Vol knob basics.

[Chuck H]

Fluoroscope 5000 Ah ok so I put those pickup caps on the switch itself. That's good. I'll need to refresh myself on your cable suggestion/ I have to go over the replies again.. but as it was, getting into the aspects of cable resistance or capacitance, I was having trouble understanding.. is the the only thing.

So my 680pf cap (I think it was added to aid treble roll-off when turning down the vol-?) is actually ok then? & the rubbish quality green other one.. ok too?

thanks, SC

The "rubbish quality green capacitor" you have will be fine as long as it's functioning properly and can be resoldered to the new pot. You'll need to get a 330pf capacitor to make the change shown on the volume pot. And you do need to make this change if you want to get any joy from your new audio taper volume pot.

[Fluoroscope 5000]

Fluoroscope 5000 Ah ok so I put those pickup caps on the switch itself. That's good. I'll need to refresh myself on your cable suggestion/ I have to go over the replies again.. but as it was, getting into the aspects of cable resistance or capacitance, I was having trouble understanding.. is the the only thing.

So my 680pf cap (I think it was added to aid treble roll-off when turning down the vol-?) is actually ok then? & the rubbish quality green other one.. ok too?

thanks, SC

Listen Bozo , you can abbreviate me to F5k.

I suggested ordering 10-12' of Sommer LLX cable with two noiseless HICON plugs from here if shipping isn't expensive:
Sommer Cable 300-0091 SC-Spirit LLX Low Loss Instrument Cable - per foot (haveinc.com)

Might be cheap direct from Sommer.

You could make one an L plug so you can sit down with the Tele and snake the cable through the strap above the rear pin. The ~160pF load will bring the resonance peak on each pickup above the harshest sounding 3-3.5kHz range and smooth it off a bit. Now, that's the 4th time I've said it, including in my video.

The C & R on the volume keeps the treble from rolling off when the volume is rolled down. 680pF is fine, but I guess you could instead wire it in series with just the 100k R, as Chuck illustrated below, so that the taper is not as affected.

There's nothing wrong with the green cap at all. Cap type/brand makes no audible difference in a passive guitar circuit. Technically it might be better not to use ceramic caps because they can resonate in higher V circuitry, but the V is far too low in guitar circuitry to do that.

[Sea Chief]

Without troubling with anything else right now I'll just address the initial troubles you started this thread for.

Do this and all your knob adjustment problems will go away. Note the change to the cap and resistor arrangement on the volume control. Don't bother trying this with your existing tone pot and don't bother trying this without scratching through the pot track as shown.

So, as you can see, you can leave things wired as they are for the most part. I've tried to make it as simple as possible to make the necessary changes.

Hi Chuck,

ok so let me get this right, the suggestion is:

1. replace the A500k tone pot, with a Bournes B250k pot.
2. Replace my 680pf cap, for a 330pf cap
3. Cut the track as indicated (before installing).

Have I got that correct? is your pot pic the view from same as my diagram/ (which is looking at the backside).

Thanks, SC

[Fluoroscope 5000]

Hi Chuck,

ok so let me get this right, the suggestion is:

1. replace the A500k tone pot, with a Bournes B250k pot.
2. Replace my 680pf cap, for a 330pf cap
3. Cut the track as indicated (before installing).

Have I got that correct? is your pot pic the view from same as my diagram/ (which is looking at the backside).

Thanks, SC

While you wait on Chuck's reply, I'll just add that the efficacy of his TB network is still dependant on the cable capacitance. Lower C is better.

While being a tad brighter as the V knob is turned down, the 680pF cap will work. A 330pF cap is better. You might order several of different cap values in roughly 1, 2-3 & 5 increments from pF > nF > uF rating from ~100pF or the 330pF just so you can use them in future to create whatever value you want with no more than 3 in parallel. Again, the brand/type doesn't really matter. I get them for 10~50 cents/ea in the States. Maybe do the same with resistors.

