Converting bipolar fuzz to Single supply power

[John Lyons]

The jumper would not do anything. Still just using the switch as a single throw make or break switch.
Not sure what the thought is on using a jumper...
The switch would break the connection between pin 6 and 2. Disabling the 47pf/700k.
Those rough cap values should be right Mac. Compare to the other schematics.

Shouldn't pin 4 be grounded?
There isn't a direct ground connection to the chip otherwise.
The level pot should be 10k.

[EATyourGuitar]

EATyourguitar, Do you have C3 and C5 backwards in the above drawing (values swapped)?

no sir! you could however bring R3 down to some other ground instead of pin 3. for example connect R3 to pin 2 or v- ...not sure if it would be better.

Also I am still wondering how the switch ties in, there appears to be a jumper on the switch, which I can't wrap my head around...

I'm like %99 sure that switch shorts both sides of that little blue cap to remove it from the circuit and make it just a wire. I need to really spend some time reversing his vero since that must be something different then what I posted. if you short that 47pf in my schematic you have 700k in parallel to the 1M pot and that is about 400k max thus cutting your 1M pot down a lot. the only explanation is that his 47pf goes to ground or some other rail. you can also see a resistor there in series to the 47pf so when you jumper it you just bring pin 6 down to ground through 10k or something. there are a lot of assumptions here and I'm just guessing. we still don't know the value of the cap. I started at 47pf to not change the sound of the pedal too much. I will wait to hear everyone's thoughts before I etch this modded one.

[EATyourGuitar]

The jumper would not do anything. Still just using the switch as a single throw make or break switch.
Not sure what the thought is on using a jumper...
The switch would break the connection between pin 6 and 2. Disabling the 47pf/700k.
Those rough cap values should be right Mac. Compare to the other schematics.

Shouldn't pin 4 be grounded?
There isn't a direct ground connection to the chip otherwise.
The level pot should be 10k.

you found all my mistakes. give me a minute and I will fix it.

[EATyourGuitar]

John that Jimmy behan vero looks to me that the little blue cap is in parallel to the switch. follow the switch back to the vero traces even though we can't see where the cut traces are. it is a very good guess. trying to have a vero like that with the little blue cap in series to the switch would be increasingly difficult the way it is in the photo.

[John Lyons]

With that switch you can short the cap without the jumper.
It does like like it shorts the cap though.

[EATyourGuitar]

tried 700K + 47pf feedback and it worked. you loose just a bit of brightness with the mod so maybe 1M + 100nf would be a better choice. I really like this pedal. sounds like nothing else ever. I did not try the 5M + 5M common ground version yet. I dont think I want to. this thing sounds great. so what it has a power switch. anyone that needs this layout for etching just ask and I will post.

[rocket8810]

glad to see someone figured it out, does it sound like the original osculations and all? can it be daisy chained and have a 9V jack? i've been trying to get it and got nothing. can you post the layout or veroboard?

[EATyourGuitar]

this is the original version with the anti-whistle mod on a switch. I did not build the single supply common ground version yet. I prefer power on a toggle switch but you could find a way to put it in the footswitch. the problem with that is you won't really know if the power is on just by looking at it. I don't know if power on the footswitch creates pops but I guess anything is possible.


schematic

PDF ready to print and etch

[Mac Walker]

Looks good, thanks for sharing.

A couple points of clarification -

EATyourGuitar - on the output, the original drives the wiper (term 2) of the output pot.  Your version uses the universally accepted method of driving 3, and picking off 2 for the output to feed an amp.  Again, with the original version..........weird.  Not sure if it is even a mistake in the original sketch.

Rocket 8810 - this version would not work with a 9V jack and be daisy chained, the chassis voltage sits at a value other than 0 V (like a PNP fuzz, where the chassis sits at -9V)

EATyourGuitar, can you measure the voltage on SLEEVE relative to BAT_NEG, for both conditions where 1) guitar is plugged in and 2) guitar not plugged in

I still haven't had a chance to breadboard

[EATyourGuitar]

EATyourGuitar - on the output, the original drives the wiper (term 2) of the output pot.  Your version uses the universally accepted method of driving 3, and picking off 2 for the output to feed an amp.  Again, with the original version..........weird.  Not sure if it is even a mistake in the original sketch.

the pot is off board so if it makes you feel more vintage correct, just wire it how you want. connect the PCB pad V3 to 10KA vol pot lug 2. I guess it is possible to have a variable output impedance if you wire the opamp output to lug 2. this might be important for a trans-impedance opamp configuration. I am tempted to go and rework my finished build now that you got me thinking.

