megi
Meter Reader 1st Class
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Post by megi on Jan 17, 2012 5:38:54 GMT -5
Hi, this question probably shows off my ignorance but I thought I'd ask the forum anyway. We are commonly told by various sources that humbuckers like 500K pots and single coils like 250K. I'm building a strat at the moment, and have used 500K pots for everything, including the tone control. I understand that some people say this gives a sound which has too much high end when set at 10, if used with single coils - hence the recommendation for 250K, which will still bleed off a little more treble to ground, even at 10. But I reason I can always turn down the 500K pot a fraction to get the same effect, and surely it's better to have the option of more high end, even if I don't want that all the time.
Is there something I'm missing though? i.e. is there a sound quality that can only be attained with 250K tone pots, which a 500K can't quite replicate? Thanks your for help, apologies if it's a dumb question!
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Post by 4real on Jan 17, 2012 6:29:19 GMT -5
Well, the dual coils in an HB are more powerful and so a 500K is advisable and with fender SC things are brighter and having a lower value is more appropriate..however...
Sure, it is not as if it does not work and as pots are logarithmic, half a 500K is not literally in the middle of the dial, more like about 8. In fact, take a multimeter between one side and the middle 'tags' and turn till it reaches 250k and you will know exactly where that is...at that point it will sound no different than a 250K on max.
Sure, high end, though of course, this can often be a bit excessive at times. I've even used 1meg pots (2x500k) to give more top end on an HB say, turn it down a touch.
A lot of modern pups and noiseless types like I use, perhaps with an HB in the bridge with single coils as on my guitar, I use 500Ks...I did find the 1meg in my bright tele far too excessive and took it back down to 500k and generally do turn it down a notch...that way I have a little extra bright and volume if I need it (be great if you play with distortion and need some cutting power). I would not use a 'treble bleed' as with a very bright guitar, I like that it dulls a bit with the volume turned down a touch.
A lot of players never touch the volume control, but it can be quite an effective control...remember EVH labels his 'tone' for this reason!
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Post by asmith on Jan 17, 2012 7:20:30 GMT -5
Also, bear in mind that these pots all have the same travel distance. If 250k is providing you with a tone you find acceptable, then you have 1-10 of control. If, like 4real's said, you prefer the 500k sound, then that 1-10 on the 250k has been shifted to 1-8 - presuming you're using a log pot.
If you keep going like that, then it's been reported by some on the board [citation needed] that when you start heading into the 1M-2M range, the change in volume is so drastic over the travel of the pot that it starts working like an on/off switch.
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Post by ashcatlt on Jan 17, 2012 11:53:18 GMT -5
Well, the dual coils in an HB are more powerful and so a 500K is advisable and with fender SC things are brighter and having a lower value is more appropriate..however... I'm pretty sure you know what you mean here, but other folks probably don't. "Power" has nothing to do with it. We're talking about frequency response here. All other things being equal the HB will generally have about twice the inductance of the SC. It already has less treble coming out of it. You can't really get any more out, but you can try to lose as little as possible by keeping the overall load impedance as high as possible. Yes, overall load impedance. That means any and all pots and the input-Z of the first active stage (pedal or amp, inboard buffer, wireless transmitter...) after the guitar. Oh, then there's the cable capacitance, which is really what's stealing the treble we're talking about here.
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Post by reTrEaD on Jan 17, 2012 15:00:13 GMT -5
But I reason I can always turn down the 500K pot a fraction to get the same effect, Yes, you could. and surely it's better to have the option of more high end, even if I don't want that all the time. Better? Maybe not. If you find you like the added highs, sure. But if it's not a sound you use on a regular basis, you'll discover that fiddling with the tone control to tame down the highs to be a bit of a nuisance. There's no hard and fast rule for the resistance values for the volume and tone pots that you "must" adhere to. Use what suits you. Oh, then there's the cable capacitance, which is really what's stealing the treble we're talking about here. Definitely a huge factor when rolling down the volume control, because of the LARGE resistance now in series with the output. Combined with the cable capacitance, this forms a low pass filter. But with the volume control at max, the parallel resistances of the volume and tone pots have a more significant effect. Try removing the pots completely and send the output of the pickups directly to the guitar's output jack. Even with a long, high capacitance cable, the tone is unbearably brittle.
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Post by 4real on Jan 17, 2012 15:20:38 GMT -5
Sorry if the lay term 'power' confused...you are right of course. Many speak of HB's in such terms because of their 'higher output' and midrange content, especially in those over-wound pups which can sometimes benefit from a larger pot I've found. from stew mac.... www.stewmac.com/shop/Electronics,_pickups/Potentiometers.html The 1Meg pot thing is not that uncommon a thing and not found them to work as on/off switches myself but generally not a sound I like any more so not advising them...just pointing out that one can use pots to ones liking really. Many people find a 'quick' pot to be not such a bad thing at times either, all a matter of taste and how you use them really...even on a 1 meg pot there will be a 250k along it's value it will be just trickier to find. I dare say there might be a way to alter the taper and total value by adding in a resistor if there is a problem...consider this article on such things and altering values to taste... www.projectguitar.com/tut/potm.htmA little on how pots work in the guitars and the increased gain and frequency response from Torres Engineering... torresengineering.stores.yahoo.net/how1and2megp.htmlHow anything works or sounds is always in the ear of the beholder of course, it is not that anything is so much a rule as a guideline is it not?
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megi
Meter Reader 1st Class
Posts: 80
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Post by megi on Jan 17, 2012 15:33:13 GMT -5
There's no hard and fast rule for the resistance values for the volume and tone pots that you "must" adhere to. Use what suits you. Try removing the pots completely and send the output of the pickups directly to the guitar's output jack. Even with a long, high capacitance cable, the tone is unbearably brittle. Thanks for the discussion of pot values guys, I think you have covered everything I needed to know, plus possibly some things I didn't even consider (but perhaps still need to know! ;D) so highly useful as ever, much appreciated. I think given what retread says re pot values above, I will try the 500K logs I've wired in and see how I go - I think it's likely that I will be fine with turning the tone down to 8 or so if needed. I did once fit a complete tone/volume bypass switch to a guitar (suggested as a mod on a different website) but as you say above retread, it was indeed unbearably brittle sounding - a lesson learned the hard way. Cheers again folks!
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Post by ashcatlt on Jan 17, 2012 21:58:46 GMT -5
But with the volume control at max, the parallel resistances of the volume and tone pots have a more significant effect. Try removing the pots completely and send the output of the pickups directly to the guitar's output jack. Even with a long, high capacitance cable, the tone is unbearably brittle. Okay, sorry. Cable capacitance moves the cutoff, pot value varies the height of the resonant peak. This is technically true, but - ignoring the frequency dependent components - the difference between 250K and 10M (!) is about a third of a db when the DCR of the pickup is 10K. This is enough for tone snobs to quibble over, but not enough for any normal human to notice. Yes, the added high frequency response will produce a slightly greater increase in overall level, but it's still fairly slight when one considers how little those higher harmonics actually contribute to the total output. It will likely sound "hotter", though, because of those added high frequency components.
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