Varitone switch part number

Pickups, wiring schemes, switch techniques and onboard active electronics for guitars and basses
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cbriere
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Post by cbriere »

Need help finding a proper switch sourcing info.
And clear wiring diagram.
It seems there is a need to connect to the 2 poles to have the inductor connected properly.
help!

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mauman
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Post by mauman »

StewMac carries 6-position 2-pole rotary switches, item # 3511 on this page: https://www.stewmac.com/electronics/com ... -switches/

There's an Epiphone Lucille stereo Varitone thread here with a diagram: viewtopic.php?p=286516

The Gibson mono and stereo schematics are widely available with a quick Google search.

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karul
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Post by karul »

supposedly factory schematic from a gibson forum
https://forum.gibson.com/topic/127119-varitone-wiring/

it seems that 6x1 switch can also be used for mono version. capacitors values on these schematic differ a little bit from the kits they are selling on ebay or can be found on the web.
Attachments
varitone mono.png
varitone stereo.png

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freefrog
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Post by freefrog »

The Gibson schematics work. Simplifying them might give a different behaviour to the VariTone circuit.

Proper rotary switches can normally be found in various web shops - Stew Mac, WDmusic, Thomann... At least that's where I've bought such parts in the past.

Capacitors: some vintage Gibson included "multi-cap" chips but regular caps will do the job as long as they are not too cumbersome.

The most critical part is the inductor: its value was not 1.5H in real vintage VariTones. It had a much higher inductance and "1.5H" in the Gibson schematics appears as a typo error, intentional or not. It can be guessed by watching real vintage "chokes" as pictured on commercial websites.

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Post by Cub »

freefrog wrote: 12 Oct 2022, 05:05 The most critical part is the inductor: its value was not 1.5H in real vintage VariTones. It had a much higher inductance and "1.5H" in the Gibson schematics appears as a typo error, intentional or not. It can be guessed by watching real vintage "chokes" as pictured on commercial websites.
Attached is the schematic of the Gibson Bueshawk, it uses a 7.2 Henry choke.
Gibson Blueshawk factory schematic and wiring diagram (20 May 1996).pdf
Gibson Blueshawk factory schematic and wiring diagram (20 May 1996)
(134.72 KiB) Downloaded 159 times
Also interesting is this thread on the good old GuitarNutz 2 forum.
The Gibson Varitone | GuitarNutz 2
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Post by freefrog »

Cub wrote: 12 Oct 2022, 05:57 Attached is the schematic of the Gibson Bueshawk, it uses a 7.2 Henry choke.
Gibson Blueshawk factory schematic and wiring diagram (20 May 1996).pdf
Yes and Stellartone was even selling 15H chokes as being the real deal a few years ago... Here is a post from a fellow member on MLP about that:

https://www.mylespaul.com/threads/humbu ... st-7863051

I've tried myself VariTone circuits with all kinds of inductive values, from 1H to more than 20H. IME and IMHO, a too high inductance is not a benefit for a guitar and might even make the circuit less efficient. But conversely, a low inductance makes the thing closer to a Lawrence Q filter than to a real VariTone... Reason why I take Internet topics with a grain of salt when they mention low inductance chokes like in the flawed Gibson schematic.

Oh, and the original "chokes" used by Gibson were labelled either GA-90-IC, either TF-90-IC if memory serves me.
Equivalent inductive values can be found in some mini-transformers, for the record.

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cbriere
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Post by cbriere »

thanks Guys,
i did my tests with this circuit. I had a 1.5H inductor. This inductor is keeping the highs with the capacitor in the circuit.
i was looking for the mid bump that the King Tone switch is doing for the stratocaster neck PU
I found out that a simple 1nF direct to ground is doing the job.
So i opted for a simple pull switch on the bottom TONE control that activates the capacitor.
Pretty pleased with this configuration.
we'll see in the long run if that makes it with the band.

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Post by freefrog »

cbriere wrote: 12 Oct 2022, 22:14 thanks Guys,
i did my tests with this circuit. I had a 1.5H inductor. This inductor is keeping the highs with the capacitor in the circuit.
With a 1.5H inductor, the circuit is lowering the output level and increasing the high range, exactly like with two pickups in parallel. Reason why the 2d and 4th positions of a Strat can be emulated with a 2H choke + a properly selected RC pair. :-)
That's the recipe of the Q filter and it works well with high inductance pickups but way less with standard transducers.

With a high inductance choke, a VariTone leaves the output level unchanged and the resonant peak of the pickup(s) almost identical but generate various mid dips (and no mid bump) according to the capacitor selected .

i was looking for the mid bump that the King Tone switch is doing for the stratocaster neck PU
I found out that a simple 1nF direct to ground is doing the job.
So i opted for a simple pull switch on the bottom TONE control that activates the capacitor.
Pretty pleased with this configuration.
we'll see in the long run if that makes it with the band.
If you want(ed) a mid bump and no dip, a mere capacitor is obviously better than a VariTone...

