Dearmond Rhythm Chief 1100

[belwar]

The volume read 1.125MOhm
The tone read 337.4KOhm

So likely 1m and 300k.

[pedrometer]

volume tone values

Hi,
Thanks for the information. It is very kind of you. I will post the circuit when I've drawn it out after I know it all works.
Cheers
Peter

[Sweetfinger]

I've got a couple of the vol/tone housings laying about- both measure about 280K for the tone pots and 1M(and change) for the volume. A slightly worn 250K could read from 280 up to 350K.

There are two different Manufacturers of pots represented. The first housing has: Tone R - 20 1376025, Vol R - 15 1376047. Safe to say this housing is from 1960 w/CTS pots. The cap is a yellow cylindrical film type. Writing is rubbed off

The second housing has: Tone R - 20 235632, Vol R - 15 1377225. This one has had the vol changed at some point. The 235 prefix pot (Mallory?) is physically smaller at 1/2 " diameter. The cap is a .1 100V IFC? green chiclet.

I'm guessing that R-15 and R-20 were house numbers that Rowe had stamped onto the pots no matter who the manufacturer was. The 235 pot is likely from '66.

Hey, hope someone who cares finds this info useful.

....and I'm guessing that the batter recipe from Art's is HAND mixed?
couldn't resist - I KEEED!

[David Schwab]

A slightly worn 250K could read from 280 up to 350K.

Doesn't even matter if it's worn. It's within the rated tolerance. They never read what their value is.

[Corianman]

DeArmond contol box

Peter did you ever get the circuit drawn and working?

[pedrometer]

Hi Corianman,
no, my computer lost it's mind... I lost all my passwords and programms etc so it has taken months to get back on line. I am on the case now and will post something soon.

Cheers
Peter

[TheEHMan]

Any better gut shots of the module?

[pedrometer]

Hi Corianman, Not Yet. My pots need changing and I'm having trouble finding the time to source the right types. But any day soon.
Cheers
Peter

[pedrometer]

Hi TheEHMan,
I have yet to put the whole thing back together on account of the fact that the pots need changing and I don't seem to have the time.

Regards
Peter

[rjb]

Only a year late...

Here's my version of the schematic; use at your own risk.

It's based on my reading of the discussion in this thread, plus photos from this one:
http://music-electronics-forum.com/t15107/

I'm building a slightly modified version of the circuit, with the components mounted directly on a plastic archtop guitar pickguard- I guess you could call it a control box without the box.

Also want to mention, you-all might be interested in this site I ran across- lot's of info on DeArmond pickups:
http://www.musicpickups.com/Home.html


Here's a fer instance:

The rhythm switch acts as a filter, eliminating low frequency reproduction and permits the playing of rhythm without the usual masking effect. In order that the rhythm switch may operate most effectively, the tone control must be in the treble position.

[marku52]

how bout RDC, L, Fres, and Q before you take anything apart? B at pole pieces is also cool.

[belwar]

I posted all of that information in another thread.

[bob p]

Here's my version of the schematic; use at your own risk.

It's based on my reading of the discussion in this thread, plus photos from this one:
http://music-electronics-forum.com/t15107/

I'm building a slightly modified version of the circuit, with the components mounted directly on a plastic archtop guitar pickguard- I guess you could call it a control box without the box.

Also want to mention, you-all might be interested in this site I ran across- lot's of info on DeArmond pickups:
http://www.musicpickups.com/Home.html


Here's a fer instance:

I'm very interested in this, as I'm thinking about putting one of the new DeArmond 1100 reproductions on an archtop. Unfortunately Guild sells reproduction pickups but not the controller box, and try as I might I can't find a schematic -- when it comes to the electronics side of things there's a big gaping hole out there.


Sadly, your schematic seems to have been lost. Can you re-post it?

[rjb]

Sadly, your schematic seems to have been lost. Can you re-post it?

I'm not sure if I've still got a copy, but don't think it would be of much value anyway.

I abandoned the circuit for one closer to G&L's S-500, which worked better for my guitar and pickup.
http://music-electronics-forum.com/a...patrician-.jpg
The pickup connects where the "output" of SW2 is shown in the wiring diagram.
C3 is optional - it just "takes a little off the top" of a trebly pickup.
For a DeArmond style "rhythm switch", replace VR1 with a latching pushbutton.
According to this discussion, it appears I used 1.5nF instead of 2.2nF for C1, and added an unswitched 4.7nF in series to prevent low note "farty distortion" and feedback.
http://music-electronics-forum.com/t31838/#post292985

If you want a "historically accurate" RC control box, I think Dave Schwab's sketch is pretty accurate.
(Not shown, the pickup would connect to the wiper of the volume control.)
http://music-electronics-forum.com/t31838/#post293011
You may note that (with different component values) the Rhythm Chief circuit is the S-500 circuit "flipped around"; if you hooked up the pickup to the output of the S-500 circuit, and took the output at the pickup selector switch, you would have a Rhythm Chief circuit.

EDIT: IGNORE THIS PARAGRAPH
I'm not 100% sure about this- but my interpretation of these photos was that to build a "really, really accurate" R.C. control box reproduction, you would not only "flip the S-500 circuit around" but also swap positions of tone control components VR3 and C4. (The output would then be tapped at the junction of bass block cap C1 and treble rolloff cap C4.)
http://music-electronics-forum.com/t15107/#post120793

Well, that's the schematic in words, more or less. But as I said, you probably don't want to do it that way anyways.

-rb

[bob p]

I'm looking for the original circuit. If you have a proper schematic I would appreciate seeing it. As they say, a picture is worth 1000 words. The whole idea behind schematics to to de-mystify paragraphs of writing and remove any ambiguity about what is being said.

I haven't seen David's schematic. so far the only thing I've found on the jazz guitar sites is this layout diagram that looks like it was drawn by an end user. It certainly doesn't look like it was drawn by anyone with an electronics background. I'm not sure if that thing at the top is supposed to be a switch or the signal input. It's probably an end user's idea of what a switch looks like, and if that's the case then there's no signal input on the diagram. The sketches of the 2-tap pots aren't particularly clear either. That sketch should have been drawn with a crayon.