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Hi, I've got a strange problem, tone control on my archtop works only, when volume knob is set on maximum. When I move the volume down a little, tone automaticly goes to maximum and I have no control over it. Is it going to be hard to fix? Thanks for help in advance.
Last edited by katamaranos; 05-14-2015 at 02:52 PM.
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05-14-2015 02:36 PM
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No ideas?
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Quite easy: you need to check the wiring. Not so easy: get access to the pots and cables. Take it to an experienced luthier if you don't want to ruin your nervous system...
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If it's an Asian made guitar (as most of mine are) you'll find that the pots and caps are utterly awful and can fail on even a recent vintage instrument. I would get them changed out to CTS pots and decent caps rather than trying to troubleshoot poor components.
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Sounds like the problem is with the volume pot, cutting the tone control out of the circuit when rolled away from the full on position.
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you might try rolling the controls back n forth really hard & fast a couple of times -- sometimes it breaks some BS loose. Not exactly a fix per se but occasionally effective . . . .
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Yes, it's an Eastman. Thank you all for your help, I'm going to give her to luthier.
Originally Posted by Spook410
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Could you recommend me any specific models of pots and caps? Originally Posted by Spook410
EDIT: It'll be nice if there are available at thomann.de
Last edited by katamaranos; 05-17-2015 at 12:37 PM.
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CTS audio taper pots, for humbuckers most people use 500k pots, but Gibson used to use 300k pots in the 50s. I have a 500k volume pot and a 250k tone pot on my archtop as recommended to me by Kent Armstrong.
The influence of caps on tone is overrated. The important thing is the value. The signal that goes through the cap goes to ground and is inaudible. Ceramic, paper-in-oil, etc., have a lot of hype but the auditory difference is nil. I've tried 'em all and they all sound basically the same. The main difference, I would say, is the accuracy of the rating. Caps can be off by 25% from the rated value (which can actualky help find the tone you want).
On my archtop guitar I have a Classic 57 with a CTS 500k audio taper volume, CTS 250k audio taper tone, .047 cap. On my Tele I have a Dimarzio Area T neck & bridge pickups with CTS 250k pots and either a .033 or .047 cap. My GB10 has whatever was stock for that instrument in 1980.
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Can't speak to what is available in Europe. Otherwise, exactly what Cunamara said with couple of additions: if you have a pickup switch, those made by Switchcraft are a good swap. If you have under the pickguard tone/volume controls, Schatten is the way to go. I've used the 500K/500K ones and they're fine but a 500K/250K would be better.
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Ok, fortunately CTSs are available here in Poland, but I've got a question, what's the difference between those?
http://static2.redcart.pl/templates/...8390aa819e.jpg
http://static1.redcart.pl/templates/...712a9fac15.jpg
Is this cap ok?
Orange Drop 0,047 uF
http://static3.redcart.pl/templates/...d957cfe31f.jpg
EDIT: My guitar is Eastman Pisano AR680CE with stock Kent Armstrong pickup.Last edited by katamaranos; 05-17-2015 at 04:04 PM.
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One set of pots has a split shaft for press-on plastic or wood knobs, the other is solid shaft for knobs that attach with a set screw (or grub screw it's called by some). For your guitar you'll probably want the split shaft to reuse the knobs you have. Also note that the shafts come in 1/4" and 6 mm options; match the shaft diameter you already have (probably metric). Originally Posted by katamaranos
That cap would be fine.
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There also appears to be a difference in the length of the shaft as measured by the threaded length. I've never swapped pots in an Eastman but I'm guessing the longer shaft is what you want. Not sure CTS offers different shaft diameters and the holes on the guitar may have to be reamed out slightly.
If you're doing this yourself be sure to look at a few youtube videos on swapping parts in an archtop. There are several tricks that make it a lot easier.Last edited by Spook410; 05-17-2015 at 04:53 PM.
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No, I'm going to give it to luthier in my area, but I want to buy spareparts myself.
Long shaft ones are also available, is this one going to be ok?
http://static1.redcart.pl/templates/...a8c0591227.jpg
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That depends on how thick the top of your guitar is. The threaded part (called a bushing) has to reach through the top with room for the dress washer and for the retention nut to grab the threads to be tightened down. The long ones are 3/4 inch, the medium ones are 3/8 inch and the short ones are 1/4 inch. The last are mainly for Teles with a thin control plate; the 3/8 inch ones work with thicker pickguards like a Strat or in my case the fingerrest on my archtop. The 3/4 inch ones are required for Les Pauls and probably for archtops with thicker tops. Yours might need those, I don't know how thick the top is. Originally Posted by katamaranos
The safest bets would be to (a) let your luthier deal with it (he or she may have the right ones in stock) or (b) take one of the existing pots out and look at it.
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Whats the difference between a 500k volume 500k tone vs a 500k - 250k tone pot configuration
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Alpha pots are also good quality. If the guitar is an acoustic archtop (i.e.not a Les Paul style) you don't need long shaft pots. Medium shaft is what you want. It's easy enough to measure the thickness of the top around the f hole.
Higher resistance pots maintain more high frequency when the pot is at maximum value. A 1 meg ohm pot is very bright and full sounding while a 250k ohm pot is darker sounding. single coil pickups with magnets in the core tend to be bright sounding so 250k ohm is typically used to tame the harshness. Mixing 500k and 250k pots means at maximum value there is slightly more signal being shunted to ground compared to two 500k pots. High frequencies tend to be shunted first, hence a slightly darker sound.
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I typically use the medium length shafts. I've also heard Alpha pots are fine. They are a bit less expensive than CTS.
Caveat: This is merely my understanding. You need to do your own homework.
As for pot values, there are additional considerations. In general humbuckers are designed to work with 500K pots and single coil pickups with 250K. The higher value does 'block' more signal from the capacitor sending the higher frequencies that particular cap value sends to ground.
However, if you are using an audio taper (log) pot for tone, you'll notice that all of the control is in the first 1/3 of twist. This is why linear taper is (IMHO) better for tone control. If you are using an audio taper 500K pot and you keep it no higher than say 7-8, you're already running 250K and you may find you have more tone control switching to a 250K pot. Also, roll off curves being what they are, going to a 250K tone pot isn't as radical as it may sound.
You can also vary the size of the capacitor to vary where the 'knee' for where the roll off is. I'm used to 500K pots and .047uf caps. Also, I tend to want a more acoustic sound and don't want to lose too much of the higher frequencies at the guitar. I might even be better off with a lower value cap but many pickups don't produce great sounding higher frequencies anyway.
Regardless, when I rewire my next guitar with a built in humbucker I may be looking for a darker tone and not more acoustic. I'll probably use a 250K tone pot though I may try a 500K linear as well.Last edited by Spook410; 05-18-2015 at 04:19 PM.
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