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Post by unreg on Jan 29, 2022 21:26:52 GMT -5
Hi all,
Simple question: If I remove my 500K audio taper tone pot, with its 2 one meg resistors, across lugs 1 and 3, that reduce it to 250K, and replace it with a resistor-less 250K audio taper pot; will my tone change?
I do realize/remember that the 2 resistors remove some of the signal strength; AND that they also affect the pot rotation effect.
My guitar, now being hum&buzz free, made me notice that the sound is borderline loud enough to be recorded. And my tone drastically gets much worse if I barely move the tone knob to either side of its perfect spot. *Thought changing the pot would fix both these usefulness-downsides; don’t have a clue if my tone would change; the new pot would also be a CTS.
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I’m sure the amp would become tons louder if I turned its “Volume 2” knob from 7 to 10; but I really enjoy 7-would just like the guitar to be a bit louder.
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Post by newey on Jan 29, 2022 22:45:17 GMT -5
Simple question: If I remove my 500K audio taper tone pot, with its 2 one meg resistors, across lugs 1 and 3, that reduce it to 250K, and replace it with a resistor-less 250K audio taper pot; will my tone change? It won't change it much at "10", but those resistors alter the effective taper of the pot, so as you turn the tone control down, it won't operate quite the same. Whether the difference is for the better or for the worse is for you to decide. |
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Post by Deleted on Jan 29, 2022 23:52:12 GMT -5
I'm not sure what looking at here
Typical Tone Resistor from say 0 to 500K then a capacitor from 10nF to 50nF
And how I read this (so maybe wrong) Potentiometer setup with 1M between lug 1&2 and 2&3 [guessing a capacitor at lug 2 to ground] 1/((1/R)+(1/1M)) the other resistor isn't doing any thing.
Unless lug is to ground then you get
1/((1/[500K-R]+(1/1M)+(1/Xc))
Im sure I've seen this chat before
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Post by newey on Jan 30, 2022 7:43:42 GMT -5
@angellahash: And how I read this (so maybe wrong) Potentiometer setup with 1M between lug 1&2 and 2&3 No, he's got 2 1MΩ resistors, both wired in parallel between lugs 1 and 3 of a 500K pot, to give an effective resistance of 250K. |
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Post by sumgai on Jan 30, 2022 11:32:46 GMT -5
unreg, So long as the Vol pot is dimed, you won't see any difference in volume, and I doubt that your tone will change all that much. However, turning down the real-life 250K unit will give you a much more predictable change in volume, and it should also give you no "unexpected" results when you rotate the Tone control. However, it's quite possible that you'll find that the Tone control's "sweet spot" will be moved to some other location on the dial. If you didn't already have a treble-bleed circuit on the old setup, then you probably liked the tone as it was, so I don't think you'll need one with the new pot. But be prepared, I might be wrong!  HTH sumgai
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Post by unreg on Jan 30, 2022 22:09:24 GMT -5
Thank you newey! 😀 Sry @angellahash, my wording wasn’t greatest… forgot “parallel”. And should have used “between” instead of “across”. 😔 unreg, So long as the Vol pot is dimed, you won't see any difference in volume, and I doubt that your tone will change all that much. However, turning down the real-life 250K unit will give you a much more predictable change in volume, and it should also give you no "unexpected" results when you rotate the Tone control. However, it's quite possible that you'll find that the Tone control's "sweet spot" will be moved to some other location on the dial. 😀 Hmm… I think I’m understanding you correctly; just want to note that my volume pot will remain 500K. EDIT: sumgai, no treble-bleed circuit… that’s what 500K reduced to 250K is for. |
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Post by sumgai on Jan 30, 2022 23:46:41 GMT -5
and replace it with a resistor-less 250K audio taper pot just want to note that my volume pot will remain 500K. Something isn't computing for me. I'd like to buy a clue please, Pat. no treble-bleed circuit… that’s what 500K reduced to 250K is for. Now I'm lost. As I read it, you seem to be saying that if a pot is 250K, then you won't need any kind of treble-bleed, is that about right? I've spent a good chunk of my life thinking that we install a treble-bleed to retain some small amount of higher frequencies (brightness) when the pot is turned down. This applies no matter what the pot's value might be, the t-bleed still does its job, i.e. mitigate the effects of a turned-down pot muffling the tone. It's a well-known fact that the lower the pot's value, the less bright the tone. In your case, that's a good thing, but for many folks..... I personally like using 1Meg pots, I can always turn down to 9 to sound like a lower value pot. But for the most part, I prefer to play while "dimed", so who am I to dictate what others should use.  |
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Post by newey on Jan 31, 2022 6:10:57 GMT -5
sumgai- Something isn't computing for me. I'd like to buy a clue please, Pat. His Volume pot is 500K, tone pot to be replaced with a 250K in lieu of the 500K one with resistors. But you're right, a treble bleed is useful either way. What's confusing is that unreg seems to be saying a treble bleed on his new tone pot; it's the volume pot that should get the treble bleed.
