Will a buffer reduce incoming voltage from EMGs?

R

russellconner

Member
I ran into an odd problem. After great experiences with the Walrus Audio Ages, Eras, and Eons, I purchased an Iron Horse V3. After plugging it in, I observed a gated effect due to my guitars’ EMG pickups overloading it. This would happen when pedal gain was at 60% or higher. When I turned guitar volume down about 50%, the issue went away.

I sent the pedal to Walrus, who tested it, heard the same thing with an active-loaded guitar, said it was functioning as designed, and the overloading is normal for active pickups.

So…now I’m wondering if having a buffer between the guitar(s) and Iron Horse will reduce the EMG voltage and help with giving the pedal enough headroom to use more of its gain range.

Passive pickups have a typical voltage peak of 0.5V. EMGs peak at about 1.75V. Anyone know what typical peak voltage is for a buffer?

All I’m able to find online is output impedance for buffers, and no info on their output voltage. Thanks!
 
Just grab a cheap SD-1 and keep it off and run it before that pedal. You’ll buffer it with JFETs and not have to worry about the feel changing much or running into the same problem with another buffer based on its design. That’s what I’d do.
 
Thanks for the input, you two. (no pun intended) I’ve got an update:
- Over the weekend, picked up a Polytune 3 with buffer dirt cheap. Set it to buffered bypass.
- Also over the weekend, set EMG 81 heights to 4mm from strings (started at approx 3 mm, when issue was first observed)
- Received Iron Horse back from Walrus today.

Signal chain goes like this:

ISP Decimator G String —> Polytune 3 —> Digitech Drop —> Crybaby from Hell —> Iron Horse V3

In playing today, had new details for the issue, relevant to my Digitech Drop (true bypass) that I love. When Drop is bypassed, allowing standard-tuned EMG guitars through, the clipping is significantly worse. When Drop is engaged in any dropped tuning, the clipping all but disappears.

My sense is that the Drop somehow reduces or compresses the signal. Now, I’m wondering if I need a compressor or some sort of volume-attenuating pedal on the front before my distortion pedals. Two questions though:

What would a compressor do to the tone?

What kind of volume-attenuating pedals are there that wouldn’t alter the instrument EQ or cut highs like rolling guitar volume down?

Thanks in advance for any additional help!
 
Does rolling down your volume pot on guitar affects your tone that much? What is the value of the pot used?

What is the behavior, if you engage buffered mode on Polytune?
 
Comes to show you, every rig combinations have their own solutions and problems.

I took out my EMG 81 and EMG 85 out of my Gibson Flying V and put in some Schaller Actives .... next thing, I had was my buffers could still be use and I can use the benefits of active pickups .
 
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