Building the Chopped OC2

[Taylor]

If the diode and flip flop are all that you changed, I wouldn't expect that to make any difference. The diode is there to add a DC offset to the waveform in the "phase-flip" section, which has an effect on the timbre of  the octave sound, but nothing to do with the tracking.

The tracking is really all there in the lower filter (on the schematic) and the two precision rectifiers. The major change to tracking would be to change the cutoff of the sallen-key filter in the lower half of the schematic.

[p_wats]

Alright, I'm determined to get this guy boxed up finally, but still can't get rid of the fuzzy signal underneath everything. I've tried it with a buffer too. It's noticeable enough that when ALL controls are completely counter-clockwise (ie, off) I can still play a fuzzy guitar (with a volume drop). I can't imagine this is normal?

One thing I'm noticing is that my 4013 gets hot. Is that common? I'm hoping not and that it points to a failed component somewhere...

Any suggestions? Thanks!

[Seven64]

mine is making some insane nintendo type sounds.  with normal all the way up its 80% clean signal and 20% fuzzed.  when octave is all the way up, it is choppy, has almost no sustain, and jumps around notes that sound really 8bit.  im thinking i need to remove the ic's and socket the chips with some replacements, but im not sure.

[Seven64]

bump?

**edit**

nevermind.  i rolled off some treble and switched to the neck pickup and am hearing much cleaner, crisper single notes for the most part.  chords and fast picking still sound like nintendo, but it sounds like that is because the circuit does not know which note to take the octave off of.  i do hear that fuzz that most people talk about, but its only when the clean side is turned up. 

nice pedal, and pretty trouble free in my part.  next time i will mount the pots to the back of the pcb, as to not take up almost the entire box!

great job taylor!

[Taylor]

Right, that's pretty much how analog octaves all work. They are monophonic pedals, so if you try to play chords, the tracking section will have no idea what to do. Just a limit of the technology. Glad it's working!

[SteveFromBerlin]

Unfortunately I'm too late and i's sold out. Do you think you will have another bunch of these someday?

[Taylor]

Yep, definitely, just making some tweaks to the board before the next batch.

[SteveFromBerlin]

AWESOME! 

Just let me know and I'll be happy to be the first one to buy, build and do a little vid like this one (german).

All the best from Berlin!

[Beo]

I've never played through an octave pedal before, and I'm not exactly sure what tracking sounds like. But on my pedal, which I really like so far, when I hold a low note on the E or A string, the octave note bounces up and down octaves. Is this normal, and is there a way to fine tune it to hold the octave more stable?

[Taylor]

Yes, that's how this type of circuit reacts. The common tips are to play with your tone control rolled off, neck pickup, and typically higher up on the string tracks better. Low notes will always tend to track worse.

If you want to get into modding the circuit, you can tweak the cutoff of the filter in the tracking portion of the circuit, and if you want to go nuts, a compressor in front helps too. The problem with changing the filter is that then you will have a harder time getting an octave on higher notes.

[SteveFromBerlin]

I play bass and I'm addicted to it. Cant wait... how loooooong?!? 

[merlinb]

I play bass and I'm addicted to it. Cant wait... how loooooong?!? 

Might be quicker to learn how to make your own PCBs! 

[SteveFromBerlin]

I play bass and I'm addicted to it. Cant wait... how loooooong?!? 

Might be quicker to learn how to make your own PCBs! 

I'll soon give it a try, but even if can do it, I don't have the pcb-layout for this chopped Analog Octaver.

[merlinb]

I'll soon give it a try, but even if can do it, I don't have the pcb-layout for this chopped Analog Octaver.

There are others...
http://www.freewebs.com/valvewizard2/uboat.html

[SteveFromBerlin]

I'll soon give it a try, but even if can do it, I don't have the pcb-layout for this chopped Analog Octaver.

There are others...
http://www.freewebs.com/valvewizard2/uboat.html

MERLINB, THIS SOUNDS FANTASTIC!!!

I'll defenitely give it a try!

Thanks a lot!!!

[Taylor]

Thanks for posting that, Merlin - I have directed people towards your project before. Looks great!

[telebiker]

Taylor, any news with pcb?

[Taylor]

Not any news, but I'm working on it. For the time being, if you need to build an octave I recommend Merlin's project, linked above.

[telebiker]

Not any news, but I'm working on it. For the time being, if you need to build an octave I recommend Merlin's project, linked above.

There's no rush about it, just asking. Will purchase PCB after you finish

[megalodon]

Hi, can anyone tell me what the 1uf cap from pin 1 of U1A is for? All it seems to be doing is putting a loud clean signal into pin 5 of U1B, which overpowers the octave down, I only got results after I removed this. Another thing, is using a j201 neccesary? I'm using a 2n5485.