Here's a place in the UK that sells the Spirit LLX cable cheap, but not HICON plugs. Use any plugs you want that will fit over the cable. Neutrik makes noiseless and L types if you want that:
Sommer SC-SPIRIT LLX "LOW LOSS" Instrument Cable. Low Capacitance. Guitar RCA (designacable.com)

[Sea Chief]

While you wait on Chuck's reply, I'll just add that the efficacy of his TB network is still dependant on the cable capacitance. Lower C is better.

While being a tad brighter as the V knob is turned down, the 680pF cap will work. A 330pF cap is better. You might order several of different cap values in roughly 1, 2-3 & 5 increments from pF > nF > uF rating from ~100pF or the 330pF just so you can use them in future to create whatever value you want with no more than 3 in parallel. Again, the brand/type doesn't really matter. I get them for 10~50 cents/ea in the States. Maybe do the same with resistors.

Here's a place in the UK that sells the Spirit LLX cable cheap, but not HICON plugs. Use any plugs you want that will fit over the cable. Neutrik makes noiseless and L types if you want that:
Sommer SC-SPIRIT LLX "LOW LOSS" Instrument Cable. Low Capacitance. Guitar RCA (designacable.com)

Hi Flour50,

I'm sorry I'm lost again. What does TB network mean?! jeepers I've never been so overwhelmed with info. I've got to go over it all again to make sense of this cable capacitance thing- at the moment I haven't the foggiest idea. Low-loss it says.. but loss of -what- tho? ('capacitance' I fear might be the answer.. but would only lead me back in a circle not knowing what that implies).

I wonder what my cables are.. would there be a 50/50 chance they might be 'low-loss' i wonder? thing is, I haven't ever once thought 'that cable sounds better than the next', its never something that's ever been a question to ask, or a consideration to make personally. They sound the same, cheap nasties to curly wurlys to solid 80's high quality ones.. to me. So I'm quite baffled by this tbh.

I am reminded of my (no1 passion) hifi cable 'discussion'.. slightly alarmingly, because there are loads of folks saying naim speaker cable sounds better, but when I do a comparison I can tell no difference between naim expensive stuff (for eg) & far lesser stuff. I have a feeling there, naim state their cables are a -must- because of capacitance matching to their amps.. & their followers, follow (I -am- a firm naimee, but reject the dedicated naim cable thing) imploring only their speaker cables be used. Not (oh no it can't be) that, in fact it's more likely just a clever marketing idea. Hey ho.

Thanks SC

[Chuck H]

Hi Chuck,

ok so let me get this right, the suggestion is:

1. replace the A500k tone pot, with a Bournes B250k pot.
2. Replace my 680pf cap, for a 330pf cap
3. Cut the track as indicated (before installing).

Have I got that correct? is your pot pic the view from same as my diagram/ (which is looking at the backside).

Thanks, SC

Almost correct. The only change would be that you'll omit the 47k resistor (the one you weren't sure about) and the new 330p capacitor will be in series with the 100k resistor instead of parallel with it. Just like the modified drawing I posted.

[Chuck H]

Hi Chuck,

ok so let me get this right, the suggestion is:

1. replace the A500k tone pot, with a Bournes B250k pot.
2. Replace my 680pf cap, for a 330pf cap
3. Cut the track as indicated (before installing).

Have I got that correct? is your pot pic the view from same as my diagram/ (which is looking at the backside).

Thanks, SC

Almost correct. The only change would be that you'll omit the 47k resistor (the one you weren't sure about) and the new 330p capacitor will be in series with the 100k resistor instead of parallel with it. Just like the modified drawing I posted. Where to cut the pot in the drawing IS in the correct aspect for almost any single gang pot.

[Fluoroscope 5000]

Hi Flour50,

I'm sorry I'm lost again. What does TB network mean?! jeepers I've never been so overwhelmed with info. I've got to go over it all again to make sense of this cable capacitance thing- at the moment I haven't the foggiest idea. Low-loss it says.. but loss of -what- tho? ('capacitance' I fear might be the answer.. but would only lead me back in a circle not knowing what that implies).

