Jim Dunlop JD-F2 Germanium to Silicon BC108C transistor conversion.

Hey Everyone,


Recently, my red Jim Dunlop JD-F2 Fuzz Face died and stopped working while I was in the process of doing some re-organizing of my pedal board so I could add my Boss MT-2 Metalzone pedal, well, my red Fuzz Face pedal actually didn't just suddenly stop working, it started oscillating and then stopped working, so seeing as I had been looking for a good excuse to convert it over to silicon BC108C transistors from the stock NTE 158 Germanium ones, I decided to go ahead and remove the stock circuit board and replace it with one that happened to have two BC108C silicon transistors soldered onto it.


It's a well-known fact that Germanium transistors are temperature-sensitive, and, while the stock JD-F2 circuit board does incorporate a board-mounted thermistor as a way of mitigating any temperature effects, I decided to just cut-to-the-chase and do the conversion to silicon transistors since they are far-less temperature sensitive.


The replacement Fuzz Face circuit board I used was one that came as part of a kit of parts I had ordered from a company in England, called Pigeon FX....if my memory serves me right.


I'll post a pic of the insides of my red Jim Dunlop JD-F2 Fuzz Face, which I took after the conversion had been done, and I'll also post a link to a demo I uploaded to my soundcloud account, so you can hear what it sounds like.


Here we go:


Insides of the red JD-F2 Fuzz Face after the conversion to BC108C silicon transistors.

Attachment 30029


And a close-up pic of the replacement circuit board.

Attachment 30030


The two silver things with three legs are the two BC108C silicon transistors.


And here's a link to the demo I uploaded to my soundcloud account:

https://soundcloud.com/drnomis_44/re...DJu00W1fAYuF_4


Here's a link to the Pigeon FX website if you're interested in ordering some circuit board kits from them:

https://pigeonfx.com/


Note that the circuit board kit pricing is in English pounds, so you might need to open an account with paypal.

So today I decided to order some new caps for my red Fuzz Face pedal from Evatco, one leg of the original 10nF output cap literally fell off it as I was doing some troubleshooting of the pedal to figure out why it sounded real blatty when first switched-on, after a while the sound would gradually become more like what it was supposed to sound like, I thought that maybe one of the solder joints might be dry and need re-doing, so I went through all of the solder joints and re-worked them, when I got to the solder joints for the 10nF output cap, I used some solder wick to remove the old solder so I could put new solder on, and as I was in the process of removing the 10nF cap one of the solder legs literally fell off, I didn't have any spare 10nF caps so I used a 47nF/630V greencap as a temporary replacement to get the pedal going again, that got rid of the initial blatty-ness.

I ordered the following caps from Evatco:

X1 .01uF/630V Metalized RT.

X1 2.2uF/100V Electrolytic RT.

X1 20uF/50V Electrolytic RT.


I went with express postage so the new caps should arrive by maybe next week at the latest.


If you look at the close-up pic of the circuit board in my previous post, the output cap is the one closest to the two mounting screws for the circuit board.

Woohoo!!!!......the new caps for the Fuzz Face just turned up in the post today, so I'll be installing them on the circuit board tomorrow.

Attachment 30397

New caps installed on the replacement circuit board:

Attachment 30410


Gave it a test out and it's all working as it's supposed to, so I'm calling it job done.

I've always been amazed how influential a tiny two transistor circuit has been to the industry...

Not eggzachery the same but for me it's a Big Muff that does the job .... or my RAT ...

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Originally Posted by Marcel

I've always been amazed how influential a tiny two transistor circuit has been to the industry...

Not eggzachery the same but for me it's a Big Muff that does the job .... or my RAT ...

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Both the Big Muff and the Rat are just as famous and popular as the Fuzz Face is, I happen to have a Big Muff pedal that I made myself, it uses the 4-transistor Triangle circuit rather than the later one that uses an Op-Amp IC, I used to own both a Rat and a Turbo Rat before I moved to Darwin, missing them, one day I might see if I can build a couple of Rat pedals.

