Joyo - JF-07 Classic Flanger  [schematic]

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

atreidesheir wrote:
BaldPaul wrote:Can't say what this is a clone of but it replaced an EVH mxr flanger on my board. There was no comparison, My mxr is noisey as all hell and the joyo is not. Sounds exactly the same IMO but with very little noise. The paintjob has got to go though!
I have tried almost all the joyo pedals. None are noisy. NONE.
My AC Tone is quite noisy.

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atreidesheir
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Post by atreidesheir »

I am talking everything but the amp simulators of course. Even the Joyo high gain distortion is not noisy for a high gain distortion.
"Contemplate it - on the tree of woe." :Thulsa Doom

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tabbycat
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Post by tabbycat »

drbob1 wrote:I played it back to back with my EVH and the EVH will likely be going down the road. They sound so close that I have to say it's a sonic clone if not a circuit clone. Very decent box for a remarkably small price (got it for a 4 for $34 each deal). The only problem is that I think they're phasing out (not flanging out) the metal box pedals in favor of the lumpy plastic ones...
Fender3D wrote:
jrod wrote:I'm kind of hoping this is a copy of the old MXR flanger!
nope it looks like a couple MN3xxx - MN 31xx BBD and clock
nothing to do with 4013 + trannies 8)
tube-exorcist wrote:The Ibanez FL9 schematic should do the trick.
consensus for this one seems to have settled on this being an as-close-as-dammit clone of the ibanez FL9, but the various comments about it being able to nail some of the mxr flavour made me wonder exactly what are the essential circuit differences between this and the mxr 117?

basically i've got the joyo (harrier jump-jet box) and it gets me pretty well into that 80s gothy zone for pennies, but what it lacks is that particular searing blowtorch fingernails-down-the-blackboard thing that seems to lie at the very extremes of the mxr 117's range (the cut down mxr micro flanger doesn't seem to hit those extrems either). everything up to that extreme the joyo does a pretty good job of, so it made me wonder where that extra edge comes from, in circuit terms.

i can't justify the expense of mxr 117 so am planning on building the madbean collosalus 117 clone that replaces the sad1024 ic with 3007. unfortunately the pcb is out of stock for a month so i thought i might see if it was possible to mod and tweak my joyo in some way to see if ic ould push it further re the characteristic blowtorch sounds of the mxr on full tilt.

i compared the two schematics
Image
Image

and it struck me that the lfo section is pretty similarly set up. the flanging section i generally find harder to decrypt. but the clipping diode section looks pretty similar in layout, though with different values. and the final gain output stage bears a close resemblance too.
so i just wondered what is going on in the middle bit, where the actual flanging tkaes place, that marks their tones at the extremes?

as the joyo is so cheap £20ish and the mxr 117 around £150 for a new version (and mad money for a sad1024 original) i wondered whether this one might be ripe for mxr themed modifications? even if it required patching in an extra ic on a vero daughterboard to add another stage it might render results worthy of the experiment.

anyway, i thought i would express my curiosity to see if anyone else had thoughts along the same lines.

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Post by Fender3D »

Almost every flanger on earth has that LFO,
the same for clipping diodes before BBD.
Delay time(s) has a big inpact in flangers and chorus sound...
That's why I opened this thread https://www.freestompboxes.org/viewtopic ... 28&t=22623

When I was adapting micro-flanger for Greg's BBD R51xx, I noticed that the presence of Q2 between Q1 and Q3 (on MXR 117 schematic) widens the sweep range, so I added it to my micro flanger schematic.
http://www.wizardinside.it/foto/schemi/ ... 51-sch.pdf
Fender3D wrote: nope it looks like a couple MN3xxx - MN 31xx BBD and clock
nothing to do with 4013 + trannies 8)
This is not entirely right, since MN31xx are actually 3 inverters + half 4013 used as frequency divider...
Though it won't clock as high as 4013 ...

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tabbycat
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Post by tabbycat »

many thanks for the opinion and link, fender3d.

i read through of the thread you posted and then returned to studying the two schematics, ibanez FL9 (joyo classic flanger believed to be) and the mxr 117.

the more i looked the more surprised i was to find how similar the topographies are. i haven't been hugely interested in flangers before now, so the similarities (lfo, clipping) were new to me, but thanks for explaining that that is a common-to-most feature.
on closer inspection, i picked out (and colour-coded) the paths between and around the two transistors you mentioned on each schematic, and they are pretty damn close in structure if not values.
as you say, there is an extra transistor in the mxr layout. i blocked it out in pink on the schematic extract below.
ibanez FL9 edit copy.jpg
mxr 117 edit copy.jpg
do you think it would be worth trying to patch that extra resistor (with accompanying resistors) into the joyo flanger/Ibanez FL9 circuit in order to get a more harsh and severe mxr 117 type tone?

as the mxr 117 runs at 15v would exploring the viability of upping voltage on the joyo/Ibanez be worth considering too? am not sure what the ICs and caps in the joyo are rated at (will check inside next time i have it out) but if the extra transistor demanded more kick from the circuit maybe that could be forthcoming.

also notice that the width pot (which is at the end of that particular signal path) is 50K in the mxr and 100K in the ibanez. could increasing or reducing the value increase the harshness of the tone?

am just curious about how the joyo might close ground on the mxr, since the more i study the two schematics the more resemblances i see.

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Post by tabbycat »

correction:

"do you think it would be worth trying to patch that extra resistor* (with accompanying resistors) into the joyo flanger/Ibanez FL9 circuit in order to get a more harsh and severe mxr 117 type tone?"

* should say 'transistor' not resistor.

(no edit facility in this thread).

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Fender3D
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Post by Fender3D »

yes I do,
I mean, it provides noticeably changes in micro-flanger...
I would check for min. and max clock freqs though.
MXR's C21 was selected for a proper clock, it will provide the max clock, then look for a cap which gives you ~960KHz clock, then trim for a minimum ~32KHz clock.

I think it might be useful to check LPF cutoffs also.

Another point to evaluate:
SAD's typ. gain is 1.2dB whereas MN's is 0db (but it will be much lower when clocked higher than 100KHz).
In my M117 retrofit, I added an NPN on BBD's output.
An improper wet/dry mixing will make huge differences...

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tabbycat
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Post by tabbycat »

thanks indeed for the detailed suggestions and theory outline fender3d.

i get the general gist of what you are proposing and some of the reasoning behind it, but i definitely think i need to read more into clock frequencies before attempting it. i only have a basic idea of what they are and how they can be controlled, and this mod seems to be beyond that level for me at the moment. i can change values, swap components around and patch things in and out, and i have a dmm for basic stuff like hfe, but this sounds like a maths and scope thing. serious tech. so more reading for me required i think.

but at least the idea seems to stand up in theory, and the threads are here ready for anyone else looking into trying this route. and it's interesting that they share so many similarities when the prices are so dramatically different. that’s often an open invitation to a mod.

as to the addition of the post bbd tranny to make up gain to SAD levels and the wet/dry thing, that i can deal with though. so just clocking to crack.

will update here as and when i can.

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Post by caspercody »

Tabbycat,

Do you have any new updates on this topic? Did you try any of the changes you and Fender3d were talking about?

Thanks
Rob

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