I wonder what my cables are.. would there be a 50/50 chance they might be 'low-loss' i wonder? thing is, I haven't ever once thought 'that cable sounds better than the next', its never something that's ever been a question to ask, or a consideration to make personally. They sound the same, cheap nasties to curly wurlys to solid 80's high quality ones.. to me. So I'm quite baffled by this tbh.

I am reminded of my (no1 passion) hifi cable 'discussion'.. slightly alarmingly, because there are loads of folks saying naim speaker cable sounds better, but when I do a comparison I can tell no difference between naim expensive stuff (for eg) & far lesser stuff. I have a feeling there, naim state their cables are a -must- because of capacitance matching to their amps.. & their followers, follow (I -am- a firm naimee, but reject the dedicated naim cable thing) imploring only their speaker cables be used. Not (oh no it can't be) that, in fact it's more likely just a clever marketing idea. Hey ho.

Thanks SC

TB network = Treble Bleed. If you look up the term "electrical network", you'll see it is indeed the correct term, rather than "circuit".

"Low loss" does refer to the C (Capacitance), which is 52pF/Meter. Yes, cable marketing is largely hype. Cable C makes very little difference in active circuitry, but the total C value b4 the first preamp/buffer stage can make a big difference in passive Hi-Z circuitry. The ~160pF value I gave for 10' of the Spirit LLX cable with the HICON plugs should result in a resonance peak just above 4kHz for the 3.7H bridge TS pickup with 500k pots into a standard 1M Ohm pedal or guitar amp input. I've already explained several times why that matters. You might discover the C of your cables if you can find out the brand and model, but many manufacturers don't supply the cable C value anyway.

I assume you are in the UK? If so, the Spirit LLX cable in the last link I gave is cheap enough that it's worth considering if shipping isn't expensive. You can solder whatever plugs/connectors will fit over it, but some plugs have a surprisingly high C value. I've seen one measurement of 60pF for a radial L-plug! Most plugs are much lower than that -- maybe 5-10pF. The HICON plugs excellent quality with a built-in switch that disengages the hot lead when the plug is pulled from the jack so it doesn't make a loud "boom-pop" that can damage speakers and whatnot -- hence the "noiseless" moniker. Neutrik also makes noiseless plugs, but they are kinda' long. Shorter plugs generally put less stress on jacks.

Misinformation abounds on the topic of speaker cables, as is true for many topics. In fact, 18AWG lamp cord is excellent speaker cable, as long as the DCR for a given length is not greater than 1/10th the speaker Ohm rating and the amp power is so high as to cause the cable to melt the insulation. Shielding is not recommended for speaker cable because it doesn't do anything but trap heat. It's very unlikely heat would become an issue with 18AWG lamp cord even running from a 400W bass amp. The DCR for 18AWG wire is only 21 Ohms/1k Meters, so, go figure. A good test for speaker cable noise is to unplug it from the amp and put your ear right up to the speaker. You hear any noise? It's a non-issue. Going on 9 pages on this. I think you have enough to proceed with confidence. I'd look up a soldering video to make sure you are following proper procedures. I discovered a few errors I was making after some 40 years since I soldered my first cable.

[Sea Chief]

Almost correct. The only change would be that you'll omit the 47k resistor (the one you weren't sure about) and the new 330p capacitor will be in series with the 100k resistor instead of parallel with it. Just like the modified drawing I posted. Where to cut the pot in the drawing IS in the correct aspect for almost any single gang pot.

Hi Chuck- am I allowed to go 220pf cap? only bc I have one (silver mica).. & it seems pretty close. I'll go back over your posts & double check things.

47k resistor will be ommited, & 100k k will go in seeies instead/ noted.

Great help- thanks so much. SC

[Chuck H]

Hi Chuck- am I allowed to go 220pf cap? only bc I have one (silver mica).. & it seems pretty close. I'll go back over your posts & double check things.

