Joyo - JF-06 Vintage Phase

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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CheapPedalCollector
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Post by CheapPedalCollector »

I posted the gut shots to this a while back here viewtopic.php?f=11&t=30938

The original thread for this was for the first version which was different and the schematic pics are long gone.

I got around to tracing it myself, it's slightly different than a phase 90, just some different part values and an extra resistor on the output. Enjoy.
JoyoVintagePhase.png
Last edited by CheapPedalCollector on 06 Dec 2020, 02:02, edited 3 times in total.

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ppluis0
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Post by ppluis0 »

Hi CheapPedalCollector,

You made a little mistake in your drawing connecting together the drain of all the jfets and hence the four inverting inputs of the op amps at each phasing stage.

Each jfet and the associate 22K resistor must be connected to each op amp input.

Cheers,
Jose

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Post by CheapPedalCollector »

Thanks, silly mistake of mine. Fixed.

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Post by CheapPedalCollector »

Corrected error in the oscillator circuit.

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Post by CheapPedalCollector »

Fixed mistake in the bias circuit, it should work now.

I'm working on some mods for it, I need to order a 500KC rate pot.

Depth, Regen, possibly Manual offset control. I want the regen buffered like the Ross phaser so it can be none to max, Mix control, probably a Phase 45 switch. Once I get that working I may design a new version with two more shift stages and post it in the DIY sub.

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slcidea
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Post by slcidea »

Thanks for the great work you did tracing the board. I was going to do this if I couldn't find a schematic. You saved me a lot of work. I ordered the phaser on Amazon and plan to turn this into a switchable Phase 45/90 by adding a SPDT switch that selects the output either from the second phase shift stage or the last which is the default. It should be a simple mod.

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Electricfreedom21
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Post by Electricfreedom21 »

What component(s) would cause this problem:
When footswitch is pressed, there is a 1 second pause between the dry bypass signal and the phase effect audio output. Makes this pedal unusable for gigging! The LED responds normaly to switch activation, but audio is delayed.
It sounds (the phase) better than my mxr 90....thicker. I would like to repair, even knowing this pedal is dirt cheap.
Thanks!

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Post by CheapPedalCollector »

Sounds like the switch is bad, easy replace. All my Joyo pedals don't have any delay. I do notice that if the pedal doesn't have enough voltage the LFO will not work correctly.

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OC26
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Post by OC26 »

I think Jfet//Resistor networks must be connected to the opamps non inverting inputs, not the inverting.

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Post by CheapPedalCollector »

OC26 wrote: 08 Dec 2021, 17:03 I think Jfet//Resistor networks must be connected to the opamps non inverting inputs, not the inverting.
You're correct, this was the first thing I traced after a decade of not doing it. Haha, I'll fix it, the oscillator is wrong too and I think one other thing.

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Post by CheapPedalCollector »

Corrected opamp errors, should be correct now.
JoyoVintagePhaseFixed.png

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HunkFunkPedals
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Post by HunkFunkPedals »

Does anyone know how the footswitch is wired?

The ribbon cable is gone from my project and I'm trying to wire in a new 3dpt.

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