Mine is a RAT2 which I bought in Brisbane only a few months ago and for my needs & purposes is just as good as the original or any variation. It sits beside my TS9 and my kit Klon clone and 5 other pedals (2 dly, tune, gate & phasor) on my current pedal board. Sadly as my power supply has only 8 outlets this means my reissue original spec Big Muff sits for the moment idle, though I'm not too fussed as there is plenty to "play" with as it is...

As I read I'm wondering what I ever did with my original Russian big muff pedal from the 90's. Couldn't miss it, it was such a big green tank! Such a cool sound.

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Originally Posted by Bakersdozen

As I read I'm wondering what I ever did with my original Russian big muff pedal from the 90's. Couldn't miss it, it was such a big green tank! Such a cool sound.

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If it was a vintage one, it would have been worth a bit.


Pedals currently on my pedal board are my red Fuzz Face, Ibanez TS-9 (re-issue), Boss BD 2 Blues Driver, Boss MT 2 Metal Zone, Jimi Hendrix Wah, Boss CH 1 Super Chorus, home made Univibe w/ext speed control pedal, and Boss RE 20 Space Echo, power is via an MXR power brick.

Quote:

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Originally Posted by Bakersdozen

As I read I'm wondering what I ever did with my original Russian big muff pedal from the 90's. Couldn't miss it, it was such a big green tank! Such a cool sound.

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I had one of those, olive drab, big assed knobs and heavy and dirty as all get out. Loved that thing.

Quote:

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Originally Posted by FrankenWashie

I had one of those, olive drab, big assed knobs and heavy and dirty as all get out. Loved that thing.

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Yep that's the one mate. With the cool timber box it came in. There more I think of it, it's bringing back more and more memories of lugging it round to jams and gigs .. so so cool

Many many moons ago I had the need on my workshop test bench for a multi isolated outlet 9VDC supply. Found one on Fleabay by Viloos for AU$34. It came with leads, 8x9V plus a 12V and 18V outlets, and a 1.5A 18VDC AU plug pack to power it.

After a few months I found it worked so well on my bench that I bought 2 more for my rig, one for the input jack pedals and one intended for the effects loop pedals thus dispensing any need for a bucket load of 9V batteries. It's not exactly as how things are today as the 2nd supply intended for the effects loop is in my travel case for those times where I want to play away from home. Other than the bright Blue LED's on each output jack when a 9V lead is plugged in I've never had an issue, so I'm reluctant to spend the huge money on upper end 9V distribution gear like the MXR power brick.

FYI, the 'other 5' on my current 'home board' are a Poly tune 3, TCE Helix, NUX Time core, Catalinbread Echorec and a Behringer NR300 gate..... so many hours of fun, noodling and writing...

You can't go wrong with a good Fuzz pedal on your pedal board, one of the very first FX pedals made for the electric guitar, way back in the early 60's, and it all started with a faulty Langevin mixer preamp when Marty Robbins was in the studio recording the song "Don't Worry".


Bit of trivia there for you.

Gave my red Fuzz Face a test-out to see if it's still working, cause I'm going to use it at an up-and-coming gig at the Nirvana club on Thursday next week, fortunately it is still working perfect.


It's a surprisingly simple circuit, but what a raw tone it produces, very vintage-sounding, definitely nothing like what you get from plugging straight into an overdriven tube amp, but definitely thick and smooth like a typical Fuzz should be, it does tend to sound a bit woolly in the low end, but I think that's a good thing since it compensates for pickups that tend to be a bit ice-picky in the high end, one thing I will say is that it is very sensitive to how you set the volume control on the guitar, you can get various shades of Fuzz from a slight breakup to full-on psychedelic Fuzz just by turning the volume up or down, it also responds to your picking-dynamics too, pick softly and you get a slight smokey breakup, pick harder and it gets more saturated, if you turn the Fuzz control up to full and pick hard, you get a sort-of compression effect on your pick attack and then a blooming effect when you sustain a note.

Note: It does tend to sound smoother and better through a tube amp.


And for those interested in building a Fuzz Face pedal for themselves, I'll post a hand-drawn circuit diagram tomorrow, based on what is currently in my red Jim Dunlop JD-F2 Fuzz Face pedal, and what's on the replacement circuit board I installed, including voltage measurements......stay tuned.