47k resistor will be ommited, & 100k k will go in seeies instead/ noted.

Great help- thanks so much. SC

220p will be fine. I used a 220p/100k treble bleed for years. But I'm typically getting down around 1 to 2 on the volume control to clean up because of the gain level I dial in. If your circumstances are different then your needs will be different. But sure, try it. In this scenario the values aren't etched in stone. Far from it.

And since we're discussing "treble bleed" circuits for guitar volume controls, I should mention that the new series wiring for the treble bleed will be less effective at maintaining the brightness from 10 down to about 7 than the parallel circuit you have now. BUT it will give your volume control a true audio taper. So if you hope to use your volume control to go from a distorted tone to a clean tone the series circuit I proposed will make for an easier adjustment.

[Fluoroscope 5000]

Sounds like it's starting to click for you, Sea Chief. There I was talking about a "network" being the correct term for the TB vs "circuit" and I said "noiseless" when the HICON plugs are clearly listed as "noisefree". Anyway, it was all worth it if you have a better understanding of things.

[Sea Chief]

220p will be fine. I used a 220p/100k treble bleed for years. But I'm typically getting down around 1 to 2 on the volume control to clean up because of the gain level I dial in. If your circumstances are different then your needs will be different. But sure, try it. In this scenario the values aren't etched in stone. Far from it.

And since we're discussing "treble bleed" circuits for guitar volume controls, I should mention that the new series wiring for the treble bleed will be less effective at maintaining the brightness from 10 down to about 7 than the parallel circuit you have now. BUT it will give your volume control a true audio taper. So if you hope to use your volume control to go from a distorted tone to a clean tone the series circuit I proposed will make for an easier adjustment.

This opens up a sort of new avenue of things I dont understand tho. I have no idea how this 'roll the vol down to clean up' happens. What situation allow it. Its always been 'yet another amp/ gtr mystery'. I thought it wasn't something I could ever achieve, mainly because I won't have any amp "naturally distorted" (the recent huge gremlin noise at MV at just 2, getting louder with knob increace, has put me off the idea of diming an amp over say 5w: if it suddenly occurs & might induce a heart attack with a 15w amp cranked, its a terrifying prospect).

Now I think, it can only be achieved, by using an amp 'dimed' (or rather it has gone into distortion situation vol 7 up say) & from that situation you can use the gtr volume knob in this way: i don't know, but if so, its a pipe dream for me & just not achievable then. So if this is the reason for your suggestions of this rejig, most likely because it works great for you (& your amp I can only assume is dimed to be able to do it).. but.. if the caveat is, a diminishing of the treble when turning the vol down, then it might defeat the objective for my situation.

My objective is simply 1) to get a useable volume control, even if not perfectly incrimentally even (because I cannot ever do the roll vol down to clean up thing so I dont need perfection- just a roughly even taper is fine), & 2) to keep the treble even/ not lost, when I do go to use the volume. That's all I need.

If I could, possibly be in a situation to do the 'vol down clean up thing' (Ive no idea if it could ever be realistically achievable) but in doing so the sound gets darker & muddier the more vol is turned down, my ears will just not permit me to deem the gtr useable in any other position than full rotation. To me, the sound simply gets worse in quality, the more treble is lost. That's not to say I'm a "MusicMan + 500k tele bridge pickup only country Joe all the time".. no I'm not. But bassy/ muddy guitar pickup sound is the one thing I do my utmost to steer clear of. In my case, its always simply been use vol @ max, I dont know exactly why, whether the caps as 'standard config' Ive always bought guitars new & used in this state (never bought one modified, ever) simply are in an "inferior state" this way, why they would be sold like so, so you simply cannot do the 'roll voldown clean up thing' -without- there being this awful cello tone creeping into proceedings as a 'pay off you have to accept'.. is yet another mystery.

