Active Blend Circuit Eliminates Insertion Loss

Today we are happy to share a schematic for a blend pot conversion that will eliminate the insertion loss effect that creates a volume dip at the center of rotation of a blend potentiometer when using active EMG pickups.

There is significant conflicting information regarding blend potentiometer sizing and wiring. This is a common toping in many online forum with players offering their best advice and experience to others who are on a journey to find a blend potentiometer that actually offers a smooth transition from Neck to Bridge without having a volume dip in the middle.

The problem is that blend potentiometers are not a one-size-fits-all solution. Passive pickups require different values than Active pickups. The situation is even more confused as the EMG site also lists conflicting information regarding which blend potentiometers are recommended for their own pickups.


As of this writing (August 2023) the EMG website offers conflicting information and implies the ABCX control is only for their X-series pickups whereas the ABC is for everything else. However, the PDF information for each control accurately represents the correct usage. Unfortunately, most potential shoppers do not download the PDF until they have the hardware on hand and read for installation.

The short version is:

  • If you have ACTIVE pickups, you need the EMG ABCX (B118) active balance control.
  • If you have PASSIVE pickups, you need the EMG ABC (B125) active balance control.


After many years experimenting with different potentiometer values, tapers, and wiring schemes (even the infamous “unbalanced blend” wiring) I always ended up using the ABCX balance control as it provided a smooth transition with no volume loss.

So how did they do it? I disassembled one to find out.

Ironically, the secret is nothing more than a simple mixer circuit that has been around for decades. By using a resister and capacitor on the output of the blend potentiometer, the insertion loss effect is eliminated while allowing a full 20Hz to 20kHz signal to pass freely.

The EMG ABCX control includes an opamp buffer as part of the the circuit. HOWEVER, if your signal path follows the standard flow (Pickups –> Blend –> Volume –> Preamp EQ) the buffer is NOT needed!

Why? Your preamp EQ already has a buffer in it! Why buffer it before it goes into a buffer again?

Pull out the soldering iron, grab a couple resistors and caps, and give it a try. You’ll be happy you did!