Octavio (JH-OC1), on/off switch mod for octave effect?

[themuckypaw]

Hey folks,

I'm new to the forum and not very knowledgeable about electronics, I've built one DIY delay pedal kit so far.

I have an Octavio (JH-OC1). Took me a while, but I've grown to like it. I particularly like the fuzz it produces and have wondered for a while if it would be easy to mod it so that I can turn off the octave effect so that I can use the fuzz on its own?

I had a quick search but can't find a forum post on this, sorry if I missed it.

So, can anyone help me please. Is it possible (I imagine it is)? Has anyone designed the circuit mod already and can point me to it? Is it a simple enough mod that even a newbie like me can manage?

Cheers.

[patrick398]

Welcome to the forum!
I'm not familiar with the circuit, do you have a schematic? Is it one you built or a production pedal?
A quick search for octave kill mods yielded this fuzz central article.
Assuming the circuit functions similarly it seems like a very straight forward mod:
http://fuzzcentral.ssguitar.com/octavia.php

[themuckypaw]

It's a production pedal I bought new.

Did quick search and found this ... http://i195.photobucket.com/albums/z210/alex_frias/OctavioDunlopTest-3-1.jpg ... I'm not sure how accurate it is.

That link you posted looks a little "double dutch" to me, but I might be able to work it out if I study it enough.

Thanks for the reply.

[Mark Hammer]

My best guess is that you would need to do the following:
1) Get a SPDT switch of some kind, whether toggle or stomp.
2) Connect the common/middle lug of the switch to the point where the two diodes and volume pot meet.
3) Disconnect/lift the end of the "lower" diode in the drawing that would normally meet the other diode and volume pot.
4) Connect one outside lug of the switch to that (now) "free" end of the diode.
5) Connect the other outside lug of the switch to the end of the other diode, where it meets the transformer.

In one position, the switch will have both diodes connected to provide the octave-doubling.  IN the other position, the switch will disable one of the complementary rectified signals used to produce octaving, and bypass the other diode to get what is essentially the "raw" distorted and boosted sound of the circuit through the transformer.

[themuckypaw]

I think I understand what you said, I'm very inexperienced at electronics. I have drawn onto the circuit diagram what I think you mean. Did I understand correctly?

Thanks for replying.

https://photos.app.goo.gl/yC7Cd1woGTnSxKQ29

[idy]

BYOC uses this circuit for their "Octave Fuzz" and uses the solution Mr Hammer suggested, disconnect one diode. I have one and it works fine that way.

He is saying life one leg of one (either) diode and use a switch to fill the gap.
Fancy name is turning a full-wave rectifier into a half-wave...

           

[Mark Hammer]

I think I understand what you said, I'm very inexperienced at electronics. I have drawn onto the circuit diagram what I think you mean. Did I understand correctly?

Thanks for replying.

https://photos.app.goo.gl/yC7Cd1woGTnSxKQ29

You understood accurately.
Personally, I prefer to bypass the diode when in the non-octave setting.  There will be a volume boost from doing so, but you sidestep the crossover distortion the diode would otherwise produce.

The deluxe version is a 3-position on-off-on toggle, wired up the same way.  In the middle position, that one diode stays in circuit, and you get the crossover distortion, but without the octaving.  The two side positions provide exactly what I described earlier.

[themuckypaw]

Cool, I'm not as dumb as I thought I was, or more likely, you did a good job of explaining it. 

I might try the three-way option, but either way, I now know I can mod it to do what I want. Excellent.

Thanks for the help.

Josh from JHS recommended this forum. Seems he was right about you all being so nice and helpful.

Cheers.

[themuckypaw]

BYOC uses this circuit for their "Octave Fuzz" and uses the solution Mr Hammer suggested, disconnect one diode. I have one and it works fine that way.

He is saying life one leg of one (either) diode and use a switch to fill the gap.
Fancy name is turning a full-wave rectifier into a half-wave...

           

Thanks. 

[themuckypaw]

Hey guys!

I know it's quite a bit since I asked you about modding my Octavio and you were so kind to give the info I wanted. It took me ages to get around to doing the mod, partly as I was a little bit scared of ruining my pedal, but I summed up the courage last night and did it. I did the "deluxe version" as Mark suggested with a 3 way toggle switch, and boy I'm blown away by how good it is. Not only can I now switch off the octave and use the fuzz by itself, which is just sublime and sounds so much like Jimi's fuzz, but I also really like the "crossover distortion" too. Instead of being a bit of a one trick pony, that I was struggling to get the best out of, I now have an amazing pedal that can do so much more. I can't thank you guys enough. If I could I'd buy you all a drink.  😊

Thank you, thank you, and thrice ... thank you.   🤘😎🤘

[Mark Hammer]

You're welcome, you're welcome, and (third switch position) you're welcome.  Glad to hear of your success and satisfaction.  As I've learned here, time and again,"little changes" to established circuits can often make them come alive in pleasing ways.

[quidane]

Hi everyone! I'm new here and really newbie about electronics, mods and stuff. But I know how to solder, like I do my own patch cable :p

I would love to mod my Octavio (JH-OC1) with the "deluxe version" you talk about. I understood all you said here theoretically but I'm not sure enough where exactly I have to cut the circuit and where to solder on the circuit itself  I don't want to mess it up ahah

Maybe, themuckypaw, you will be kind enough to put some photos of your pedal circuit with the mod to make me feel safe about it! :p

I'm sure it will help other guys too!
Thanks in advance!

I'm french, so my english is not perfect though

Peace!

[anotherjim]

I do wonder how much DC voltage develops on the output of these circuits during strong & continuous picking.

Is it enough to change the input bias of those FET/Tube-based circuits that don't have input blocking capacitors? If it can, is it affecting in a good or bad way?

[iainpunk]

I do wonder how much DC voltage develops on the output of these circuits during strong & continuous picking.

Is it enough to change the input bias of those FET/Tube-based circuits that don't have input blocking capacitors? If it can, is it affecting in a good or bad way?

i believe that is affects it in a ''unique'' way, the rectifier wiring in one of my guitars can really mess with a distortion/fuzz in a cool and broken way, but other fuzzes just fart out and sputter on the attack, and come in after a little while. tube amps without blocking caps also don't like that wiring, i guess my guitar would benefit from a blocking cap on that circuit...

cheers

[anotherjim]

Would it be different if the rectifier diodes were reversed so the DC goes negative?

[iainpunk]

Would it be different if the rectifier diodes were reversed so the DC goes negative?

i might try that in the future, but the switch i chose (for aesthetic reasons) was a bitch and a halve to solder on to, HUGE pads that dissipate the heat quickly...
the next guitar i put the mod on ill try them the other way around and test it with the tube amp and Jfet pedals.
here is some more info about the wiring scheme i call ''jawari''

cheers

[oscelf2]

Hi guys!

Thank you so much for the inspiration and awesome ideas!
I ended up modifying my own Octavio,

I chose to go for a two-way switch that simply cuts of one of the diodes and removing the octave effect (see pic).
At the same time I took the opportunity to change the original basic true bypass switching to an improved one with an led using the awesome guide at stinkfoot.se --> https://stinkfoot.se/archives/2233

The previous owner added the DC-jack (:

I really like the non-octave fuzz, and as someone previously said the pedal is so much more flexible.
Thanks again, hope more people give this a try!