Rocket 8810 - this version would not work with a 9V jack and be daisy chained, the chassis voltage sits at a value other than 0 V (like a PNP fuzz, where the chassis sits at -9V)

EATyourGuitar, can you measure the voltage on SLEEVE relative to BAT_NEG, for both conditions where 1) guitar is plugged in and 2) guitar not plugged in

all voltages refrenced from battery V-

battery V+ = 9.52v
sleeve = 4.8v
sleeve with guitar plugged in = 4.8v
sleeve with guitar vol rolled down = 3.95v

not sure where my 10k vol was on the pedal but the opamp is driving 10k + 10k all day with opamp wired to V3 through R4 and V1 to sleeve so we can probably just think of it like a fixed 20k resistor and output tip float for all measurements.

[rocket8810]

hmmm, this will be my first PNP build, so excuse my ignorance with the following questions.

1. what are the following and how do i hook them up F1 &F2, S1 & S2, V3, V+, and sleeve?
2. can i use the following diagram to wire a stomp switch, jacks, and possibly add the 9V in? less concerned about the 9V in.
http://www.beavisaudio.com/techpages/StompboxWiring/
3. is this similar to the jimmybehanfx version with the switch you're talking about?
http://www.jimmybehanfx.net/wp-content/uploads/2011/04/P1020826_600.jpg
4. does the type of caps, and resistors matter, ie: ceramic disks and carbon like the original, or can i use any type?
5. how can i transfer this to a stripboard instead of pcb, some of my pcbs havent behaved and want to try strip for this one.

i know i'm a noob and trying to learn as much as i can. thanks for all the help in advance, it means a lot.

[EATyourGuitar]

1. what are the following and how do i hook them up F1 &F2, S1 & S2, V3, V+, and sleeve?

F1 and F2 are lugs of the filter pot 1M linear
S1 & S2 can be any switch. any kind of toggle. it just needs to break the feedback circuit for vintage mode.
V+ is directly connected your battery red wire +
sleeve is the sleeve connection on the audio jack
battery black wire - is connected to the switch. that switch connects to BAT_NEG on the board.

2. can i use the following diagram to wire a stomp switch, jacks, and possibly add the 9V in? less concerned about the 9V in.
http://www.beavisaudio.com/techpages/StompboxWiring/

no you can not. follow the picture I posted. the input to the box and the input to the board are all blue.

3. is this similar to the jimmybehanfx version with the switch you're talking about?
http://www.jimmybehanfx.net/wp-content/uploads/2011/04/P1020826_600.jpg

any switch will work. any SPST, SPDT, DPDT or a footswitch

4. does the type of caps, and resistors matter, ie: ceramic disks and carbon like the original, or can i use any type?

I don't think it does when you have THIS much distortion in the pedal to start with. this is the type of effect that benefits from bad ceramic caps if your trying to go for the most awful thing. I wanted to use ceramic but I was all out when I built it so I used poly. it still whistles with poly film caps.

5. how can i transfer this to a stripboard instead of pcb, some of my pcbs havent behaved and want to try strip for this one.

i know i'm a noob and trying to learn as much as i can. thanks for all the help in advance, it means a lot.

try DIY layout creator. you can draw your own vero layouts. you can also do it on grid paper pretty easy for small circuits. if you say you are new, I think that is even more of a reason to try your hand at making your own vero layouts.

[rocket8810]

Awesome EATyourGuitar. Thanks for all the help, gonna get started on it tonight, I can not wait.

[Goodrat]

I used to work at Earth Sound Research in the late 70's in customer service repair with a guy named Tony. Then we moved and shared a building with Qualtrol (their pcb supplier).
Once Tony left for Telephonics, it was only me for about 6 months then they closed, then I went to Telephonics also. ESR owner became head of Telephonics (just giving a little history in case any ex-employees come across this).
The ground should be between the two 10K resistors that are across the battery.
It oscillated all the time. The IC was a 741 op amp.
Tony had made a change. I don't remember what that was. I thought the caps across the 10K's were bigger.

[Goodrat]

Just for kicks, here is the original since I see many incorrect.

[glops]

Just for kicks, here is the original since I see many incorrect.

Thank you!

[Goodrat]

OOps, forgot the 10K in series with the output pot wiper.