As I cant make head nor tail of pretty much everything gtr & amp related with regard to distortion & volume interactions.. I stick to a clean sound, tele on max. Dip into a distortion pedal maybe.. urgh/ sell it. Back to clean, tele on max. Its -sooo- damn limiting, Ive literally missed out on making music for 35 yrs as a consequence (with the added frustration of folks often saying 'I turn down vol to clean it up'.. as if they know some trick I'm just not allowed to be privvy to).

Thx4readingmyspiel- SC

[Fluoroscope 5000]

Chucks TB "network" and V pot hack will RETAIN the bass to treble balance as the V knob is turned down, as well as offering a more linear level decrease -- assuming you do not use a fairly high C cable b4 the first preamp buffer stage. That's the whole point. It will offer better clarity when reducing overdrive via the V knob so you won't get that "awful Cello" sound (Cellos sound awful?).

Keep in mind that the C from each cable will sum when a true bypass pedal is disengaged. That could defeat any benefit of the TB network. You may need an always on buffer b4 your distortion pedal if that's the case, as well as a very low C from the guitar...mystery solved.

Say, what distortion pedal and amp are we talking about?

[Sea Chief]

Chucks TB "network" and V pot hack will RETAIN the bass to treble balance as the V knob is turned down, as well as offering a more linear level decrease -- assuming you do not use a fairly high C cable b4 the first preamp buffer stage. That's the whole point. It will offer better clarity when reducing overdrive via the V knob so you won't get that "awful Cello" sound (Cellos sound awful?).

Keep in mind that the C from each cable will sum when a true bypass pedal is disengaged. That could defeat any benefit of the TB network. You may need an always on buffer b4 your distortion pedal if that's the case, as well as a very low C from the guitar...mystery solved.

Say, what distortion pedal and amp are we talking about?

Hi Flour50,

No, cellos & my favourite, violas, sound the best of all stringed instruments (bar a strad violin) but If your violin sounded like a cello, something wouldn't be right/ something would bug you/ it should not sound like it. Its an analogy -a guitar is voiced more akin to a viola in my book- but it serves to put my point across.

Ok all I can do is do the changes Chuck suggests & see, but good to read perhaps the treble will be retained too. I will do this 1 st, then go over the cable capacitance thing again.. its still is not clicking with me: if the loss thing is clarity.. I dont need clarity per se; if the loss thing is treble a tonality thing.. then Im on board. I will try my best to understand it.

--

As to distortion pedals, Ive just bought a 'vox distortion' i chanced upon used locally.. because I wasnt getting much joy from the attenuator + ac15.. a frustrated buy of yet another pedal. Its fairly good, I think, but can it do the vol turn down/ clean up thing? Until the treble is retained doing so, I cannot make a clear judgement you see. Im not sure I can make a judgement even so, so confused I am with it all my mind I cannot trust isnt playing tricks sometimes.

What I need to understand is in what situations this vol/ clean up facet can be employed. Only with an amp dimed? Plus perhaps only with 'tube driven' distortion pedals-? Ive no idea Im throwing things blindly out here. Or should - any- distortion pedal be able to offer this facet? ( if so then I give up.. bc for 35 yrs it simply does not work with me). Or do you have to 1st modify the guitars tone/ vol gtr circuit before, to them employ one of these situations, in order to achieve it? Its probably the biggest most long enduring mystery to me. As said, with an off the shelf gtr, off the shelf distortion pedal, off the shelf amp ( ie no gtr circuit modifications, with just a std amp/ not some super ace amp in super ace full throttle set up, with a standard distortion pedal.. it does not work when I try: simply the volume is just diminished, & the ammount of distortion remains the same: this is fundamentally, totally, different).

thanks SC

[Fluoroscope 5000]

Hi Flour50,

No, cellos & my favourite, violas, sound the best of all stringed instruments (bar a strad violin) but If your violin sounded like a cello, something wouldn't be right/ something would bug you/ it should not sound like it. Its an analogy -a guitar is voiced more akin to a viola in my book- but it serves to put my point across.

