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| 1966 DeArmond Rhythm Chief Model 1100 Gold |
About
The DeArmond Rhythm Chief is one of the most esteemed acoustic pickups from the 20th century, they found their way onto numerous Gibson, D'Angelico, Epiphone, and even Kay and Harmony guitars. According to the catalog scans on www.MusicPickups.com, they first appeared in the 1950s and were produced, at least, until the late 1970s. DeArmond produced pickups until 1985 and years ago I worked on a Rhythm Chief that had pots dating to 1982, but failed to document it so take that as you will.
Despite the popularity of these pickups, its surprisingly difficult to find information about how the internals are wired and, you'll find, that few people have identical answers. In my initial research, I was unable to find a diagram that matched the Rhythm Chief I was working on. Driftwood Music in St Charles, Missouri presented me with an incredible opportunity when I was handed a box of four dead DeArmonds and asked to rewind them.
Guild produces a reissue which drops the control unit box and mounts via a bar that is screwed into the side of the fingerboard instead of the monkey-on-a-stick. Their pickups are also wound to 6k which is standard for a single coil but is mostly inaccurate for a Rhythm Chief replica. There is also an individual on Reverb who sells 3D printed replicas for the archtop mounting stick, they are of a fair quality and a great find if you don't have an original.
Common Problems
If your DeArmond pickup is reading 'open' and/or produces no sound, there are a couple suspects that find their way back again and again.- The lead wire has shorted out.
The lead wire from the pickup to the control unit is multilayered with a center 'hot' wire and a stranded 'ground' wire wrapped around it with only a layer or rubber insulation keeping them apart. The rubber becomes stiff, crumbles, and suddenly your hot and ground are touching and now you are without sound.
The only solution is to replace the lead wire which will require careful disassembly of the pickup and control unit. It is very important to use a hair dryer to warm the pickup before attempting to remove the cover. If possible, leave the decorative faceplate attached because it protects the coil. Soldering the leads to the pickup wire is not for the faint of heart.
Update 5/13/2024: Mojotone long since discontinued their replica DeArmond wire.
This looks promising as a replacement
- The capacitors have failed
As sometimes happens with vintage electronics, certain types of capacitors are more prone to failure from age and degradation. This can be the reason behind the 'rhythm' switch silencing the pickup or the tone pot acting like a volume pot as it shunts the signal to ground. I found paper-in-oil capacitors in all of the units I worked on and they are easily identifiably by their waxy coating. I opted to replace them all at once since failure is inevitable and there is no mystical tone benefits from the composition of these caps.
If you have the ability to test a working capacitor, you can get its true reading and order a replacement to match. These have a tendency to drift unpredictably away from their labelled spec. But a dead capacitor is a dead capacitor, if it doesn't work just buy another one that matches.
Treat it like a 'cap job' on a vintage amplifier, its routine servicing.
- The coil is damaged
A damaged coil is one of the most disappointing realizations as you do lose value when selling a 'rewound' pickup and the sound may not be exactly the same. This can occur if corrosion finds its way into the pickup or you don't heat the pickup before disassembly, ask me how I know. If there is a visible break, you can remove winds until you reach that break, test for continuity, and repair or make that the new end wire. But sometimes a full rewind is the only solution.
- Scratchy sounding pots
This is an easy fix about 90% of the time. I use DeOxit contact cleaner and liberally spray into the potentiometer and then repeatedly turn it back and forth until the scratching disappears. This is usually attributed to dust that has gotten into the unit and the contact cleaner helps to dislodge the debris but oxidation can be a real concern too.
Wiring Diagrams
As I noted above, few people seem to say "hey that's how my Rhythm Chief is wired" and it appears that they were constantly changing the design, capacitor values, and potentiometer values. This makes it difficult to state that there is a definitive Rhythm Chief wiring schematic.
I've documented each of the pickups that I have worked on and included their wiring diagrams below so that you can find a schematic that most closely matches what you are looking for. I am not an electronics engineer, I just fix guitars, so these diagrams are a combination of looking up some basic symbols and drawing to match what the control unit looks like with the backplate removed.
Also as a resource for DeArmond pickups, I'd highly recommend https://www.musicpickups.com/
1960
Model: 1000
Coil Reading: 15.8k
The capacitor denoted by a star was a different style and composition than the CRL capacitor, its possibly a later replacement. Also I know now that its Leviton and not Levitron, oh well.
1962
Model: 1000
Coil Reading: ~dead~
1967
Model: 1100
Coil Reading: 14.42k
19??
Model: 1000
Coil Reading: 7.3k
This schematic was not functioning properly before and after replacing the capacitors so I rewired it according to the 1962 specs.
I have the opportunity to a DeArmond-Rowe #1100 that's in time capsule condition never used still in the box everything original. I think it's worth spending the money to get it!!!!!!
ReplyDeleteIt definitely could be! Those time capsule finds are always incredible
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