The Amp Garage

Hey Brian,

After looking at your build pics, I noticed your screen grid resistors are 470k! (yellow-purple-yellow). It would probably be a good idea to check them and lower them to 470R or 1k, depending on the power tubes you're using. Good luck on your build!

Sounds like a fun build! I'll keep an eye on this thread to see what results you come up with. As far as the MPPs, they sound decent in the PI as couplers, but I prefer 6PS's or 715Ps there in my Ultraphonix Bassman 100 build. It will probably be up to some experimentation, but I bet you couldn't go...

I'm not sure who supplied them with caps, but if you know of where to get those JB capacitors, please let me know! Especially the 0.1uf @630v caps.

I say go ahead and try it! As long as the voltage ratings on the caps are correct for the implementation. Don't forget about the foil ends either! I used two 0.047uf's NTE caps in parallel in my UP building for the AC shunt cap since I had no 0.1uf NTEs, and I think it works great! The small differe...

I'll have to give those a try! I'm always trying to find new stock parts that sound good!

Looks fantastic! Super clean workmanship. What brand of CF and MF resistors did you use? I recognize the Dales.

Thanks guys! Whopper, I will have to give the 716p a try! I know for a fact dumble used them in the Tweedle Dee modifications, so I'm sure it'll add a different flavor. I'll also take a lot and see if I can find some better electrolytics. There's barely any brands than make 220uf with high enough vo...

Glad I could help! Also to keep in mind are the tubes I used for this build: JJ803s in the Preamp and JJ 6L6GC's in the power amp. I wanted new glass to mod around for the sake of easy replacement. (I've been down the rabbit hole of NOS tubes before!) I have some Panasonic ECQs on order from Mouser ...

Hey all, Longtime lurker/first time poster! I've been really getting into messing around with dumble designs lately, especially the Ultraphonix models. I've dissected a 1973 Bassman 100 and completely rebuilt the amp using the original iron and pots. Through lots of tweaking, and great information f...

I'd love to see some photos still!