Replace Germanium with Silicon Fuzz Face Clone (Solaris Aion)

[eskimoquinn]

So I was under the impression that I could replace germanium transistors with silicon in the circuit linked below. (Aion Electronics Solaris)

https://www.dropbox.com/s/gf1adkf9upq5xds/aion-solaris-fuzz-face-documentation.pdf?dl=1

I built the circuit originally with these Japanese germaniums: http://www.smallbear-electronics.mybigcommerce.com/transistor-pair-the-fuzz-face-pnp-japanese/

Then I bought some BC109C Silicon Transistors thinking I could just substitute the BC109s for the Japanese Germaniums. Here are the BC109s I bought: http://www.smallbear-electronics.mybigcommerce.com/bc109c-sgs/

But there is barely zero output when I have the silicons in the circuit. When I turn it up to full volume, I can hear what is basically a clean signal.

Where did I go wrong? Any thoughts?

[brianq]

Have u verified u have transistors pins right? Is the original circuit positive ground? You'll definitely have sound difference if you're using npn transistors in a pnp circuit, you'll need to switch battery/ground connections as well as flip polarized caps?

[eskimoquinn]

Yeah both sets of transistors are PNP.

[brianq]

But bc109c is an npn?

[R.G.]

Yes, BC109 is DEFINITELY an NPN. If you have or can get any silicon PNPs, the circuit should work. I suggest trying common, cheap PNP devices in the TO-92 plastic case, any type number at all, to see if it works OK for you; then later substituting in any special type numbers you think might sound good. In fact, this is one of the few situations where I might suggest using a transistor socket.

The circuit as shown is more complicated than an ordinary PNP fuzz face because it uses the original PNP transistors and "positive ground" power supply, but uses a charge pump voltage inverter (the 8-pin IC) to create a -9V supply for the circuit. If you decided to use your NPN transistors, the charge pump circuit is not needed.

What follows may be more advanced than your current set of skills and learning, but it is possible to convert the circuit to use NPN devices.

You can use BC109's in that circuit if
(1) You match the pin placement inserting the transistors; collector to collector hole, base to base hole, emitter to emitter hole
(2) You reverse the electrolytic capacitors, swapping (+) for (-) pins
(3) You remove the polarity converter chip and all the components associated with it
(4) You bridge the incoming power supply to supply the

[MaxPower]

...to supply the ??

I hope RG is okay.

[eskimoquinn]

Ok this is awesome...this forum is great. I am going to try getting some TO-92 PNP transistors for this.

[smallbearelec]

I am going to try getting some TO-92 PNP transistors for this.

I would not suggest using PNP silicon; building the FF with PNP devices introduces difficulties. Take R G 's advice and build without the polarity converter chip using inexpensive, readily available NPN silicon. Here is an article that explains how to set up the silicon FF and line up the bias:

http://diy.smallbearelec.com/HowTos/BreadboardSiFF/BreadboardSiFF.htm

I also give some suggestions for selecting transistors. IMO, you may find the BC109C a little harsh-sounding in the FF.

[eskimoquinn]

Thanks again, I was just reading your article on this smallbearelec.

http://diy.smallbearelec.com/HowTos/FuzzFaceFAQ/FFFAQ.htm

I think it is something I am willing to try. I will let you know how it goes!

[PRR]

(4) You bridge the incoming power supply to supply the

{guess} to supply the raw +9V to the now +9V power rail.


I suggest you stick in a small resistor as shown, so the diode don't die trying to fight a hi-current supply and the cap has some leverage against supply crap.

[eskimoquinn]

Awesome So I guess I do have have a further question, how can I set up the Silicon NPN transistors so that I can use this pedal with a daisy chain? If I bypass the charge pump, will this pedal require its own power supply? I couldn't quite figure that out with what I was reading.

[brianq]

In that schematic use everything but the charge pump,u see  there's a 100 ohm resistor a capacitor & diode? That's your power supply filter wich will work well with power supplies, even daisy chains. It's an NPN circuit so it's negative ground so it should work with wall warts

[R.G.]

...to supply the ??

I hope RG is okay.

Me too. 

I just got interrupted while editing the post.