The latest Mongrel Strat (artist's conception).
Welcome to the second installment in the Mongrel Strat Series!
If I were a sensible person, I would have split this week’s experiments into several posts. But much like eating pistachios, it’s tough to know when to stop .
Anyway, this project tackles three topics:
1. Several readers dug the sound of the Telecaster-inspired Seymour Duncan Twang Banger pickup used in Mongrel #1, where I paired it with a Duncan Lipstick Tube for Strat neck pickup and a Alnico II Pro middle. But I wanted to hear how the Twang Banger sounded in a more traditional Strat array, so this time I paired it was a couple of vintage-accurate SSL-1s, with a reverse-wound, reverse-polarity model in the middle position.
2. Over in The Secret Room, a participant brought up the subject of the Vari-Tone control used in the Gibson ES-345. I wanted to learn more about this often misunderstood circuit (well, I never understood it, anway) and explore whether it had relevance for Strats.
3. In response to another Secret Room topic, I wanted to resolve whether there’s any sonic benefit in bypassing the tone circuit completely.
And the results? You tell me — here’s the video:
Some observations:
I’m loving the sound of the Twang Banger combined with vintage-style Strat pickups. Obviously, many players have have issues with vintage-style Strat bridge pickups. Some address this by using louder/darker/fatter high-output bridge pickups. But there’s something compelling about going to the opposite extreme. The clangorous Twang Banger with its copper-coated steel backing plate is bright as hell, but definitely not thin-sounding. It you dislike traditional Strat bridge pickups for their thinness rather than their brightness, I heartily recommend this cool alternative.
Now let’s talk Vari-Tone. (If you already know the hows and whys of the circuit, skip this next bit.) In a conventional tone control circuit, the tone control removes highs, with the amount of removal determined by the value of the capacitor (as explained here). The Vari-Tone departs from this scheme in two ways:
- It adds a second rotary pot that selects between multiple capacitor values. In other words, one knob rolls off treble and the other determines the amount of roll-off.
- The circuit also includes an inductor. Unlike a capacitor, which removes treble, the inductor preserves it. Result: twisting the tone knob sculpts the midrange without nixing highs. It’s like a subtle version of a wah effect. Sounds promising! But since it’s a passive circuit, it can’t actually raise the levels of mids, but only lower the surrounding frequencies. Which means that there’s a noticeable (and potentially problematic) volume drop when you engage the circuit.
In the demo, I connected the inductor via a push/pull pot so I could remove it from the circuit. (This is not an original idea — several DIY sites have explored the idea, and I learned a lot from this one in particular.) With the inductor removed, you get only treble cut.
I’m of two minds about the Vari-Tone circuit. No — make that six or seven minds. It definitely adds new colors, but the two-potentiometer layout is a space hog, and the volume drop is a drag.
Next time I want to try a dumbed-down version with no inductor and only three cap values, selected via a mini-switch rather than a cumbersome rotary pot. Expect to see it in a future mongrel project!
Finally, I wired in a tone control bypass to hear whether, as some claim, there is a meaningful improvement in volume and/or brightness when the circuit is bypassed, as some have claimed.
Sheesh — I don’t hear much difference!
As my San Francisco neighbors, the Mythbusters, might summarize:
Tele-style bridge pickup in a vintage-style Strat? Confirmed.
Vari-Tone (or some variant) in a Strat? Plausible.
Does it sound better to bypass a guitar’s tone circuit? This myth is BUSTED.
Great demo Joe. It was very instructive to hear the Vari-Tone in an A-B comparison. I do wonder about the inductor as inductors can vary quite a bit, they have a Q rating which describes their bandwidth shape it has to do with resistance of the wire used, core material and winding physics AFAIR (it’s been a long time since electronic school). So different inductors may change the sound a bit mostly the width of the wah effect. One thing that does come to mind is to put one in a fuzz box, which has been sort of done before but I am not sure about the inductor being very common. Here is a link to the Gibson schematic of the ES345 it’s a bit more complicated than I thought it would be:
https://www.gibson.com/Files/schematics/ES345.PDF
It has a separate set of Vari-Tones for each pickup with some resistors as well. Also the tone controls are pre-Vari-Tone which would definitely change the response a bit. I am not sure how much difference it would make in overall sound but it would be a bugger to fit in the Strat control cavity.
