New scheamatics

[col]

Richard has very kindly posted two schematics I drew from pedals I got from a car boot sale. I've not seen them before on the net so they might be of interest to some people. They are the Guyatone Zoom Distortion and the Carlsbro Suzz. The Suzz isn't very exciting, I seem to remember mine being a lot more fuzzy but that was in a plastic case and it was 20 years ago so who knows? The Zoom Distortion is very good though.The links are as follows;
http://aronnelson.com/gallery/albums/Richard-Boop-RLBJR65/suzz.gif
http://aronnelson.com/gallery/albums/Richard-Boop-RLBJR65/Guyatone_Zoom_distortion.gif
Out of interest does anyone know if the later Suzz in the plastic case had the same circuit?

Col

[Zero the hero]

No answers to your question but thanks for sharing anyway!!!

[bioroids]

Cool, thanks for sharing!

Miguel

[markm]

Doesn't the Guyatone circuit look like the OD250 Dist+?

[ildar]

Doesn't the Guyatone circuit look like the OD250 Dist+?

Yeah, and a bunch of other diode clippers. Look at that (relatively) huge cap across the diodes  Maybe that should be 47pf, not 470?

[wampcat1]

Doesn't the Guyatone circuit look like the OD250 Dist+?

Yeah, and a bunch of other diode clippers. Look at that (relatively) huge cap across the diodes  Maybe that should be 47pf, not 470?

I don't think so - some circuits use a .001uf there. The rolloff with the 470pf would be 28k or something like that wouldn't it?!
I think I would go something closer to .0015 or .0022uf.

bw

[Dan N]

Thanks Col and Richard! Fun to see new (old) stuff!

I have an old board shot of the zoom box and it looks like some values are different from yours.

http://users.rio.com/senorris/junk/guyazoom3.jpg

Should that input bleeder cap be 1n and the input cap be 10n?

Anyway, thanks again!

[col]

Dan,

The values on the schematic are correct for the version I've got. The op-amp on mine is a more modern plastic one rather than the metal can one in your pic and looks to be original. Maybe they switched components around over the production life of the pedal? I't good to be able to put something back into the forum and share info where I can.

Col

[cab42]

Col, thanks for the schematic.

I'm very tempted by the Guyatone zoom as I have a few spare 741's. 

I did a quick search and found on Diskofreq's site that its the same circuit as the Vox 1901 distortion (http://filters.muziq.be/model/guyatone/box/ps102). On the page there is also a link to a handdrawn schematic. Direct link: http://www.voxamps.co.uk/downloads/1901dist.jpg

I haven't compared the two schematics yet, but it seems that the 741 used, is a round one in a metal can like on Dans image.

Regards

Carsten

[Ge_Whiz]

Some of the crossovers on the Guyatone schematic seem to be genuine crossovers, while others could be where two wires are connected. Some connection points have dots, while others do not. Could you clarify this, please?

[col]

If it is a crossover there are no dots. The dots signify a connection where wires cross. I didn't put the dots on where there is just a three node junction as I didn't think it was necessary? If I do any more of these in future would it make it esier to include dots at all junctions or put 'jumpers' over the wires? I have seen both used and there doesn't seem to be a standard for this. I also forgot to put the numbers for the op amp on the Suzz diagram but that should be pretty easy to work out.
I checked the Guatone last night and the small cap is definately 470pF as it says 471. The op amp is original as far as I can see and it's a plastic CA741CE with RCA 336 beneath it. The board also has the two small holes on it next to top amp that Dan's has.

Col

[davebungo]

My first pedal (back in 1979 ish) was a Carlsbro Suzz.  It was made up of a wedge shaped extruded aluminium case with screw on sides I seem to remember.  I also remember it being pretty awful but better than nothing for bashing out those Black Sabbath riffs.