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|5/25/1999 11:37 PM|
||DeArmond Volume Pedal|
I recently picked up a DeArmond volume pedal, model 610. I noticed that it has two pots in it. One I know is for the normal volume +/- but what is the other for? Tone adjustment? The second is not actually hooked up to the pedal, but is part of the circuit. It also has gears attached, were those spares for the other pot???
thanks for any help!!
|5/26/1999 1:35 PM|
I don't know this model number, but whip off the back plate and answer the following questions:
1) Is there a capacitor ANYWHERE in sight?
If not, the second pot is volume related.
If yes, the second pot may be for tone. Some pedals have a forward/backward
mechanism for volume, and left-right
mechanism for tone.
2) Is there a mono or stereo output jack, and
if stereo, are all terminals used?
If it is a stereo jack and there are
several leads, the second pot maybe for a
second channel, panning, or some other two
input or two output arrangement. Even if
it isn't, you could MAKE it do that.
Note that some pedals come with a secondary pot to adjust the range of volume control, or the "taper" of the volume sweep - i.e., how much of a change in volume is created by pedal movement in different parts of the pedal's range of movement. An excellent use for this supplementary pot is to build a simple pre-amp into the pedal, stick a garden variety SPST footswitch under the foot platform (just like a wah-wah), and use the switch and extra pot to select between two different pre-amp gain settings. Depending on the design of the pre-amp, and supporting circuitry, the footswitch could select between a foot variable and preset (pot determined) volume, or between two different foot variable volumes, with gain of one preset, and the other variable with the pot.
There are a bazillion simple one op-amp or one transistor pre-amp circuits out there that have low noise, nice buffering capabilities, and run a long time off a 9v battery. Trust me, you'd like buffering because of what it does to your high end.
|5/27/1999 11:08 PM|
I opened it up and it has two caps in it. I messed with the pedal and slid it side to side. Low and behold a tone circuit. A little grase and she will be ready to go.
by the way your other ideas are fantastic.
|5/28/1999 9:34 AM|
Thanks for the feedback.
I've been listening to a lot of Danny Gatton lately (he ain't nicknamed "the humbler" for nothing), and he has/had a unique tone control on his Tele that allowed him to use it like a sort of wah. Perhaps, if you could find out more about the specifics of such a circuit, your side-to-side tone feature could emulate that. As well, since most passive tone controls are simply variable resistors (only 2 lugs needed) rather than voltage dividers (all 3 lugs used) there are many possibilities for modifying the taper of your tone pot to give different feels or rates of change. I have some information that would assist you in that area.
Finally, volume pedals are notorious for eating up tone unless they are well designed, buffered, etc. Typically they don't include any bypass switches, so whatever degradation of the signal they provide can never really be removed. There are ways of addressing this with the volume control (e.g., Fender-style compensating cap), but the tone control is a bit more problematic.
Here is a possible solution drawn to my attention by some Ampage readers.
Find the end/side of the tone pot that the wiper moves to at full treble. Gently pull up the tabs that retain the back of the pot covering the mechanisms inside. You will see an omega-shaped piece of conductive material inside. The pot-wiper touches this along its' path. As long as the pot wiper is in contact, there will always be a path from the signal to the tone cap to ground, set by the value of the pot. What you would like to be able to do is lift this connection so that the resistance becomes effectively infinite (i.e., open circuit), thus disengaging the tone cap from the circuit and permitting the full signal to pass without as much treble loss.
Clean the conductive material with some sort of alchohol so that it is good and dry. Then, carefully apply some nail polish or other lacquer to the last teeny bit of the conductive material so that when the wiper has moved to the full-treble side it is no longer in electrical contact with the conductive material (even though, by spring-like tension it is in physical contact).
Let dry well, and when you put everything back together, you will have a foot-operated tone control with a switchless "true bypass".
|5/28/1999 4:12 PM|
||Gatton's wah-like tone control|
As far as I know, the entire pickup circuit in Gatton's '50s (53?) Tele was stock. The key was the larger knobs with a heavier knurling that allowed the easy pinkie wah swells.
I've done this with my Strat (re-wired for bridge+neck volume, master tone, middle volume from top>bottom) and it works great.
|5/31/1999 10:45 PM|
||Re: DeArmond Volume Pedal|
Another great idea, but I think a can of tuner cleaner and lots of playing is in store for this thing. Your right it does suck the tone right up but now that I've found the tone adjustment it's alot more usable.
all your time!!
|6/1/1999 3:05 PM|
De nada mi amigo!
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