For the record, a 1nF cap on a push-pull is EXACTLY what I have in my main Strat: it shifts the resonance of my low inductance pickups @ a frequency close to those of "hot" single coils (SSL5, Ibanez Super 6 and so on). The output level is not increased, of course, but simple low value caps are very efficient as tonal shapers for standard single coils. After all, that's why some Strat heroes were using high capacitance cables....

Enjoy with your guitar!

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Post by cbriere »

freefrog wrote: 13 Oct 2022, 04:40
After all, that's why some Strat heroes were using high capacitance cables....
Oh, makes lots of sense. thanks for sharing.

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Post by Cub »

freefrog wrote: 12 Oct 2022, 08:59
Cub wrote: 12 Oct 2022, 05:57 Attached is the schematic of the Gibson Bueshawk, it uses a 7.2 Henry choke.
I've tried myself VariTone circuits with all kinds of inductive values, from 1H to more than 20H. IME and IMHO, a too high inductance is not a benefit for a guitar and might even make the circuit less efficient. But conversely, a low inductance makes the thing closer to a Lawrence Q filter than to a real VariTone...
What value for the choke, would you say, ticks all the right boxes in a VariTone circuit ?
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cbriere
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Post by cbriere »

[/quote]
What value for the choke, would you say, ticks all the right boxes in a VariTone circuit ?
[/quote]
i have tried a 1.5H
part Xicon ; 42TL021-RC
https://www.mouser.com/ProductDetail/Xi ... cyCode=CAD
And you can hear the high frequency coming back, most prominent when the high value cap are switched in.
With the 1nF , there is not much difference.

Also i have tried my coil guitar cable, witch measure 1.5nF with the capacitance meter. And the sound is not as clear as with a 1nF right in the guitar.
I would say its more muddy sound, the highs nd the peak resonant mid-high bump are not as clear as with the 1nF.

Chris

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Post by freefrog »

Cub wrote: 14 Oct 2022, 05:53 What value for the choke, would you say, ticks all the right boxes in a VariTone circuit ?
Not an easy question for an old geek like me :-P... It depends on the guitar & pickups involved, IMHO & IME. And even on the harness.

Gibson did mount 15H chokes in guitars and 30H in bass, AFAIK...

Theorerically, there's a continous shift of frequencies while the inductivity of the choke rises: the higher its inductance, the lower in the spectrum are the various mid dips due to the caps in series with it AND the main resonant peak of the pickup(s) selected.

Practically, it's not so clear because the VariTone + its wiring introduce some stray capacitance, as if the guitar was played through a longer cable. This stray capacitance shifts down the main resonant peak while the parallel inductive value of the choke does the contrary.

When this "balancing" relationship is neutral or almost neutral, the inductance of the choke is the right one. IME, it's usually an inductance equal or superior to the inductive value of the transducer(s). Hence the 7.2H of the choke in the Nighthawk, not far from the inductance of a generic P90...

That said, the circuit will also behave differently if the VariTone is after or before the volume and tone controls. LOL.

FWIW.

Off topic: I love your avatar. ;-)

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Post by freefrog »

cbriere wrote: 14 Oct 2022, 12:36
i have tried a 1.5H
part Xicon ; 42TL021-RC
https://www.mouser.com/ProductDetail/Xi ... cyCode=CAD
And you can hear the high frequency coming back, most prominent when the high value cap are switched in.
With the 1nF , there is not much difference.

Also i have tried my coil guitar cable, witch measure 1.5nF with the capacitance meter. And the sound is not as clear as with a 1nF right in the guitar.
I would say its more muddy sound, the highs nd the peak resonant mid-high bump are not as clear as with the 1nF.

Chris
A VariTone with a 1.5H coil in series with a 1nF cap will/would create a mid dip somewhere around 4100hz or something like that. It will/would affect the harmonics like a DiMarzio Dual-Resonance, while a "real" varitone is meant to affect mainly fundamental notes (somewhere between low E and the highest note of the high E, IOW between 82hz and 1319hz).

Consequence: the highest capacitive value useable with a 1.5H choke would be 10nF and not 1nf. :-)

Regarding the 1.5nF coily cable: yes, normally, it's "muddier" than 1nF, since if shifts down the resonant peak.

A cable long of 150m to 220m would have the same effect than a regular tone pot @ 0/10, for the record. :D

High cable capacitance is a good thing or not depending on the guitar, amp and cab used, IME and IMHO. YMMV.

Back to life: enjoy with your gear, I'll try to do the same with mine. :shred:

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Post by Cub »

freefrog wrote: 15 Oct 2022, 07:00
Cub wrote: 14 Oct 2022, 05:53 What value for the choke, would you say, ticks all the right boxes in a VariTone circuit ?
IME, it's usually an inductance equal or superior to the inductive value of the transducer(s). Hence the 7.2H of the choke in the Nighthawk, not far from the inductance of a generic P90...

Off topic: I love your avatar. ;-)
That's some great information right there, thanks !

Happy to see you love those two fellows as well. ;-)
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