70's pedal circuit

[Mark Abbott]

I recall sometime ago people here were experiementing with the Fulltone 70's pedal, I remember a clipper circuit was also mentioned.

If someone could be so kind as to forward me a copy of the circuit I would appreciate that.

Thanks for your assistance.

Yours Sincerely

Mark Abbott.

[Mark Abbott]

What no takers?

I remember someone having a circuit for this thing.

Yours Sincerely

Mark Abbott.

[ErikMiller]

I thought the '70 was a silicon Fuzz Face....

[Russ]

It is. I'd love to have a copy also, if someone would be so kind.
Thanks, Russ

[Dai H.]

hi, it's at the Yahoo schematic_trading group

[Mark Abbott]

Dear Dai

Could you give me the address of this schem trading group?

Much thanks.

Yours Sincerely

Mark Abbott

P.S. Someone did send me a copy of the circuit which I really appreciated.

[cedric]

pic is here:
http://f1.grp.yahoofs.com/v1/UOR7QCpeFxryQr0EIuFtaZaDTBKSzZEsSZ9xTp2mVssIJ83yJCPnkjxQoFSXFnReWg0NOHW6TBG2iS3KYqKfyE8OT-8h4QPwIiju/Fulltone%20%2770.GIF

and the group is here:
http://groups.yahoo.com/group/schematic_trading

[phillip]

Here's a PCB and Layout for the Fulltone '70 that I drew a while back when I was going to build it.  I got distracted with other projects and never got around to it, but the layout should work fine:




I'll leave them posted until midnight tonight, then I'll have to take them down.

Phillip

[Phorhas]

Perhaps a silly question but... how does it sound?

BTW what R the original transistor used by fulltone?

[phillip]

The one that Luke traced out had a pair of 2SC828 transistors, which have a B-C-E pinout.  There's nothing really special about those though...a medium gain transistor like the 2N4401 will work fine in its place.  I have heard of other versions that used a BC108 and BC183L combination...not sure which went in what position.  I would think that some of the European-made audio transistors like the BC108s or BC109s would be even better sounding in there than the 2SC828s

Phillip

[petemoore]

IIRC the 70 enjoys the lower gain transistor in Q1.
 and 4401 should be good. I ended up either with 4401 or NTE123, in Q1 but I think a Tin can 2n2222 might be a good suspect. Q2 is a BC 109 in mine.
 I think it sounded good, Fuzzy and hard driving. Also I used a 2k gain knob...the extra knob actually works pretty neat, adds gain and midrange if Im not mistaken.
 Very nice, actually a little mean buggar. aggressive. I think would do well in a Blue Cheer tribute band. Been a while since I tried that one out.

[dev]

How do the diodes affect the 70's pedal sound?  similar to the common diodes to ground or is it more subtle?  I've never seen diodes in this configuration, is this found in some other pedal?  
thanks Dev

[nightingale]

i can't see the schem~
would someone mind emailing it over to me?

ryansusa3@msn.com

thanks,

[Dai H.]

Dear Dai

Could you give me the address of this schem trading group?

Much thanks.

Yours Sincerely

Mark Abbott

P.S. Someone did send me a copy of the circuit which I really appreciated.

Cedric beat me to it, oh well.  :wink:

re: the sound, I converted my Si FF to the circuit shown, and I liked it. More like a Ge one, I guess. Single notes were real fat and synthy, is how I recall it last time I used it. I used what appears to be an alloy junction Ge and not those (point contact?) glass ones like 1n60, etc. The exact type seems to make a diff., or perhaps the gains were accidentally correct w/the ones I like(?). The normal Si FF sounds a bit flat to me compared to  the Ge version.

[Phorhas]

Thanx Alot for everyone responding

[petemoore]

Oh yes the diode...I didn't get much yardage with that thing, and ended up leaving it out...synthy...yepp...reall gainy and Fuzzy though..

[Mark Abbott]

I have a Schaller Fuzz that is a copy of a Si FF, it used BC239C's, I think that they have a gain of roughly 500, (according to my multimeter.)

To get to the point, they sounded dreadful in this circuit, a friend who has a Dunlop Jimi Hendrix FF also thought this pedal sounded dreadful, I can't remember what transistors were in the circuit, but I do remember that they had a high beta.

Yours Sincerely

Mark Abbott

[phillip]

There are some very low gain Silicon transistors that have the promise of sounding pretty good in a Fuzz Face circuit.  Jack Orman used one of those low gain types in his YAFF, the 2N2369, which has a gain between 40-120.  Mouser has ran out of stock of that part number, I think because the companies have "obsoleted" them.  Mouser still has the PN2369A though, which is pretty much the same.

Phillip

[jimbob]

phillip- i think im gonna build that sucka in the next few days.. has it been tested to work yet? or been built yet? Looks great though! nice work!!

jim

[phillip]

I haven't built it yet, but I plan to at some point!  I've checked the PCB layout many times and it looks like it's ready to go.  

Phillip