Akashic Guitar effects circuit lookup
SPEEDDEPTH

Enclosure not stated · 2 knobs

Eff Dub Audio

The Wahscillator

Based on the Run Off Groove Phozer· 1 other board clones it

Controls
Speed · Depth
Price
see vendor

From the vendor

I always liked the original ROG Phozer’s base sound, but the LFO wasn’t really that useful at lower speeds. So I took the basic idea, which is the Tim Escobedo’s Idiot Wah + LFO, and kicked it up a notch. Instead of the Phozer’s input JFET buffer, I went with an op amp buffer, and since there’s an extra amp in the package, I also added an output buffer. The LFO is the Shoot The Moon tremolo. For the variable resistor element, just about any of the usual suspects will work: LED/LDR combo, vactrol, or even one of those optical ICs such as the H11F1. And that’s how the Wahscillator came to be.

It’s not a phaser. It’s not a vibe. It’s not a tremolo. It is…..sort of just like a smooth wah (no inductor) with a mildly choppy LFO. Surely there are many mods and tweaks to be made to improve, extend, or expand the tones available. I offer this working, fun, useful circuit to the community to experiment with and renovate. Changing the variable resistive element type and LED color/intensity varies the tone quite a bit, from watery pseudo-phaser to straight-up wah.  Can’t wait to see what you guys do with the Wahscillator.

If you are looking for LDRs, I’ve had good luck with these LDRs , as well as part LDR-P9203 from StompBoxParts.com.

As always, some links might be affiliate links. Think of all the pennies I will make!

Schematic

The schematic is in the post. Open it at Eff Dub Audio. No KiCad fragment has been drawn for this circuit yet.

Parts list 44 rows

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ocr read from an image · sch paired from the schematic · fixed corrected by hand. Check marked values against the build document.

RefValueNormalizedTypeNotes
Resistors 22
R12M2fixed2.2M
R22K2fixed2.2k
R3470Kfixed470k
R41Mfixed1M
R51Mfixed1M
R61Mfixed1M
R710Kfixed10k
R810Kfixed10k
R9470Kfixed470k
R102M2fixed2.2M
R11220Kfixed220k
R12220Kfixed220k
R13220Kfixed220k
R14220Kfixed220k
R152K2fixed2.2k
R161Kfixed1k
R171Kfixed1k
R18470Rfixed470
R19100Rfixed100
R20100Rfixed100
R21100Kfixed100k
R22100Kfixed100k
Capacitors 14
C1100nfixed100n
C2220pfixed220p
C31ufixed1u
C422ufixed22u
C5680pfixed680p
C66n8fixed6.8n
C722ufixed22u
C8100nfixed100n
C91ufixed1u
C1010nfixed10n
C1110ufixed10u
C1247ufixed47u
C1347ufixed47u
C1447ufixed47u
Diodes 1
D11N4148fixed1N4148
Transistors 1
Q1MPSA13fixedMPSA13
ICs 2
IC1TL072fixedTL072
IC24558fixed4558
Opto 1
OK1H11F1MfixedH11F1M
Potentiometers 2
SpeedA250KfixedA250kPotentiometer
DepthB2KfixedB2kPotentiometer
Trimmers 1
Bias1Mfixed1M

Other boards based on the Run Off Groove Phozer