Saturday, July 9, 2016

Joyo Vintage Overdrive mod - Tube Screamer clone


The Joyo Vintage Overdrive JF-01 is a Tube Screamer guitar pedal clone.


I've checked it against the TS-808 Tube Screamer schematic, and what I've found is that it has the circuit, it also has the same components values of the Tube Screamer.
Indeed, at least to my ear, it's sounds like a TS-808.


But, because i would like to experiment a little, i apply some mod on this pedal.
I've basically given a little more distorsion to the pedal. I also add a "Fat" switch, to makes it sounds fatter, and I've replaced the two clipping diode with two 5mm IR leds. Also I've changed two electrolitics caps of this pedal with two film caps.


Below you can find my schematics.




I would like to thank my friend "Bond" that lends me his Tube Screamer clones, which I've used as reference in addition to a genuine TS-808 by Ibanez.

Notes
  • read risk disclaimer
  • excuse my bad english

48 comments:

  1. Hello David i have a cuestion, i need replaced de Capacitor 10? or add the new capacitor with fat switch?

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    1. Hello, good question, It's not weel explained in my post above. Anyway, the fat switch select from the C10 cap between a 100nF or 390nF, but you can experiment other values that may sounds better to you.

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  2. Hallo,if you can know how much the value of C2 and DO, less clear writing

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    1. Hello, D0 is a 1n4004 it's just a reverse current protection diode, C2 is 100uF.

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  3. Hello Davide, I too have this pedal and I wanted to change the bypass switch with a Click-Less True Bypass Kit
    relay module. My question is how do I know which one of the wires are the pc in and the pc out coming from the pcb board of the pedal . I need to connect these 2 wires to the new relay module but I cant see anything showing them marked on the pedal . Thanks in advance. I am new to this but I am eager to learn .Rey

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    1. Hello, now my pedal is attached to my pedal board, so I can just tell you how can you do, not what wire is to attach. Anyway that should (not tested) be ~almost~ https://mike-bland.com/images/3pdt-wiring.png the wiring of the true bypass of this pedal. Start with a multimeter, and find the +9v and GND connections, trace out that using a continuity test on the pedal board, or looking at the board. Then continue with a continuity / eye test and trace out the other 4 wires, the input/ouput jack plug can help you having contact exposed.

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  4. Thanks Davide . Much help . Very generous
    Rey

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  5. This comment has been removed by the author.

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  6. Hello, Im from Chile and I'm trying to repair this pedal. It has a diode burned (D0). Can someone tell me the specs of D0 to see if I can get it in my country please. Thx and excuse my poor english please

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  7. Hello - very nice sounding mod!
    So you permanently change R4 and R6? C10 switches between 0.047 microF to 0.4picoF (400nF). So can't switch to original R4 and R6?
    Thanks
    Paul

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    1. Hello Paul, thank you. Yes, permanently changed R4,R6,D1,D2. The only thing switchable is the C10 cap.

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  8. Thanks for your great post!
    Which electrlytic caps did you replace?
    Thanks!

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    1. Hello Rs_Zz, just the C10, conneted to a switch to engage it for a "fat" sound. Look at the schematics above, you should find it.

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  9. Thank you Davide. Maybe I wasn’t clear enough. I was not asking for the “fat switch”.
    You say above you changed 2 resistor values, c10 (with a switch), the clipping diodes and: “Also I've changed two electrolitics caps of this pedal with two film caps.”
    I’d like to know which caps you changed.
    Sorry for the misunderstanding and excuse me if the info is somewhere and I couldn’t find it.
    Thank you!

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  10. can I permanently ad the fat sound without ading the switch by just changing C10

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  11. Can I permanently get the fat sound without the switch by just changing C10?

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    1. As comment above, yes of course you can. Please do not double post.

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  12. How do you wire the fat switch?. I am not an electrician so the schematic is confusing.

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    1. Hello, use a spdt switch, connect the center pin to one terminal of the C10 pot, like the one that is connected to R6. Then use one of the other pin of the switch to connect the 100nF, the other pin to 390nF caps, then both the cap connected to the C10 terminal, the one connected to R4, of course remove C10.

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  13. Hi Davide. Very nice work you've done here. Im finding some discrepancy between your schem and others as concerns what you have labled as R4, and what Voltage its connected to? Can you confirm? Also, R17, which is to be part of the voltage divider.. By board has this going other places. I appreciate all the efforts you have made here! Im modding for Fat, and upping gain. BUt my pedal as a notoriously high amount of buzz/hiss. Trying to solve that. Also swapped in a TLE2072!

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    1. Thank you Steve. R4 should be connected between C10 and ground. R17 is as you said part of the diveder. I can not confirm this opening the pedal again couse is wired on my pedal board, but looking at the picture I've made, maybe i reverse the naming, can you confirm this? R17 is R5, and so on... Thank you. As a side note, mine haven't got that big hiss. The XinSound Fuzz FD-20 has, this one not.

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  14. Thanks for your reply Davide... Other sources have the R4 going to 4.5v ...as does my pedal. and R5 and R17 are reverse-labeled on your image. R5 is closest to C3 and R17 is closest to the Tone Pot. After spending many hours on my mods I am quite happy with my pedal and its much improved. Thanks to YOU for all the work and component location that you did. Ultimately I found I had dialed in too much gain, so I dialed that back a bit and am Happy. I also modded the Tone circuit, after finding the pot actually shorts it self completely and affects R9's loading of the neg input. I cut the trace and added some R between R9 and the Tone pot. Now tone can be opened fully without the weird interaction.

