Joyo Ultimate Drive Mod
9:39 AM
The Joyo Ultimate Drive is a cool little pedal based on the Fulltone OCD. In fact, the circuit looks a lot like a V3-4 OCD. But what we're looking at today is how to take a cheap, $35 pedal and turn it into something awesome. We're going to be changing the gain pot so it has a smoother taper as well as changing the values of the other pots to do some filtering.
A while back, a company called Freekish Blues used to mod these to sound more like a "Dumble" amp. Not a big deal, except that they put it into a new enclosure, said it was their own design and then sold it for a huge markup (which the DIY folks did not like). So long story short, they went out of business. But we don't care about any of that. We're looking at what they modded and going from there. I have a couple slight tweaks and personal preferences to add as well. I'll explain how to do the mod and what each part does.
The Mod
Parts:
- Joyo Ultimate Overdrive
- 500K Log Potentiometer (link has a drop in replacement for the board mounted one)
- 1K5 Resistor
- 470K Resistor
- 100nF Capacitor
Schematic
Here is a schematic of the changes we'll be making. We'll then go step by step through how to perform the mod.
Steps
When desoldering, it will probably be easiest to do it from the underside of the board. I recommend marking which components to remove on the underside. Then you can put the board back into the enclosure and use the enclosure to stabilize the board while you desolder.- Desolder the drive pot and replace it with the 500K Log pot. This will give you a smoother transition through the gain range of the pedal. Alternatively, you can solder a 330K resistor across the outside lugs of the gain pot per the original mod.
- Solder the 1K5 resistor to the outside lugs of the Tone pot. (You may find it easier to do this on the under side of the board)
- Solder the 470K resistor to the outside lugs of the Volume pot. (See note in step 2)
- Remove C9, a 1uF capacitor, and replace it with the 100nF capacitor.
Note: If you have a board version prior to "2010.11.24" then you'll need to replace C7, which is a 10uF, instead. - If you're board has a version date of "2010.11.24" (which all the recent ones do) then you'll need to remove the germanium diode and turn it around. The silkscreening is wrong and means that only one half of your signal will be clipped if you don't change this. I put sockets on the underside so I can easily swap out different diodes to taste.
- Optional: The wires from the footswitch to the main board are cheap and prone to breaking. I recommend replacing all of them with some good wire so it doesn't die on you when you're playing live.
What it does
The mod is fairly simple as far as theory goes. The original mod by Freekish Blues uses 3 resistors in parallel with the pots to lower their values and thus limit their range. By using a 330K resistor, the gain pot goes from 1M down to 250K. I prefer to just swap it for a 500K Log pot since this is the preferred value on the OCD. Also, the log taper makes it a smoother transition across the gain range so it doesn't need to be limited to just 250K. The volume pot gets reduced in the same way from 500K to 250K.The tone pot is a bit more interesting. It forms a simple low pass filter with the 100nF capacitor. With the pot turned all the way up the cutoff frequency is originally about 16k. By reducing the value of the pot with the parallel resistor, we get a different cutoff frequency. The 1K5 resistor takes our tone control down to a value of 1.3K which is pretty cool since we can't just go buy a potentiometer of this value. By doing this the cutoff frequency becomes roughly 122K. Now, to be fair, you can't hear about 80% of those frequencies...but it is brighter. Also, since the tone pot is a log taper, you're going to have a really wide range of usable settings across the whole knob.
Lastly, the capacitor change just limits how much bass is allowed to pass through the circuit before hitting the tone control.
I hope you found this a helpful bit of info. If you did then leave a comment telling me what you found most useful so I can focus on those things in later posts. Also feel free to leave a link to any pics of your mods.
43 comments
hello, could you post a schematic? Thanks, Antonis
ReplyDeleteSure thing. I took a schematic from the Harley Benton branded version of this pedal and added in the changes for the mod. It's after the Parts section. Let me know if that helps.
DeleteMy board has d3 and d4 which from the above mention I'm assuming d3 needs switched around? I didn't see d4 on the schematic so I'm a little lost. Any help is much appreciated. Thanks.. I just ordered all components listed above as well.
ReplyDeleteI don't have my board in front of me, but I believe it's D3. It's a clear glass diode between two FETs on the upper left of the opamp (when looking at the component side of the board).
DeleteD4 is more than likely something to do with the Millenium bypass switching this circuit board implements. The schematic shown here doesn't include that portion of the circuit.
Thank you.. On mine d3 and d4 are side by side top right hand corner above gain and are normal diodes.. D2 however is between q2 and q3 on the left side of the low/high switch. Board reads:
DeleteJOYO JF-02
2010.11.24
Edit! D3 and d4 are above level not gain..
