I updated my 22/7 PCB. I had these boards made at PCBWay.com. These boards are great quality. Very cost effective. I’m a fan of OSH Park.com. They are good when you want only three boards, are in the US and need quick shipping. The PCBWay boards are very clean, they offer a range of colors, and their design rules support smaller trace sizes. If you need three boards and need them quick OSH Park is good. If you need more than three boards and can wait for slower shipping PCBWay is the better deal.
The 22/7 is a design by RunOffGroove.com. It’s a very innovative take on the Big Muff. It replaces all of the transistors with CMOS inverters. This version uses a 4049UBE hex inverter. I’m working on a version that uses the 4069UBE. Look for that in the future!
Hex inverters have been used in many popular pedals. These have a great amp like over drive. In the case of the 22/7 I’d say the magic happens in the first and last invert stages. Looking at the schematic you can see the second and third stages use the hard clipping from the Big Muff. The first stage can be over driven from the input and the last stage can be driven from the preceding stages. I think this keeps this circuit from getting that closed off over saturated sound you can get with a Big Muff when the input is too hot or the gain is too high.
I designed this board with the power at the top and other off board connections at the bottom of the board. I used the style from PedalPCB.com. I think everyone should do this. It makes for a clean and easy to assemble board. I didn’t even have to look any the wiring diagram as. I built this one.
With the pots, switch and LED on the board assembly is a snap. It also makes it easy to remove it all from the box if necessary. The clean assembly makes for fewer errors also!
I built this one in a love green powder coated box. I had some of these knurled aluminum knobs. I really like these knobs they have a great grip and the size is good. If the line was on the top they would be perfect.
This is a PCB for the Big Muff. I design this in Eagle. I used the Part numbering from The Big Muff Page here. With this board you should be able to build any version of the standard Big Muff. Just choose a schematic and match the part numbers to this board.
Here is a gallery of the completed build. Note! Astute observers will notice that I mixed up the Tone and Volume controls on the enclosure of this first build! Follow the guide above, it is correct Volume is center bottom and Tone is upper left.
Just milled these enclosures and it looks like the holes are all off by about an 1/8″ except the toggle switch which seems to be in the right place. What do they say about measure twice cut once? I Swear I must measure five times and still missing something.
I got the file out and moved everything down a bit. Looks like the washer and knob will cover the error. Hand tools save the day again.
And here’s a close up for people who really like to get up close and close and personal with at the site of an accident.
I just got some new pots from Tayda and they are not quite the same as the standard pots. They have a clear plastic cover. The back side is branded Tayda.
And, best of all, they don’t have that little tab that needs to be broken off. I can’t believe it took 20 years of pedal making before someone made a pot without this tab!
I think I like these new pots. I don’t think they are so different in quality. They do look a little cleaner. Not having to break that tab off is convenient and saves me from having little tabs all over the place.
Here’s another epic pedal build. The Lovetone Doppelgänger is a phase shifter with lots of extras. It has 4 phase shift stages and two LFOs and options for all of this. The Quadratron is not a direct clone of the Doppelgänger. It’s faithful to the original but makes a few changes.
Both are four stage phaseshifters with capacitors separates by octaves. This is a classic mod for the MXR Phase 45. The Doppelgänger divides these into a a low band and high band and adds a control for the intensity of each band. It has a color knob that sets the intensity of the effect. There is a blend knob to blend the effect with the straight signal. It has a vibrato mode, which outputs only the wet signal. When using this the blend control needs to be all the way up since the dry signal is not present.
The effect has two LFOs and has options to use one or both. When only one LFO is used it modulates both the low and high band phase shift stages. There is a switch to modulate these out of phase, when the low band is on the high band is off. For the first LFO there is a square and triangle option. It has a rate control for each of the two LFOs and switch that extends the slow range for super slow modulation. When two LFOs are engaged the second controls the high band at its own rate.