I was a bit confused about the video tho’ for position 2 you had the Twang Banger + RWRP and position 4 bridge + middle that seems like it must be wrong since the text says RWRP was in the middle but they sound different.
In any case I need a Twang Banger in my Strat!!!@
BTW is the amp you were using a Bandmaster? It sounds great!
Have you had any experience with the switching setup in a Les Paul Signature? It is a full hollow body with a mahogany block under the adjusto-matic bridge/ stop tail piece it is 335 shaped with asymmetric cutaways. It was made originally in the early 70’s I think. It had a three position rotary switch that changed the taps on a transformer with 2 low impedance pickups they used 2.5K pots and it had a polarity switch. It also has a treble bypass on the volume control. The taps go from a sort of lipstick pickup airy feel in position 1 to a slightly hot strat-like sound in position 2 to a raging Les Paul sound in position 3 at least on my Epiphone reissue (which I think was made around 2001 AFAIK). The Epiphone Jack Casady Signature bass is like this but with one pickup (his original Gibson bass has 2 pickups). Jack is one of my heroes he influenced my guitar playing with his bass playing . I fell in love with this guitar after seeing Michael Ward playing one when he toured with John Hiatt on the “Perfectly Good Guitar” tour (great show I saw them 3 times in a week). The original Gibson Les Paul Signatures I have found are out of my price range but when I hit the lottery 🙂 I’ll get one. Anyway that is a truly unique switching system with 12 different sounds (three positions of the transformer taps times the three positions of the pickup switch and the phase switch). That could be an interesting experiment to try if you could find the right pickups and it might work on active pickups pretty well. My Epi Les Paul Signature is a great guitar it is a feedback monster and can make a 4-12 cab jump up and down!!
https://www.gibson.com/Files/schematics/LPSignature.PDF
The wiring is very different from the Les Paul Recording model.
Finally this is the link to the official Gibson schematics which you may find useful:
https://www.gibson.com/service/tech/schematics/
Have always kinda had a thing for the varitone just because of Alex Lifeson , he had that 335 forever used it on first 4 albums then he got the 345 with the varitone. One thing his custom sig model has is a 2 way on/off switch goes straight to bridge pup wired series. Lot of info on the interweb about tweaking the varitone just takes a little digging to find something that works for you. I have been thinking about some kind of onboard boost to combat the volume drop.
As for that tone control bypass I have seen one place it did make a difference. I had a 1M volume pot in my Strat which had Virtual-Vintage pickups which are stacked humbuckers (I won’t blaspheme by naming their manufacturer on this blog). I also had a 500K tone control with a push push switch that took the control in and out of the circuit. When I bypassed the control on this guitar it became very bright and would cut thru the mix like a razor blade (I was not crazy about the tone). However at the time I was playing in a band with a great but extremely loud guitarist that was unable to realize how loud he was no matter what. It was the only way I could play a lead and be heard. This other guitarist could be ridiculously loud even when we made him buy a Fender Blues Jr to replace his Fender Evil-Twin for this band. He can perfectly mimic any guitarist from the classic rock playlist very convincingly with just a Les Paul and a few pedals. But the one thing he can’t do is play at a reasonable level no matter what we tried. I even modded his amp, put it on a chair, tilted it towards him but no dice, I think it was a sort of passive aggressive thing with him even tho’ he is a sweet guy.
I never play with him these days so I ditched the tone bypass as even at it’s very best was always harsh sounding. I know a lot of guys that like having the tone bypass on their guitars but I will never have one again. I would rather use a treble booster like my Devi Ever Ruby (Dark). I bought a travel size guitar recently with no tone control and I am going to install a stacked control to have a tone control. The travel guitar also has just a bridge pickup so I really need to tame it down (I am a neck pickup user mainly).
I like your artists concept of the mongrel strat. Here is a little pic I always get a bit of a giggle from having owned a cheap Yamaha key-tar for 20 plus years.
That illustration is 100% scientifically sound. Zoologists have long since established that platypuses gravitate toward the Keytar. 😉
what inductor did you use
This one: https://www.mouser.com/Search/Refine.aspx?Keyword=42TL021
0.Couldn’t you fit a blower and install the vari-tone before the jack?
Regarding the Varitone;
it’s a midrange notch filter that uses an inductor. When I had a Les Paul Standard, I always hated the usual two volume/two tone setup, since it’s redundant. So I wired it for two independant volumes, a lá a Jazz bass or Rickenbacker, a master tone and the Varitone.
