RunOffGroove 22/7 Build

Here is another 22/7 build. It’s a Big Muff variation. This unique circuit replaces the transistor stages of the classic Big Muff with CMOS inverters. It’s a unique flavor of Muff. CMOS inverters have their own unique flavor of distortion and have been used in many classic pedals like: Craig Anderton’s Tube Sound Fuzz, Way Huge Red Llama, Blackstone Appliances MOSFet Overdrive.

The 22/7 was created by the unstoppable genius over at They have a lot great stompbox designs and great information, be sure to check out their site.

Build your own

I designed the PCB and created a project over at OSH Park. Check out my build Docs to read more about the circuit and learn how to make your own! The PCB is designed with the the pots, switch and LED mounted to the board for ease of assembly.

Build post here for parts and PCB:

Build Process

For this build I used a powder coated enclosure and milled the labels and logo through the powder coating with a desktop mill. This process works for me and I can do everything myself at home with no chemicals and little set up and clean up. I want to give UV printing a try in the future, I’ve seen a lot great results! I’ll be writing a blog post about it in the future.

What’s it sound like?

Sounds a lot like a Big Muff but with its own character. The hex inverters have their own flavor but the strong clipping inherent in the Big Muff architecture dominates the sound giving it the characteristic Big Muff sound. I suspect you hear hex inverters as the last inverter is overdriven by the rest of the circuit. I’d say you get the classic Big Muff clipping sound but you don’t get the over saturated sound you can get with a Big Muff when the input is too hot or the sustain high.

The 22/7 has a switch that changes the range of tone control through three different ranges. This changes the range and sweep of the tone control to match other big muff models. There is a Classic option which is described as an average tone model of classic Big Muff models. A Flat option which creates a flat tone response removing the mid scoop of the classic mode, this is a well known mod. Last is the Scoop mode which creates a deeper mid scoop, I compare this to the sound of the original Way Huge Swollen Pickle.

I like the last mode on its own, but the flat mode sounds better with the band. writing this in 2021 I’m spending all of my time playing at home so all the modes sound great!

This has been my favorite Big Muff of late! It’s got a good sound and the tone control hits a very usable range.

22/7 on OSH Park

Built and test this second version of the 22/7 by Sounds good. This is a great alternative for Big Muff fans. The OSHPark project is public and verified.

22/7 is a Big Muff built around CMOS inverters in place of the transistors used in the traditional BMP circuit. The CMOS inverters have a tube like sound when over driven.

Order PCB here: 22/7 PCBs on OSHPARK

Parts List

C1        100µ
C2                   33n
C3            100n
C4             220p
C5               150p
C6                150p
C7             100n
C8              100n
C9                  3n3
C10                6n8
C11                 10n
C12                10n
C13               100n
C14               150p
C15     100n
D1-4    1N914
D5              1N5817
D6           LED
IC1       CD4049UBE
R1      100K
R2                 470
R3       1M
R4       1K
R5      33K
R6       1M
R7        33K
R8       1M
R9        39K
R10         27K
R11                  1M
R12      1M
R13               330K
R14           100K
R15         RLED
TONE    B100K 16MM


If you don’t want to build your own this one is for sale on Reverb.

UBE Screamer PCB v1.1

This is the second version of the UBE Screamer board. This version fixes a mistake with the reverse polarity diode. I’m calling this ready for public consumption and will add it to the OSH Park projects pages soon.

The enclosure is grounded through the jacks. The bottom cover though doesn’t make an electrical connection to the main enclosure body due to the powder coat. I used a drill bit to remove the powder coat inside the count sink recess, this allows the screw to make contact with the back cover for full shielding.

Order PCBs at OSH Park


C1      10n
C2      2n2
C3        470n
C4       100n
C5        1n5
C6        150p
C7         100n
C8       100n
C9        100n
C10       100u
D1        1n4148
D2         1n4148
D3         1n5817
D4             LED
IC1      CD4049UBE
R1       1M 1M
R2         470k
R3          470k
R4        100k
R5          100k
R6        10k
R7        1m
R8       10k
R9        100k
R10       100k
R11       100k
R12       220k
R13      Rx  (see note)
R14       330
R15         RLED
TONE   B500k 16MM      
VOL      B100k 16MM    
GAIN    B500k 16MM
UBE Screamer Parts list


Build your own! Check out my OSH Park projects page. Or buy this one at my Reverb shop.

UBE Screamer by RunOffGroove

This UBE Screamer by is a unique twist on the venerable Ibanez Tube Screamer TS-808. It replaces the op-amps and transistor stages with a single hex inverter using an inverter in place of each op-amp and transistor. This has a great sound that stands up to all of the other overdrives. Read more about it over at

Well worth the effort, build it yourself! I’ve created a public project at OSH Park. Order boards and follow the build docs.