Origins: A Familiar Fuss

wintercept

wintercept

Well-known member
Don't ask how or why, but I was looking at some Kustom amp schematics at 4:00AM 🤪. They are cool solid state amps with interesting circuits from the late 60's and 70's; famous for their tuck and roll upholstery and use by John Fogerty. So as I was skimming the preamp schematics for the, dated 4-70, I saw something familiar:

fuss200.jpg
Hey, that's a Bazz Fuss! It's so cool to find that this 20+ year old DIY classic is actually a lot older.

There's obviously a lot more going on here with the "Harmonic Clipper" circuit. Firstly, it runs on the same dual supply as the rest of the preamp, at +/-8V. Secondly, it is preceded by the input stage providing volume and some tone shaping, including a "Bright" switch. Like other fuzzes, the Bass Fuzz sound relies on being loaded by the pickups. In my experience, it doesn't sound bad after a buffer, but it does sound completely different and a lot noisier. Here, it does have a fairly low impedance output before it. Lastly, it is followed by a buffer straight to the collector and the rest of the preamp stage which I haven't shown. This includes a James tone stack (at least I don't see a feedback path to make it Baxandall), gain recovery, and a switchable "Boost" stage. The switch for teh clipper circuit looks like it toggles two transistors to either mute the dry or the clipper depending on how its set. Here is a link to the full schematic and here is the site I found with all the Kustom schematics.

The transistors are all SE4002 (which Small Bear has funnily enough), except where noted like the 2N3638 in the input section. Standard silicon stuff. I think other transistors would sub fine. That FD111 is a silicon rectifier diode from what I've read.

The Bazz Fuss needs no introduction. It was my first successful build and probably the same for many of you. It is a really simple design credited to Hemmo P, who was active on early pedal forums like DIYstompboxes. Some of you probably know the history a lot better than I do.

Now, I don't really know what these amps sound like. Never played one, never really listened more to Fogerty/CCR. However, the preamp circuit overall is interesting and I think it would make a cool pedal adaptation.

So yea.. I'll get on that and keep ya posted 😉.
 
If you search the underbelly of DIY you'll find a vero layout for a Kustom Klipper circuit; I think tinkered by Pink Jimi Photon with a Digi2T layout, IIRC.

Don't recall if it's the same circuit or another, but it's also Fogarty related: PJP's "Suzy-Q".
 
Feral Feline said:
If you search the underbelly of DIY you'll find a vero layout for a Kustom Klipper circuit; I think tinkered by Pink Jimi Photon with a Digi2T layout, IIRC.

Don't recall if it's the same circuit or another, but it's also Fogarty related: PJP's "Suzy-Q".
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I checked that out while looking to see if anyone already made something based on this and did some more digging. They found their circuit on a patent from 74’, which first appears in Kustom amp schematics from 71 like the 150 and 250. It’s a hard clipper circuit not unlike the Electra, which is what they ended up using at the center of their design because the patent schematic lacks values.

I’ve since read that Fogerty used a 200 series amp, which are circa 68-70’ and would have had the Bazz Fuss thing in it.

So based on that they got it wrong in the Fogerty sense, but of course I mean no disrespect in that. Their interpretation of the circuit they found is pretty neat, and it was cool to read about their process. As far as I’ve found, any Kustom themed “Harmonic Clipper” pedal ever made and sold is the PJP/D2T design.

The Kustom amp designs evolved rapidly into the early 70’s, and they were using opamps for most things by the end of it.

Shit, I feel like some audio circuit Indiana Jones right now 🤠.
 
My original look at the Kustom schematics was out of curiosity, as I saw one for sale near me. I’m not interested in chasing any tonez, and I’m not well listened in Fogerty’s work.

The plot thickens, however, as I have found schematics to the Kustom 200A series of amps. The original post shows the clipper circuit of the 200B. Of course, the 200A is completely different, and, of course, John is said to have used a 200 A4, with the full compliment of effects including the clipper, vibe, trem, and spring reverb.

The schematics are dated 67’, and the clipper circuit is not a Bazz Fuss, nor is it the later 150/250 series clipper that they found over at DIYstompboxes. It is two transistors and a diode, and I think it will work by itself. So, I will post it to this thread soon for those of you who like to tinker with vintage fuzzes. I’ll get around to trying it too.

My main goal now is still to adapt the 200B series preamp and clipper to a pedal format, likely using a charge pump circuit to get the +\-8v.
 
wintercept said:
That’s awsome, I would love to hear that story.
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So when I was 17 or 18. I went into a music store in Concord, NC. John Fogerty happened to be there as it sold old vintage guitars. At the the time I recall him buying old Silvertones. I was not a huge CCR fan at the time. I was bigger into Pink Floyd, Led Zeppelin, and Rush. Someone told me, hey do you know who that is? Of course I wasn't sure at the time. But it was John Fogerty. So I went up to him and talked to him for a bit. He had a guy with him from the Fender Custom shop. I ended up buying a 1990 Strat Pus with Lace pickups that I have until this day. The Fender shop guy setup my guitar and I played with John for about 30 minutes. Super nice guy, salt of the earth. And that is my celebrity story.
 
This is a cool thread because it’s making feel nostalgic. My first amp was a Kustom 10w practice amp in the mid 90's. Honestly, it sounded like garbage but it was all I knew at the time so I loved it. Being from Ohio and knowing that Kustom was based in Cincinnati made me appreciate the brand. Fast forward to 2006, and joining a somewhat popular band in the local scene, I ended up with a Kustom quad 100 with a matching 4x12 cab... To this day I still maintain that it was one of the best sounding solid state amps on the market.
 
I'm into cars, so of course some naugahyde on an amp intrigued me when I first discovered Kustom.

I'd still love a Kustom bass amp and cab, or even just to cover some DIY Greenboys in '70s Norton FAT-metalflake orange tuck'n'roll...


Looking forward to following your 200B exploits, wintercept.
 
Alas, the real Naugas have all been hunted to extinction, and now we've only got cheap vinyl fake naugahyde...

b49b9509a15b75a1021836f1b6591ac3.jpg
 
A-Series-Clipper.jpg

Posting this a bit later than intended. oops..

Here is the Harmonic Clipper circuit from a Kustom A series schematic (Fogerty is said to have played the 200A4). These amps were designed modularly, so the effects are on their own board that could be installed and populated depending on the model. The A4 had all the goodies: vibe, reverb, and clipper. Schematic is dated 67'.

I have not tested this circuit, but I plan to and it's here for all you fuzz heads to tinker with. The topology looks like that of a fuzz face at a glance, but it has a few key differences. For one, the second transistor stage is a buffer with the signal taken from the emitter. Thus, it lacks the second gain stage and the bypass cap that make a fuzz face FUZZ. Second, the shunt resistor for the negative feedback from Q2 emitter is 10k, and it's in parallel with a diode. I hypothesize that this circuit works essentially like the Bazz Fuss, with the diode doing effectively the same thing bias and feedback wise.

The circuit is run on +13v in the amp; but I don't see why it wouldn't work at 9v unless the voltage at the emitter isn't enough to conduct the diode. I haven't done the maths :).

Enjoy!
 
Bricksnbeatles said:
Isnt the aforementioned Digi2t (MrDigi2t on YouTube) the guy who runs DeadEndFX?
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From their about page:

“Dead End FX is a Transatlantic endeavor by "PMowdes", and "digi2t"...”

They have a lot of bigger projects that I would love to try someday. They also have a store section for effects designed by pinkjimiphoton (PJP).
 
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