Rhythm circuit volume knob causes tone to change as I roll it down

[alexpigment]

[NOTE: I realize the title is very "captain obvious", but there is more nuance to the report]

In my endless search to find the most useful mod for the rhythm circuit, yesterday I rewired it such that the rhythm switch goes to *just the volume knob*, and works on all 3 pickups. This means that I get a brighter/slightly louder version of my tone compared to my main circuit, which uses 250k pots. It's actually quite useful, since it means that I can give a little extra boost for leads, or perhaps just more jangle/spank when I need it.

However, there's a usability problem. The rhythm circuit tone gets darker as I turn down the volume, which means that I really only get more brightness when the volume is at 10. Normally I get around this on my guitars by changing the wire connecting the volume and tone pots (i.e. '50s wiring' or 'Fezz Parka' mod), however, in this case I only have the 1meg volume pot so that mod is not applicable here. Is tone change when lowering the volume inherent on a volume-only circuit? If so, is a treble bleed the only way to get around this?

Currently my thinking is that I don't really want to mess around trying to find the correct treble bleed resistors/caps, as I would have to order several resistors, and it's very trial-and-error from what I understand. If the volume is only brightest at 10, I might as well just take the volume out of the rhythm circuit and make it a blower switch (i.e. straight to the output jack), which would have the benefit of being slightly brighter and I could take out some weight in the guitar.

Any thoughts or suggestions are welcome. For context, the rhythm circuit is the stock volume pot from a Squier JMJM; I'm not sure if the quality or construction of that pot could have an effect.

[Telliot]

In my experience, this is normal and the only way I know to ‘fix’ it would be a treble bleed mod.

The mod you made is a series/parallel mod that gives you a more humbucker type of sound; thicker and slightly louder. IIRC, that only works when you’re in neck/both pickups position in the lead circuit, right? I had that wiring on one of my old JMs but I don’t remember exactly how I engaged it (I seem to recall getting no sound if my lead circuit was switched to the bridge pickup?). I have a 4-way switch on my Tele that gives me that series/parallel option, which I love.

[alexpigment]

In my experience, this is normal and the only way I know to ‘fix’ it would be a treble bleed mod.

The mod you made is a series/parallel mod that gives you a more humbucker type of sound; thicker and slightly louder. IIRC, that only works when you’re in neck/both pickups position in the lead circuit, right? I had that wiring on one of my old JMs but I don’t remember exactly how I engaged it (I seem to recall getting no sound if my lead circuit was switched to the bridge pickup?). I have a 4-way switch on my Tele that gives me that series/parallel option, which I love.

No, I didn't do a series mod on this one. I've had that before on other guitars and for me it doesn't work as well in practice as it does on paper (usually because you need to compensate for the added resistance of the series mode in some way). All I did was wire the rhythm toggle so that it switches the *output* of the 3-way pickup selector between my standard 250k vol/tone pots and a 1meg vol pot in the 'rhythm circuit' area before going to the output. Effectively, it's just a bright circuit that works on any pickup position.

Again, the thing that's odd to me is that I can easily work around this when I have a vol/tone knob. In my mind, I assumed the tone change was directly related to the interaction of the volume and tone knobs. In this case, there is no tone knob, so obviously there's some other factor that I don't fully understand.

[Telliot]

Ah. Sorry, I misunderstood.

[jvin248]

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Here's the full detail deep dive on treble bleeds.
https://guitarnuts2.proboards.com/threa ... ed-circuit

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[Lost In Autumn]

+1 for a treble bleed circuit.

[Lost In Autumn]

Also, a volume knob itself adds resistance and darkens the tone, much like a tone circuit. I’ve modded all of my offsets with 1meg, ‘no loaf’ pots for this reason and either use the tone knob to brighten or darken the tone, or employ the rhythm circuit, on the guitars that have them.

[andy_tchp]

I’ve modded all of my offsets with 1meg, ‘no loaf’ pots

[alexpigment]

Well, it sounds like I have a few options here. I’m ideally just wanting to make the tone brighter with the the rhythm switch. Currently it works but the downside is that I loose the brightness over the 250k pots below 50% volume. In other words, at low volumes the bright switch becomes the dark switch. It doesn’t make much sense to me but oh well.

Perhaps there’s another way of tackling this though. Is it possible to add in a resistor that just darkens the tone of the regular circuit without messing up the natural sweep of the vol/tone knobs? For example, could I use 1meg vol/tone and then have the switch effectively make them 250k? I feel like there are some gotchas here but maybe not.