ODS #004 For Sale

[martin manning]

Is that starve resistor a 12Meg????

Sure looks like it to me. Wonder if that's supposed to be 1.2M and we're just not seeing the dot.

As it was written / drawn in Europe odds on that it would have been noted at 1M2 if it was a 1.2meg resistor.

I have waded thru European schematics for years. (27 years with a Dutch semiconductor equipment maker).

They like to place the multiplier at the decimal point position (which makes total sense!!).

But note in other cases the scribe used a decimal point. Gotta be 12M.

[crbowman]

Is it just me, or does the Rock/Jazz switch wiring look a little weird?
I'm counting a total of 8 contact points there.
Definitely appears different from 2nd Gen hookup.

[David Root]

Also the PI entrance cap is not specified, for some reason. Anyone know what it is and/or what it was originally? The output caps are 0.1uF so maybe PI entrance is <0.02 uF?

[ElectronAvalanche]

Hi Gary,

as said, the Starve switch really reduced the overall volume quite drastically. So I guess Dumble dropped this feature due to that.


Cheers,

Electron

It would also appear that if Lindley's amp had a starve switch he liked it and used it.. both circled in the up position

Tony

I talked to David today and was asking about the starve switch. He said the ODS's he owned / owns did not have the starve switch installed. But he knew of the mod and he does have a Dumble modded bassman that has the starve switch.

Ok here is the history on the starve switch according to Mr. Dave. Dumble had a fender bassman on his bench that he was working on, the amp had a problem and did not make enough power, but the tone was "incredible" according to David. Turned out to be a bad tube socket (maybe carbon arc or something along those lines) and that supposedly is where the mod originated.

More Dumble Myth and Lore ............

[marcos]

Also the PI entrance cap is not specified, for some reason. Anyone know what it is and/or what it was originally? The output caps are 0.1uF so maybe PI entrance is <0.02 uF?

Hi David,
I never noticed that. The 2nd generation amps had .005 µF,
but I remember a post by Brandon a long time ago where he specified
.001 µF for a seventies amp. Maybe Tony knows?

Marcos

[jelle]

I have done this one a while ago. It is quite gainy.

[talbany]

Also the PI entrance cap is not specified, for some reason. Anyone know what it is and/or what it was originally? The output caps are 0.1uF so maybe PI entrance is <0.02 uF?

Hi David,
I never noticed that. The 2nd generation amps had .005 µF,
but I remember a post by Brandon a long time ago where he specified
.001 µF for a seventies amp. Maybe Tony knows?

Marcos

Marcos
My info has .005 same as in the 70's Overdrive Deluxe !!
Hope this helps!!..BTW Same era brown caps..CDE's..


Tony

[crbowman]

I have done this one a while ago. It is quite gainy.

Please tell us more Jelle!
What other impressions did you have?

[David Root]

.005 does not surprise me. Jelle, loosen up, eh!

[marcos]

I have done this one a while ago. It is quite gainy.

Jelle, I am curious too.I always suspected that with the 100k/100k
voltage divider at the OD entrance you would get massive overdrive
at V2a, unlike all the other Dumbles. Also, how does the OD level pot react?
It would be great if you could comment

Marcos

[Aaron]

Wow, thanks Marcos!!!!!

Now I know what to spend my tax return on, building a #004 clone (don't tell the wife)

[glasman]

While exploring the world of old Dumbles...

Here is another one that I have in my archive of stuff. Not sure if this truly a Dumble schematic, but some of the aspects are there.

It has an interesting sided chained effects loop that when used is mixed in parallel with the overdrive section.

Source : totally unknown.....


Gary

[FUCHSAUDIO]

Uh, that source was originally me...lol. This stuff just runs around the interweb don't it ?

It was handed to me by the HAO pedal guy at a NAMM show. He was fawning over my amps saying "greatest Dumble style tone", and said "maybe you would like this....I drew this myself " and gave it to me. Never saw another amp even close to this diagram. Strange stuff indeed. Nicely drawn though.....

[two tone]

low voltages,around 145v on v1 plates,
~ 175v for v2,
3k9-33k-10k string

[crbowman]

Yep, sounds about right. Also no reference at all to bias circuit.
Still, this is VERY cool!
Thank you Marcos!

Also, what's up with the switchable 68K and the dotted line in FET circuit?
Haven't seen that one yet.

Gotta try the parallel effects loop at some point also. The old passive loop on these things without the Dumbleator leaves a bit to be desired.