The Steel Guitar Forum

Fender did use 1 meg pots. Pretty sure that's what's in the Deluxe 8 I just sold. And that pot appears to have been purposefully loosened up to make Boo Wha easier.
Danny Gatton used them on his Tele's to get the "Wah" sound. I put it on one of mine, which now has a Lapdancer squareneck conversion on it, and it definitely works, if your signal is hot enough. But for a steel circuit, electronically, it was different. On the Tele mod, you get the full sweep of the tone in 1/4 turn of the pot, as Fender used 250K pots for Tone.

Well, John, that's fine for Fender. I need to know what the proper tone pot value would be for the Magnatone I have. In my search for the tone pot info, it looks like I jumped to the conclusion that it would be the 1 meg linear, but like I said, I came-up with the Fender info, instead of Magnatone info. Did I wrongly look at that and think the 1 meg. pot can be used on ALL guitars? So, I'm still confused!

Butch, I'd measure the good one. That way you'll be certain. If you don't have a VOM, get a cheap one. They're handy!
http://www.radioshack.com/family/index. ... Id=2032305

I've got a meter. But, I need to know how to use it to check the tone pot?

Butch Pytko wrote:I've got a meter. But, I need to know how to use it to check the tone pot?

With the pot disconnected you can measure resistance across the 2 outside lugs. To get an idea of the taper, set the knob / shaft to the middle of its travel and measure outside lug to center. If its around 1/2 the reading that you got from the outer lugs, its most likely a linear taper.

Tom, when you say "with the pot disconnected", do you mean removing the wires from all of the terminals? And, the 2 ways of measuring--would I have the meter mode switch on RESISTANCE?

Yup.

My confusion gets greater! I followed Tom's directions, removed the wires from the pot, and first measured the RESISTANCE of the 2 outside lugs, which was: 265K. Then, with the shaft set at about half of it's travel, I got 243K from one outside lug to center and 250K from the other outside lug to center. Must not be a linear taper. I wish someone that has done this on a Magnatone would come forward with the necessary information, I'd deeply appreciate it!

Butch,
What you have is a "250K" audio taper pot.
The resistance you measured, 265K, in within the
tolerance range.

Blake

Yup.

OK, it's an audio taper pot. I'm trying to understand what's going on here. Is this Magnatone's design to use a 250K audio taper with a .02 cap as the tone pot or did someone put the wrong pot on? All 4 pots look identical and they have the same numbers on them. I'm looking at Peter's 53 Magnatone wiring diagram--what is a TBX pot? And, it doesn't have a .02 cap like the one on my guitar.

Butch Pytko wrote:My confusion gets greater! I followed Tom's directions, removed the wires from the pot, and first measured the RESISTANCE of the 2 outside lugs, which was: 265K. Then, with the shaft set at about half of it's travel, I got 243K from one outside lug to center and 250K from the other outside lug to center. Must not be a linear taper. I wish someone that has done this on a Magnatone would come forward with the necessary information, I'd deeply appreciate it!

Something is wrong with your measurement... your measurements of each leg to middle should add up to your measurements across the outside.

At these resistances your fingers can affect the reading... don't hold your fingers on the metal you're measuring (at least not on *both*).

If you have a 250K linear pot, you should measure about 125K from middle to each outside leg (half-travel). Anything radically different from this would indicate an audio-taper pot. Linear pots are normally used for tone controls, IIRC.

You might try contacting some of these guys;

http://steelguitarforum.com/Forum2/HTML/005707.html

Peter's wiring diagram might be for a Maggie Typhoon which is a regular guitar. That is the only one I've seen photos of that has more than 2 pickups.I have a Lyric and going by the pots it is a '52. Clarostat Mfg is the maker and they are marked 500k,they are also solid shafts. I'm thinking there might have been some inconsistency in the parts dept. at Magnatone.

I took new readings without touching the terminals with my fingers and got 270 on the outside lugs, 247 on one center to outside, and 23.0 on the other center to outside lug. I probably got a decimal point reading before, but my meter has a very small LCD screen and overlooked the decimal point. Anyway, what does that small number of 23.0 mean? That would be way less than half of the outside lugs reading.

It is an audio taper pot. 23 + 247 = 270.
As Stephen pointed out.

I agree that Magnetone used "parts on hand" for their various guitars. Unless you can find some
factory diagrams, just look at what you have and if
the solder joints and the wiring appeears undisturbed
it is probably original.
Soldering to the back of the pots is a common practice in guitar wiring.
You can use either an audio taper or linear for a tone control. Just depends on the effect you want.
The audio taper will give you a better "boo-wah" effect. The linear will let you set finer variations.

OK, then reasoning this-out, Magnatone may have or purposely used the 250K audio taper pot for the tone pot, right? If that's the case, then I've decided to replace this tone pot with a 250K audio pot. On this tone pot that has the broken stem, it looks to me that someone did mess with it, but the rest of the soldering/wiring looks undisturbed. However, I've seen some high quality redo-type work through the years, so, I can't be 100% sure. When I tried the guitar through the amp, the tone control functioned as it should, and it sounded fine to me--at this point, I really don't know if I would like the tone pot to operate as a "boo wah" or have the other "finer variation settings". Come to think of it, I've hardly ever used the tone control on my guitars--I've always used my amp settings to get the tone I wanted. I've never had a Magnatone, so in a sense, I really don't know what to expect from it, as far as the tone control. I really only bought it for what I think has a very distinct TONE.

If you run the pot in the full treble position
which is fully clockwise, then the cap is effectively
out of the circuit.
You can set your tone with the amp as you normally do.