Dumble 150w

[dr. who]

There is a signal path diagram of this amplifier on page 730 of the 4th edition of "The Tube Amp Book" by Aspen Pittman.’ does anyone have this book? Can anyone please post? Thank you.

[odourboy]

Here you go:

[dr. who]

Thanks...
Does anyone have the interior shots of this one? I am interested in the od section in particular. All info appreciated.

[Funkalicousgroove]

That amp uses a 7247 (12DW7) for the OD which is a Hi-Mu triode on the A side, and a Med-Mu triode on the B side.

My guess is that he used the "B side" first, The "Trigger" control is the same as the internal gain trimmer, just on the outside (Probably 250K concentric pot) of course Level and ratio are standard, and the HF taper is off the output of the level control, and is a 250K pot wired as a VR, with .001uf to ground.

I'd also speculate that the Concentric pots are 250K Audio, and made for guitar.

you'll have a heck of a time finding the concentric pots in anything other than 250 and 500K (Sometimes in 10K)


That's my ejemukatid guess.

[dr. who]

so is it a SSS with od?

[Funkalicousgroove]

Far from it.

It is just a big ol ODS with reverb and trem.

[Max]

Here are some nice pics of this amp:

http://www.ten-guitars.de/gallery.php?g=29&si=3

[tele_player]

you'll have a heck of a time finding the concentric pots in anything other than 250 and 500K (Sometimes in 10K)

DigiKey lists Alpha concentric pots in quite an assortment, both audio and linear taper. The 1M dual Alpha is used for master volume in Allen amps, at least the two that I have.

[odourboy]

Here are some nice pics of this amp:

http://www.ten-guitars.de/gallery.php?g=29&si=3

Wow! Has that one ever been nicely dolled up. I really dig the footswitch!

[jackdc100]

OK, a silly question. If there is a circuit diagram in a mass-published book then why is there such mystery about what is "under the goop" in these amps and why is everyone so interested in taking apart real dumbles? In addition, wouldn't HAD himself have a problem with this schematic being published? I must admit that I am not an amp builder, so there might be a really obvious answer to these questions.

[dave g]

It's not a schematic. It's just an extremely generalized black box flowchart, basically. You can't clone an amp from a sheet of paper that has a box labeled "OD Process" on it.

[jackdc100]

It's not a schematic. It's just an extremely generalized black box flowchart, basically. You can't clone an amp from a sheet of paper that has a box labeled "OD Process" on it.

OK gotcha. Where do you guys get the schematics for D-style amps then?

[heisthl]

OK gotcha. Where do you guys get the schematics for D-style amps then?

Hi - you must be new to the forum - If you are serious about building one please start by reading this forum beginning to end - your questions are answered within...Welcome aboard

to jackdc100: I'm not picking on you and I don't mean to be a smartass with this canned response but seriously this is just another example of something that has been covered many times and it's getting to the point that a lot of bandwidth is being wasted on reiteration.