DeleteAfter opening mine up I can say that D3 and D4 are used for protecting against reverse polarity voltage sources. They just implement both ways of doing reverse polarity protection.
DeleteD2 is the diode that needs to be flipped (or removed and socketed/jumpered).
I want to thank you for all your help. It has been an experience modding my first pedal. I added a socket for D2 and have been messing around with different diodes. it seems if I take the diode out of circuit it makes the overall tone brighter. I will continue to try different diets variations until I find one that works best for me. Again thank you for all your help.
DeleteHi, someone can help with a true bypass mod for this pedal? thanks
ReplyDeleteThe pedal is implementing a version of millenium bypass which is a variation on true bypass. It shouldn't alter your sound in any negative way. You will just need to make sure that you have power running to the pedal for your signal to pass through.
DeleteIs there a particular reason you want to swap from millenium bypass to true bypass?
I use a germanium fuzz face. When the ultimate drive is off, it alterate the fuzz's tone. I need all my pedals be true bypass. Sorry the bad english.
ReplyDeleteDoes it change the sound when the Joyo is after the fuzz face?
DeleteI only ask because with the jacks being mounted to the PCB it will be quite difficult to change this to true bypass. You would have an easier time making a true bypass looper or placing the pedal after the fuzz in your signal chain.
it changes in any position. I made a loop switch for line 6 roto machine and a flanger, but ins't a good position to the joyo. Maybe i'll do a zendrive clon and sell the Joyo.
ReplyDeleteThat's great! Thank you! I was wondering if I could use NE5532P opamp instead of the stock one? I haven't got the pedal yet but many say it's very noisy, would it get rid of noise? if yes, will it change the tone? Thank you very much.
ReplyDeleteYou could definitely swap it out. Just be very careful because the pads are very easy to burn off on the cheap board.
DeleteHonestly, by doing these mods I've reduced the noise in mine quite a bit without having to swap out the chip. The original gain knob added in a lot of noise because of the taper. By moving to the Log taper pot you'll get a lot more useable range out of the knob and with a lot less noise. So I would do the mods listed here before trying to swap out the chip. It's just a bit difficult to do on such a delicate board.
If you've found this helpful, then I'd really appreciate it if you purchased the pedal through the link at the top. It helps support the blog. Thanks!
Stephen, do you have any suggestions on how to reduce the bass response of this pedal? I had been thinking of replacing R2 (2k2) and/or C2 (68n) as that would be similar to the pre-clipping Bass cut control on the Timmy pedal. Any suggestions on what values for me to try?
ReplyDeleteThanks for posting a very informative article on these mods and answering questions in the comments section!
I do have some thoughts and you're definitely on the right track. I wouldn't worry about R2. It's part of the high pass filter that R2 and C2 form, but if you change out R2 then you'll be changing the gain of the pedal. However, if you change C2 then you'll just be affecting the bass response of the pedal by shifting that high-pass filter.
DeleteYou can also change the input capacitor (C1) in order to limit the amount of bass that enters the pedal. The coupling capacitors in the signal path form high-pass filters where the impedance of the next stage is the resistance. So if you lower the input cap, you should be able to reduce the bass entering the pedal.
I will say that the corner frequency of the high-pass filter in this pedal is about 1kHz and the corner frequency on a tube screamer is 720Hz. Since tube screamers are often criticized for cutting too much bass I would start by changing the input capacitor (C1) to a lower value (like 10nF). If that doesn't quite get you there then I'd start playing with the value of C2 in the high-pass filter. Lower values will reduce the bass. I'd start with a 47nF cap since that gives you a corner frequency of 1.5kHz. If that's still too much bass then it might be an issue with how your rig is set up.
Be sure to socket both of them since the board is fairly cheap and the pads may lift off with repeated soldering.
Also, what does your full signal chain look like? I'm curious because I normally can get this pedal to balance out fairly well. Have you done the mods from the blog post yet?
A friend asked me to mod his Joyo pedal to reduce the bass response. He plays mainly Les Pauls and the neck pickup can get a bit boomy (esp. with the Gibson 490R's.) He used to gig exclusively with a Silverface Super and a Deluxe Reverb reissue but he's been using a Bugera V22 Infinium the past few years.
ReplyDeleteI haven't tried your mods yet but I had him listen to the Anderton video of the Alpha Drive and he thought that had too much bass, too, hence my question to you.