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    1. Thank you Steve. So, to correct my picture, I just have to revert R5 and R17 label, right? What about R4, is not to GND? There should be a resistor there connected to GND (like the Tube screamer anatomy image here: https://www.electrosmash.com/images/tech/tube-screamer/tube-screamer-block-diagram.png), or maybe I made a label mistake here again? Thank you for the tone mod suggestion, it may helps!
      I've notice right now, this mods will play in the Steve Miller Band :)

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  15. Ciao Davide voglio aumentare l'impedenza d'ingresso Qualle resistenza devo cambiare? Il pot del tono vorrei che quando sia tutto aperto no taglie le basse frequenze si può fare?

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    1. Ciao Difary, non sono un ing. analogico, quindi potrei sbagliarmi, per l'impedenza aumenta la resistenza di pullup dell'input buffer, quella a 510k attualmente, ma non vedo perchè lo dovresti fare però. Per il tono, quando è completamente in passa alti, non dovrebbe tagliare le basse frequenze. https://www.electrosmash.com/tube-screamer-analysis#tone-stage

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  16. Ciao Davide, grazie per il post, una modifica FAT per rendere più grosso il suono di questo pedale è proprio quello che stavo cercando. Il problema è che, non essendo un tecnico, non capisco bene che tipo e il valore di condensatore che dovrei mettere al posto del C10. Personalmente non ho intenzione di aggiungere uno switch ma solo di rendere il suono più grosso in via definitiva perchè il suono del Vintage Overdrive non mi piace proprio, lo trovo troppo sottile e stridulo rispetto ad un vecchissimo TS9 che avevo.
    Ti ringrazio

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    1. Ciao Lenz, grazie. Se non vuoi mettere uno switch, metti un 390nF, o comunque qualcosa di più alto dei 47nF che dovresti trovare in un pedale originale. Ti consiglio comunque di dissaldare l'originale, saldare due cavi aggiuntivi, e provare con un componente "voltante" il suono.

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  17. Davide, ti ringrazio, farò proprio come mi hai suggerito. Proverò a vedere cosa trovo tra i condensatori che ho in casa perchè al momento, come sappiamo, è impossibile uscire. Eventualmente un condensatore elettrolitico potrebbe andare bene ugualmente?

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    1. Ciao, si va bene ugualmente, cambia leggermente il suono ma è questione di orecchio, potrebbe anche suonare meglio. Anche qualcosa di simile, 470nF forse taglia un pò troppo, ma fai tu qualche tentativo ad orecchio. Se hai qualche circuito "rubato" alla discarica potresti trovare del materiale anche li. Fammi sapere. Buon lavoro.

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  18. Caspita, è vero...purtroppo, dopo vari tentennamenti, ho buttato alcune vecchie schede di un tv color anni 80 poco tempo fa perchè non sapevo cosa farne, mannaggia...per il momento ho trovato solo un degli elettrolitici da 4,7 micro, 10 micro e 33 micro. Farò una prova con quelli, collegandoli con i fili come già detto. Ti faccio sapere, grazie ancora!

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    1. Bene, 4.7micro però è un pò eccessivo come taglio a mio avviso. Comunque fammi sapere.

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  19. Hello i did the mod. Its working but i think that my gain know have low response. when i have vol on max and i turn gain from 0 to 100% it has very low increase of gain. The pedal sounds okay but i think it should be louder (on 100% vol and 1/2 gain its same loud as Boss BD-2 on 1/2 and 1/2 setting)

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    1. I used same values as you but i used 1N34A diodes...

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    2. Hello LukesOn, with the volume at 100% i think the gain behavior you have it's normal. The problem is that the volume should not reach 100%, or you lose dinamics. Mine works like a charm, no problem with volume. Have you checked it before the mod?

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    3. Before the mod it was working normaly... Dont you think that diodes do less cliping or i dont know how the gain knob is working...

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    4. This mods only affect the gain, If i remember, when i was doing this mod I've checed multiple types of diode, stardard LED, IR led (which to me sounds better), 1N4148, but all of mine are silicon diodes, so.. you could try silicon one. Let me know how it goes.

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    5. I have some LEDs, but if u say that IR is better i should buy some and try them... But as for Ge diodes maybe try to tweak some rezistors (to make it louder) ?

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    6. You can try leds, no problem at all, IR just sounds slightly better to me.. but it's just my opinion. You can tweak resistor of the gain stage of course.

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  20. As a rule of thumb, the nominal output amplitude of most pickups is between 60 to 200 mV (single coils) and 200 to 600 mV (humbuckers and hot pickups), with hot pickups the picking transient can be as high as 2Vpeak. The Tube Screamer with the gain set to minimum (12) the clipping amplifier is able to give a range of clean/unclipped sounds while Vin< 90mVpeak

    In my case i have at minimum 23 and Vin = 15mV what is that mean ?
    If i get it right i need to have more than 90mV to get cliping ?
    https://www.electrosmash.com/tube-screamer-analysis

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    1. Hello Lukes, take a look at the formula below the one you pointed here, if Vout-Vin < Vf no clipping. Vf for germanium diode is usually less than silicon one, almost 0.3. Applyed: Vf/(G-1) becames 0.3V/(23-1). It means that if your input signal is below 13.6mV you will never clip.

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  21. Hi Davide!!
    When change the electrolytic capacitors C4 and C5 for some "normal capacitors", I understand that you do not have to take into account the polarity, right?

    Thanks for share it!!!

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    1. Hello, that's right! You can event forget the polarity on non polarized caps.

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    3. Thanks!! Ill try this mods!!
      Regards

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