BJFE / BearFoot fx Guitar Effects Community

Good places to get parts from and parts lists for those that want to do the sourcing themselves....

Anyone know the best setup of germanium transistors, say from Small Bear, that would be best for this project?

Also, I noticed the list of parts jfromel was planning to include had alot of 1/4watt resistors. The original diagrams I have had me looking for either .6w or 1/6 watt resistors. What kinda tonal difference, if any, does this switch make?

I just noticed the discrepancy while looking over some diagrams?

Tonefishin wrote:Anyone know the best setup of germanium transistors, say from Small Bear, that would be best for this project?

Curious as to why we're sourcing germaniums when the layout calls for silicon transistors that are currently available?

BMF Effects wrote:

Tonefishin wrote:Anyone know the best setup of germanium transistors, say from Small Bear, that would be best for this project?

Curious as to why we're sourcing germaniums when the layout calls for silicon transistors that are currently available?

the 3.5% solution BJ provided over on TGP lists both transistor types for T1 and T2.

that's the version (3.5%) we're doing here, isn't it?

here is the BOM by Location. Remember that there are no hard and fast rules for this build. Bjorn has encouraged us to experiment with different values of caps, resistors, and trannies and the PCB layout that Nick at NOC3 put together allows for a few different types of clipping circuits.....

C1 0.047
C2 10u/25
C3 10u/25
C4 150pF
C5 10u/25
C6 100u/35
C7 .022uF
C8 10u/25
D1 1N4002
D2 1n914
D3 1n914
D4 1n4001
D5 1n4001
led2 red led
led3 red led
R1 1M
R2 47K
R3 100K
R4 100K
R5 1K8
R6 100
R7 10K
R8 100
R9 10K
R10 10K
R11 10K
R12 100
R13 100
R14 10K
T1 2N1306
T2 2N1306
T3 2N2219A
T4 2N2905

And here is the BOM by quantity for the kit that I will be doing up, of course feel free to change it up as you want.

2 1/4W 1% Metal Film Resistors 100Kohms 1% 50PPM
4 1/4W 1% Metal Film Resistors 100ohms 1% 50PPM
1 1/4W 1% Metal Film Resistors 1.0Mohms 1% 50PPM
5 1/4W 1% Metal Film Resistors 10Kohms 1% 50PPM
1 1/4W 1% Metal Film Resistors 47Kohms 1% 50PPM
1 1/4W 1% Metal Film Resistors 1.8Kohms 1% 50PPM
2 1n914 Diodes - Small Signal 100V 4.0ns Diode Single Junction
2 1n4001 Rectifiers Vr/50V Io/1A T/R
1 1N4002 Rectifiers 100V/1a Rectifier General Purpose
3 2N2219A Small Signal Transistors NPN General Purpose
1 2N2905A Small Signal Transistors PNP Gen Pur SS
3 Standard LEDs Red Tinted Diffused
1 Mica Radial Lead Capacitors 150pF 500V +/-5%
1 Radial Polyester Film Capacitors CAP 100V .022uF 5%
1 Radial Polyester Film Capacitors CAP 100V 0.047uF 5%
1 Audio Electrolytic Capacitors 35volt 100uF 20% Radial
1 Audio Electrolytic Capacitors 63volt 10uF 20% Radial

After looking at the schem drawn by Bjorn, it looks like the 0,6w resistors are metal film and the 0,25w resistors are carbon comp on the spec. I typically use .25w 1% metal film resistors for all my projects so that is what I sourced for the BOM. If Bjorn has some input on this it might help.

I am going up to Anacortes to see an old TV repair guy who has buckets of germanium trannies and diodes perhaps I can pick up some good ones for less than Small Bear has them for. However, Small Bear has tested and matched trannies that I think are worth the price they charge.

Hi,

This is the Folk Fuzz 3,5%. To get higher gain and lower noise I use T1=BC550C and R2=2K0. I'd use a 2N1306 for T2 but for T3 and T4 I've used either complementary PNP/NPN or an N- or P-FET connected as diode( hook the drain and source together and you'll get a diode). Various variants of connecting CMOS transistors also works and if you'd like the unit to double as a booster connect a switch for the clipping section as described in the instructions for Folk Fuzz 2,8%.
The capacitor of 150pF is the main rolloff: foruse with guitar choose a value between 47pF to 180pF. I'd use a very low noise silicon transistor in position one to keep the circuit stable and also to give the highest gain aswell as giving the highest signal to noise ratio. For position 2 I'd prefer a germanium as this is the 'colouring' transistor put very simplified.
The 2N1306 is one of the last generation of germaniums and just as germaniums finally got rid of plague of popcorn noise and poor gain and high leakage they also became too expensive as compared with the silicon alternatives. There are few numbers of these last generation germaniums. If needed I can post a list of numbers.
There are a couple of million transistor types while they all belong in families. Many of these were originally made for a product most often forgotten these days and so Phillips had their own partnumbers for instance. In view of this there are about 30 types that are high quality germanium NPN transistors.
I have choosen carbon resistors for such positions that are noncritical in terms of noise and just as sidenote carbonfilm resistors burn when overloaded to create an open circuit while metalfilm resistors create a short when burned.This is maybe a subconcious thing guiding this as there would be no risk of overload in the circuit

Gentlemen have great fun
BJ

Ah yikes I did not manage to copy the schematic into this post but perhaps someone more skillfull at such things can copy the schematic into this thread?