms.

I've added a overdrive channel in parallel with the vox preamp. I need to incorporate a SPDT switch for changing channel, preferably a relay. Both channels feed the phase inverter, but without mixing resistors, since I'm feeding both sides like an ac30. (I prefer the long tail pair)