Posts Tagged ‘Rothstein Varitone circuit’

Part One: Tone Launch though “varitone”…


Okay, here we go. Next up on 3 easy mods, we’re plugging the new Epiphone EB3 Bass in to my Ampeg B15R (awesome vintage inspired bass amp!) Volume up, tone up.  What no varitone? NO VARITONE circuit?!! What?!! ARE YOU   %*&$*%#!!!  KIDDING ME?!!! And so I discovered that what looked like a varitone was not one at all.  Such dastardly wretched duplicity!!! Such deceitfulness!!! A simple chicken head knob with three positions: neck pick up, neck and bridge pickup, bridge pickup. Basically this is the same circuit as on your garden variety toggle switched Les Paul, dressed up to look like a varitone!!!

Epiphone Custom Shop EB3 sans Varitone

What?! No Varitone?!!!
You kiddin’ me?!!


What a bummer, what a misconception! I felt like I was misled at first, but in reality this basic three piece circuit was staring me in the face. On close inspection of the control plate underneath said chicken head knob were the numbers 1,2,3.  That’s it. Right out there in the open, NOT hiding! I just never expected to see them and so I didn’t,.. obviously. All I saw was the preconceived 4 position varitone circuit in my mind and displaced it on to this bass until suddenly the dawn of reality rushed in.  Don’t get me wrong, the bass sounded pretty darn good as it was, but to me, it wasn’t an EB3 without a varitone circuit , dig?


So what to do? And so I searched the net for any Gibson EB3 varitone circuit equipped wiring harnesses figuring that there must be some floating around as presented by the host of scavengers who in their vulture like fashion dismantle perfectly good instruments to part them out and sell the guitar parts for a tidy piece by piece profit. Nothing… Ebay had nothing. Nobody had anything except once in a while a choke which is a part of the circuit, would show up. A lot of good a choke is going to do for me, a person who is not  about to construct a wiring harness from scratch even though there are schematic diagrams for this control set up available on the net for this purpose.


I kept putting in searches for the circuit varying the theme here and there to see if I could get a different result somehow. Then I came across a very  interesting site called Rothstein Guitars: They claim that the “cornerstone of their business is their highly regarded prewired assemblies”. I searched through the site but could find nothing that would meet my needs and so I decided to shoot off an email to Andy at Rothstein Guitars to see if they could help me out.


Hi Andy,


I recently bought an Epiphone Custom Shop EB3 bass. I did not realize until I got it that what looks like a varitone is not. The rotary switch is 3 position only and is really simply a rotary pick up selector. Not that this is inherently a bad thing and it does work as expected, but I was hoping that this bass had the four position varitone circuit which it does not. I guess this was done simply to mimic the look while keeping costs down.

Anyway, I came across your site and was hoping for an “Ahaaaa!!” moment but did not find what I was looking for. By any chance would you make a pre wired Gibson EB3 varitone circuit assembly that I could install in this bass or know where I might find such an assembly?

Thank you very much.

Very Sincerely,



With my last ditch effort to upgrade this bass to the way it is supposed to be I patiently waited for a response………….. A few days later I checked my email inbox and there it is! An email from Andy at Rothstein guitars!!! 


Chuck –


We have had quite a few people ask us for wiring harnesses for EB-3 so we have been planning on offering some mods. We manufacture our own varitone (Platinum Lab Varitone) that is 6 positions (5 filters and a true bypass).  We could certainly wire up a harness that has 2 independent volume and tone pots, as well as a master varitone. There would of course be no method of pickup selection, except by lowering the volume of which ever pickup you want to shut off.




I got back to Andy to let him know that  I liked what he had to say and wanted to proceed with designing this.


Hi Andy,

That sounds great! And as far as your statement; (There would of course be no method of pickup selection, except by lowering the volume of which ever pickup you want to shut off ) that wouldn’t be a problem as my ’62 reissue Fender jazz bass has the same situation and it never bothered me. I do like the fact that it would be wired and ready and that it is inherently superior with 5 selections and true bypass. If you could get back to me with regards to pricing and shipping I would greatly appreciated it.




