Blue box Graft?

[Jaicen_solo]

Has anybody here had any experience of grafting on the 4116 octave down section of the blue box to the back end of a fuzz face??
My friend wants an octave down + fuzz face in a guitar, but i'm wary of both the size and current draw of the blue box circuit.
I figured it might work, but then what do I know?!

[Mark Hammer]

I *think* you mean 4013,since a 4116 is an older DRAM chip if I'm not mistaken.

But that aside, the key thing is that the signal fed to the flip-flop chip be high enough amplitude to fall above the critical threshold for detection as a logic-high signal.  I don't think the normal Fuzz Face output will do that.  It's "hot" but not that hot.

[Jaicen_solo]

I did indeed mean the 4113, the 4116 is a RAM chip used in the old VIC20. I'm after a few if anyone has any lying around

What I meant by the output of the FF was taking a feed directly from the collector of Q2, which is a very hot signal indeed! If that's not enough, an extra transistor gain stage could be used I guess, but i'm sure it wouldn't be needed.
If i'm correct, anything above 3v will be enough to give a logic 'on' ?? 

[Mark Hammer]

I did indeed mean the 4113, the 4116 is a RAM chip used in the old VIC20. I'm after a few if anyone has any lying around

What I meant by the output of the FF was taking a feed directly from the collector of Q2, which is a very hot signal indeed! If that's not enough, an extra transistor gain stage could be used I guess, but i'm sure it wouldn't be needed.
If i'm correct, anything above 3v will be enough to give a logic 'on' ?? 

1) I might actually have some 4416's in one of the (too numerous) mobos I have in the garage.
2) Yep, as far as I know 3v oughta do it.  Keep in mind, though, that you really want to have as little harmonic content going into that divider as possible, or else you'll get it triggering for all sorts of crap.  As well, note that one of the properties of the FF is that it "cleans up" when you back off the guitar volume control.  Unfortunately, that is more than likely to introduce undesirable instability in the octave division.  What works well for the fuzz portion may be counterproductive for the octave part.  Personally, I think the proposed graft is more likely to cause headaches than to turn out as well as you imagine.  Just an opinion, and a case where I'm just as happy to be proven wrong as right.

[Jaicen_solo]

To be honest Mark, i'm sure you are right as you almost always are (though I've never known you to be wrong yet).
I just thought it would be an interesting excercise, since I have a few FF's lying around I figure I could perf up one half of the octave down thing and see what happens. To be honest, the guy i'm building this for wants something that's heavy and chaotic, so exact tracking isn't a big deal. I think he just wants to hit the low E and go BOOOOOooooom 
I actually had some success grafting the octave section of the RM Octavia to the back end of the FF, which sounded really good. Adding an octave down would be pretty sweet too. My WhammyWah has a similar setting which I like a lot.
Whilst we're on the subject though, I don't suppose you have a copy of the schem for the fundamental extractor from the EHX Octave Multiplexer?? I'm working on something else i'd like to use this for, but it would also be good for a re-designed blue box type thing.

[Mark Hammer]

You should probably take a look at Tim Escobedo's Circuit Snippets site, then.  There are plenty of interesting, simple, and counterintuitive pedals there with octave-down capabilities.  Perhaps just as pertinent, a great many of them have been built by multiple parties here at the forum, so you'll be in a better position to have sage advice from those who have experience with the particular circuit.

[Seljer]

I've always wanted to try putting the 4013 octave down into Tim Escobedo XOR octave up for a poor man's EHX Guitar Synth (along with a buffer in the front and a mixer on the back so you can create any mix of clean/fuzz/octave up/octave down)

[Jaicen_solo]

If anyone is interested, I have prototyped this with some pretty good results, sort of
If you take a feed directly from the collector of Q2, into the flip-flop circuit, that will give you enough gain to produce a heavy square wave octave down. However, because of the extra harmonic content from the fuzz (I assume at least) and the asymmetry of the clipping, the tracking is pretty mental! Sounds a lot like an Atari 2600.
I also managed to kill the fuzz that i'd grafted it to somehow (poking around as usual), so there will be no soundclips from this baby for the foreseeable future. I think I need a better octave down, something more stable that will track below the 7th fret on the low E. Anybody have any suggestions?? I did have a DOD FX35 for a while which used the 4013 but in a PLL configuration, and that tracked much better. Anyone know how I could clone that? The schem I found on the net is wrong and I no longer have the pedal to work from :<