New PCBs

I had a few new PCB projects manufactured. Here are three projects I had been working on. These were drafted up in Eagle. I had these made at cost was about $45 for 30 boards. I order 10 of each of three designs, they sent me 11 of each, which was a pretty reasonable deal, less than $1.50 per board the quality is very great, and you can choose the colors!

Joe Davissons Vulcan is a silicon transistor Overdrive that sounds great. It’s an original circuit with a unique design. It sounds great. Easy to build and uses common parts. This is an update of the first version I did of this PCB. See my projects page. It fits a 1590B.

Tim Escobedo PWM takes your guitar signal and turns it into a square wave. It proves control over the duty cycle of the wave. It also has a modulation circuit that animates the rate and depth of the width of the wave. This is an update of the first design that had a few flaws. This project fits a 1590BB.

Nicolas Boscorelli Tremolo-matic XXII. Nicolas Boscorelli published a news letter called Stompboxology way back around 2000. This is before the boom in stompbox builders. He also published a book called the Stompbox Cookbook. Then disappeared. No one has heard from him since. He missed his opportunity. If he had been publishing in the last few years he would have found a huge audience for his work.

This is a tremolo from the “Going Discreet” issue of the Stompboxology news letter. This issue was all about building with transistors. This fits a 1590BB.

22/7 4069

RunOffGroove 22/7 4069

First build of 2022! This is a 4069 version of RunOffGroove’s 22/7. The original uses the 4049 hex inverter. This the same circuit using the 4069. Both chips contain 6 inverters but the they differ in format and layout. The 4049 is a 16 pin DIP and the 4069 is a 14 pin DIP. One is a drop in replacement for the other.

While it’s possible to make an adapter I decided to make a a new PCB based on the 4049 board I had already made since the board will be more reliable and make a better build than using an adapter. Now days it’s cheap and easy to have boards manufactured. The cost is around $20 for 10 boards is money well spent if you consider the time invested make boards from scratch. I had these boards made at They service is pretty cheap and easy to use.

Build your own 22/7

You can order these boards and build your own! Order from the shared service at PCBWay here. Then follow the 22/7 Build Guide.

Does the 4049 sound different from the 4069? Not that I can tell. But discerning ears might detect a subtle difference. I’d like to hear your opinions. The best thing about this project is that it this is a a great sounding circuit and it gives me a place to use this bag of 4069 chips!

AionFX Quadratron LoveTone Doppelganger clone

AionFX Quadratron

I always build three of everything. I got three of these boards when AionFX released them. I built one and gave it away. I’m finally getting the other two finished.

This is not straight clone of the Doppelganger it has some changes that are updates and improvements, and a few changes that are opinionated. Read the documentation there are some interesting thoughts in there about pedal design.

Here are some progress shots. I have the boxes drilled, and everything installed. Just need to wire up the interior. With 5 jacks there’s a a lot to do here!

Tim Escobedo’s PWM


Tim Escobedo was this wildly creative force in the early DIY Stomp Box community. His circuit snippets page was had a lot of really great ideas. One of the ideas there was the PWM, which stands for pulse Width Modulation.

This circuit converts your input signal into a square wave and varies the amount of on and off time or duty cycle of the wave.

I had these boards manufactured through The quality is great. Ignore the bad silkscreen that was my fault. The cost was $5 USD for 10 boards which is very reasonable.

I designed this board to fit a 1590B enclosure in landscape. The cutout is for the power jack. I thought it would work well… After getting the boards I realized I would have trouble getting 500k 9mm pots that mount at 90 degrees. I going to have rethink this project. I also botched up the silkscreen. This is going to need a second try.

UBE Screamer 4069

UBE Screamer 4069

This is a version of the UBE Screamer using the 4069 in place of the 4049. Essentially these chips are the same. They both contain 6 inverters. The 4049 is a 16 pin DIP while the 4069 is a 14 pin DIP. Electrically the should the same but the pin arrangement is different.

The original circuit from is a very interest evolution of the Ibanez Tube Screamer TS-808. RunOffGroove has an article describing how to make an adapter that adapts a 4069 to a 4049.

I decided to just make another PCB since I had already created a PCB for the original 4049 circuit. The adapter would work but ordering some PCBs from costs about $25 for 10 boards which worth the time spent hacking a solution. And, the boards are well made and reliable!

