What does the dumbleator do to sound?

[Tdale]

I see that some have either built in or external dumbleator, that they use without any effects used. In what way does the dumbleator affect tone?

Isn't it basically just a second gain stage, more or less?

Tommy

[Harris]

I'm gonna bump and hijack your post. Sorry about the hijacking part. However, I think the answer to your question is that it doesn't/shouldn't effect tone at all. It only provides a buffer in between the preamp, the effects, and the power amp. I suspect, although I don't know, that there are some effects that you can use without a dumbleator and some you can't. Can anyone shed light on the effects loop and use of dumbleator?

[dogears]

Actually it does change the tone in a very noticeable way. I have an exact Dumbleator circuit built into my amp. There is a switch to bypass it if I want. Ignoring the obvious tone difference of the speaker phase changing as it is switched in and out, the Dumbleator is a preamp gain stage. It uses 20M of local feedback on the recovery amp. Basically a 70's Dumble V1b if you will. The effect is that the tone is a tad smoother and not as bright as bypassed. There is a slight effect on the bass as well. The tone may be a tad thicker with the Dumbleator engaged.

As for uses:

1) Series Loop
2) Extra gain stage (capable of lots more gain when cranked)
3) In my case, it is also where I send and return the amps built in tube reverb
4) the smoothing effect of just being in the circuit at parity gain

Hope this helps.

[jelle]

Hi Dogears,

How do you use the dumbleator send and return to drive the reverb?
Do you use the one tube reverb with the one tube ( of course) Dumbleator?

Thanks,
Jelle

jwelagen (at) hotmail.com

[dogears]

Standard 2 tube Fender style. Send from the cathode of the Dumbleator and returned to the grid. Carefully selected reverb mix resistor on the grid and special pot value and wiring scheme as to not load the circuit in a noticeable way.

Hi Dogears,

How do you use the dumbleator send and return to drive the reverb?
Do you use the one tube reverb with the one tube ( of course) Dumbleator?

Thanks,
Jelle

jwelagen (at) hotmail.com

[ODwan]

I've hacked the Dumbleator into SPICE simulating software and run a freq response. Guess what?! It boosts the lows!
Timo

[Darkbluemurder]

Timo,

I suppose the dotted curve is the one with the D-lator, right?

DBM

[llemtt]

no the d-lator is the solid line! (the dotted line is the phase angle)

I went to the same results years ago, you can still get it from my site:

http://www.m-elli.it/dumbleator_freq_resp.pdf

teo

[HiGain]

I've hacked the Dumbleator into SPICE simulating software and run a freq response. Guess what?! It boosts the lows!
Timo

Does anyone have a gif or jpeg image of this file? Thanks,
Jake

[llemtt]

here is a poor quality gif

http://www.m-elli.it/dumbleator_freq_resp.gif

[HiGain]

Thanks!!!

Jake