Tone Pot Response

[blackcat]

I originally posted this in the Eastman thread, but wonder if it might attract more replies if posted separately. Hope that's OK. Problem is not Eastman-specific of course.

Tone pots.

Apologies for reviving this thread, but hopeful that somewhere in here lies the answer to my problem uncovered today. According to the Eastman spec' they fit four CTS linear pots to cover volume and tone requirements. My luthier fitted a Seth Lover in the neck position this morning ( could not get on with the boominess of the '59 ) and replaced the two original volume pots (linear) with 500k CTS linear and the two tone pots with CTS audio taper pots. I believe the capacitor value os 0.47.

The problem is that whilst the linear volume pots work as expected, the tone pots give 'instant Metheny' from 0 - 3 or 4 and then virtually no perceptible difference up to 10. I understand the difference between the two types of pot but surely this is not normal? Is it likely that the two (audio) pots could both be from a bad batch? Could the capacitor have 'failed'? I am lost. My guy is a superb builder with lots of experience and a family background in electronics but is unsure what the problem is.

Please can anyone comment? Many thanks.

David

[TOMMO]

"Audio taper" is a misused term imo. Correct would be logarithmic. So what is "audio taper" - 80/20, 70/30, 65/35 or even 60/40 which is close to linear?
Also your cap value is not suited to a PAF style humbucker pickup. .047 caps are what you find in a Telecaster.

[blackcat]

"Audio taper" is a misused term imo. Correct would be logarithmic. So what is "audio taper" - 80/20, 70/30, 65/35 or even 60/40 which is close to linear?
Also your cap value is not suited to a PAF style humbucker pickup. .047 caps are what you find in a Telecaster.

Thanks TOMMO - 0.47 is the Eastman default on 'our' model. Have you changed yours? If so, what to?

Thanks again,

David

[TOMMO]

Thanks TOMMO - 0.47 is the Eastman default on 'our' model. Have you changed yours? If so, what to?

Thanks again,

David

Didn't know that. Along with the pots I have ordered (and received today) two Orange Drops .022 caps. .022 is the classic value for a humbucker, .047 rolls off too much high end.

[blackcat]

Didn't know that. Along with the pots I have ordered (and received today) two Orange Drops .022 caps. .022 is the classic value for a humbucker, .047 rolls off too much high end.

Here we go: AR372CE - Eastman Guitars And four linear pots.

[Clint 55]

It's not the taper or cap (although I do prefer 22nf or less). Audio taper turns down faster. If you used 500k linear for the tone, there would be even less effect in the top of the sweep. It's the value. 250k is about the threshold for being mostly out of the way on 10 and then you'll start to get some noticeable darkening as soon as you turn it down. What I do is use 250k no load tones for everything. That way I know I have max bright on 10 and then I'll start to notice darkening effect as soon as I turn to 9 or 8. If you want a longer sweep, the absolute max value that is needed would be 300k. 500k is way overkill imo. It's basically all coloring effect from about 250k to 500k and no real darkening.

[Woody Sound]

Not to derail this thread but on my Sadowsky, when I roll of the tone pot, it gets slighlt darker and darker, then toward the bottom it suddenly gets a nasally and honky, mid-rangy sound. I do know the pot and probably the cap are not original, someone worked on it.

[Clint 55]

^ That means it's a cap probably in the 10nf - 22nf range. Those middle value caps retain mids when rolled off. So when the pot is all the way down you'll still get mids coming through that made the cutoff but all the highs have been chopped off ergo the honk. If you don't want that and want it bassier, use a cap in at least the 18nf and up range. I would be surprised if a 22nf cap gave you that effect, but it's possible. Just raise the value.

[aquin43]

The capacitor resonates with the pickup inductance to produce a peaked response a bit like a wah wah pedal. A fixed resistor of a few k in series with the capacitor will tame this.

On the original topic, the standard log pot isn't ideal to give a linear feel to the tone roll off. Entwistle sells a pot with a steeper initial curve that he claims gives a better feel. Entwistle Custom Pickups --- Smoothtrak Pots

[blackcat]

It's not the taper or cap (although I do prefer 22nf or less). Audio taper turns down faster. If you used 500k linear for the tone, there would be even less effect in the top of the sweep. It's the value. 250k is about the threshold for being mostly out of the way on 10 and then you'll start to get some noticeable darkening as soon as you turn it down. What I do is use 250k no load tones for everything. That way I know I have max bright on 10 and then I'll start to notice darkening effect as soon as I turn to 9 or 8. If you want a longer sweep, the absolute max value that is needed would be 300k. 500k is way overkill imo. It's basically all coloring effect from about 250k to 500k and no real darkening.

Really helpful. Many thanks. David

[icr]

The problem is that whilst the linear volume pots work as expected, the tone pots give 'instant Metheny' from 0 - 3 or 4 and then virtually no perceptible difference up to 10.

What were you expecting with the audio taper tone pots?

[blackcat]

What were you expecting with the audio taper tone pots?

Good point. I suppose I expected a little more differentiation between say 4 and 10.

[Clint 55]

Really helpful. Many thanks. David

No prob.

[Amberville]

Good point. I suppose I expected a little more differentiation between say 4 and 10.

CTS audio pots come in different tapers. They do a TVT line (true vintage tone) with a custom taper, which themselves can be specced to order for resellers.

Can make a difference.