Joyo - JF-02 Ultimate Drive "2010" MISTAKE  [schematic]

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Re: Joyo - JF-02 Ultimate Drive "2010" MISTAKE

Postby Intripped » 27 Oct 2016, 00:11

alexradium wrote: [...] By the way,it is my understanding that this method uses the internal silicon diode between source and drain,no big deal compared to normal diodes...


Yes, I agree.
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Re: Joyo - JF-02 Ultimate Drive "2010" MISTAKE

Postby Intripped » 27 Oct 2016, 00:46

PS: ...even if I've never made a listening comparison between a usual silicon diode (1n4148, 1n4007, ...) and the mosfet's internal diode.
Who knows, maybe there actually are some little differences.

One difference i know, is that If I measure the fw voltage drop with my multimeter I get:
Around 700 for 1n4148
Around 670 for 1n4007
Around 620 for 2n7000's internal diode (S+G and D)

But still I know nothing about the clipping "knee"
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Re: Joyo - JF-02 Ultimate Drive "2010" MISTAKE

Postby Intripped » 27 Oct 2016, 01:27

Sorry for triple posting...
I've found an interesting discussion, expecially reply #68, here is the link
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Re: Joyo - JF-02 Ultimate Drive "2010" MISTAKE

Postby DavidRavenMoon » 12 Feb 2017, 21:16

I just picked up one of these pedals... it was $20, including shipping! ($17 and change). I've tried an OCD and actually hated it. It's got this harsh quality that sounds like op amp distortion or something. Why are they so popular? Makes me wonder why I bought this! lol

Anyway, I read through this thread, and decided to flip the diode around. I notice from looking at ODC schematics that compared to the OCD, both MOSFETs are backwards in the Joyo. After I had the diode out, on the end of my hemostats, it decided to make a run for it! Even after sweeping the floor I could not find it! So instead I just inserted a jumper in its place. I also soldered a 1M resistor across the two output lugs of the gain pot to reduce it's value to 500k. Now I have a bit more useable range and less gain on the low end. I also changed the tone cap to .047µF, as I felt it got too dark. The smaller value doesn't really help much!

Now I kind of like the pedal on the lower gain end, and with the gain about 12:00 it can get a Big Muffish tone. But I'm thinking it still needs some lows rolled off the inout, so I might reduce the input cap value, and I notice it lacks the 10k resistor after the input cap as compared to the OCD. So maybe a little resistance there would help.
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Re: Joyo - JF-02 Ultimate Drive "2010" MISTAKE

Postby obieito » 23 Mar 2017, 14:01

amonte wrote:Hey, just wanted to post a follow-up on my experience with this pedal. I have the same PCB version and bought my pedal at some point last year. When I took it apart today, the diode was going the correct way. So it seems they did (at some point) figure out the issue.


Same here.. Just wanted to share that I got mine around summer 2016 ant the diode came already in the corrected position.

Thanks all!
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Re: Joyo - JF-02 Ultimate Drive "2010" MISTAKE

Postby DavidRavenMoon » 23 Mar 2017, 15:49

It sounds much smoother without the diode. There's something about the OCD I never liked. And it's that diode. Gives it a hard edge I didn't care for.
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Re: Joyo - JF-02 Ultimate Drive "2010" MISTAKE

Postby howmuch » 23 Mar 2017, 18:38

obieito wrote:
amonte wrote:Hey, just wanted to post a follow-up on my experience with this pedal. I have the same PCB version and bought my pedal at some point last year. When I took it apart today, the diode was going the correct way. So it seems they did (at some point) figure out the issue.


Same here.. Just wanted to share that I got mine around summer 2016 ant the diode came already in the corrected position.

Thanks all!


Out of interest, have they corrected the silkscreen and the diode?
Or are you saying the diode is now fitted opposite to the direction shown on the silkscreen?
A clear photo would explain a lot.
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Re: Joyo - JF-02 Ultimate Drive "2010" MISTAKE

Postby DavidRavenMoon » 23 Mar 2017, 20:57

howmuch wrote:Out of interest, have they corrected the silkscreen and the diode?
Or are you saying the diode is now fitted opposite to the direction shown on the silkscreen?
A clear photo would explain a lot.


No. But the transistors are also reversed as compared to the OCD, so the diode is not actually in backwards.
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Re: Joyo - JF-02 Ultimate Drive "2010" MISTAKE

Postby alblupo » 25 Oct 2017, 11:59

I can confirm that in 2017, at least in the one I bought directly from China, the diode is still reversed... thanks howmuch for pointing it out long ago!
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Re: Joyo - JF-02 Ultimate Drive "2010" MISTAKE

Postby potul » 04 Nov 2017, 11:47

Hi

I just want to thank the OP. I checked my Ultimate drive, and it also had the diode reversed. I did the modification and flipped it, and for sure it has lost some harshness. It now has some less highs, and can be a little muddy at the same settings. But playing with the tone control I can dial a good tone.

I'm not certain if really it will make a big difference, but for sure this is how the circuit was ment to be.

Thanks again

Mat
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