Joyo - JF-36 Sweet Baby  [schematic]

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

This is going to surprise no one...

Here's a partial schematic. The SMD LEDs glow red. IC is RC4558.
Image

Gutshots. I ripped up some pads while desoldering the pots... might not be able to reassemble it :cry:
https://i.imgur.com/bJ5gh36.jpg?1
https://i.imgur.com/3rvsv6k.jpg?1

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Brink
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Post by Brink »

Volume (VR3) is B50K, Focus (VR2) is B50K, Drive (VR1) is A500K - just like on the Mad Professor Sweet Honey Overdrive.

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vikingz
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Post by vikingz »

Yepp,confirmed accurate clone.I´ve built a few of these with some degree of variation.The Ultimate Drive is kind of inaccurate from the OCD,but easy to modify if you know how to handle a soldering iron.

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terrydavis
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Post by terrydavis »

The Joyo Sweet Baby overdrive is pretty good but it seems to thin out the sound where as I'm looking to round out a sound for some nice jazz distortion ala Mathew Stevens. Sure would like to know what he uses for distortion...so natural.

In any case anyone know some mods for the Joyo? I added a tone knob to see if that would do...helps but no prize. Thanks, Terry

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candidate
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Post by candidate »

do you own a compressor?

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terrydavis
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Post by terrydavis »

no

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tasteless
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Post by tasteless »

It's a clone of something , Yeah ? ( Mad Professor Sweet Honey Overdrive perhaps ? ).
I reckon a Schematic for the original would offer a few clues - Should be one kicking around in here somewhere.
Had to search for Mathew Stevens , As I was unfamiliar - Cool stuff ! - Gonna check out some more.

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candletears7
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Post by candletears7 »

Try different values for the input or output caps, as well as in the tone control section. Got a shot of the pcb at all?

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jtran3000
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Post by jtran3000 »

I'd like to boost the bass on my SB OD to alleviate its thin-sounding tone. I see 6 caps on the circuit board but I don't know which one to swap out first. I see markings of C2, C13, C14, C9, C11, and C5. Also, will a higher or lower uF value yield darker tone? Can anyone point me in the right direction? Thanks

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Post by TubeDude22 »

Picked up three Joyo pedals, American Sound, Us Dream and Sweet Baby, to see what all the hype was about. Of the three, I liked the Sweet Baby the least. It was too bright and crunchy for my tastes. So, out came the soldering Iron. I removed the treble bleed cap at the volume control, which helped a lot. But it was still too crunchy. Next I used a single 2N7000, wired as an asymmetrical clipper, and tacked it in parallel across the two LEDs in the first stage clipper. That did it. My Joyo Sweet Baby now sounds kinda more like a Fender Silverface Champ Amp. Hope this is useful.

TD

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Post by TubeDude22 »

There they are! Thanks for the links Desdog. :applause:

The cap I removed is C3 on the Mad Professor - Sweet Honey OD schematic. D3 & D4 is where I installed the 2N7000 clipper in parallel across the LEDs.

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Post by mildew »

Just added some bass and gain to my sweet baby by removing smd resister r14 (47k) and replacing with a 100k through hole. Drops highpass from 720 to 338hz.
sweet baby bass mod.jpg
sweet baby bass mod.jpg (12.21 KiB) Viewed 8915 times
Also added a 300k resister to the gain pot wiper. Now it does fat high gain tones 8)

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Post by mildew »

Replaced the gain pot with a 1 meg, the sweet baby with bass and gain mod is now my #1 dirt box.

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spectreman
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Post by spectreman »

When you replaced the gain pot, did you use a linear (B1M) pot, or a reverse taper (C1M) pot? would either make much of a difference in this case?

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mojah63
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Post by mojah63 »

Funny thing.. I was trying to find a boost that didn't color the sound of the cranked AC30 in my 11R and after going through all my pedals tried this one. Gain on zero, tone around 9 - 10 o'clock level 2 - 3 o'clock works perfectly. I absolutely hated this pedal when I bought it and it just sat in my last fx drawer for a couple years unloved. Ya never know what may work.

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eriwebnerr
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Post by eriwebnerr »

mildew wrote:Just added some bass and gain to my sweet baby by removing smd resister r14 (47k) and replacing with a 100k through hole. Drops highpass from 720 to 338hz.
I browse here from time to time and rarely log in since most of this is over my head. But I just logged to say this is a genius and simple mod. The SMD is a real pain but once I got the 100K resistor in there it totally transformed the pedal! The entire frequency range is balance and the the low end nice and full. It makes the gain and focus controls usable across the entire range too. Thank you sir for this excellent little mod!

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mprall00
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Post by mprall00 »

Thought I would add my experience since this post was extremely helpful for me as i struggled to find a use for the sweet baby. I swapped in the 100k resistor in R14 and really liked it. But I didn't get it on to the SMD pads well enough and it eventually broke free from an enthusiastic stomp. When I went to solder it back on there, I lifted the pad entirely. Pain in the butt. Wrestling with the thing trying to get it back i ended up taking out C12 next to it too.

So i flipped the board over and C11 is through hole. R14 and C12 come after C11 and connect to the Volume pot. I soldered a 100k resistor and 4n7 capacitor between the C11 and the volume lug 1. Back up and running! If you are considering this mod, I would just take out R14 and C12 to start with and solder on the back.

This also let me play with values. Swapped in cap values and eventually landed on 47n with 100k resistor. Much more bass and much less shrill. I wasn't a fan of this pedal until now. Now its somewhere between the overly bassy Honey Bee clone I made and the naturally thin Sweet Baby.

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