Dumble Standalone Preamp

[LeftyStrat]

Does anyone have any experience building a standalone preamp? Just wondering if I could build say an early gen preamp, a later high plate skyliner and run them into a single dumble-inspired power amp.

Obviously there would be differences, since the two preamps and power amp don't share any interaction in the power supply,

[Bear]

Just yesterday I had the flash of doing two clean pre's, one a classic, one a Skyliner, into a shared power amp, kinda like a Bassman head.

You might consider the Boogie Quad preamp for the idea of two different preamps each with their own overdrive section. That includes how people run them. A lot of guys tap the effects loop outs to go right into a power amp rather than going through the output stages in the preamp -- having the option of some sort of output driver like a cathode follower that is an option might be useful to get through a variety of situations.

[10thTx]

Does anyone have any experience building a standalone preamp?

Some of this may or may not be useful?

Geezer on EL34 World (Hoffman forum) built a D'Mars OD Special preamp that he runs into a power amp. It's a D-style inspired amp

http://www.el34world.com/Forum/index.ph ... #msg134491

And Doug Hoffman built a stereo preamp that he uses for recording. He has some schematic, layout and photos here:

http://www.el34world.com/projects/StereoPreAmp1.htm

With respect, 10thtx

[da Geezer]

Works great in my experience. I like the idea because you can run the same preamp into larger or smaller power amps (depending on the venue) and still have the same basic tone.
I built mine into a Valve Jr head box (because I had it & it wasn't much good for anything else!). Had the chassis bent at a local metal shop for ~$10, used the stock VJr PT and added a small 6v tranny for the relays.

Here's a clip I did of that preamp into a 2x 6AQ5 PA.....no changes were made to the amp controls during the whole recording, just channel switching & guitar volume/tone controls adjustments, and switching guitars (humbuckers to tele) halfway thru.

http://soundcloud.com/dageezer/dumars-noodles1-0

G

[M Fowler]

Ha I'm going to be the only guy with a stock Valve Jr head amp and your going to jealous

Very nice sounding Dumble-Marshall DaGeezer, sounds great.

Mark

[briane]

Dumble used to do this - called the phoenix.

I think 1 was sold - I dont think it was very popular - us designers want every tone - most guitarists want 'their tone' - no need for so much versatility if your buying the amps for business.

I keep saying if I keep building I am going to start doing this with my personal builds - with some good high quality cable and connectors you can also feed the B+ to the preamp - and thus not lose the interaction.

that said yes - I do it all the time - thats what I really see the benefit of send/return - just take your 20 amps or so and mix and match pre and post as you want - DONE - no building required.

[Colossal]

http://soundcloud.com/dageezer/dumars-noodles1-0

4:12 to end is the '87 Telecaster w/ Bill Lawrence pickups

Great tone!

[Structo]

Nice tone and playing Jeff.

I liked the New Skyline and Skyline clip, nice Allman Bros flavor on that one.

But this is my favorite.

http://soundcloud.com/dageezer/bluesmaster-non-hrm-demo

[LeftyStrat]

Works great in my experience. I like the idea because you can run the same preamp into larger or smaller power amps (depending on the venue) and still have the same basic tone.
I built mine into a Valve Jr head box (because I had it & it wasn't much good for anything else!). Had the chassis bent at a local metal shop for ~$10, used the stock VJr PT and added a small 6v tranny for the relays.

Here's a clip I did of that preamp into a 2x 6AQ5 PA.....no changes were made to the amp controls during the whole recording, just channel switching & guitar volume/tone controls adjustments, and switching guitars (humbuckers to tele) halfway thru.

http://soundcloud.com/dageezer/dumars-noodles1-0

G

Great clips. Is yours based on just two 12ax7's, or do you use a third stage like a Dumbleator send?

[10thTx]

I believe this is what DaGeezer used.

with respect, 10thtx

[ATL Strat]

Bludotone recently sold a prototype of a stand alone preamp on ebay.

[roberto]

Hi,

I use this old thread because it's the argument of my question: is there on the market (or a gerber file as well) a pcb for the Dumble preamp only?

Thanks

[martin manning]

With all the interest in preamps for working with DAW's these days, I would imagine so. I recall a couple of builds posted here (one with a few source follower output, iirc), and there are already some tube pedals on the market (Kingsley, e.g.). What is your thought, a rack unit?

[roberto]

Hi Martin, thanks for your prompt reply.

I've built two poweramps to be fitted in standard head amps (no rack) and I would add two dumble-like preamps to them.
I've seen those circuits with IRF820 mosfet source followers, but I would like to stick on original all tube preamps where the signal has alot of swing (so it could be ok as last stage, like a fx send.

I've seen this project: https://github.com/tristancollins/amps/ ... tar-Preamp
but needs further work to become a Dumble.