A few Shocktave questions

[gutsofgold]

I just built a shocktave and I'm not getting any octave down sounds. It has a very subtle distortion but no octave sound. The "mix" pot works but when I move it towards the octave side the volume just drops a lot.

Could this be the result of bad transistors? I soldered them directly to the perfboard and I usually socket them, maybe the heat killed them. The schem called for 5089s but I used 5088s, the 5088s are supposed to be similar to 89s only slightly less gain and a bit noisier.

Finally... the schem calls for a 3.3M resistor but theres two layouts on the internet and they both have a 4.7M resistor in that spot. I can't imagine that making a big difference.

[ambulancevoice]

how long did you hold the iron on the transistors for when you soldered them?
its possible that the heat screwed them up a little
i best way to solder transistors to the board is to use an alligator clip (or one of those clip on heat sinks) as a heat sink for the transistor, just clip it across the legs between the transistor body and the pcb, but still don't hold the iron on there for too long
5088/9 thing shouldn't really be a problem

[oldrocker]

I just built another Shocktave that I'm going to give to my brother.  I used Marco'2 layout and etched a PCB.  I posted pics of it below. 
I soldered my 5088's right to the PCB but didn't heat them up too much.  They can usually take a fair amount of heat before they fry but it is possible to damage them.  My first Shocktave I used 3904's  on perfboard and it sounds great.  I socketed those.  Be careful when doing the flipflop part of the circuit where the base of the last 2 trannies cross each other.  I screwed up there when I first built mine on perf.


http://i218.photobucket.com/albums/cc93/ftrock/st6q.jpg
http://i218.photobucket.com/albums/cc93/ftrock/st10q.jpg

[gutsofgold]

Thanks for the help so far. I've gotten a pretty good octave down sound from it finally. The only problem is that it's a very spitty octave down, not a clean signal at all. Is this normal? Would GAIN MATCHING the 5089's help at all? I just picked some random ones and put them in there.

[ambulancevoice]

well, according to JD, it is a bit distorted, so it may be normal
could we hear it???

[gutsofgold]

Here's an example...

http://www.soundclick.com/bands/default.cfm?bandID=560990
(click the song "shocktave")

notice how the distortion it creates is very choppy and the tracking overall is not smooth. Is this common?

[jonjon]

bump. because i would be keen to make this if it tracks a bit better

[gutsofgold]

Can anyone give me some insight? Is it supposed to sound like that?

[anchovie]

Thanks for the help so far. I've gotten a pretty good octave down sound from it finally. The only problem is that it's a very spitty octave down, not a clean signal at all. Is this normal? Would GAIN MATCHING the 5089's help at all? I just picked some random ones and put them in there.

The octave down sound will never be clean because it is a square wave by nature that comes from any flip-flop method. Clean octave down is really only available in the digital domain. The Shocktave comes with the same caveats that several octavers have, which is that the best tracking comes from playing through the neck pickup with the treble rolled down.