Fulltone '70 schematic?

[jrc4558]

I lost mine. Is it still online somewhere?
If not, could somebody please send me one to
ac_128@yahoo.com
Thanks a lot!

[cd]

http://img31.exs.cx/my.php?loc=img31&image=fulltone703ng.gif

[jrc4558]

THANKS, MAN!

[Melanhead]

hmmm! .. thanks! ... I was looking for this as well.

Torchy had a layout posted for what seems like a day! ( as well as one for the Rat that I'd love to get my hands on .. wink, wink     )...

Anyone know if the pots are A or B

[Bucksears]

I whipped up a PCB for this a while back, but haven't tried it out.
Anyone want it e-mailed?

-Buck

[Melanhead]

I would but I've been doing vero builds only as I don't have time for PCB making ...

Just a note re the schematic:

I've had a 70's open in front of me and on this particular one the resistor accross the mids pot is 470 ohm, the volume pot is 500k log and the input cap is 2.2uf not 22uf.

.... The other 2 pots were 1K linear.

[cd]

I would but I've been doing vero builds only as I don't have time for PCB making ...

Just a note re the schematic:

I've had a 70's open in front of me and on this particular one the resistor accross the mids pot is 470 ohm, the volume pot is 500k log and the input cap is 2.2uf not 22uf.

.... The other 2 pots were 1K linear.

Did you happen to note if the transistors were different?

[mojotron]

I would but I've been doing vero builds only as I don't have time for PCB making ...

Just a note re the schematic:

I've had a 70's open in front of me and on this particular one the resistor accross the mids pot is 470 ohm, the volume pot is 500k log and the input cap is 2.2uf not 22uf.

.... The other 2 pots were 1K linear.

On the one I had - I did not remove the circuit board, but I did not notice the 1n914 or Ge diodes. The Q2 B-C cap was more like 50pF - which I did not visually inspect - I cloned the design and then swapped in ceramic caps until the sound was identical. And, the output pot measured 100k w/audio taper - although I did not visually inspect it via disessembly. And, the resistor across the mids pot was 1k. And yes the input was 2.2uF and the transistors were the same and 2SC828.

So, I built the GGG Boutique Fuzz (NPN Si) and used a 30pF Q2 cap (my preference) and a 100kA output pot and it sounds exactly the same.

Were the Diodes on the under side of the PCB on the one you looked at?

[wui223]

What diode is that? Germ and Sili... And what do the numbers under diodes imply?

[Melanhead]

I would but I've been doing vero builds only as I don't have time for PCB making ...

Just a note re the schematic:

I've had a 70's open in front of me and on this particular one the resistor accross the mids pot is 470 ohm, the volume pot is 500k log and the input cap is 2.2uf not 22uf.

.... The other 2 pots were 1K linear.

Did you happen to note if the transistors were different?

Well Q1 is a BC108B ( metal can ) and Q2 is, well, not sure ... The code has been covered by what looks like a black marker but it seems to say SXR 199 ... doesn't ring any bells with me ...

I see the disc cap underneath the board but can't tell it's value and can't find either diode! ...  :shock:

The reads the "69" underneath ... hmmmm

[Melanhead]

I would but I've been doing vero builds only as I don't have time for PCB making ...

Just a note re the schematic:

I've had a 70's open in front of me and on this particular one the resistor accross the mids pot is 470 ohm, the volume pot is 500k log and the input cap is 2.2uf not 22uf.

.... The other 2 pots were 1K linear.

On the one I had - I did not remove the circuit board, but I did not notice the 1n914 or Ge diodes. The Q2 B-C cap was more like 50pF - which I did not visually inspect - I cloned the design and then swapped in ceramic caps until the sound was identical. And, the output pot measured 100k w/audio taper - although I did not visually inspect it via disessembly. And, the resistor across the mids pot was 1k. And yes the input was 2.2uF and the transistors were the same and 2SC828.

So, I built the GGG Boutique Fuzz (NPN Si) and used a 30pF Q2 cap (my preference) and a 100kA output pot and it sounds exactly the same.

Were the Diodes on the under side of the PCB on the one you looked at?

Nope ... I'm assuming you put 'em in your clone

[mojotron]

I would but I've been doing vero builds only as I don't have time for PCB making ...

Just a note re the schematic:

I've had a 70's open in front of me and on this particular one the resistor accross the mids pot is 470 ohm, the volume pot is 500k log and the input cap is 2.2uf not 22uf.

.... The other 2 pots were 1K linear.

On the one I had - I did not remove the circuit board, but I did not notice the 1n914 or Ge diodes. The Q2 B-C cap was more like 50pF - which I did not visually inspect - I cloned the design and then swapped in ceramic caps until the sound was identical. And, the output pot measured 100k w/audio taper - although I did not visually inspect it via disessembly. And, the resistor across the mids pot was 1k. And yes the input was 2.2uF and the transistors were the same and 2SC828.

So, I built the GGG Boutique Fuzz (NPN Si) and used a 30pF Q2 cap (my preference) and a 100kA output pot and it sounds exactly the same.

Were the Diodes on the under side of the PCB on the one you looked at?

Nope ... I'm assuming you put 'em in your clone

The '70 I bought was from Feb. 2004. The transistors were covered in black marker - rubbing alcohol took that right off to show a pair of 2SC828 transistors.

I did not see any diodes on mine, I built my clone from my own schematic that I got when I drew the circuit. So I did not add any diodes. My clone sounds identical to the '70. The circuit is too easy to mess up.

[Melanhead]

hmmmm another schematic ... Can I convince you to send a copy my way

[Melanhead]

hmmm actually I unless there's any other changes you haven't mentioned, then I guess there's really no need  ... I was asleep and hadn't had my coffee when I wrote the above post!

[mojotron]

hmmm actually I unless there's any other changes you haven't mentioned, then I guess there's really no need  ... I was asleep and hadn't had my coffee when I wrote the above post!

Right, the schematic I have (which is in my notebook - so I don't have a digital copy yet) is just a GGG Boutique Fuzz (http://www.generalguitargadgets.com/diagrams/fuzzface_b_sc_nn.gif), with:
Q1=Pn2369
Q2=2n5088
R10=100kA
Added a 50pF cap between Q2's Base-Collector
Added a 1k resistor across the terminals of R8
This gave me the exact sound I got with the '70


Now, later on I changed:
The cap across Q2's base-collector to 30pF
And, I removed the resistor across R8
These last 2 changes gave me a bit more high end flexibility, making the FF more useful at lower settings.

I've been doing a lot of Fuzz Face related stuff in the last couple of weeks. I don't know why FFs can be so interesting - it's really strange considering how little goes into them. But, they are an excellent diversion from the 8 knob OD pedal I've been working on.  

I have found a few interesting sounds with the stuff I had mentioned. So, I'm actually going to post several FF schematics (a Boutique-ized Axis Face, and this '70 schematic) in the next couple of days and kind of compare the 2 sounds.

[Melanhead]

great ... thanks for the info.

[mojotron]

great ... thanks for the info.

This is all very subjective, but I'll add this too: if you can get some BC108 transistors and sort them as per gain/hfe as disscussed elswhere - these truely sound the best to me.

BC108C, BC109 sound good too.

The PN2369/2N5088 combo is a close 2nd, but I like this because it works 100% of the time. The PN2369/2N5088 gives just a bit more fuzz, but if I back off the fuzz knob a hair - I get very close to the BC108 sound.

[Melanhead]

great! ... I'll have to track some down to try ...