Do you have a good source for sockets? I never thought of using them for caps, etc., just ICs and LEDs. BTW the 5 Second Fix "As Seen On TV" would work great to make sure that component leads would stay firmly in a socket. It is not a glue but a liquid plastic that is cured by the LED light on the other end of the dispenser pen. It is easily removed with a sharp knife. A tiny dab on pot and jack nuts will make sure that they don't come loose until you need to remove them. (While it retails for $10 you can get it a lot cheaper than that.)
I was thinking of adding the 1K5 resistor to my version 2 OCD pedal as well as the Danelectro Cool Cat Drive V1 clone since you explained how it brightens up the Joyo pedal a little bit. (I don't hear much over 8khz but the frequencies above 25khz can add a certain ambience.)
Thanks for your suggestions!
Good idea having him check out the Andertons video. Since the idea behind the mod is to get more of a D*mble sound it's going to be a bit more bassy since that's a key characteristic of those amps.
DeleteHonestly, if he thinks the original pedal has too much bass then he may want to steer away from it (since it's basically a F***tone OCD). However, if he really wants this pedal to work for him, I recently made some suggestions on reddit about parts to change to increase bass, you can simply do the opposite and lower the values instead of raising them. That's all detailed here: https://www.reddit.com/r/diypedals/comments/7051iv/does_anybody_know_of_any_good_mods_to_improve_the/
As for where to buy sockets, I get all of mine from Tayda Electronics and I haven't had any issues with them (unless the part has undersized leads). I'll have to check out the 5 second fix stuff cause that sounds like it could be handy.
Yeah with the 1.5k resistor I believe you're allowing more harmonic content than the original value. So go ahead and try it out in one of your pedals and see if you like it.
C9 in the newer version (2010.11.24) is a 1 uF electrolytic capacitor. Not 10 uF.
ReplyDeleteThanks for letting me know. I'll make a note of that in the instructions.
DeleteThat's great! Thank you!
DeleteI replaced C1 and C2 with 22nF caps and C9 and C10 with 47nF caps. Haven't done the resistors across the pots yet. I love how it sounds now I couldn't stand it before I thought I'd just throw them 25 bucks away but I'm loving it now.
ReplyDeletehttps://youtu.be/Om3xQZoGJZw
Oh and I bypassed the diode by soldering a piece of lead wire between the diode leads on the solder side of the PCB.
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DeleteHey you all, I did the gain and volume mod. It sound soo good in this way. Much better than the original. But the tone mod is not good: The low pass filter is formed by the 33and22 k (R9/R10) and the 100nF! The pot will influence only the amount of passing frequency's. So when you leave it as it is the the cutoff freq will be 72 or 144Hz in the lowest pot setting. The higher the pot is turned the least influence this the sound. Great pedal, great mod, great sound. Love it
ReplyDeleteIn my last comment I refer to R9/R10. These are the numbers of the harley Benton schematic. I found a schematic by Alberto Ansaldo, this seems to be the joyo version. I was talking about R11/R12 in the last schematic. I did some more mods: C8 to 470pF to kill agressive high freq., turned D2 around and added a 3way toggle switch. Now I can toggle from mosfet/mosfet+Gediode to mosfet/mosfet and only 1 mosfet clipping. All three sounds very good. This pedal is really great, but I missed some low end. So I took out R5 and C4 and replaced them for 4k7 and 100n! This gives a good amount of bass in the signal. Very happy with this result. I only use it with low gain to emulate SRV tones, this is far my fav pedal for this purpose. And I have a few, lol.
ReplyDeleteImportant note: I have the Harley Benton ultimate drive BUT the Parts are numbered as in the Joyo ultimate drive schematic!! This is a bit confusing when talking about part numbers. So when I re write the above with the HB schematic at the top it must be: C6 to 470pF, and R3/C2 to 4k7 and 100nF.
ReplyDeleteAny chance to hear it? Thanks
DeleteHello, everyone. I tried the mod, but the low end was way too much for my taste and somewhat unbalanced when increasing the gain.
ReplyDeleteSo I tried changing C1 values to 10nF (still didn't like it) and then after to 1nF.
Wow! 1nF capacitor gave the pedal a really balanced low end if compared with other overdrive pedals I have here (EHX Crayon, Angry Charlie v3 mod Clone and Maxon SD9)
Increasing the gain also increases the bass, but with low gain, the pedal doesn't get muffed like while using the stock C1 value.
I also soldered a 1M resistor (instead of 330k) to the Gain pot, making it a 500k pot. There is a bump at 9 o'clock leading to high gain setting too fast, but it can be tamed with little tweaks on the knob and the switch.
What do you guys suggest in order to get a little more highs when maxing the tone pot? I like the way it is, but maybe it can have more high-mids or highs.
