Sunday, 20 January 2013

Univox SQ-150 Square Wave





And a little clip with a small cap to tame the squeels and a LPB-1 with a trimmer at the output to fix the level issue.



24 comments:

  1. You can tag this one as verified. Built mine with a 2N5457 and a BC549C. Great sounding dirty, velcroy fuzz, been meaning to build one for ages and now I know just why..!

    Only problem I'm having is it's giving me a lot of hiss and oscillation, might try to replace the 47uF for a 100uF, though I would have expected it to be enough?

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    1. Cool, thanks Alex! I'll tag it right away.

      Original has 4µ7 for a filter cap, so you could try that..
      +m

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    2. maybe shielding both in and out would do the trick ?

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    3. This comment has been removed by the author.

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  2. This is absolute filth, I need to build this right away! Are there any acceptable alternatives to the listed transistors? I've had a bit of a parts buying mission recently and would like to avoid buying more stuff if I can help it. My parts drawer (at the moment) has 5457s, 5458s, 2222s, BC109s, and 5088s. Would any of those suit the job? Cheers

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    1. 2N5088 should be fine. Just note the pinout, as the transistor image is for BC550.
      +m

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  3. Ooooh! NASSSSSTY!
    Don't think I ever heard of this filthy little gem. Thanks, and I think I've got all the parts around here somewhere...

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    1. http://youtu.be/ERLLUoZn0mM - I, Treguard, give you the Pedal of Fuzz...

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  4. Finally got round to building this and it's a dirty little filthmonger. Had to make some substitutions in Q1 (used a 5088) and some of the resistors - namely soldering different values together to create some of the odd values like 3.9K 270K and 2M that I either couldn't find or didn't have.

    However as Alex says, I'm getting a lot of hiss and oscillation when I'm not playing. Did anyone figure out if a filter cap was the answer or if the 47u needs upping to 100? Cheers

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  5. sorry but the farts after eating the bean soup sounds better

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  6. sorry but the farts after eating the bean soup sounds better

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    Replies
    1. Why do people build circuits they don't like and then complain?
      +m

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  7. Hi!,
    Thank you for this vero !
    I don't know how to place diode because its ge and the black ring is shorter than the white (transparent). How do I place them?

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    1. The diode image is sort of inverted, making it look like the 1N4001. The black ring is indicating which side is the cathode. That's white in diodes that have black body.

      In this case, as the diodes are paired for clipping, it doesn't matter which is in left and which is in right - just that they are "back to back".

      Anyway - D1 is black ring up, D2 is black ring down.
      +m

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  8. Hi all, I've been fiddling with this some more and added a 3rd pot to control the distortion with lug 1 between the Signal leg of Q2 and the +ve terminal of the 33uF cap, lug 2 to lug 3, and lug 3 to ground.

    I added it at the suggestion of someone on the diystompbox forum when asking how I could get rid of the excessive noise produced by the 2 knob version. It sounds pretty good until the resistance drops below about 2K, then that nasty high pitched oscillation appears again.

    Does anyone have any suggestions as to how to get rid of this oscillation, asides from setting the resistance to just over 2K ;-)?
    I really like how the pedal sounds with the distortion maxed out but that high pitched squeal/howl that comes in if I stop playing even for a very short time kills my ears. Thanks

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  9. ok so I finally got round to finishing this one today. I added an extra 5k lin pot between Q2/33uF and gnd to control the distortion and boxed it all up. Sounds great on it's own and devastating when chained after my sovtek big muff pi! Thanks Mark+Miro!!

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  10. Build two of these boards with BC549C and 2N5457 today. Very nice mushroom coud-style fuzz! Meaner than most tonebenders!

    Although i did experience the same massive hiss as couple of other builders above. I simply cured it with 100p cap between BC549C base and collector (there's a nice place for that cap above the input wire). That cured the oscillation hiss on both of my boards. The output level is sufficient, but not too great. I might try 100K or even 250K lin pot for level at some point before boxing these up.

    Mean little circuit!
    +m

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    Replies
    1. Did you notice any adverse effects from adding the B-C cap, Miro?

      My Fuzz Stainer build sounds super cool but I'd love to minimize the hiss.. I'm thinking a B-C cap might do the job and also maybe roll off a bit of harsh highs too

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    2. Tested the theory with 1n cap, which muffled all the highs. 100 was just spot on, killing the oscillation but keeping the desired highs in tact. You could try 47p, 100p, 220p and other values to see which gives you the best results.
      +m

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  11. Cool, I'll give it a try, and there are two perfect spots for a B-C cap for Q1 on that Fuzz Stainer layout!

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  12. A 100pf on Q1 didn't do much of anything. Do you think it would be more effective on Q2?

    It didn't mess anything up though so that's nice

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    1. I really wouldn't know about the Fuzz Stainer as i haven't built one myself...

      100p works for square wave.
      +m

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  13. Right on thanks dude.

    You should give the fuzz stainer a try. It's a cool fuzz that can go from a sweet overdrive to a weird gated mess. It's not going to replace my number one but its lots of fun

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