Here's the latest revision of the wiring in my red JD F2 Fuzz Face, the reason why I did the wiring revision is mostly because I found that the wire I had used previously was prone to breaking at the solder-joints due to how thin the inner conductors are, so I decided to replace all the existing wire to improve reliability, here's a pic so you can see how it all turned-out, I used a photo of the insides of a vintage NKT275 Germanium transistor Fuzz Face as a guide:

Attachment 37963


This is pretty close to what you would see if you looked inside a vintage BC108C Silicon transistor Fuzz Face pedal.

Lol... you said "vintage BC108C".... First time I had my hands on and was soldering in BC108's was back in 1973... Yeah, that was more than the vintage spec 25y ago.... LMAO & ROFL ...

Quote:

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Originally Posted by Marcel

Lol... you said "vintage BC108C".... First time I had my hands on and was soldering in BC108's was back in 1973... Yeah, that was more than the vintage spec 25y ago.... LMAO & ROFL ...

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Yeah I know, but nowadays an original silicon transistor Fuzz Face from the late 60's to early 70's would be considered vintage, apparently Jimi Hendrix used one of the early turquoise silicon transistor Fuzz Faces at the original Woodstock music festival, which started on the 15th August 1969, the exact same month and year that I was born (I was born 16 days later how cool is that?), which makes it about 51 years ago, since I'm 51 years old now, and the early silicon Fuzz Faces used the BC108C.

My guess is that the reason why Dallas Arbiter chose the BC108C was not only that it was far less temperature-sensitive than the AC128 or NKT275, it was probably a fairly cheap and readily available transistor as well, who knows.


Here's an interesting webpage article on the history of the Woodstock music festival:

https://www.history.com/topics/1960s/woodstock

Hey Everyone,

Just thought I'd do an update on this forum thread I started, so here goes........


Earlier this year I ordered two new Issue 2 Fuzz Face pcbs online from Pigeon FX in the UK, I used one of them to replace the original Issue 1 Fuzz Face pcb I had in my red JD-F2 Fuzz Face pedal because I noticed that the copper pads on the undersize were starting to lift, last year I bought a set of 8 CDIL BC108C NPN transistors on eBay and I went through them and picked two of them with the highest gain of the lot, one had a gain of 635 which I used for Q1, the other had a gain of 660 which I used for Q2, I paid a visit to my local Jaycar Electronics shop and bought packets of 1W/5% Carbon Film resistors containing two resistors of the following values, 330 Ohms, 470 Ohms, 8k2, 33k, and 100k.

Using a 330 Ohm, 8k2, 33k, and a 100k 1W/5% Carbon resistor, the three capacitors on the old Issue 1 pcb, and the two selected CDIL BC108C transistors, plus an extra 1nF/100V greencap I soldered to the underside of the new Issue 2 pcb in parallel with the 100k resistor, I re-built the Fuzz Face circuit, I used some short pieces of clear heatshrink to insulate the base leads of the two transistors so they wouldn't short-out against the other transistor leads, this was necessary because the solder pads for the transistors on an Issue 2 pcb are configured for BCE transistor lead layouts rather than CBE.

Just recently I ordered a set of two new TRS Cliff Jacks from Evatco, they arrived in the post yesterday and I installed them in my red JD-F2 Fuzz Face pedal.

So, now, my red JD-F2 Fuzz Face is as close as I can possibly get it to a vintage Silicon Transistor Fuzz Face, once my mobile phone has finished charging I'll take a couple of pics of the insides and post them here.....stay tuned....


Here we go....

Attachment 44084

Attachment 44085

Last year, or maybe the previous year, I managed to buy a second-hand Fuzz Face pcb on eBay, it originally came out of a Jim Dunlop JD-F1 Jimi Hendrix Fuzz Face, the turquoise one, and I installed it in my red Jim Dunlop JD-F2 Fuzz Face, the JD-F1 Fuzz Face pcb uses two BC108B NPN silicon transistors, it also includes a couple of surface mount trimpots, and some other surface mount components on the underside of the board, I'll post a pic of the insides shortly.


Okay, here we go:

Attachment 45066

And, a closeup of the Jimi Hendrix JD-F1 Turquoise Fuzz face pcb I bought on eBay:

Attachment 45067