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Post by unreg on Jan 31, 2022 11:55:50 GMT -5
sumgai, newey is correct. My 500K tone pot is currently reduced to 250K with two 1 meg resistors in parallel between lugs 1 and 3 of my tone pot. My volume pot is 500K. Forever ago, I was blessed to visit a forum with an experimenter’s list of resistor values and a short description of how each would affect treble, if it was spanned between a 500K tone pot’s lugs 1 and 3. Chose two 1M resistors; had no clue that pot values could be changed. The treble-bleed circuit idea was shunned bc I had 0 skill with electronics. Surprisingly, a 250K-value tone pot created, for me, an excellent sound. I’m not saying that treble-bleed is pointless; it just wasn’t possible for me at the time… and I love how my treble-bleed-less guitar’s tone turned out! 😀
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Post by newey on Jan 31, 2022 12:59:27 GMT -5
I’m not saying that treble-bleed is pointless; it just wasn’t possible for me at the time… and I love how my treble-bleed-less guitar’s tone turned out! 😀 A treble bleed on the volume pot wouldn't have (and won't) affect your tone pot, and won't affect the guitar's tone with the volume at "10". The treble bleed only has an effect as you turn the volume control down. You could have, if you wished to do so, put one on the volume pot along with the 1Meg resistors on the tone pot. |
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Post by unreg on Jan 31, 2022 15:46:17 GMT -5
I've spent a good chunk of my life thinking that we install a treble-bleed to retain some small amount of higher frequencies (brightness) when the pot is turned down. This applies no matter what the pot's value might be, the t-bleed still does its job, i.e. mitigate the effects of a turned-down pot muffling the tone. It's a well-known fact that the lower the pot's value, the less bright the tone. In your case, that's a good thing, but for many folks..... A treble bleed on the volume pot wouldn't have (and won't) affect your tone pot, and won't affect the guitar's tone with the volume at "10". The treble bleed only has an effect as you turn the volume control down. You could have, if you wished to do so, put one on the volume pot along with the 1Meg resistors on the tone pot. & sumgai, thank you so much! 😀 I thought it bled/reduced treble, but now I really understand the purpose of treble-bleed; don’t think I’ll use one now, but that’s great to know newey!  |
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Post by sumgai on Jan 31, 2022 23:01:14 GMT -5
unreg, newey caught me out; you've been talking about a Tone pot and I've been talking about a Volume pot (notice my caps). OK, that tosses just about everything I've said above right into the toilet. Moving on..... You've said that you like the guitar's tone when at "7" on the dial. I'd say that you should use a meter to measure the old assembly, while at "7" on the dial, and write those results in your notebook. Next, set your new 250K pot to that same pair of values. (Don't worry if the two previous values can't be exactly achieved, just get close.) Chances are, the percentage of rotation won't be the same as the previous rig. Now insert it into your axe and test for tonality. Adjust the Tone pot to recapture that sweet spot, and make a note of that new position on the dial. Finally, just for drill, re-measure the new sweet spot resistance values and make a note of them. You never know, some day down the road, you'll be glad you kept notes. (Just ask newey.) Can't get the sweet spot at all? I don't think I need to tell what to do at this point. Two more things: a) Yes, treble-bleed means "bleed through", not "bleed away". b) No they don't. At least, they won't do that if they aren't connected to ground. For a standard Tone pot, only two terminals should be used. Grounding the third terminal does indeed cause a loss of both signal strength and desired tonality. HTH sumgai |
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Post by unreg on Feb 1, 2022 11:47:49 GMT -5
Moving on..... You've said that you like the guitar's tone when at "7" on the dial. I'd say that you should use a meter to measure the old assembly, while at "7" on the dial, and write those results in your notebook. I’m sure the amp would become tons louder if I turned its “Volume 2” knob from 7 to 10; but I really enjoy 7-would just like the guitar to be a bit louder. “7” on my amp’s “Volume 2” dial. How do I measure resistance around my amp’s dial? Or maybe you misread? (Now my “its” seems conveluded. 😔) Anyways, thank you sumgai! 😀 EDIT: I will measure my current resistance value on my Tone pot, record that, and then find the new sweet spot with a new 250K Tone pot and record that. Thank you. 😊 |
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Post by reTrEaD on Feb 1, 2022 15:15:26 GMT -5
Simple question: If I remove my 500K audio taper tone pot, with its 2 one meg resistors, across lugs 1 and 3, that reduce it to 250K, and replace it with a resistor-less 250K audio taper pot; will my tone change? It depends. At 10, you won't hear any difference. As you rotate the volume CCW, you'll be have more series resistance for the same amount of voltage division with the 500k pot than with the 250k pot. IF you have your tone cut connected to the wiper ('50s style wiring) the additional series resistance will make the tone control more interactive with the volume setting. Also, the additional series resistance makes a treble bleed circuit almost mandatory. Tagging in (a) resistor(s) between lugs 1 and 3 is an effective quick fix to determine if a lower value volume pot will gain the desired effect, but replacing the pot is better as a permanent fix.