Ok all I can do is do the changes Chuck suggests & see, but good to read perhaps the treble will be retained too. I will do this 1 st, then go over the cable capacitance thing again.. its still is not clicking with me: if the loss thing is clarity.. I dont need clarity per se; if the loss thing is treble a tonality thing.. then Im on board. I will try my best to understand it.

--

As to distortion pedals, Ive just bought a 'vox distortion' i chanced upon used locally.. because I wasnt getting much joy from the attenuator + ac15.. a frustrated buy of yet another pedal. Its fairly good, I think, but can it do the vol turn down/ clean up thing? Until the treble is retained doing so, I cannot make a clear judgement you see. Im not sure I can make a judgement even so, so confused I am with it all my mind I cannot trust isnt playing tricks sometimes.

What I need to understand is in what situations this vol/ clean up facet can be employed. Only with an amp dimed? Plus perhaps only with 'tube driven' distortion pedals-? Ive no idea Im throwing things blindly out here. Or should - any- distortion pedal be able to offer this facet? ( if so then I give up.. bc for 35 yrs it simply does not work with me). Or do you have to 1st modify the guitars tone/ vol gtr circuit before, to them employ one of these situations, in order to achieve it? Its probably the biggest most long enduring mystery to me. As said, with an off the shelf gtr, off the shelf distortion pedal, off the shelf amp ( ie no gtr circuit modifications, with just a std amp/ not some super ace amp in super ace full throttle set up, with a standard distortion pedal.. it does not work when I try: simply the volume is just diminished, & the ammount of distortion remains the same: this is fundamentally, totally, different).

thanks SC

How the cable C affects the TB response depends on how much C there is b4 the first buffer stage (a preamp is a buffer that can also boost the signal). The treble may be lost when the V is turned down if the cable C is high enough.

The loss you’ll get with a higher C cable is in the treble range. It will increase the level of the resonance peak a bit, but at a lower freq.
Your AC15 combo will indeed have plenty of 2.4kHz clarity if it has a 25W G12M25-75 “Greenback” speaker, but it won’t have much 4kHz+ treble. The classic chime of a Vox ACxx amp came from the AlNiCO "Grayback" or Blue speakers. They have a lot more 4kHz+ range than a Greenback. You might consider a different speaker if you want that classic chime.

The easiest affordable solution for that amp would be a WGS 'Retro 30'. It has plenty 4kHz+, a fuller midrange response with an eardrum saving 3kHz dip, and a tight bass response generally better for amps like an AC15 that don’t incorporate any GNFB (Global Negative Feedback) that would otherwise tighten the bass response. The 'Reaper HP' is similar but with a tad less high-end. It's like a 50W version of a Pre-Rola G12H30-75. If you want deeper bass and a smooth extended high end, the 30W cloth-surround Weber '1230-55' is a very nice 55Hz cone ceramic speaker. 55Hz cones normally have a more scooped sound, but the cloth surround reduces the high-end peaks a bit. I'd opt for at least the "Heavy" doping on it to minimize cone cry. "Pre-Rola" is probably worth it. Still, your ears do need to be within 20d on-axis of a 12” guitar speaker to hear the high-end chime.

Guitar V knob controlled gain clean up that results in a Brian May-like sparkle can work well with either an overdriven amp or distortion pedal depending on the sensitivity of the amp or pedal gain stages, although May’s Burns Trisonic pickups are ~nearly ½ the inductance of yours so he could use a higher C cable to achieve the same resonant peak freq as either of your TS Pickups. FI, you can get that clean sparkle with the right guitar circuitry configuration and an old Germanium FF pedal because the interaction with the very low input Z of a Ge transistor rolls off the high end when the guitar V is up, and brings it back up when the V is turned down. Ge transistors are very temperature sensitive though, so they can be unpredictable. Brian May used to plug into a Ge transistor Treble Booster, but he now uses a custom Silicon version, which may be configured with a Lo-Z input.