Joyo Ultimate Octave: how to make it useable?

A forum devoted to mod, tips and suggestions for upgrading and rehousing your VERY CHEAP commercial stompbox to near boutique excellence.
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Chrisfromiowa
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Post by Chrisfromiowa »

jneilson wrote:I have a Voodoo Octave I plan on modding. While I'm working on it I was wondering if it would be possible to modify the tone control to use an expression pedal with it? It gives a nice swooshy sound when you turn it back and forth.
Not sure if you'd seen this, but http://www.geofex.com/ has a nice segment about adding expression pedal jacks etc...

jdom84
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Post by jdom84 »

Well my sad story is.. I actually thought it sounded ok but thought maybe it would sound better after the mod. After frustrating time playing around I now have a broken pedal.

I reversed the polarity and it seemed to make no difference at all except the sound would cut out when pressing the octave button. So I thought I would put them back the right way. One or two botch jobs later and now it works in bypass and does nothing when activated into fuzz mode. So I just killed my pedal.

Sad really considering I thought it sounded fine already. It looked the same as the photos people posted of the insides, as in the "wrong" polarity supposedly. But as I say reversing did nothing if anything it made it worse. Is it possible I have the right polarity? My PCB is dated 2010!!! So nearly 10 years old! Crazy..

Well now I have two broken fuzz pedals from my botched work, maybe I should give up... I would like to get these working. I guess I need to work on my soldering skills.

Regards,
Dom.

alexradium
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Post by alexradium »

yes,Joyo pedals are pretty good copies of originals,but not modder friendly,you need skills and good desoldering tools,otherwise its easy to damage traces and holes,they are very thin and small.

jdom84
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Post by jdom84 »

Hi thanks yeah I guess so. Anyway I managed to get this working again back to how it was with the original polarity. I had burned the PCB board and the caps were not contacting the pcb metal wiring. I just scraped the holes to make it stick and added loads of solder! :-) Filled the holes and got it working again. Maybe one day I will try once I have mastered my skills and bought some better equipment.

I wondered has anyone come up with a solution for the high pitched whining sound I am experiencing whenever the pedal is engaged? Constant. I am on DC psu havent tried with batteries yet but apparently it gets rid of the noise. Any way to fix this with some simple soldering? Considering I have all my kit out and its dismantled still (but works! :-) )

Thanks.
Dom.

alexradium
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Post by alexradium »

if there is whistle your supply is not really good,anyway,try inserting a 100 to 470 ohm resistor between the positive voltage in input and the main filter capacitor,that should cure most of the problems.

jdom84
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Post by jdom84 »

alexradium wrote:if there is whistle your supply is not really good,anyway,try inserting a 100 to 470 ohm resistor between the positive voltage in input and the main filter capacitor,that should cure most of the problems.

Hi thank you. But I do not have this issue with any other pedals? The power supply is decent quality from amazon with good reviews. I doubt it is the PSU.
I will try the capacitor idea, filter cap? Is that the first one the power meets as it comes in?

Thanks so much for helping me.

jonathandean
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Post by jonathandean »

I've been following this thread for years and have finally got round to cracking mine open, as I had to replace the fat/bright switch

The two caps off the switch in mine (possibly 10 years old, I forget) are 3n3 and 15n, so I'll leave them alone. I will swap over the two box caps in the wrong places

To replace the 10u "reversed" electrolytics I have either 10u non polarised electrolytics or 10u ceramics - what would people advise?

Thx all

R_Norris
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Post by R_Norris »

I'm not so sure about this capacitor orientation mod. I made the swap - lots of background noise - and worst of all made it a little boring. So I changed it back. Fried the trace too so resoldered the caps with jumpers on the reverse of the board. Checking the fulltone circuit and the fuzz-central Foxx TM circuit it appears the caps were correctly installed in the first place.

Antigua
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Post by Antigua »

I just did the cap swap and reverse mod, I think it sounds a little better but I'm honestly not certain I hear a difference. I like that with the gain all the way down, this pedal is almost clean, and that just turning up the gain slightly gives a fizzy clean, and the tone control works awesome, extremely broad attenuation profile. I'm tempted to buy another one just to A/B them. I like it enough that I wouldn't mind having two of them on hand.

I see some people had the switches/LED break while doing this mod, that happened to me too, it was because the strip cable wire is extremely thin, and torquing the cables caused them to break easily. I had to remove the goop, which comes right off, and resolder them.

I didn't have as much trouble working with the board as others have had, except that I had to use both fine tipped and broad tipped solder tips in order to get the components free of the circuit board. I have a Weller solder station with the heat setting maxed out. The trace delaminated in one spot, but didn't break, so it was all good.

Thanks to everyone who makes this information publicly available.

Antigua
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Post by Antigua »

I like the Voodoo Octave pedal so much that I bought a second one, and I modded it also, but this time I made bode plots of the response before and after modding:

Image

This doesn't speak to the differences in clipping, but it shows differences in frequency response.

There is an overall 4dB boost from 50Hz up to 500Hz. The mid cut frequency shifts from 500Hz up to 700Hz, I assume that's a consequence of swapping the two red ceramic caps. Beyond 700Hz, the plots are essentially identical. So post mod, it's a warmer, fatter sounding pedal.

Murrayhawk
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Post by Murrayhawk »

Hi! I bought a used voodoo octave pedal a few days ago, and I noticed that the volume is very low, at max level can't even match the amp volume, is this normal? I opened the the pedal to check if there was any mods but no changes were made over the board. Any thoughts?

UPDATE: I returned the pedal.

Mazda198
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Post by Mazda198 »

Hello everyone, I know it's an old thread, but hopefully there's someone can answer my questions.
I have done the modifications to my joyo ultimate ocatve, and the results were satisfactory, however the original circuit had some different yet useful arrays of sounds, and I am planning to add a switch to reverse the cap polarities to have the original voicing as well.
My question is: how is it possible to add a octave blend to the pedal to control the amount of overtones added to the main fuzz? Can I simply add a potentiometer to the output wire from the octave foot switch? If so, what would be the best pot for this purpose? If not what would you suggest to do? Cheers!

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