Fulltone 70 schematic

[ringworm]

Can't seem to find one based on this one here:

http://i2.photobucket.com/albums/y31/mothra2005/ebay%20-%20new/IMG_0994.jpg

the 18k in the pic is for the led (!?) seems high but...
I've left it off and the 2 x 1M (i'll be using a dpdt when I build & no led)

Does this look right?

[Renegadrian]

Hello, instead of opening a new thread I want to use this one to keep the forum clean and also we have a (older!?) schematic of the 70 for direct comparison.

I want to report my experience with this pedal here, which is actually a fuzz face, no doubt about it.
A guy here in Rome asked me to build one for him.
I read a lot about it, here, in the other forum, in other sites as well...So I learnt that
* mid pot is very subtle or doesn't do anything
* the diodes (in the latter schem!?) are quite useless
* the 1k res before the trimmer is quite useless (IMHE)
I built it using the vero layout by MARK but experienced the flaws above.
I just found another schematic, it's not about the fulltone but it's a FF, similar to the schem of the first post, but with no diodes and mostly important two caps tied to the mids pot that aren't in that schem...needless to say that now it works as it should...
someone wrote they had no access to the back of the original pcb and guessed there were some hidden components...maybe it's the two caps that make the difference!!!

I ditched that 1k res before the trimmer which is now a 10k and not 5k (original fixed resistor is 8.2k) and put a 1k res for the 220r/330r/470r (as per the axis face ckt and description here http://fuzzcentral.ssguitar.com/axisface.php)
Also ditched the useless diodes.
1kC pot for the gain is not so easy to find, I had a 5kC and put a resistor in parallel to change its value, not the best solution but a little better than the regular 1kB.

so here is what is a closer version of the 70.

[Cozybuilder]

Hi Adriano-
I think you're onto something here. I breaded it to see how it sounds, then changed a couple of things- 10nF cap, 2K pot, 100nF top of pot, and 1uF input cap is getting it closer. Am going to play with it some more. Circuit components are 2N3094 in Q1, 2N5088 in Q2, 33K Q1C to V+, 1K2 V+ to trimmer, 10K trimmer to Q2C, C1K to Q2E, 22uF on the wiper, 100K feedback, 100n output cap, A100K vol.
Thank you for sharing

[Renegadrian]

Yes Russ, I guess this is the best FF arrangement.
have you got some 2369 around!? they have lower hfe and sound so good in FF.
Another good suggestion from the fuzzcentral page is a 100p on Q2 C-B.

[Cozybuilder]

I took your suggestion and tried out a pair of Motorola ST992 8503 metal cans (2N2369) and 100pF cap. After biasing to 4.5V on Q2C this is sounding real good! All the other components are as I described earlier. This is getting close- my taste is for a little more treble, so Im going to play with this some more, definitely worthwhile.

[Renegadrian]

This thing sounds like crazy...this tone arrangement is very good and it really gives different nuances to the sound...
everyone should try it out!!!