22/7 4069

22/7 4069 PCB

Here is a version of RunOffGrooves 22/7 using the 4069. The original circuit uses the 4049 Hex inverter. The 4049 is a 16 pin dip with 6 inverters. Here is the 4049UBE data sheet.

You can see it has 16 pins with 6 inverters. There is a power Vdd pin 1 and ground Vss pin 8. And two unconnected pins 13, and 16.

The 4069 is essentially the same chip. Here is the 4069 data sheet. Here is a picture of the chip:

The 4069 is a 14 pin chip with 6 inverters. Pin 14 is power and pin 7 is ground. There are no unused pins.

The two chips should be the same and interchangeable. Of course we of discerning audio tastes can sometimes hear subtle differences in devices. So of course we have to build both and see what they sound like! has notes on building an adaptor. You can check out the instructions here.

I had the PCB designed for the 4049 already and PCB manufacture these days is pretty inexpensive. I updated my 4049 design and had some boards made. It cost about $25 for 10 boards. I figure that’s worth the couple hours time it might have taken to make the boards myself, and I get high quality boards! Manufactured boards have two sides, are pre tinned, and have tighter tolerances which allow you to get more in a smaller space. I used low cost prototyping service to create these.

UBE Screamer v2

UBE Screamer 2 PCB

I made an update to the RunOffGroove UBE Screamer from a suggestion in their notes. This version adds a mix control the blends some of the original signal with the distorted signal.

The original uses Rx to set a fixed mix amount. The notes suggest a value of 100K to 470K for this resistor with a 100K for lower output pickups like single coils and 220K to 470K for hotter pickups like humbuckers. There is a suggestion in the notes to make this a trimmer. With this board I made this an outboard control.

These boards were done through The quality is great. It was abut $25 for 11 boards so the price is pretty reasonable.

I built his up and after testing I realized I needed another resistor in the mixing section. I should have seen that earlier, oops. This wasn’t hard to fix by cutting the leg off the blend pot and inserting a 100k resistor in its place. This idea will take a another revision to get it working as it should.

I left R13 out. This is needed mixer is not working when the Blend pot is at a low resistance. I clipped a leg off the blend pot and replaced it with a 100k resistor as a patch. Then updated the schematic.

Weston Audio AD110

AD110 Front

I built this as a DIY project. They offer it assembled also. It’s a Eurorack adaptation of the drum sounds from the Boss DR-110. All the sounds are analog, not samples.

The project comes as three PCBs and a front panel. It’s all through hole parts. The parts are fairly easy to get. I few of the parts are harder to get. For example the project asks for some very specific resistor values like:

  • Many resistors are listed as 0.1% tolerance. These are not hard to get but also not common. You can order these at for most. But some of the values were not available. I rolled my own with series and parallel resistors. I couldn’t get within the 0.1% tolerance but got reasonable close and things still seemed to work.
  • Uncommon resistor values like: 442K, 86.6K 0.1%, 127L 0.1%, 107K 0.1%., 374r and more. As I said above you can get most of these at but some were out of stock or otherwise unavailable.

Other parts list obscure part numbers but mundane substitutes can be used instead for example:

  • 1SS133M – General purpose diode. I used 1N914/1N4148
  • TZX9V1D – Zener diode. I used a random 9 volt zener here
  • KSC945 – Seems to be a general purpose NPN BJT. I used 3N3904

I had a problem with my build where the electrolytic capacitors were shorting out on the solder traces in the board above. Most common sizes for these is 10mm which is the space between the boards. Either get shorter 7mm caps or bend the caps over 90 degrees. The bill of materials lists 7mm caps but I had plenty of caps on hand I wanted to use.

The build process is pretty straightforward and the documentation is very good. The board is all through hold part with fairly generous spacing.

Here is a short sound clip. I used Temps Utile to trigger the AD110. Im using the Bass, Snare, open and closed hats along with cymbal. The only sound not used here is the hand clap. I used the mix out and sent a periodic trigger to the accent input.

PCBs with pots and LED

22/7 PCB

I just built a PCB project without the LED taken care of on the board, what a headache! In the old days everything was like that but we have evolved since then! in my most recent projects I have been following the layout used by PedalPCB. I feel like they have hit on an arrangement that works well.

Here’s my proposal: Let’s make this a standard! If everyone does it this we all know what to expect, it’s easier for everyone to wire board, and the build process is easy. It also makes for a clean build which leads to more successes and less debugging.