Bingo!!!  And so Andy and I went back and forth a bit on the design layout for this circuit until we decided what worked best. In the meantime a seller on Ebay that I inquired to about the same thing finally got back to me telling me that he could faithfully replicate the 4 position varitone circuit as was used on the Gibson EB3 but by this time I was totally stoked with the Rothstein 6 position design which I thought was a far superior approach and so I stuck with it. I know what  you are thinking; “He’s deviating from the original design!!” Look, this bass will never really be a replication of the Gibson EB3 anyway as it says Epiphone on the headstock, yes? Not that I have a problem with that as previously discussed in my last post; Gibson EB3 Bass. “CREAM” of the crop. Why you need one! Even the Epiphone Elite which is as close to original as you can get will, like this one, only be technically considered a “tribute” instrument. Okay, so who really cares about this semantic game? As it is so poignantly said at times like this; “it is what it is”; let us move on……

Rothstein Varitone Wiring Harness

Rothstein 6 position varitone layout


I sent Andy the pre requisite $150.00 plus shipping and then anxiously waited for delivery of my new  6 position varitone circuit equipped wiring harness.


Okay! A few weeks later it finally arrives!! I open the package and there it is totally laid out and labeled on a piece of cardboard ready for drop in installation. I guess this is the equivalent of a heart transplant for an electric bass and it is time to get the patient prepped for surgery.


First thing is to lie it on my rubber guitar mat face up. I remove the knobs and the all mounting hardware from the existing wiring harness. Next flip the bass, open and remove the control panel cover, de solder the pickup connections, ground wire, and make a  note of what goes where for future reference. Okay, next is to lift out the wiring harness leaving a stark bare control cavity awaiting its new heart.


Epiphone EB3 Control Cavity

Epiphone EB3 stock electronics

Epiphone EB3 wiring

Epiphone EB3 prepped for “heart transplant”

Epiphone EB3 Empty Control Cavity

Epiphone EB3 Empty Contol (chest) Cavity “out with the old”..

You know how they say that things don’t always go as expected? Well, one thing I didn’t anticipate was that the potentiometerswould be so heavy duty and therefore with a larger girth on the Rothstein harness that they would not fit through the existing holes. Time to get the drill out! Talk about heart transplant! Now this is getting as serious as a heart attack to me!

Epiphone EB3 Rothstein Varitone install

OMG!! That ain’t no Dental drill!!!

The wood in this area is  so thin that it could easily split and shatter should the drill bit “grab” the wood. Looking back, I think I could have slowly and methodically filed the holes to a larger size, but at that time in my excitement and rush to get the install done, it never dawned on me to employ this safer approach. What I did do for precaution was to tape off the areas to at least give the wood some reinforcement. Okay, I sized up the drill bit to match the potentiometer took, a deep breath, and drilled out four holes. Exhale!!! …..Went smooth as silk. Whew!! Luckily the varitone switch and output jack fit with no alteration.


Next, I dropped in the new “heart”. Just made it!! If those potentiometers were any wider I would have had to enlarge the control cavity. It was that close. I then reattached the pickups and the ground wire.

Epiphone EB3 Rothstein varitone install

Wiring the pickups (lungs) into the circuit (heart).

I had to sort of press and fit the wiring as the control cavity was now pretty much filled to the max with wiring “business”.

Epiphone EB3 Rothstein Varitone install

Wired up! (In with the new) Ready for a test run.

Screw the control cavity cover plate back on, flip the bass over, mount the pots, knobs, and chicken head varitone knob and we’re set for a test run.


Epiphone EB3 Rothstein vartione front view

Epiphone EB3 with Rothstein Varitone circuit.
Postion 6 “bypass” left blank

Once again plug into my Ampeg B15R and power up. Nice!!!! Clear, deep, middy full, versatile, are some of the adjectives that immediately come to mind. Okay so here is the basic theme to the varitone. Position One is quite trebly and can actually do a good approximation of a Chris Squire Rickenbacker Bass; clean and deep but also with just a bit of EB3 darkness thrown in. From there as you progress through to position 5 the treble slightly attenuates and the midrange becomes accentuated. Position 5 gives you considerable “bark” and it is so satisfying it might make even Jack Bruce smile!! Position 6 is true bypass meaning that as the varitone circuit is disengaged, there is no defaulting coloration to the bypassed tone. In bypass, it is as if the varitone circuit was never installed.


Bear in mind that with this circuit, even tiny adjustments to the volume and tone mix can yield some very unique tonal differences and because you decide what pickups you want on with the volume control you can even varitone a single pickup, or any combination of both pickups together. The tonal possibilities are quite endless!!


All in all, I could not have been happier with how things came out despite it added another $150.00 to the price of admission.


Next up, Part 2; bridge replacement.




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