Old School Brandon Style Dumbleator Build (x2)

[Charlie Wilson]

Hello, just finished two Dumbleator builds. Followed Brandon's tutorial exactly. The only thing I might do differently in future Dumbleator builds is not use the Gepco shielded cable. It sounds good but is kind of a pain in a smaller build.
CW

[dreric]

Great work!

[jam-mill]

Charlie,

That sure is a nice looking build.

-jack

[BarryW]

Nice! beautiful work. What are you using for the transformer?

[M Fowler]

Great build Charlie thanks for posting.

Mark

[Charlie Wilson]

Well I guess I didn't state it before but I sold both Dumbleators and delivered them today. Got to try them out through a real deal Overdrive Special, sounded like a low plate classic(sounded amazing!). I also got to A/B them with a real Dumbleator and I have some observations and questions. They sounded good but different than the real Dumbleator. The drive in the real one is much hotter and it is clearer and brighter sounding than my versions. My customer actually liked the sound of mine better because they are a bit smoother and compressed sounding. I should also note that the real Dumbleator is a Dumbleator 2 using only one out for mono. So can anyone tell me what the component(circuit) differences are between the two knob and three knob including the value of the fixed resistor that takes the place of the recovery send? I think I would like to build a two knob version. In the future I may be able to get inside the Dumbleator 2 and get some intel.
CW

[erwin_ve]

Charlie, check this out: https://tubeamparchive.com/viewtopic.php?f=5&t=5961
Unfortunatly the schematic is gone in that thread. I can go through some old files on previous computers if you,'re interested.
On the brighter and hotter sound: coupling caps make a big difference: I built several with 6ps Ods and Cde dme's and the latter was a lot more bright.
Also there are some variations on the cathode follower circuit, not sure how much it colors the sound.
And last but not least the Lnfb on the second triode. Omit this and all will be a lot brighter and hotter.
For the 2 knob version I used a 220k fixed resistor to ground(instead of the middle knob). Sounds fine to me.
Edit: here's the schematic.

[Charlie Wilson]

Thanks guys. BarryW, I used a Heyboer PT-135 HTS-8883 power transformer. It is the same transformer that Brandon was selling a long time ago. There is nothing really proprietary about it, so they made me one and if anybody wants one, they can order using those numbers. Thanks Erwin ve, I thought about maybe trying some NTE polyester in the next build. I guess another obvious difference would be the tube. Since we were using rack mounted processers with input level LEDs, I could tell that the original was driving the effects hotter than my build. I would also like to add a switch to defeat the lnfb on the second triode. Thanks for the schematic.
CW

[jam-mill]

Thanks guys. BarryW, I used a Heyboer PT-135 HTS-8883 power transformer. It is the same transformer that Brandon was selling a long time ago. There is nothing really proprietary about it, so they made me one and if anybody wants one, they can order using those numbers. Thanks Erwin ve, I thought about maybe trying some NTE polyester in the next build. I guess another obvious difference would be the tube. Since we were using rack mounted processers with input level LEDs, I could tell that the original was driving the effects hotter than my build. I would also like to add a switch to defeat the lnfb on the second triode. Thanks for the schematic.
CW

Charlie,

Thank-You for providing the transformer information.

-jack

[BarryW]

Thanks Charlie, I appreciate it!

Thanks guys. BarryW, I used a Heyboer PT-135 HTS-8883 power transformer. It is the same transformer that Brandon was selling a long time ago. There is nothing really proprietary about it, so they made me one and if anybody wants one, they can order using those numbers. Thanks Erwin ve, I thought about maybe trying some NTE polyester in the next build. I guess another obvious difference would be the tube. Since we were using rack mounted processers with input level LEDs, I could tell that the original was driving the effects hotter than my build. I would also like to add a switch to defeat the lnfb on the second triode. Thanks for the schematic.
CW