Shocktave question?

Started by doug0147, April 07, 2009, 11:58:14 AM

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soggybag

Speaking of matching transistors. I always thought this might be built best using a transistor array like the LM3046/3086. This way the transistors would be matched. Everything would be on one chip, which might make for a more convenient build.

I gave it a try once on a breadboard some years ago without any luck. Either I made a mistake somewhere or the transistors were to low gain. Or a combination of the two.  I still think this would be the way to go to

ddpawel

Quote from: soggybag on February 15, 2010, 02:23:26 PM
Speaking of matching transistors. I always thought this might be built best using a transistor array like the LM3046/3086. This way the transistors would be matched. Everything would be on one chip, which might make for a more convenient build.

I gave it a try once on a breadboard some years ago without any luck. Either I made a mistake somewhere or the transistors were to low gain. Or a combination of the two.  I still think this would be the way to go to

I've seen project with these transistor arrays - www.jhaible.de/tau/jh_tau.html, relly good phaser.
LM3046 arrays have low hfe=110.

But as I see on http://www.falstad.com/circuit/e-multivib-a.html, there shouldn't be difference in signal if hfe is 100 to 10000, so it should work. Of course if hfe is bigger it has better characteristics. Maybe pair of MPSA13 can help?

And what about Op-amp schmitt trigger driving multivibrators? Can it be better than two transistors like in  regular Shocktave?

caburron

AM getting the same result :poor or lack of octave sound ,i thing that there's not enough voltage on the oscilator.maybe the schematic is wrong,becouse i check the shin ei octaver in the oscilator ,and has his on 9 volts ,instead of chopped voltage from the transistor base of this circuit,i  need help in this one ,what  i did wrong? The fuzz is fine.Iwas trying to get the "everyone's a winner " guitar sound .Have auditioned many fuzz octave boxes on youtube and no luck.THE fuzz part is a little like gated or sputtered on the song and  a littlle octave down and then up .thx

Quackzed

try a booster in front or overdrive with the vol cranked...
nothing says forever like a solid block of liquid nails!!!