Dumbleator Layout

[Steve AA1164]

Thanks Martin,

" FW Doubler will produce (120*1.414 - 0.7)*2 = 338 VDC." I got mixed up with the Ripple voltage of 3.2 x the load current. I've read up on ripple current and have a better understanding now.

Thank you for the PT recommendation, I'll consider building a tag board FBR for the E-lator PCB or ask Modulus or Ceriatone if they have a PT with the correct values.

Regards,

Steve

[martin manning]

I'll consider building a tag board FBR for the E-lator PCB or ask Modulus or Ceriatone if they have a PT with the correct values.

It'd be nice if you could use the power supply components on the PCB you have. Here is another option for a D'lator PT that has been proven to work: https://ampgarage.com/forum/viewtopic.p ... 79#p464179
Don't know if you can get that part shipped to AUS, and note that in that thread the C-lator PT was found to be junk.

[Steve AA1164]

Thanks Martin, I've ordered the 1N1729

1n1729.pdf

Regards,

Steve

[Steve AA1164]

I've just edited my post on page 5 dated Sun Jul 13, 2025 3:20 pm. How do we get to the 365V B+ listed on the schematic with a PT secondary of 125V AC. Something to do with my understanding of the voltage doubler CCT. Would someone be able to check my workings out and point me in the right direction?

Edit....

I just re read Martin's post. "A 120VAC secondary with a FW Doubler will produce (120*1.414 - 0.7)*2 = 338 VDC."

So (125*1.414 - 0.7)*2 = 352.1 Vdc. This is close to the 365 V dc B+. The 2k2 2W is a series limiting resistor to limit the amount of current flow through the diodes (1N4007 rated at 1000V 1A) and also drops the voltage by 5V to get to the target of 360 B+1.

I think I'm on the right track?

Regards,

Steve

[Charlie Wilson]

About a decade late but the correct spelling is Dumblelator not Dumbleator.
CW

[martin manning]

...not Dumbleator. :D

Good name for a beer, though ;^)

[mlynn02]

i recently built a lator and used this transformer:

https://www.hammfg.com/part/262F6

i followed the AA electronic schematic exactly and it works great using this xformer, 120V primary USA. it was cheap and available from digikey.

[caesparza]

Hi guys,

Recently I bought a Heathkit Electronic Crossover XO-1 that uses a couple of 12AX7 tubes. My idea is to build a dumbleator on it.

I was wondering if it could be possible to use the extra tube to add a switchable overdrive stage within the loop. I'm planning on using the unit with a Wonderland Build I just finnish and as you know, that is a clean amp.

It would be something like Input ---> Dumbleator Drive Tube ----> Switchable Gain Stages (2) ----> Dumbleator Recovery ----> Output

I just mixed a couple of diagrams I found, you can check it in the attached image.

Dumbleator + OD.jpg

It that OD addition is not a possibility, any suggestions on how to use the second 12AX7 (maybe an independent boost to the front of the amp?).

All the best.
CE

[GAStan]

Stereo Dumblelator?

[caesparza]

I'm currently building the one I posted. Not interested that much on the Stereo version (probably sounds great, but overdrive is on a higher ranking among the desirable things I want to add to the amp), thanks for the suggestion anyway.

Will report the results.

[M Fowler]

A Dumblelater makes every pedal sound incredible.

Mark