Thanks!!!
Nice! That chang in C1 would increase the high pass filter from about 10Hz to roughly 338Hz. So you're definitely getting rid of a lot of that woofy bass end. When I play live I usually have a high pass on my amp around 220Hz for just that reason.
DeleteAs for changing the mids, I'm not 100% sure at the moment. I need to go in a do a circuit simulation of the tone control to get a better idea.
If you want to increase the treble and mids overall then I know that decreasing C5 will increase the corner frequency (a.k.a. roll off point) of the high pass filter in the second feedback loop so you could play around with that. You'd be cutting some bass but your ears would hear it as a midrange and high end emphasis. You could also try decreasing each of the 220pF capacitors in the loops of the opamps (C3 and C6 in the schematic). Those are taming some high end. A tubescreamer usually has them around 50pF so if you play around with those you may notice some more treble overall.
Nice clarifications, Stephen! Thank you very much. I'll try some values you've suggested.
DeleteCheers!
Hello from France,on my Joyo UD board i can read "Joyo Ultimate Drive V1 , Nov 2009".
ReplyDeleteIs there a mod for it and what will it had?
Thanks
Absolutely. You should be able to do the exact same mod as shown above. The only difference (as noted in step 4) is that you'll change C7 (10uf) instead of C9.
DeleteSince your board is from before 2011 you can also skip step 5 entirely. You don't need to do anything with the diodes.
Oups ... add
ReplyDeleteHey Stephen! I do my own mod based on this article and in the guys comments!!
ReplyDeleteThe modifications: Change C1 to 470pF, and C8 to 470pF too, remove D2 (Germaniun Diode) and wire to jump the circuit.
Results: The C1 alters the high pass filter, originally the frequency to cut was 7.23Hz, with this change the frequency to cut now is 338.63Hz, i tested with 1nF too (159.15Hz), but i prefer 470pF, no muddy bass anymore!
The C8 alters the filter in tone control, originally this pedal have a lot of aggressive and crispy highs, changing C8 to 470pF, the "bees" are gone!
The D2 is a germanium diode in series with a MOSFET transistor, making an Assymetrical Cliping, removing this diode and jump the circuit, this makes a symmetrical clipping, less volume, but smoother tone!
This pedal now is very awesome!! great sound! no more muddy bass, no crispy highs and smoother tone!! But still fat sound and the same amount of gain!
Important point: My pedal is a Shelter Ultimate Drive, it's a version distributed here in Brazil, but in the circuit board is writed Joyo JF-02 2010.11.24, same pedal, another skin!....kkkkkk
Thanks Guys!! This article was so helpful for me!!
hello, had to buy one (joyo version) to see what everyone thinks is so great about this pedal. can only really find one ok setting, level on 3/4 , tone all the way down, gain on about one, and tone switch on bass.on these settings you can kind of get a marshall to vintage output sound which is nothing special. the overdrive when you start to push or turn up the gain just sounds terrible.this pedal sounds like vintage scooped poo's well as far as i can imagine anyway. do you reckon these mods are likely to help or better to rewire the whole thing or just sell it as is to some sucker?
ReplyDeleteThese mods are intended to fix up a bunch of those issues. The sweep of the gain pot is fixed by adding the resistor or swapping it for a logarithmic pot. The sweep of the volume is addressed by adding the resistor. The capacitor changes and resistor in the tone pot are used to help make the tone knob much more usable.
DeleteIf you're comfortable soldering then you can turn this into a pretty cool pedal. If you don't have any prior experience then I might try returning it or selling it. It's not a great pedal without modding in my opinion.
If you are inclined to opening it, desolder some components and resolder others, then it is totally worth it, it'snot an easy board to work with, it took me two pedals, luckily they are cheap
DeleteHi I cannot open any of the pictures that come with the comments. Never modded a pedal in my life and really needs pictures of what to do, any help please? I have a recent version of the joyo Ultimate overdrive. Board is dated with 2010.11.24, but also says 08 19, wich I believe is the production date. I've read on other blogs and fora that the Diode in more recent versions of the pedal is in the correct position.Also read the transistors next to the diode need to be flipped How can I check all this? My worst agrivation is with the pots they are terrible. Al the action is in the last 10% of the turn. Please send me some pictures so I can check. Thanks in advance.
ReplyDeleteHi there, can you help me find c7? My sons pedal was the one with c9. I could find that one. Sounds great but my pedal is of a different build.
ReplyDeleteThanks for your help.
Sure thing. Send me an email with a picture of the PCB to prentisseffects@gmail.com
Delete