Side note: BBCode doesn't work on thread titles and the clutter looks like a hot mess. Feel free to edit your OP to change the thread title. |
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Post by unreg on Feb 3, 2022 15:59:11 GMT -5
As you rotate the volume CCW, you'll be have more series resistance for the same amount of voltage division with the 500k pot than with the 250k pot. IF you have your tone cut connected to the wiper ('50s style wiring) the additional series resistance will make the tone control more interactive with the volume setting. Hmm… I do keep the volume slightly below “10” or max to reduce some of the treble. If changing to 250K Tone pot, are you saying that the slight turn of 500K Volume knob for treble-reduction would no longer be available bc of the lack of series resistance? StewMac doesn’t sell 250K Long Shaft CTS pots… so maybe I’ll just keep what I have? I need to use a long shaft pot for my guitar. |
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Post by unreg on Feb 10, 2022 21:42:07 GMT -5
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Post by unreg on Feb 11, 2022 11:23:26 GMT -5
As you rotate the volume CCW, you'll be have more series resistance for the same amount of voltage division with the 500k pot than with the 250k pot. IF you have your tone cut connected to the wiper ('50s style wiring) the additional series resistance will make the tone control more interactive with the volume setting. Also, the additional series resistance makes a treble bleed circuit almost mandatory. Ah. So, switching to a 250K Tone pot would reduce the amount of series resistance relative to its voltage division. Therefore, my new tone control will be less interactive with my volume setting. Does “less interactive” mean my (500K) Vol pot would no longer reduce as much treble as it does now, currently paired with my originally-500K Tone pot, when its volume knob is turned down just a smidgen below max volume? |
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Post by reTrEaD on Feb 12, 2022 0:51:02 GMT -5
Ah. So, switching to a 250K Tone pot would reduce the amount of series resistance relative to its voltage division. Therefore, my new tone control will be less interactive with my volume setting. Uh, no. This has become so convoluted I don't know where to begin. Why are you talking about voltage division in the tone pot? Only two terminals of that pot are in use and the treble-cut tone circuit is a shunt device not a voltage divider. And whether or not your tone control is interactive with the volume control depends on whether you're using '50s wiring (interactive) or modern wiring (not interactive). |
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Post by unreg on Feb 12, 2022 11:16:50 GMT -5
Why are you talking about voltage division in the tone pot? (I knew nothing about voltage division; now I know a tiny bit.) As you rotate the volume CCW, you'll be have more series resistance for the same amount of voltage division with the 500k pot than with the 250k pot. Currently, it makes sense that you were talking about the Volume pot. That pot has been set up as a voltage divider; thus it causes the volume level to change. I’ll always have less series resistance from my 250K Tone pot bc 250K is less than 500K, right? If so, I misinterpreted and misunderstood your general statement as a specific learning opportunity. I’m sorry sir. 😔 EDIT: And I believe I’m using modern wiring. Thank you! 😊 |
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Post by ashcatlt on Feb 13, 2022 11:33:36 GMT -5
Just to make sure everybody is as confused as possible, I thought I’d pop in and point out that Everything Useful Is A Voltage Divider. Yes, that includes the Tone pot. “But we don’t use all three lugs...” Well no, the T pot is a variable “bottom resistor” in a voltage divider where the “top resistor” is the impedance of the pickup. That “top resistor” is relatively small (compared to the T pot at 10) at lower frequencies, but it gets big fast for higher frequencies. At some frequency, it’s big enough to cause significant division with the T pot. As you reduce the T pot, that frequency gets lower. But anyway, no part of that T pot is ever in series with the signal going to the output jack. The series resistance discussed above is the top half of the V pot as it’s turned down, and what that does with the T pot is going to be the same whether that T is one 250K or 500K parallel to two 1M. It’s still 250K either way when the pot is at 10. As you turn it down, that gets lower, and you have the same range of lower values either way, though they may be at different points in the rotation. The taper is different, but the value is the same, and the overall action is the same. Anyway, swapping out the T pot definitely will not make your guitar louder no matter what, so if that’s what you’re trying to achieve, probably skip it. Turning down the V pot definitely does make the guitar quieter, though. You’ve said you like to turn that down to kill treble, which happens because the top part of that pot ends up as the top part of a divider whose bottom part is the capacitance of the cable, which looks small at high frequencies, but that’s on top of the broadband division you get from the divider in the V pot itself. If you want more broadband volume and less treble, turn the V pot up and the T pot down, or swap out the T pot for something smaller than the 250K so you can just leave them both all the way up. Or just buy a booster pedal.  But realize that the tone you like with your amp at 7 WILL change when the input gets louder. At least, if you’re saying you get exactly the amount of overdrive/distortion/saturation/crunch/whatever that you want when the amp is set to that particular amount of gain, well, adding gain at any stage is going to change that, so... Buy a bigger amp.  |
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