freestompboxes.org

So does the Joyo have the zener diodes in the feedback loop of the distortion generating opamp like the Tech 21?

Hmm, I can't see the schematic in the thread, was it censored or anything?
Giorgio

Caferacernoc wrote:So does the Joyo have the zener diodes in the feedback loop of the distortion generating opamp like the Tech 21?

Yes, it does. They are not in a 3-legged device though, just normal SMD diodes.

Ihunda wrote:Hmm, I can't see the schematic in the thread, was it censored or anything?

This is because the schematic was never posted here : it's in the Tech21 Character Series thread. The only difference is in some components changed to the values i've posted above.

Hi,

Can this pedal be directly connected to a PA, just like the Liverpool? Thank you.

This is a really great thread and I put together a PDF with the initial posts along with their attached drawings and added in the Liverpool schematic from another thread. I have attached the file to this message or you can view and download it from my page on Box.com:

https://www.box.com/s/t0yj65rshmkuacnte68j

Steve Ahola

I'm going to buy an AC tone (or some other Character clone from Joyo) just to mod it and get a VT bass out of that (check the Character topic. I've updated it with missing values from VT).
Anybody knows if pots are all 100KB in this Joyo thing?

I was going to try disabling the speaker sim and maybe adding a switch in my AC Tone, but I opened it up and it looks totally different than the pictures that were posted earlier in this thread. So I'm kinda lost as how to go about doing it. I've attached a pic of the inside of my actone. Any ideas?

Hi I have an American sound and I too was just about to try a speaker sim bypass but it looks the same as your pic. Does anyone have an updated pic of how to do this?
Thanks

The parts in the updated layout:

mrmeister wrote:The parts in the updated layout:
[ Image ]

Awesome, thanks for that! Have you figured out how to bypass the speaker sym in this version?

I had some time so I sat down and figured out the speaker sim bypass on the newer PCB.

WARNING: be very careful with your soldering, the traces on the board are very fragile.

I used 26AWG wire for my connections. Start by removing the 0 ohm resistor shown. Solder a wire to each of the three places shown in red. Once your wires are in place put a small blob of hot glue over the connections to the board. I didn't do this to the wire soldered to pin 3 of the level control as it is plenty solid. solder the other end of the three wires to your switch and you are good to go. Works great!

How about to simply bypass the speaker sim without installing a switch? Is there some single component that can be removed?

Remove the part shown and add a jumper wire duplicating the switch in the down position.

Ripdivot wrote:I had some time so I sat down and figured out the speaker sim bypass on the newer PCB.

WARNING: be very careful with your soldering, the traces on the board are very fragile.

I used 26AWG wire for my connections. Start by removing the 0 ohm resistor shown. Solder a wire to each of the three places shown in red. Once your wires are in place put a small blob of hot glue over the connections to the board. I didn't do this to the wire soldered to pin 3 of the level control as it is plenty solid. solder the other end of the three wires to your switch and you are good to go. Works great!

Hi, thanks for that. I did it on my American Sound (Harley Benton, not a Joyo, but the pcb is the same). It works great.
But, to avoid the immense differences in volume in both positions of the switch, I took a DPDT-Switch. One area of the switch I soldered as you mentioned, the other area switches a resistor between the first and second lug of the volume pot (from left to right in your picture) when in SpeakerSim OFF position.
To get the right value of the resistor I soldered two lugs of a 10k-pot instead of a fixed resistor and turned it as long as I got nearly the same volume in both positions. Then I disoldered the 10k-pot again and measured the resistance between the affected two lugs. In my case it was around 3k3. So I soldered a fixed 3k3 resistor instead of the 10k-pot and it works great in all positions of the Volume-pot. Maybe values between 2k2 to 3k9 will work. Just have a try or do it with a potentiometer like I did.
Note, that this resistor is not affecting anything, when in SpeakerSim ON-position.

Thanks again for your work on the new pcb-layout - now it is a very versatile component of my pedal-board.

Music is the best

jockie wrote:

Ripdivot wrote:I had some time so I sat down and figured out the speaker sim bypass on the newer PCB.

WARNING: be very careful with your soldering, the traces on the board are very fragile.

I used 26AWG wire for my connections. Start by removing the 0 ohm resistor shown. Solder a wire to each of the three places shown in red. Once your wires are in place put a small blob of hot glue over the connections to the board. I didn't do this to the wire soldered to pin 3 of the level control as it is plenty solid. solder the other end of the three wires to your switch and you are good to go. Works great!

Hi, thanks for that. I did it on my American Sound (Harley Benton, not a Joyo, but the pcb is the same). It works great.
But, to avoid the immense differences in volume in both positions of the switch, I took a DPDT-Switch. One area of the switch I soldered as you mentioned, the other area switches a resistor between the first and second lug of the volume pot (from left to right in your picture) when in SpeakerSim OFF position.
To get the right value of the resistor I soldered two lugs of a 10k-pot instead of a fixed resistor and turned it as long as I got nearly the same volume in both positions. Then I disoldered the 10k-pot again and measured the resistance between the affected two lugs. In my case it was around 3k3. So I soldered a fixed 3k3 resistor instead of the 10k-pot and it works great in all positions of the Volume-pot. Maybe values between 2k2 to 3k9 will work. Just have a try or do it with a potentiometer like I did.
Note, that this resistor is not affecting anything, when in SpeakerSim ON-position.

Thanks again for your work on the new pcb-layout - now it is a very versatile component of my pedal-board.

Music is the best

Great! Glad it all worked out for you. I have the AC, British, American and California. I've done this mod to all of them and it is well worth it. Makes the pedals so much more versatile.

jockie, are you able to post a drawing or photo of your mod with the DPDT switch? thank you.

Sorry to reopen an older thread but does anyone know what the main ICs are on the board and if they are common to all versions of the pedal? I have heard (no pun intended) that they were chosen for power over noise considerations and that replacing the main op-amps can make the pedals much quieter.

Cheers,

iep

Sorry, scrub that, it was listed earlier in the thread. TL062.

iep

Ripdivot wrote:I had some time so I sat down and figured out the speaker sim bypass on the newer PCB.

WARNING: be very careful with your soldering, the traces on the board are very fragile.

I used 26AWG wire for my connections. Start by removing the 0 ohm resistor shown. Solder a wire to each of the three places shown in red. Once your wires are in place put a small blob of hot glue over the connections to the board. I didn't do this to the wire soldered to pin 3 of the level control as it is plenty solid. solder the other end of the three wires to your switch and you are good to go. Works great!

I have damaged the solder pad to the right of my 0 ohm resistor. Is there an alternative spot I can wire to to get the speaker bypass on the newer pcb.

Thanks

A friend brought me a Joyo Am Snd in a very well F_ed up condition, and (among others) it lacks that tiny smd resistor near the volume pot, labeled R47 (as shown in the attached pic).
I would be very grateful if anyone would be kind enough to provide any info on its value, so to have it replaced with a new one.

btw, C21 doesn't seem to exist in my friend's pedal, too.


Thanks in advance.