This was so much more useable than the stock wiring.
Oh yeah, I meant to point out that the Varitone cuts mids, it doesn’t not boost mids or cut the frequencies around the mids. That would be a “band pass” response. This is a notch filter.
Weird thing about the Vari-Tone, though: When you remove the inductor, the results aren’t all that different! Yes, they’re audible, but you really do get much of the same effect with just the caps. It’s not just me saying it — you’ll find the same sentiment often online.
Joe do you mean “remove the inductor” by shorting across it (or where it would have been) from the cap/rotary switch common to ground? If you simply removed the inductor without doing anything else, all the caps are just sort of hanging in mid air and really unlikely to affect anything.
LOL — yet again, you’ve clarified what I meant to say. Thanks again.
I was searching for the Varitone schematic and the first image link led me to this page, where it looks like just what you are talking about is shown.
https://andrew-kul.livejournal.com/29118.html
Lots of caps, a rotary switch, no inductor – common just wired to ground. Unfortunately it’s in Russian and for some reason my web page translator is not cooperating.
Exactly. The page seems to show both the inductor and non-inductor versions. I urge folks to try it both ways. The differences in sound are noticeable but modest. You might be surprised.
As far as I can tell the Gibson Varitone is a mid notch filter ranging from around 300Hz up to around 4,000Hz. A series L and C resonant circuit that shunts the signal at its resonant frequency to ground. It puts a big dip in your mids but leaves your lows and highs intact. You could make the series 100K a variable control to adjust the depth of the dip. If you leave out the inductor and just run the switched capacitor common to ground then all you have is slightly more extreme switched version of a normal guitar treble roll off control.
Joe – I’m not sure that the Mouser 42TL021 will give you the real Varitone experience. Did you measure the inductance of the transformer winding you used ?
The Gibson Varitone seems to use a 1.5H inductor, I suspect the windings on the transformer might be rather less than that.
Looks like the Primary winding on that transformer is probably around 0.6H. So it is rather less than the Gibson 1.5H and your filter notches will be around 440Hz up to 6.3kHz if you use the Gibson capacitor values of between 0.22uF and 0.001uF.
Joe, I wired an "all pass" mini toggle on my strat, to bypass both vol and tone and I can tell you it DOES bring out a completely different guitar…with switch engaged, all pickups (after the pickup selector goes directly via the toggle switch to the output jack)…this does make a great increase in vol/bright tone..vol and tone are now non-operational with the switch…
Whether or not bypassing your guitars volume and tone controls makes a big audible difference depends on a number of things. If you happen to habitually run your guitar into an amp or pedal with a lowish input impedance the load from these may minimize any effect. The notional input impedance that guitars are expected to see is 1 Megohm. Many pedals are lower than this and even some guitar amps are 470K or lower.
How obvious the difference might be can also depend on your guitars pickups. The difference you might expect would be a slight increase in output and an increase in the highs. Also a long / high capacitance guitar lead may hide any difference.
Take a typical Strat pickup with a winding resistance of 6.5K, and inductance of 2.3H and a self capacitance of 110pF. With this wired into typical 250K / 250K Strat electronics with 0.022uF tone cap, controls wide open, running through a cable with 470pF of capacitance into a 1Meg input, the electronic response is flat up to about 1KHz, rises to a 4dB peak at 3.8KHz, then falls by 12dB per octave.
Disconnect the controls and the response shifts to a +15db peak at 4.3KHz. Now on a reasonably bright amp you should hear that. Although it should be born in mind that an electric guitar doesn’t put out much signal at 4 odd KHz.
Change the cable capacitance to 1,000pF (i.e. twice the cable length perhaps) and the amp input to 470K and the peak drops to 12dB at 3KHz (and 5dB at 2.8KHz with the controls reconnected). Which is a less dramatic change.
For other pickups with different resistance, inductance and self capacitance the results will be different.
Just to add to my previous post – if the question is – does it make a difference to disconnect just the tone control (rather than tone AND volume)
Going back to my first example with the controls wide open the response peaks about 4dB at around 3.8KHz. Disconnect just the tone control and you get +8dB at 4.2KHz. So yeah I guess with a fairly bright guitar and amp you should hear that. It may be worth pointing out that most guitar loudspeakers are past their high frequency peak and are normally 5 or 6dB down by the time you get to 4KHz.