freestompboxes.org

Hello,
I bought a cheap cheap Joyo Tremolo pedal.
It sounds good but i would like to make it more versatile.
For now on, sources are saying the Wave Form of the trem is Square Triangle. (something like this: )
So it let you ear a sweet tremolo.
But i would like to be able to obtain something more agressives, with more cutting edges like a Square wave ()

I saw on youtube some videos (not really enough tutorial friendly for me to understand it all) where the guy is adding a potentiometer to replace resistor R11, and listenning to what he says, turning down the value of this R11 get the Wave Form to something Square as i needed. (sources: and )

So, for testing purposes, as i am a lazy guy, i just soldered a cable to both legs of the R11 to short circuit it kinda (Two resistors in parallel with one having quite no resistance at all so)

It is still not agressive enought at all. (for example, one easy to listen sound i would like to get is the one you can ear on Greenday - Boulevard Of Broken Dreams song)

So if any of you knew any mods for this cheap and cool pedal, could you maybe share a CLEAR tutorial or something to help me out? Any mods, but the Agressive Square wave, bug tremolo, is the one i really am looking forward first of all ^^

(Maybe short-circuit the R11 and change to Intensity Knob For a higher value? 50k originally. Or any possibility to solder some resistors to the knob to increase its value? no idea)

Thanks a lot Electronic Wizards!

analogguru wrote:Joyo Tremolo (JF-09) = Fulltone Supa-Trem =~ Demeter Tremulator

So you may want to look at the 'improved' (or: corrected) Baja Trembulator thread.

Thank you.
I am reading that for now. I understand nothing yet. They built a completly new board? i just would like to mod mine to be honest.
Still going through the topic tho. We never know ^^

nammy wrote:Thank you.
I am reading that for now. I understand nothing yet. They built a completly new board? i just would like to mod mine to be honest.
Still going through the topic tho. We never know ^^

We have no documentation on this Joyo pedal at all. There isn't anything anywhere on the web? Then the only way to go about is post pictures of your unit, or trace the schematic yourself. How can you just start pulling out resistors and hope magic happens?
Once you establish schematic, you can compare to the above mentioned schemo's

you are right!
I will try to post pictures of the pcb front and back tommorow incase it helps.
thanks again for your time

Hope this helps!

*Couldn't Edit my post* sorry

I saw on another Topic here : https://www.freestompboxes.org/viewtopic.php?t=16105
That this Joyo JF-09 is a clone of the Diaz Tremodillo

If you have any question, any request about pictures values etc etc that could help you in the process, don't hesitate to ask!

I will try to draw the schema myself.. but never did that yet so it might be wrong anyway.

I saw .... that this Joyo JF-09 is a clone of the Diaz Tremodillo

It looks more like a Demeter Tremulator = Fulltone Supa-Trem (with all of their shortcomings).

hi again,
So i tried to understand how to make my own schematic from scratch of the pedal... and i can't ... i just understand nothing lol.
I wish i could contribute tho but well.

in the video i linked earlier, the guy is explaining the changes joyo made to the circuit from the demeter one.
Maybe anyone who is really speaking english could take his words to propose a corrected schem from the demeter one?

here is the video

if you need closer pictures, or anything, just ask ^^
Thanks guys

thanks for posting the gutshots, nammy. good reference material.

this link will help you perform the mod you want to do

http://dantonewac.blogspot.co.uk/2015/0 ... meter.html

what you have to do is work out on your pedal pcb layout which parts correspond to the components in this demeter tremulator schematic. as the video syas there are some different part values but the basic network (or 'topography') of the circuit should stay the same, whatever the values for particular components.

http://2.bp.blogspot.com/-4E8-KhrRems/V ... ematic.gif

for example the vactrol labelled VTL5C1 is the big plastic block with the yellow dot on top on the joyo pcb.
the depth pot is the one that links directly to this. the other pot is the speed pot.
the three black caps should be marked 4u7.
the diodes are the things that look like resistors but are made of glass and just have one single band on them.

the numbers on the symbols for the opamps depend on which opamps the joyo have. it isn't clear from the photo but should be the LM442, or something that does the same job. if you can see any numbers on them then google those numbers and the words 'opamp' and 'pinout'. the dot on the top right of the opamp indicates that that is pin 1.

the pinouts for the LM442 are like this:

http://circuits.datasheetdir.com/37/LF442-pinout.jpg

draw out all the components as they appear on the pcb and label them, then use the scematic and checking with the tracks in the pcb to join them together.

it's hard the first time and may take you a while, but once you have done it, and got the hang of how a schematic and pcb layout compare, the same method will let you trace any pedal. which is a pretty useful skill for life.

by doing you will learn.

good luck with it and report back on your progress if you manage to do it, or if you get stuck and need help.

wow excellent!!!! THANK YOU

So for the values in the JF-09 i have (its an Harley Benton for info, not officially Joyo but its the same i guess)

So :
- the three blacks caps = The two of them "aligned" far from the "external" potentiometers are 4.7µF yes (C1 C4). The third one close to pots is 2.2µF (C5).
- the depth pot is well the one you say, its a 20k one.
- the opamps : taking my last picture = the one on the bottom left is TL062CN http://pdf1.alldatasheet.com/datasheet- ... 062CN.html
the two others, in the middle and top are TL061CP http://pdf1.alldatasheet.com/datasheet- ... 061CP.html

I will try to trace the PCB layout with your infos. Not sure ill success to be honest since i tried once already xD but couldn't follow the trace at some points and didn't know from where to start.
Thanks again!

So to continue this thread,
im sorry to say its been 2 days im trying to trace the circuit layout from scratch, and i am totaly unable to do it.
I can't follow the traces, some are hidden under components, the switch pcb's traces are hidden too etc.
All i can do sadly is take a picture and note all the values for each component.
I will anyway draw the traces for all component I AM SURE they are linked... and most of the traces will be still missing. But maybe it could move the schmilblic one step more.