Four Banger Discontinued

27 02 2009

As of February 28, I am no longer taking orders for the Four Banger.
All outstanding orders will be completed, don’t worry if you’ve been waiting, it will get done and you will be contacted when it’s ready.
The response for this as been overwhelming and I quickly realized this is too big of a thing for me to tackle building at home in any kind of quantity quickly and be able to maintain the quality I desire, so I am discontinuing it in order to focus on building other things instead.

But don’t worry… the Four Banger will most likely return in a new (better) form this upcoming Summer! It will be back.



New SoulSonicFX Site

10 02 2009

Hi everyone. Today, I spent some money and purchased an honest-to-goodness domain name and webspace for my effects business so I don’t have to clutter up this wondrous place biz-related stuff. This blog is supposed to be about DIY, but it’s gotten turned into other things, and I’d really like to get the focus back where it belongs.
So here it is:
There really isn’t anything there yet, but I promise to have a full online catalog up soon.

Four Banger UPDATE!!!

13 12 2008

Hi, I haven’t posted anything in awhile. I apologize for that. But, my excuse is that I’ve been extremely busy building and designing new things; some things to sell and some things to share. Anyway, over the past few months my Four Banger: Four Boosts in One Box has gotten some attention and it’s probably the most asked for item that I build now. This is good, but having built several now, I’ve decided to make some improvements, and that’s what this article is intended to explain.

Okay, first thing; I am not building these on perf board, I only did two  like that, and one was only at special request. I have a nice printed circuit board designed for it, and it’s been turning out very well.
Four Banger Boards

I’ve also been experimenting with different colors:
Four Banger green
And even custom painted colors:
Four Banger Custom Paint
Four Banger Custom Paint1

Along with the improved circuit boards and different pain jobs, I’ve also improved the quality of the parts to put it on par with the level of quality and reliability I prefer. The main components improved were the mini toggle switches and the controls. The mini toggles are substantially better than what I had used previously, and they have a short bat which makes them less likely to be damaged if they are accidentally stepped upon. These improvements have increased the overall cost of the components moderately and I have raised the price to reflect this. I now sell the standard Four Banger for US$120.

And now introducing a new Mini-Sized Four Banger!
Four Banger Mini

By utilizing a hybrid combination of traditional thru-hole and modern surface-mounted components, I’ve been able to shrink the Four Banger to half its size. Nothing about the circuit has been changed, only some smaller components have been used in strategic locations. The sound and performance is identical to the standard Four Banger. The only difference is that the Four Banger Mini is DC power only; there’s simply no room to fit a battery in there! As you can see here, it’s quite a tight fit:
Four Banger Mini insides

Here, you can see the “secret” underside of the Mini’s pc board which shows the SMD components:
Four Banger Mini pcb

I’m quite pleased with the results. I sell the Four Banger Mini for $130. The slightly higher price is because of the increased labor of hand-soldering the SMD components and the higher price of the Tantalum capacitors used.

If you are interested in purchasing either version of the Four Banger, you may contact me at: solgrind (at)
I do transactions via PayPal and the current wait time is about 2 weeks. I will gladly ship anywhere in the world. If you want any special color or modification, please ask!


Four Banger – Four Popular Boosts in One Box

5 08 2008

Greetings, for the past two weeks I have found myself sequestered in a hotel whilst my kitchen has been completely gutted and renovated. Fortunately, my suite is equipped with a large desk which has made an ideal workbench for me to continue my experiments, studies, and builds. Actually, with nothing much else to occupy my time (other than a small commercial sound system repair/install job last week), I’ve been able to get quite a bit of much-needed work done.

Behold, this was built for one of my customers:

Four Boosts in One Box!

Four Boosts in One Box!

It is four popular boost circuits put together in one box with toggle to turn each individual one on and off. The boost which have been included are as follows and are wired in the following order: classic Rangemaster Germanium Treble Booster, a clean opamp boost of my own design, a ZVex-designed Super Hard-On MOSFET booster, and Jack Orman’s MiniBooster Mu-amp JFET boost. Individually, these are all great boosters, but when together like this, a whole pallet of different colors is available to the artist who wants options. The most ingenious part is that the toggles allow the ability to cascade several boosters together simultaneously for a wide range of interesting overdrive and fuzz flavors. The combination of the Rangemaster, SHO, and MiniBooster on simultaneously has to be heard to be believed! I may design a fuzz that’s based on that topology because it really brings some new things to the game, timbre-wise.

Here’s a look inside:



This one was all hand-wired on perf board. If I sell any more of these, I will be inclined to design a printed circuit board for it. Hand-wiring one effect is fine, but when you need to do several of them and want them to be consistent, it certainly isn’t recommended! I almost always do custom one-offs on perf board like this, but when something is more of a “production” model, a PCB is almost always a necessity for the sake of consistency and quality assurance.

There are some good tricks in this one; a MAX1044 charge pump chip is used to derive a negative supply from the standard 9v battery. This allows me to have a true bipolar supply for the opamp circuit (for maximum clean headroom) and it also gives me the luxury of being able to wire the Rangemaster’s PNP transistor “correctly” with a negative rail being referenced to ground. Some people (*cough* Robert Keeley *cough*) build Rangemasters with the circuit wired “upside-down” so that you don’t need the correct negative supply rail; they use ground to represent the negative rail in reference to the positive pressure coming from the battery. This is an okay trick, but it’s a compromise and isn’t ideal and can lead to stability problems and other unpleasant possibilities. Using the correct negative supply allows it to live quite happily alongside the other boosts in the same box and it illustrates the no-compromise approach I like to take to these kinds of circuits. Another compromise I avoided was the use of input pull-down resistors. I wanted the customer to experience the perfect sound of these boosts without the impedance mangling that can happen from the injudicious use of pull-downs. These extra resistors are used to keep the bypass switch from making a popping sound due to coupling capacitor discharge. I’ve found that with a particular wiring scheme which keeps the circuit input grounded while bypassed, this popping is minimized or completely inaudible without the use of the extra resistors.

I am quite pleased with how this project turned out. I was even able to get a satisfactory “rustic” look for the labeling using rubber stamps and “StazOn” brand solvent-based ink. If anyone is interested in having a custom booster such as this built for you, please contact me at: solgrind [at], or Gmail users may contact me at: solgrind78 [at]
I consider my prices very reasonable, and if you’d like a Four Banger such as the one in this article, I am asking only $100. (The current price a standard Four Banger is $120. Please see update post). Any other effect you may be interested in would likely be similarly priced and of course would depend on what you are wanting. I consider my work primarily custom and what I can build is sometimes limited by the availability of certain parts (i.e. reasonable quality Germanium transistors are becoming rare).

Anyone interested in building something like this for themselves, can find info about the Jack Orman’s MiniBooster at, the ZVex SHO at and, a really good article about building the Dallas Rangemaster can be found at, and the opamp boost is a fairly standard generic circuit you can find the basis of in any good electronics text book.