Joyo - JF-04 High Gain Distortion

grrrunge · Post by **grrrunge** » 05 Dec 2011, 14:14

This one definately holds some usable tones for the price, but doesn't come near any of the high gainers i've built over the last couple of months

The treble knob makes it shrill and ice-pick-y pretty fast, and overall the sound reminds me of a metal zone without the parametric mids.

Guts:

If anyone fancies it, i'll toss up a BOM as well. Perhaps we can get something properly useful out of this one

grrrunge · Post by **grrrunge** » 05 Dec 2011, 14:37

Does anyone have any clue as to which pedal this one is "loosely based on"?

analogguru · Post by **analogguru** » 05 Dec 2011, 23:37

grrrunge wrote:Does anyone have any clue as to which pedal this one is "loosely based on"?

Yes, on a Marshall Shredmaster with fixed (omitted knob) bass control.

analogguru

guycapuano · Post by **guycapuano** » 08 Dec 2011, 00:39

analogguru wrote:
grrrunge wrote:Does anyone have any clue as to which pedal this one is "loosely based on"?
Yes, on a Marshall Shredmaster with fixed (omitted knob) bass control.

analogguru

I would like to hear it side by side with a Son of Hyde or Jekyll and hyde hyde side!

atreidesheir · Post by **atreidesheir** » 02 Jul 2012, 01:02

What is better than one set of pics of dirty dirty joyo guts? that is correct more of the same. Just color me inspired by your snores. Fluxy guts!

pots are gain. treble, mids and volume

atreidesheir · Post by **atreidesheir** » 03 Jul 2012, 21:43

grrrunge wrote:This one definately holds some usable tones for the price, but doesn't come near any of the high gainers i've built over the last couple of months
The treble knob makes it shrill and ice-pick-y pretty fast, and overall the sound reminds me of a metal zone without the parametric mids.

I actually hold a much higher opinion of this bad boy. Very solid for Radiohead tone and far beyond. I dial in lots of mids and it is usable for the entire range of the gain knob from 7 to 5 0'clock. WINNER!

defec · Post by **defec** » 28 Mar 2014, 00:12

Does anyone know what the third dual opamp is for? A Shredmaster has only four opamp stages.

tabbycat · Post by **tabbycat** » 22 Nov 2014, 04:15

atreidesheir wrote:
grrrunge wrote:This one definately holds some usable tones for the price, but doesn't come near any of the high gainers i've built over the last couple of months
The treble knob makes it shrill and ice-pick-y pretty fast, and overall the sound reminds me of a metal zone without the parametric mids.
I actually hold a much higher opinion of this bad boy. Very solid for Radiohead tone and far beyond. I dial in lots of mids and it is usable for the entire range of the gain knob from 7 to 5 0'clock. WINNER!

analogguru wrote:
grrrunge wrote:Does anyone have any clue as to which pedal this one is "loosely based on"?
Yes, on a Marshall Shredmaster with fixed (omitted knob) bass control.

analogguru

have recently got hold of one of these for peanuts. it's pretty tasty sounding. bought it blind-on-hearing in a swap-thing before finding out about the shredmaster connection. but i get it. it's pretty much there. true bypass too, which the original wasn't.

am a big fan of the shredmaster's grit and squeal (radiohead 'paranoid android' hard not to like) but £100 for a real shredmaster is out if my range and a clone-build would be a mission too far for me atm.

but if there are any simple and sweet mods that can be done to this to raise its spec i'd definitely be up for trying and feeding back. got a few to try from a tdpri post (below) but has anyone experimented here?

for example analogguru says it's 'based-on' the sm with a fixed bass control. is there a straightforward way of patching that bass pot back in to the circuit? i'd like to see hear how much difference it makes to have that back in.

have to admit to being a little confused by the schematic.
http://www.matsumin.net/diy/jisaku1/shr ... ompenh.gif
i'm relatively new to the science of reading these and i've not seen a bass pot that piggy-backs, almost a trimmer, to the ground (effectively) of the tone pot.

