Ampeg Scrambler

Wired up this ampeg scrambler board I’ve had for a while. I’ve been trying to finish up all of the unfinished projects from the last few years.

Fired up first test. I used MPSA13 transistors. I got the PCB from John Lyons on DIYStompboxes. It’s the tone pad layout. The layout is set up for different transistor pin arrangements. The MPSA13s were working well, I was thinking to try some others before boxing this up.



Some Fuzz Faces

Finally getting back to building some Fuzz Face’s I started a while back. Here’s a picture, you can see the sockets for the transistors, two sets of three in a row, in the center. The input socket is two small socket pins on the right center, and the output cap is on the bottom center.

Fuzz Face with sockets

Fuzz Face with sockets

Octave Fuzz Take 2

Here’s an updated version of the octave fuzz. Q1 and Q2 set up a basic NPN Fuzz Face type circuit. While Q3 acts as a phase splitter. Q4 and Q5 act as a frequency doubler each side being fed an inverted signal from Q3.

So far the Fuzz section is working on the breadboard. The octave section is not working at the moment. I suspect the bias is off. Note the voltage around Q3. The collector and emitter voltages should be close to 4.5V. So far they are pretty far off.

Taco Fry Fuzz

Everyone’s favorite 5 knob fuzz, with custom hand drawn Sharpie design.

Hirsute Pachyderm

A four knob Si Fuzz clone. With custom Sharpie design.

Eyeball Fuzz

Here’s a Fuzz Face with custom 60s eyeball design in sharpie. This is a Si/Ge hybrid Fuzz face with a blend cap on the input.

Fuzzy Elephant

Here’s a clone of the Zvex Wooly Mammoth. Came out pretty good, sounds good too. I used strip board layout here: It’s about halfway down the page. I modified it to move the parts closer together. My layout ended up being 17 holes wide which fit in the box a little better. I used a small hex bolt and a standoff to secure the PCB in the box.

Note the “mojo” ceramic disk capacitors. I housed everything in a box from 4Site electronics. These are great boxes the finish is very nice and the screws are much higher quality than the Taiwanese boxes.

I made a mistake and couldn’t fit the DC jack in the center at the top, where I had drilled the hole. So I drilled second hole and used a piece of brass to cover the first hole. I’m trying to think of some way to stamp something into the brass plate so it will serve some purpose beyond covering the error.

I have a few spools of hook up wire from Radio Shack. This stuff is terrible. The insulation melts. I would not recommend it.

Fuzz Face for Joe part 2

Here’s Fuzz Face wired up and stuffed in a “B” sized box. This box is from 4Site electronics. Great finish and excellent screws much better than the Taiwanese boxes that are commonly available.

Fuzz Face For Joe

A few pictures of a Fuzz Face I made for a Joe. Turns out Joe hadn’t heard of the Fuzz Face. So I thought I make one for him. This one uses a Silicon 2n3906 for Q1 and a Germanium transistor for Q2. The Germanium transistor is a Chinese model not sure what the number is, that I got from Small Bear Electronics.

This has the typical Fuzz and Volume controls. The third pot is a variable input cap. That pans between an .01µ and 3.3µ cap. The tone change is not extreme but is noticeable and seems like it would be good for adjusting between different instruments.

I used some right angle PCB mount pots. These seem like a good idea.They provide a great way to mount the board and cut down on wiring. After building a few projects with these I have come to the conclusion that these would be great with fabricated PCB with through plated holes. For projects created with perf board or strip board you end up having to solder under the pot, it’s almost like building a ship in a bottle. Projects created with perf board or strip board are more prone to errors. Fixing these would either require removing the pots or bending them out the way to reach soldered connection underneath. With a through hole PCB you could solder the pots from the top of the board, and the board would be far less likely to need debugging.

Here’s a few pictures.

Silicon Tone Bender take 2

Whenever I build something I usually build two. The parts are cheap. If I make a mistake or the PCB doesn’t etch correctly I have a spare. If you build the first and it doesn’t work you can build the second and compare the two.

In the case of the Silicon Tone Bender I used Nocentelli’s strip board layout, which worked well. I built two as usual. I thought the first sounded good so I thought I’d build the second and box it up. Lately I have been trying to use up extra parts I had lying around. I found a box with an etched top that I hadn’t used.

This box was originally going to be Big Muff variant, but the box was over etched. So it was never finished. The design included three controls: Volume, Tone and Gain. which worked out for the Tone Bender.

I decided to add the Fat switch on this one so I drilled an extra hole. I soldered the “fat” cap to the switch and ran a wire to the switch and the PCB.

I used a Green LED and some Knobs I got from Futurlec. These knobs seemed like a good deal at the time. But it turns out that the hole is too small for 1/4″ shaft. They will fit on a knurled press fit type shaft. I hardly ever use those so these knobs had sat in the knob drawer for while. I finally decided to get rid of them with this project, so I sanded the shafts down until the knobs fit.

notice the PCB is mounted on a small hex bolt. I used a nylon standoff. This worked pretty well. I’m guessing it will stand up over time. The small nut has a nylon lock ring in the end.

Silicon Tonebender

I built this Silicon Tonebender posted by mictester over on Freestompboxes. I used this layout. Everything worked the first try and it sounds good. I used BC109CN for transistors. These sounded good and have that metal can with a little tab mojo. I used a ceramic .1µf cap for the input cap and skipped the Fat switch.

The fuzz is so thick you can cut it with a knife. The tone control is useful. Everything cleans up well with volume control. Would I box it up? Heck yeah! This is a keeper.

No need for expensive hard to find Ge devices. I think I might have to get a few more of these metal cans just for their mojo. If I had any complaints I would say that the Gain control lacks range. You really can’t back this off to a mild fuzz. When the effect is on you know it.

This also gave me an opportunity to use some poor quality trimmers that I had lying around.

I used sockets to experiment with different transistors.

5 Knobs

Here’s an idea I have been wanting to try in a stompbox. Small Bear carries post with long leads that can be used to mount the pot to PCB. I thought these might be good for mounting a board inside an enclosure. This is a clone of everyone’s favorite 5 knob fuzz.

This seemed to work well. But I think the knobs are a little hard to see for adjusting. Then again you might be adjusting by ear abyway. I wanted to place the switch in the center of the box for aesthetic reasons. This left a tight fit in the center of the board for the transistor, which I haven’t added yet.

Overall I would say that these posts work well to support the PCB. Mounting them to the board also does away with a lot of wiring which makes for a nice build. The down side is that they are difficult to solder to a board created with Perf. If the board had plated through holes this would not be a problem. The other down side is that this type of build could be difficult to modify or repair. As the back side of the PCB is hidden behind the pots.

Newer Posts
Older Posts