Dunlop Rotovibe Mod?

Started by sevenisthenumber, June 06, 2008, 11:57:16 PM

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sevenisthenumber

Can anyone tell me how to mod the Rotovibe (red wah type pedal) to have a little more volume when engaged? Maybe even a volume knob on the side would be cool.

petemoore

  Hardwire [on always] a modest boost circuit inside the BPSwitch, at the output of the vibe circuit?..stick a volume control on it.
  A non-board-installation method may be possible, wait around to see if a Roto-master responds, or put up a schematic.
Convention creates following, following creates convention.

sevenisthenumber

we can always use a good roto-master! thanks.

sevenisthenumber

Burst into song, "where have all the (rotomasters) gone? !

The Tone God

Awhile back someone said they were going to trace a roto. Never happened. I have been thinking of tracing mine but I don't have much free time these days and the board is fairly complicated. It will get done sometime.

Andrew

drewl

I got another one to fix this week, anyway...I have one that I put a cap somewhere which really boosted it's output when it's on, I'll check it out when I get home and post the mod.

bside2234

Quote from: drewl on August 04, 2008, 09:30:21 AM
I got another one to fix this week, anyway...I have one that I put a cap somewhere which really boosted it's output when it's on, I'll check it out when I get home and post the mod.

It takes you over 2 months to get home? I am interested in this. I am just starting to play around in mine.

skiraly017

I wish Clay would shed some light on this. I've asked him but...  :icon_confused:
"Why do things that happen to stupid people keep happening to me?" - Homer Simpson

drewl

Quote from: bside2234 on October 21, 2008, 03:16:50 PM
Quote from: drewl on August 04, 2008, 09:30:21 AM
I got another one to fix this week, anyway...I have one that I put a cap somewhere which really boosted it's output when it's on, I'll check it out when I get home and post the mod.

It takes you over 2 months to get home? I am interested in this. I am just starting to play around in mine.

---Sorry......I thought everyone lost interest....I'll try to remember this time.

drewl

I found a schem for this thing, I gotta figure out how to attatch it.


Rodgre

I have one that wasn't working and then suddenly decided it was working. When I contacted Dunlop about a service manual or sending it in for repair, they said that the version I have is an old revision that they no longer serviced.

What that means is that there might be a couple of versions of the circuit out there.

Roger

bside2234

Quote from: Rodgre on October 22, 2008, 01:29:44 PM
I have one that wasn't working and then suddenly decided it was working. When I contacted Dunlop about a service manual or sending it in for repair, they said that the version I have is an old revision that they no longer serviced.

What that means is that there might be a couple of versions of the circuit out there.

Roger

I've seen at least 3 different versions.

Drewl: I sent you a PM.

drewl

3? I thought only 2 versions.
Anyway, I sent ya the schem, normally I'd be able to attatch it, but my puter's got some "issues"......

bside2234

Well,  I've seen 2 boards that are for sure different and I have seen 3 boards with different LDR's. I can't remember if the third board was very different.

Thank you for the schematic. I will post it if you want me to.

skiraly017

If not postable I would be most appreciative if someone could email it to me. Thanks.
"Why do things that happen to stupid people keep happening to me?" - Homer Simpson

bside2234

I don't know how everyone feels about posting schematics but here it is. Remove it if you want. I will email it to anyone who wants it.


evening

I am also on the quest for a boosted rotovibe mod.
Has anyone made any progress on this?

I looked that the schem.  and my thought was to swap R21 for a larger value, since it seems to set the gain in the final output.
But I have a rev D board which differs from the posted schematic, and has TL074N instead of TL062, and different part designations.






RickL

R43 and R44 form a voltage divider with the output taken from their junction. They could be replaced with a 5k pot or trimmer which would act as a volume control.

evening

Thanks - I'll give that a try.

Joe Hart

Replace both resistors with pots or a dual-ganged pot or or just R44 (larger value here would mean more output volume?)?
-Joe Hart