Most of these options are present on the Lovetone Doppelgänger but Quadratron does things differently. The Doppelgänger used two multi position rotary switches to set all of these options. The Quadratron breaks each option out to it’s own toggle switch. So this gives us 5 switches:
LFO in phase/anti phase
There are two expression pedal inputs that allow control over LFO rate, there is one for each LFO. This seems a little ridiculous. I can’t imagine using two pedals to control the rate of two different LFOs with one fro the low phase shift band and the other for the higher band. You want over the top this it!
This is very close to the original Lovetone Doppelgänger but not quite the same. It’s possible to get some different combinations with the individual toggles not present with rotary switches of the original. The Quadratron also provides a true bypass option not present on the Doppelgänger. Overall very close but not quite the same.
the build process is straightforward after a careful look at the documentation. There are many parts but the board is pretty big, well laid out, and labeled. Here are a couple things to note.
Note! not all of the caps are used. There are options to use one cap or another in a a few places. If you want to be true to the original you opt for the electrolytic caps otherwise use film.
I didn’t have any TL022 op-amps on hand but these appear to be lower power general purpose op-amps nothing mojo here. I replaced these with TL062 types, which are a low power version of the TL072, and these worked successfully.
The row of 5 toggle switches requires accurate drilling along with soldering the switches perpendicular to the PCB. I used the drilling guide provided in the docs and paid careful attention to these switches when drilling. To get switches soldered correctly I placed them in the backside of the PCB without soldering. I carefully fit the switches and PCB in the box and put a nut on each switch holding everything in place from the back. Then I soldered. This guaranteed the switches were parallel and perpendicular.
The drill guide was great for the top of the box. When it came to drilling the back it seemed the guide placed the jacks too far outboard on both sides. I was able to correct this with hand tools. You should measure the position of the jacks on the backside before drilling!
Then I disassembled and installed the pots without soldering, put everything in the box, supporting from behind while I put a nut on each switch. Then I soldered. At the same time I put the LEDs in the PCB without soldering and guided them through their holes when the pots were in place, and soldered everything.
I followed a similar procedure with smaller board with the LEDs and switches.
This is another costly project the PCBs were $22! The 1590XX enclosure is $13 that’s $35 already. Then there’s 2 foot switches, 6 pots, 5 toggle switches, and 5 jacks. That’s a lot of parts that cost more than other components.
I used some toggle switches with longer handles. I didn’t like these and bought some switches with the short handles for the next build. I think this one from LoveMySwitches.com would be a better choice.
RunOffGroove.com is one of my favorite sites for original stomp box inspiration and innovation. I built my first projects using the schematics and layouts there. The ideas presented are innovative. I’m very impressed with the UBE Screamer and 22/7. You can find PCB projects for those here! The Ruby and other projects are DIY staples!
This is a Big Muff built around MOSFet inverters in place of the Bipolar transistors used in the standard Big Muff. This is a great sounding Big Muff. If you’ve built Big Muffs in the past you should try this one.
The tone control deserves a look. It has three modes: standard mid scoop, flat response, and mid focus.
The kit comes with three PCBs, an aluminum front panel, and 4006 shift register chip. The boards are great quality and well marked. The front panel is particularly nice. The documentation is pretty good. There are lots of parts spread across three boards. Luckily the part numbers are number well 1xx for board A, 2xx for board B, and 3xx for board C.
This is a fairly epic project. It’s three bards all through hole parts. Most of the parts are easily available. There a few things that are harder to get. The parts list show more than a few resistors as 0.1% tolerance. These are harder to get but available through Mouser. The hang for me was not all of the values were in stock! That’s another point, som of the values are very specific like 374r, 91k, 158k etc. I had many of the values on hand but there was I lot for this project that I didn’t have.
I ordered parts from mouser and Tayda Electronics. It probably cost me roughly $100+ more for parts. That will put this project in the $150 to $200. Which is about half the $385 asking price for the pre built version. Sometimes you want to be careful with DIY. There are occasions where it’s more cost effective to buy the prebuilt version!
I made a couple part substitutions. There are some diodes listed as ISS133M. I looked these up and it sounds like these are general purpose diodes, I subbed with 1N4148/1N914 types. I also subbed the ferrite beads with the closest equivalent I could get from Tayda.