Here you can see the wiring is pretty neat and tidy. Notice the input and output jacks ground to the board on the left and right sides. The wire run is short and obvious. Also, see the four wires in the center of board run in a straight line to their connection at the stomp switch. This helps make the wiring self documenting.

What way not be obvious from these images is that the pots and LED are also mounted to the board. This reduces the off board wiring and gives you a secure place to mount the and supports the LED.

Here you can see all of the pots, switches, and LED mounts to the board. This is clean neat and reliable. The board and LED have a secure mounting place.

What am I proposing here? A convention for laying out your PCB:

  • Pots mounted to the board
  • LED mounted to the board
  • 4 connections at the bottom of the board:
    • Effect In
    • LED Switch
    • LED Ground
    • Effect Out

Why? It makes building guitar pedals really easy and less error prone.

  • Mounting pots to the board saves on wiring, and makes a secure place to mount the PCB, and avoids mistakes.
  • Mounting the LED on the board saves wiring avoids mistakes and gives you a place to securely mount the LED.
  • Using the 4 connections at the bottom of the board avoids mistakes and makes wiring the switch, often a source of errors, easy and less prone to errors.

Here are a couple wiring diagrams for the project PCB above.

Check out my projects page for a closer look at building these projects. You can order boards from the PCBWay shared service, then follow the build guide on my site.

If you’re interested in making your own boards I can highly recommend using the the service. All of the boards pictured here were manufactured via PCBWay.

1981 Inventions DRV clone.

Here’s a PedalPCB Informant. This is mostly the Rat circuit with a few changes. The biggest change is the addition of a charge pump. The charge pump provides a +9 and -9 volts power for the circuit to run off. Effectively this doubles the voltage.

I have some reservations about the power supply. The clipping section clips at a fixed point. After the clipping diodes the charge pump doesn’t make any difference. With only a 9 volt power supply the circuit would running off +4.5 and -4.5 volts and there would be plenty of headroom going into the clipping section. The clipping section uses silicon diodes which will clip the signal at 0.7 volts. Which means the signal can’t really get past +0.7 volts and -0.7 volts. After the clipping section the output buffer is unity gain so nothing is added there.

The circuit does have a buffered bypass. The PedalPCB Informant offers an option to make this true bypass. The original DRV is buffered. I went with a buffered option. Here the charge pump can offer something since the buffered output can use the entire +9/-9 volt swing.

I built this is from a PedalPCB Informant PCB. The board is a great quality and set up for an easy build with all of the pots and LED mounted to the board. I would be happier to put this in a 1590B enclosure but the board is a little too large. On the other hand using a 125B allows for all of the jacks at the top.

The cost of this project was about $25. Which is pretty reasonable and took only a couple hours. The parts are all easy to get. Nothing special or hard to source. You can get everything for this at Tayda Electronics including the charge pump.

I milled the enclosure, filled the engraving with some paint and sanded the enclosure after. there is a small hex bolt between the knobs at the top. I drilled there for an LED but realized I had some of those stomp switches with the LED ring later and decided to use one of those. I used the hex bolt to fill the hole.

Serge Resonant EQ

Serge Resonant EQ

This is the last piece of musical gear for the year. It’s a fixed filter bank with 10 filters. 8 of the filters are bandpass filters. The highest and lowest bands are high pass and low pass filters. It’s like a 10 band equalizer with synth filters. The filters are tuned to major sevenths and have some overlap. The filters also resonate as you turn them up. An interesting module with a lot of utility.

I got this as a kit from Thonk. The kit was pretty solid all of the parts were there and all clearly labeled. It would be hard to fail with this kit, I could have but didn’t!

The build process was very paint by the numbers. Nothing special, no tricky situations, or small parts. Just op-amps, and they are all the same type, caps, and resistors. The instructions are clear. The only place that might make you question is where a few parts are not used. There are a few resistors and caps marked on the PCB that are not used in the build. This is clearly noted by the instructions.

Overall this is a good module. It fills a useful niche as 10 band EQ. This is really great for adjusting and focusing a sound. With the two inputs you can use it to mix and “master” before the final output, or just use it to mix and tailor a sound to fit a sonic “space”.

The design and layout of the module is nice. Makes me want to have a whole panel of Serge. The spacing is nice the layout is evenly spaced and logical. It’s not trying to pack too much into the smallest space available. The panel is clearly labeled and easy to read.