Built and test this second version of the 22/7 by RunOffGroove.com. 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.
You can order boards for this project at PCBWay.com. I have two versions of the board. One uses the 4049 and the other uses the 4069. Otherwise the rest of the parts are the same.
Order PCB here: 22/7 PCBs on OSHPARK
Parts List
| Capacitors | |
| 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 |
| Diodes | |
| D1-4 | 1N914 |
| D5 | 1N5817 |
| D6 | LED |
| IC | |
| IC1 | CD4049UBE |
| Resistors | |
| 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 |
| Switch | |
| RANGE | ON OFF ON |
| Pots | |
| SUSTAIN | A100K 16MM |
| TONE | B100K 16MM |
| VOLUME | A100K 16MM |
Wiring
If you don’t want to build your own this one is for sale on Reverb.
[…] Build post here for parts and PCB: http://www.super-freq.com/22-7-on-osh-park/ […]
What’s supposed to go to R15, what’s that resistor on the 3PDT Switch?
R15 is the current limiting resistor for the LED. Use anything from 470r to 10k depending on the LED. 1K to 4k7 is a safe choice.
That resistor on the switch in the images is a 0r (0 ohm) resistor. I used as the wire to connect the two outer pins. Take a look at the wiring diagram for the switch and compare.
Thanks for the reply. I actually figured out R15 as soon as I posted that when I noticed the trace was connected to the LED. I usually use a 2.2k resistor.