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.
Post Reply
User avatar
Chrisfromiowa
Information
Posts: 13
Joined: 28 Dec 2015, 14:28
Has thanked: 22 times

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...

User avatar
jdom84
Information
Posts: 22
Joined: 15 Feb 2019, 08:11
Has thanked: 5 times

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.

User avatar
alexradium
Resistor Ronker
Information
Posts: 313
Joined: 31 Jan 2010, 13:31
Has thanked: 64 times
Been thanked: 68 times

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.

User avatar
jdom84
Information
Posts: 22
Joined: 15 Feb 2019, 08:11
Has thanked: 5 times

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.

User avatar
alexradium
Resistor Ronker
Information
Posts: 313
Joined: 31 Jan 2010, 13:31
Has thanked: 64 times
Been thanked: 68 times

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.

User avatar
jdom84
Information
Posts: 22
Joined: 15 Feb 2019, 08:11
Has thanked: 5 times

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.

User avatar
jonathandean
Information
Posts: 1
Joined: 30 Aug 2019, 20:27
Has thanked: 1 time

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

User avatar
R_Norris
Information
Posts: 1
Joined: 14 Mar 2020, 09:41

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.

User avatar
Antigua
Information
Posts: 23
Joined: 08 Jun 2020, 17:18
Been thanked: 27 times

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.

User avatar
Antigua
Information
Posts: 23
Joined: 08 Jun 2020, 17:18
Been thanked: 27 times

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.

User avatar
Murrayhawk
Information
Posts: 1
Joined: 24 Jun 2020, 23:24

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.

User avatar
Mazda198
Information
Posts: 1
Joined: 16 Sep 2015, 07:08

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!

User avatar
CheapPedalCollector
Resistor Ronker
Information
Posts: 399
Joined: 19 Oct 2020, 15:15
Has thanked: 452 times
Been thanked: 147 times

Post by CheapPedalCollector »

I just bought one of these and I rather like it. However mine is different slightly than the pic in the OP, and I have a couple questions.

Is this pic before or after changing the cap polarity?

Also are those 1n34a's in the picture stock or were those swapped in later? Mine has silicon diodes of unknown type.

Thank you.

User avatar
CheapPedalCollector
Resistor Ronker
Information
Posts: 399
Joined: 19 Oct 2020, 15:15
Has thanked: 452 times
Been thanked: 147 times

Post by CheapPedalCollector »

I bought a second one of these to experiment on.

Can confirm that swapping the cap orientation in the latest version of this pedal makes the octave effect less pronounced and sound pretty dreadful. I would recommend leaving them as they are. Perhaps the Foxx Tone Machine schematic on the net is incorrect and someone sound check it's validity against a real one.

Swapping the tone control caps will be a matter of personal preference. It's more bassy but less smooth pot travel with them swapped around, I happen to like it with both so I'm leaving this mod.

I'm going to buy some 1n34a's somewhere and swap out the diodes too. I might add a switch to swap around different kinds of germanium and schottky diodes.

User avatar
innsmouthface
Information
Posts: 1
Joined: 31 Dec 2015, 14:33
Has thanked: 1 time

Post by innsmouthface »

I just bought this pedal used and performed the mod.

Mine is from around 2014/2015, it was the same 2010.11.24 version of the board as in Ian444's original image, with the electrolytics in the wrong direction and the two non-polarized caps mixed up.

The tone cap replacement was a definite improvement to my ear, the "lifting a blanket" metaphor describes it well.

I am not so sure about the direction of the electrolytics - the effect now is nice, and makes the sound more cutting, but the upper octave seemed more prominent/separate before, so I may undo this mod. I don't have any experience with other octave fuzzes to compare this to.

It is also interesting to note that on the PCB print itself, the direction of all the electrolytics follows the same pattern, with lines on the negative half. All the other electrolytic caps are correctly installed according to this logic, except the two in question, C9 and C15. So this leads me to believe that whatever decision/mistake they made to reverse these caps was made after printing the PCBs, but before assembling them.

Also, to anyone still wondering: I believe that Ian444's photo shows the "after" stage.

User avatar
CheapPedalCollector
Resistor Ronker
Information
Posts: 399
Joined: 19 Oct 2020, 15:15
Has thanked: 452 times
Been thanked: 147 times

Post by CheapPedalCollector »

Yeah they are installed like the photo shows now from the factory, and if you spin them around the octave effect becomes subdued the fuzz becomes raspy. Some people might prefer that, but not me. It also started to oscillate when them like that and the fuzz was cranked.

User avatar
Ramseybella
Information
Posts: 2
Joined: 21 Jan 2022, 21:55

Post by Ramseybella »

Just came on board for this thread that started in the Jurassic period.
So sorry for the expansion.
My question is.
Has anyone swapped the pots to the Foxx Tone Machine 50k liner specs?
And what sort of impact did it have?
Also what size cap replaced in what position for the boost switch, the lower one below the switch or the one on the right of the switch?
Thanks for having me on board, Pete!!

User avatar
CheapPedalCollector
Resistor Ronker
Information
Posts: 399
Joined: 19 Oct 2020, 15:15
Has thanked: 452 times
Been thanked: 147 times

Post by CheapPedalCollector »

I'm actually going to do this tomorrow with the 50K pots, and also change the diodes from 1n914 to BAT-41, I have 2n3565s too I might put in, but I doubt they will sound different. I'll let you know.

User avatar
CheapPedalCollector
Resistor Ronker
Information
Posts: 399
Joined: 19 Oct 2020, 15:15
Has thanked: 452 times
Been thanked: 147 times

Post by CheapPedalCollector »

I revisited this pedal and did some further research on it. I got the multimeter out and started measuring the idle voltages across all the electrolytic capacitors. I did the testing on one I bought from ebay to mod.

C6, C9 and C15 are the ones which are backwards. The diodes measure .305 with my fluke meter and appear to be schottky, probably bat-41 but not sure.

I also replaced the pots with 50KB ones and it sounds a lot better, I will try swapping those 2 caps.

User avatar
CheapPedalCollector
Resistor Ronker
Information
Posts: 399
Joined: 19 Oct 2020, 15:15
Has thanked: 452 times
Been thanked: 147 times

Post by CheapPedalCollector »

I swapped the two caps for the tone control, deeper sounding. I A/B'd with the stock one I have, only the tone control change really makes any difference tbh. They otherwise sound the same, and the 50K vs 100K again only makes a difference in the tone circuit.

The Pigtone/Musiclily green fuzz is a better pedal imo and has a lot more octave effect especially on the lower strings and has a warmer sound. I guess it depends on what you want though.

Post Reply