Dumble modified Fender Vibrolux Reverb

[wokkel]

https://reverb.com/item/68691026-dumble ... ring-49502

Belonged to Dennis Herris


DUMBLE MODS:

The Vibrato Channel 2 Input is now a 6-position stepped rotary knob presence/frequency control
The Vibrato Channel Volume is now a push-pull Overdrive Engage and Preamp Control. (Rotate knob for more or less distortion)
The Vibrato "Intensity" knob is now a Master Volume.
The Vibrato "Intensity" control has now been re-located to the back panel of the amp.
Reverb control is disengaged in favor of the preamp/master volume circuit.

[bepone]

nothing special inside, few dralorics and one el.cap in nfb, where is HADs work?

[Charlie Wilson]

DUMBLE MODS:

The Vibrato Channel 2 Input is now a 6-position stepped rotary knob presence/frequency control
The Vibrato Channel Volume is now a push-pull Overdrive Engage and Preamp Control. (Rotate knob for more or less distortion)
The Vibrato "Intensity" knob is now a Master Volume.
The Vibrato "Intensity" control has now been re-located to the back panel of the amp.
Reverb control is disengaged in favor of the preamp/master volume circuit.

[bepone]

yes i read, still nothing, + reverb part was the best part.

[WhopperPlate]

yes i read, still nothing, + reverb part was the best part.

If bepone modifies my amp , but doesn’t install new parts, does that mean bepone didn’t mod my amp?

…that shielded cable looks familiar…rotary switch assembly looks clean …

[WhopperPlate]

Looks like a type 3 Ken fisher master volume

IMG_2785.png

IMG_2806.jpeg

[bepone]

yes i read, still nothing, + reverb part was the best part.

If bepone modifies my amp , but doesn’t install new parts, does that mean bepone didn’t mod my amp?

…that shielded cable looks familiar…rotary switch assembly looks clean …

i was speaking that there is no value for listed price...maybe is if divided by 20-ish IMO

[WhopperPlate]

yes i read, still nothing, + reverb part was the best part.

If bepone modifies my amp , but doesn’t install new parts, does that mean bepone didn’t mod my amp?

…that shielded cable looks familiar…rotary switch assembly looks clean …

i was speaking that there is no value for listed price...maybe is if divided by 20-ish IMO

At this point …if Dumble touched it then its value is justified … whether we like it or not

[erwin_ve]

A vid of this amp emerged; interesting feature IMO is the rotary knob for the OD channel where sustain/feedback is adjustable! From 2.05-4.07.
Since we have a gut shot Im trying to figure out what is going on with the green wire at the OD entrance and that particular rotary switch..
Someone got a idea?

[Smitty]

It looks like Reverb took down the listing. One can usually see old 'sold' listings. Not in this case.

[bepone]

something is wrong with the sound on the video.. it is getting drops in volume, so i couldnt listen this bug for long time.

but it seeems that on the selector are different values of capacitors, probably coupling caps between the stages.. probably lower value is taken to not to cut buss so much, and on the other end it is adding more and more and more, which is not affected later in circuit like adding bass, it is like adding sustain only. probably bass is cut before PI with 500pf/1nF PI input capacitor

i will try one time a if is like this and see how it behaves

[Reeltarded]

A vid of this amp emerged; interesting feature IMO is the rotary knob for the OD channel where sustain/feedback is adjustable! From 2.05-4.07.
Since we have a gut shot Im trying to figure out what is going on with the green wire at the OD entrance and that particular rotary switch..
Someone got a idea?

Capacitive divider is rotary. i say. Looks like pairs? I think.

They seem really excited about it. lol

Aha. Erwin, draw the front panel control layout and look at the PP switch on Vib Volume plus the Reverb control.

[erwin_ve]

A vid of this amp emerged; interesting feature IMO is the rotary knob for the OD channel where sustain/feedback is adjustable! From 2.05-4.07.
Since we have a gut shot Im trying to figure out what is going on with the green wire at the OD entrance and that particular rotary switch..
Someone got a idea?

Capacitive divider is rotary. i say. Looks like pairs? I think.

They seem really excited about it. lol

Aha. Erwin, draw the front panel control layout and look at the PP switch on Vib Volume plus the Reverb control.

Reverb control is disengaged in favor of the preamp/master volume circuit.
Pp is to Engage the drive circuit. The rotary is close to the bright switch where no cap is visible on the pic.
I'm not familiar with the vibrolux at all, what do you mean with capacitive divider?

[Reeltarded]

?

A capacitive divider is the 6 pos switch. I am almost positive. It is on the signal side of the circuit with no DC to block at this point. I have provided a link with full description of splitting AC with caps.

2 poles, 6 positions. I count 7 caps. The largest brown cap (at left side) is bridged all positions on A (signal) side of switch.

https://www.electronics-tutorials.ws/ca ... vider.html

IMG_7921.gif

[Reeltarded]

Shit. That's tiny but readable.