My AB763 will be Dumble-ized soon... a few questions

[tsl602000]

Hi,
After succesfully converting my Ceriatone Express to a "Astroid" with Express power amp it's now time to Dumble-ize my DIY AB763 bassman.
I'm planning to use the Normster layout with Dogear tweaks, but I have a question regarding the power amp.
The AB763 circuit has a 70/70/22/22/22 B+ filter section. The layouts I see around here have one more 22uF cap.

Would it be ok to use the "stock" AB763 power amp section and just build a Dumble pre-amp?

Thanks,
Coen

[mlp-mx6]

You need:

Plate filter - the stacked 70uF in your amp, I'm guessing
Screen filter - 22uF
PI filter (V3) - 22uF
OD tube filter (V2) - 22uF
Clean tube filter (V1) - you don't have one, you need it

If your first two caps are not stacked, then you have all the filter spots you need - you may choose to mod the values.

[tsl602000]

Thanks for your reply!
The 70/70 are indeed stacked. I'll replace these with 100uF's.

[v00d00blues79]

I'm just starting to convert my AB763 to the 60's Dumble circuit with the 70's Dumble OD section. Should be an interesting experiment.

Andy

[jaysg]

Would it be ok to use the "stock" AB763 power amp section and just build a Dumble pre-amp?

Depends on where you draw the line between PA and pre. You want the PI and NFB values from the Dumble, not the Fender.

[Bob-I]

Hi,
After succesfully converting my Ceriatone Express to a "Astroid" with Express power amp it's now time to Dumble-ize my DIY AB763 bassman.
I'm planning to use the Normster layout with Dogear tweaks, but I have a question regarding the power amp.
The AB763 circuit has a 70/70/22/22/22 B+ filter section. The layouts I see around here have one more 22uF cap.

Would it be ok to use the "stock" AB763 power amp section and just build a Dumble pre-amp?

Thanks,
Coen

Yes You'll need one more 20uF cap. If you can't fit it in the dog house just put it inside the amp.

[heisthl]

Yeah there should be tons of room for almost anything you want to do. You can even have reverb and a loop and put all the controls on the front.

[tsl602000]

Yeah there should be tons of room for almost anything you want to do. You can even have reverb and a loop and put all the controls on the front.

Exactly. This is a custom chassis that's even bigger than the standard Fender chassis. I got all the room I need.
Anyway, parts are ordered.....