so thinking about it another way i looked at mirosol's vero layout from guitar fx layouts (thanks miro) and it seems more comprehensible in principle.
http://3.bp.blogspot.com/-vWMkonkn1jc/U ... master.png
take up the thread from pin 5 of the first opamp to lug 1 of bass pot and feed back lugs 2 and 3 into lug one of the tone pot. that's an oversimplification, there are a few caps and a resistor to tack in, but that seems to be the practical gist.
but this route all depends on how faithful miro has been to the original shredmaster, and how faithful joyo have been to the original shredmaster. i'm working on resolving that but am a beginner at tracing so a bit slow.

defec wrote:Does anyone know what the third dual opamp is for? A Shredmaster has only four opamp stages.

discuss...?

have found some damn useful stuff re mods for caps at tdpri (thanks chaps) which i can fairly easily cope with, diode subs are obvious (into diode subbing atm), but nothing re reinstating the bass control.
http://www.tdpri.com/forum/stomp-box/32 ... ost4180275

having done the cap rotation mods for the joyo voodoo octave (foxx tone clone) and have to say these are a dream to mod. proper bits (no sm scabs) and well spaced. so am up for taking diabolical liberties with it as i don't feel it is too easily trashed.

any ideas or thoughts from jf-04 or shredmaster fans here?

tabbycat.

tabbycat · Post by **tabbycat** » 23 Nov 2014, 21:41

if a mod would like to take a nuke to my above post it would be welcomed.

as this is basically a 'pimp-my-cheap-pedal' mod i have started a more thorough dedicated thread there.

https://www.freestompboxes.org/viewtopic ... 80#p245280

many thanks, tabbycat.

tabbycat · Post by **tabbycat** » 20 Jan 2015, 21:17

there is a new design for this one. my board dated 2010.11.24.

i have no idea what it is based on, unless it is a minimal make-over of the previously mentioned shredmaster and hyde-side of jeckyll and hyde.

detailed gut shots here.
https://www.freestompboxes.org/viewtopic ... 23#p247323

can attach them into this thread if anyone wants me to. if you need any info about details of components i can provide but i'm pretty bad at tracing so just giving what i have for now for you to use and muse over as you wish.

enjoy.

tabbycat.

howmuch · Post by **howmuch** » 13 Mar 2015, 00:11

This is a GREAT sounding pedal IMHO. Love it.
Here's a picture of mine.

And here's the schematic. Let me know if anything's wrong.

Looks like Joyo got it spot on with this one. No mistakes that I can see.
Not a 1:1 ShredMaster, but the differences seem to be deliberate - brighter, fixed bass, MOSFET input buffer.

howmuch · Post by **howmuch** » 29 May 2015, 17:13

Here's the Joyo JF-04 High Gain Distortion schematic at a finer resolution for better viewing.

Chrisfromiowa · Post by **Chrisfromiowa** » 02 Sep 2017, 16:02

Joyo - JF-04 High Gain Distortion
Postby grrrunge » 05 Dec 2011, 09:14

This one definately holds some usable tones for the price, but doesn't come near any of the high gainers i've built over the last couple of months
The treble knob makes it shrill and ice-pick-y pretty fast, and overall the sound reminds me of a metal zone without the parametric mids.

Guts:
25112011342.JPG

25112011341.JPG

25112011340.JPG

Does anybody have a diagram for the daughterboard footswitch. I purchased another Ammoon/Joyo pedal that had a melted footswitch and am having a hard time rewiring it. I thought it was standard at first, but the LED with no resistor is not what I'm used to. Thanks, and thanks again. I know this is OT and an ancient thread..... Regards CFI

petrucci38 · Post by **petrucci38** » 04 Jun 2019, 07:16

Hello, I've changed the rc4558p's by burn brown opa2134´s and the jf-04 improves a lot. It only has a problem. One of the IC´s (IC2 or IC3) produces oscillation with the battery. Nevertheless, it doesn´t produce oscillation with a power supply. Opa2134's are faster than rc4558p's so I think I have to adjust some capacitor or resistor to resolve the problem but I don´t know which one of them. Can you help me?. Thank you! A Greeting!

Joyo - JF-04 High Gain Distortion [schematic]