Help? Sonus Jimi Mod 1968 Fuzz

cruisemates · November 30, 2021, 06:00:20 PM

I am in the process of putting an LED switch into this PNP circuit, BUT in trying to get it working )going from a 6 pole to 9 pole footswitch) I screwed up the battery and DC adapter connections.

It's very hard to find schematics or pics of this pedal, so I hope someone here has worked on one.

1. On the DC jack is hard wired a 1k resistor, a 9v Zener diode and a 100 uf Electrolytic cap. CAN SOMEONE SHOW ME HOW THESE COMPONENTS ARE WIRED? They connect to the DC jack.

2. I also need to know who to wire the battery pack and the DC adapter to the "stereo" input jack.

antonis · November 30, 2021, 06:41:03 PM

1. I presume 1k resistor actually is 47R - 100R and forms a LPF with 100μF cap. One resistor leg to DC jack (+) and the other to 100μF positive leg.. (its negative leg to GND).
Zener is wired with its cathode facing to LPF junction and anode to GND..

2.

idy · November 30, 2021, 07:27:12 PM

Am I cross-eyed or does that graphic have the 330ohm series R and the Red reversed...

cruisemates · November 30, 2021, 08:26:13 PM

I don't know but it is not working for me. This is a PNP circuit (NKT germ trannys) but it also has the standard Boss DC adapter (I assume wired backwards, there is no 1044 chip to swap polarity).

I also see on the old DC adapter the secondary ground (for the battery bypass) is not connected to anything.

I really need someone who understands this pedal to help me, it seems to be an unusual design.

cruisemates · November 30, 2021, 08:30:47 PM

Here is a pic of the open pedal

cctsim · November 30, 2021, 10:20:57 PM

Something like the picture below should work. I would connect the black wire on the underside of the pcb on the top leg of the 33k resistor.

cruisemates · November 30, 2021, 10:28:30 PM

Honestly, I have never seen a DC jack wired up with diodes/cap/resistor like that and I was wondering what it is for. I got all of the orientations correct (diode anode to ground, etc), but I am not sure which DC jack lugs the legs go to.

If ANYONE has this pedal or an idea please let me know, I have been searching everywhere. If you have one pls just open it and take hi-res pictures with plenty of light so I can see the connections - especially around the top for the DC jack, and the guitar/amp jacks.

(if this had been a regular off-board wiring project to add an LED I would have no problems. The thing now is that since I took it apart (the LPF looked a little burnt so I disassembled) I cannot get the pedal to work. I am thrown off because it is PNP and the maker used some unusual grounding schemes that I can't account for.

Thank you for your help.

cruisemates · November 30, 2021, 10:37:35 PM

Quote from: cctsim on November 30, 2021, 10:20:57 PM
Something like the picture below should work. I would connect the black wire on the underside of the pcb on the top leg of the 33k resistor.

The picture is too dark for me to see all the connections, it needs to be much higher resolution and brighter. The schematic posted below is helpful but it does not coincide with what my eyes are seeing in terms of where the wires come from the battery clip and the DC adaptor to meet the 1/4" jacks. It shows connections to lugs that I can see the original maker did not use.

cruisemates · November 30, 2021, 11:40:12 PM

I think I found the pic I need - although I am still not sure how the DC Jack is wired, I guess I can figure it out.

jimitrader · December 01, 2021, 03:18:15 AM

This is similar to yours I think. Check out the 9v section
https://electronicscheme.net/jimi-hendrix-fuzz-face-pedal/

antonis · December 01, 2021, 05:25:50 AM

Quote from: idy on November 30, 2021, 07:27:12 PM
Am I cross-eyed or does that graphic have the 330ohm series R and the Red reversed...

You're probably cross-eyed..

antonis · December 01, 2021, 05:46:43 AM

@cruisemates: Check bigger electro cap connection (the one wired on Fuzz pot wiper - the smaller one should be the input cap).. If its positive leg is connected to GND (enclosure via in-out jacks) it's a positive ground circuit so IN stereo jack switches battery (+) and 9V1 Zener cathode should face to GND..

cruisemates · December 04, 2021, 07:17:54 PM

Actually, I have really FUBAR this pedal and feel like a fool. I cannot get it rewired to even work again with a battery alone. This pedal is PNP and has a BIAS pot in the middle. Anyone know of a schematic? All the jacks are on top (not the sides) so any pictures I see are not deciperable. Plus the maker used different colored wires all the time so I really need a pic where I can trace all the connections.

Thanks for help.

kaycee · December 05, 2021, 06:27:01 AM

Don't worry about the wire colours, find out where they go by using your multi meter continuity setting. Refer to Antonis' nice clear diagram and check off what you know first, then that makes it easier to narrow down the wires you are not sure of. Converting back to battery only requires connecting up the power to the board and the ground to the correct lug on the jack. Check continuity of your ground.

I can't see your pictures as I'm using an ancient iPad, I will look next time I fire up the laptop. I have a sonus modded fuzz face, but mine is battery only and no bias. Built on a repro (or original) PCB, so it has none of the filtering guff yours has. These last forever on a battery, if unplugging it all the time is a pain, consider a simple switch to break the power line.

If, Mr. Sonus passes through, great sounding pedal, as good if not better than the best ones I've done, tip of the hat.

cruisemates · December 05, 2021, 07:04:26 PM

Comments appreciated. Here is the thing - I have quite a few pictures of the original pedal and he did a few tricks on the one I have so the wiring seems a little different, like grounding the jacks to the enclosure and no ground wires.

But I understand what you are saying about just following the diagram and I am now taking it in stages. I have always been dyslexic when it comes to DC Jacks 8-]
Don't know why, but when I am looking at a picture of one and holding a real one, they just don't look like the same piece.

Question - on the DC jack for PNP wiring - the CENTER PIN is connected to the bent solder connector on the other side and that is POSITIVE (right?). This is the stuff I really need to remember, IN THE PIC BELOW, because I am doing PNP I need to use Center Negative, right?

kaycee · December 06, 2021, 04:30:11 AM

Yeah, I still get confused with it all now and then. I prefer the voltage inverter course, or stick to battery for PNP. I think if you wire as your left hand example and you connect your jack and board grounds right, it will work for battery, but not for your power supply.

cruisemates · December 19, 2021, 06:56:37 PM

Thanks for all who helped. You were correct that the left-hand diagram worked for the adapter or the battery, but not for both. IOW: you cannot leave a battery in it because it will drain as long as the pedal is on even if you have adapter power.

That explains why the maker did not connect the DC adapter sleeve which disconnects batteries - there doesn't;t seem t be a way to make that work. You can make it work for NPN if you do not have an adapter (IOW: you can unplug the guitar input and the battery won't die).

Anyway - I had built reverse NPN circuits before, but not with battery snaps. This had both but the snap was not connected. I got it working at last and just wanted to zip it up and send it back to the owner, but the DC adapter started shorting out because of all the extra components hanging off of it. I had to go back and rewire all of those. What a nightmare project.

The original maker did get back to me when I explained what I wanted to do (add an LED, but then it stopped working before I could do that, so I decided not to do that) and his first words were "wow, you must be tearing your hair out."

News:

Help? Sonus Jimi Mod 1968 Fuzz