Comments on: The Magnetic/Piezo blend pedal

By: Decibel Guitars

Decibel Guitars — Tue, 08 Feb 2011 20:30:48 +0000

Actually, no it does not.

While the Ernie Ball stereo volume/pan pedal does attenuate the A and B signals inversely over the full travel of the pot, the critical difference between the Ernie Ball 6165 and my blend pedal is that on the 6165, in the middle position of the pedal’s travel, both signals are at approximately 50% volume. On my pedal, which uses a proper “blend” pot (not simply a double-ganged potentiometer), each signal is only attenuated in one half of the pot’s motion, with a centre detent where both signals are at 100% volume.

Believe me, i researched this for YEARS before coming to the conclusion that the pedal i was seeking did not exist and designing and building my own.

By: studiodog

studiodog — Tue, 08 Feb 2011 20:25:32 +0000

The Ernie Ball 6165 DOES actually do whay your pedal does. Plug a TRS connector into IN B. In PAN mode, the pedal will inversely adjusts the volume of both input signals and output separate signals on OUT A and OUT B. In other words, the TRS mag/peizo signal from your guitar will be split to OUT A and OUT B with the pedal controlling how much volume each output gets. Full on for both at centre pedal position.

That said, I’m making my own from a Dunlop HighGain volume pedal shell!

By: Decibel Guitars

Decibel Guitars — Sun, 28 Nov 2010 07:29:32 +0000

Quite possibly, yes. I’m no electronic genius, but that sounds like it could work.

By: Mike Dunn

Mike Dunn — Sun, 28 Nov 2010 00:22:36 +0000

Wouldn’r diode inline with ground (in the proper direction, of course) also block the voltage from traveling back to ground?

By: Nick

Nick — Thu, 21 Oct 2010 23:57:09 +0000

Glad I could help. I’m not exactly sure how blend pots work, but I have a good idea. If you have a 250k pot, you could leave the wiring for the piezo signal the same, but connect the magnetic lead signal to a 225k resistor and the other end of the resistor to where the magnetic lead wire was on the pot before. If you have a 25k pot, you could leave the magnetic signal alone, and wire one end of a resistor to where the ground wire on the piezo signal is, and then the other end of the resistor to where the piezo signal wire is. Keep the ground and signal wires where they are. To find what value resistor you’d need for the second option, use the formula (R1xR2)/ (R1+R2). R1 is the value of the pot, and just guess and check until you get a resistance of 25k. If the pot works the way a normal pot does, that wiring scheme will work exactly the way you want it to. As long as you don’t use a 500k pot, the taper shouldn’t be affected noticeably.

By: Decibel Guitars

Decibel Guitars — Thu, 21 Oct 2010 14:23:56 +0000

Thanks, Nick

That info could definitely come in handy for myself or for others who may want to build one of these.

By: Nick

Nick — Thu, 21 Oct 2010 04:36:48 +0000

Hi, I’m modified my guitar with active pickups as well as a piezo bridge and the graph tech circuitry. My pickups needed a 25k pot, and I needed a 500k pot for the acoustic preamp out of personal preference. I wired it with 2 push pull pots and a dpdt switch, so that I could select the pickups normally, and only one pickup would be receiving power from the battery at a time. Pulling up the volume engaged a gain boost. Pulling the tone activated the piezos, as well a 475k resistor in series with the pot itself. It messed with the taper a bit, but it worked and sounds dead on and gives a value of 500k. Not sure if that will help you. You could also use a 250/500 k pot with a resistor wired In parallel to lower the resistance on the magnetic side of the blend pot.

By: Ed

Ed — Wed, 22 Sep 2010 00:58:57 +0000

Hmmm . . . good info, thanks. This should be a fun challenge. I’m going to pick up an EB 6165 I found used & see what can be done. Where there’s a will, there’s a way.

My two voice guitar is a 97 Hamer DuoTone with two separate output jacks, and I like the fact that the 6165 already has two ins & two outs, plus as you say – they’re very well made pedals.

By: Decibel Guitars

Decibel Guitars — Tue, 21 Sep 2010 21:34:24 +0000

I would LOVE to use the Ernie Ball pedals as a starting point, because i think they’re extremely well made and have super-smooth action.

Theoretically, it would be possible. However, the missing element is the long-shaft blend pot. Ernie Ball uses special long-shaft pots that allow the cord-and-spring assembly to be attached. Their stereo volume/blend pedals use long-shaft double-ganged pots, but they aren’t “blend” pots in the true sense. I have not seen a long-shaft blend pot readily available from any manufacturer. A custom pot could be manufactured, but they’d probably need an order of about 10,000 in order to even consider it.

If you’re handy, you could potentially weld an extender onto an existing pot shaft, but i’m not sure how well that would hold up, or if the welding process might potentially damage the pot’s innards.

This is how i ended up with a more standard “Dunlop” style pedal shell. It takes a standard pot, and while it’s not as smooth as an Ernie Ball, it gets the job done.

By: Ed

Ed — Tue, 21 Sep 2010 19:48:16 +0000

Here’s the schematic for the 6165:
http://www.ernieball.com/products/volume_pedal/pdf/po6165_vp_stereo-pan_500k_1999-10-12.pdf