Replacing Volume Knobs With Rotary Switches

keyofnight · #1 03-23-2013, 05:59 AM

Hey again, folks! I'm modding my 5-string bass again, and I could use a little help figuring out what to expect.

So far, I've added a varitone circuit to my bass: one tone pot and a 6-position rotary switch for selecting different capacitor values. I also changed the volume pots from 500k to 1M. This setup gives me control, but it gets out of my way when I don't feel like fiddling around. (:

The problem, I think, are the volume knobs. I never blend pickups. I either have both pickups at 100%, one of the pickups soloed, or both turned off; and I don't like fiddling with volume knobs to get to those settings. So…I figured I'd replace my volume knobs with 2-position rotary switches.

So here are some questions!

If I use switches instead of pots, that'll change the impedance—right? Last time I did that, the pickup's resonant frequency went from 2600Hz to 4400Hz. (The sound difference was huge…and I love the way it sounds now.) Could I expect the resonant frequency to go up even more?

Do you guys have any suggestions as to what kind of switch I should pick up?

Are there any problems I haven't foreseen? (This seems like a pretty easy peasey mod, so I'm not too worried about it…but I could always be wrong.)

Cadfael · #2 03-23-2013, 06:19 AM

When the normal volume is fully on, there is still the pot restistance parallel between HOT and GND. With just a switch, there is no parallel resistor.
Solution: A parallely wired resistor with 500k (or 1M) will solve the resonance problem.

Instead of a resistor, you can also wire a trim-pot in parallel. The middle to HOT and the left or right contact to GND. This gives you the opportunity to find the best value for the resonance frequency. A 1M trim pot should be closed about 50-100% so that you get a 500k-1M parallel resistor ...

You can put in one resistor (trim-pot) per PU (wired parallel to the PU - or only one resistor wired parallel to HOT / GND of the output jack (acting like a fully open master volume pot).

mystic38 · #3 03-23-2013, 07:21 AM

I am having difficulty understanding why, when you are looking for tone control, that you miss out of the 100 different tones by having gradual change from 0/100>100/100>100/0 and instead pick three tones from your bass.

line6man · #4 03-23-2013, 12:16 PM

Quote:

Originally Posted by mystic38

I am having difficulty understanding why, when you are looking for tone control, that you miss out of the 100 different tones by having gradual change from 0/100>100/100>100/0 and instead pick three tones from your bass.

Because it can be extremely inconvenient to have to fiddle with pots. And you do not get 100 audible tonal changes with any pot. More like a small handful.

Every so often someone is interested in a "volume presets" switch. The trouble is finding the right settings for all applications, but you can do that here, if it's desirable.

mystic38 · #5 03-23-2013, 01:16 PM

his time his money his bass.. but my opinion still stands.....

Though i was asking the OP, Its hardly a "small handful".... if you have a pair of underwound boring old dull pickups that only give 3 or 4 tones that is still 10-15 total, but if you have have overwound high output types like MFD's then take two volume pots, each with 5 to 8 noticeably different tones and that is 25-50 subtly distinct variations...

and i simply dont buy the "fiddle" argument after all, its really way easy to "fiddle" with pots to get the THREE tones he currently has... 0/100, 100/100 and 100/0

Now if he said..i dont want to fiddle with the fretboard so can i have a switch that only plays the Eb scale i would be all in....

Quote:

Originally Posted by line6man

Because it can be extremely inconvenient to have to fiddle with pots. And you do not get 100 audible tonal changes with any pot. More like a small handful.

Cadfael · #6 03-23-2013, 01:28 PM

If someone wants a toggle / On-Off without any volume, he can get it ...
Problem of sound change without any pots remains - and we have the solution ...

line6man posted a solution with several pots.
My solution is to build in a trim pot (untouchable within the cavity) which does the same as a volume pot would do ...

SGD Lutherie · #7 03-23-2013, 03:21 PM

Shouldn't you have a single 3 position rotary to control the pickups? That's less fiddling that two rotaries. Or use a toggle switch. Or get a blend control.

ctmullins · #8 03-23-2013, 08:05 PM

Five-position rotary switch: kill/neck/both/bridge/kill

And yes, it will raise the resonant peak some more. But if you don't like it, you can hardware in a resistor to simulate the load of the missing pot.

keyofnight · #9 03-25-2013, 03:50 AM

Quote:

Originally Posted by mystic38

I am having difficulty understanding why, when you are looking for tone control, that you miss out of the 100 different tones by having gradual change from 0/100>100/100>100/0 and instead pick three tones from your bass.

I had that setup for a long time…I couldn't / didn't hear much of a difference between pickup blend adjustments. I ended up wishing I had a switch like guitars do. I never even mess with volume all that much. I usually keep things full blast, control volume with playing strength.

Quote:

Originally Posted by SGD Lutherie

Shouldn't you have a single 3 position rotary to control the pickups? That's less fiddling that two rotaries. Or use a toggle switch. Or get a blend control.

I think I'm pretty set on the two switches. You're probably right: one switch would be less fiddly, but I want to use all of the hole bored out in my bass. (I've got 4, and I want every spot to do something. Goofy?—probably.)

Quote:

Originally Posted by ctmullins

yes, it will raise the resonant peak some more.

Excellent. I don't mind the resonant peak boost. I'd rather roll off mids/highs instead of wish I had mids/highs to roll off. (:

keyofnight · #10 03-27-2013, 01:45 PM

So… is there a pickup selector switch that I could use instead? Something that would fit where a volume pot would?

ctmullins · #11 03-27-2013, 02:30 PM

Yep - on/on/on mini-switch. StewMac sells them, amongst other suppliers.

keyofnight · #12 03-27-2013, 02:40 PM

Quote:

Originally Posted by ctmullins

Yep - on/on/on mini-switch. StewMac sells them, amongst other suppliers.

Aren't those too small for such a mounting hole?

line6man · #13 03-27-2013, 02:53 PM

Quote:

Originally Posted by keyofnight

Aren't those too small for such a mounting hole?

If you tried to mount them without washers, they would be.

I would go with a Gibson style toggle switch, personally.

Herbie Chesnutt · #14 03-27-2013, 02:54 PM

FWIW, and I say this as sort of arguing in favor doing something different than standard VVT with cap, on my PJ I wired in a pup selector (neck/both/bridge) and 500k master volume. I put in Darkhorse's "varitone" instead of tone pot just cuz I was bored and had the parts. Honestly I keep the varitone to bypass and enjoy that tone in each pup option more than anything else. I'm running flats and have '62 P in the neck and DiMarzio in the bridge so she is pretty dark and moody stock so in this case getting the electronics out of the way works. Not to everyone's taste, but I like her.

So I kind of agree with SGD's post earlier in the thread.

ctmullins · #15 03-27-2013, 04:30 PM

Quote:

Originally Posted by line6man

If you tried to mount them without washers, they would be.

I would go with a Gibson style toggle switch, personally.

Been there, done that. The Gibson-style requires a much larger hole than a pot does. The mini switches are a bit smaller, but the washers compensate.

line6man · #16 03-27-2013, 04:57 PM

Quote:

Originally Posted by ctmullins

Been there, done that. The Gibson-style requires a much larger hole than a pot does. The mini switches are a bit smaller, but the washers compensate.

So what?

ctmullins · #17 03-27-2013, 05:49 PM

Quote:

Originally Posted by line6man

So what?

Um, so the OP said he wanted something that would fit in an existing volume pot hole...