Me and a friend were working on a easier way to do the "Bleed Fix" mod for the Boss Super Overdive.I just need some confirmation that this will work?Here's the schematic; http://www.hobby-hour.com/electronics/s/schematics/boss-sd1-super-overdrive.gif Here's what we did;You take R1 (10k) out and solder the brown wire coming from pad 3 to the bottom hole of R1.The brown wire is glued to the input jack.You take a 10k resistor and solder one end to the brown wire,and the other end of the resistor to the input jack sleeve(ground).Here's some pic's of what it looks like; http://s1143.beta.photobucket.com/user/soupbone71/library/Boss%20SD-1%20Bleed%20Fix?page=1 Not hearing any background noise coming through now.Fixed?Possibly? :)
I must be missing something, as far as I can see if you do what you say you shouldn't get any sound at all. If you take out R1 how does the signal get from the input jack to the first transistor?
Quote from: slacker on March 15, 2013, 03:15:09 PM
I must be missing something, as far as I can see if you do what you say you shouldn't get any sound at all. If you take out R1 how does the signal get from the input jack to the first transistor?
I don't really know!lol The pedal works fine after the mod though.No more bleed through that i can tell.R1 is a 10k resistor.Just solder a 10k resistor(the same value resistor as R1) to the brown wire,where it's glued to the input jack(you have to cut it).The other end of the resistor goes to the "ring",not the "sleeve"( i think?) on the input jack.The other end of the brown wire that was de-soldered from pad 3 on the pcb,To the bottom of where the resistor was taken out.(i.e. right above the .047 cap.) Don't know if that helps or not! :icon_biggrin:
Here's some more gutshot's of the "Modded SD-1" and an Un-Modded SD-1". http://s1143.beta.photobucket.com/user/soupbone71/library/Boss%20Super%20Overdrive%20Modded%20and%20Un-Modded%20pics?page=1 I feel like an idiot about which is the tip,ring and sleeve on this boss input jack! :-[ The Un-Modded pic,the brown wire coming from pad 3 on the pcb,is going to the bottom lug on the jack.The lug right above that one has a black wire going to the battery snap,and a yellow wire going to pad 10.The lug closest to the chassis has one black wire coming from it going to pad 16 on the pcb.Just need some help identifying those 3! :icon_smile:
Quote from: soupbone on March 15, 2013, 08:10:04 PM
Here's some more gutshot's of the "Modded SD-1" and an Un-Modded SD-1". http://s1143.beta.photobucket.com/user/soupbone71/library/Boss%20Super%20Overdrive%20Modded%20and%20Un-Modded%20pics?page=1 I feel like an idiot about which is the tip,ring and sleeve on this boss input jack! :-[ The Un-Modded pic,the brown wire coming from pad 3 on the pcb,is going to the bottom lug on the jack.The lug right above that one has a black wire going to the battery snap,and a yellow wire going to pad 10.The lug closest to the chassis has one black wire coming from it going to pad 16 on the pcb.Just need some help identifying those 3! :icon_smile:
crap :icon_eek:
Anybody? :(
Ok,My friend that knows way more than i do at electronics showed me using a guitar cord and a meter how to figure out which was the tip,ring,and sleeve.So,The brown wire coming from the tip needs to be cut.Solder one end of a 10k resitor to the end of the brown wire.Solder the other end of the resitor to the tip of the input jack.Read some of the earlier comments on how to do the other part.My electronics buddy said it makes total sense.He told me how,but i went way over my head. lol So,Do you peoples think this will work?
Any chance you can draw your changes on the schematic? I still can't understand what you're actually doing.
I am wanting to fix the bleed in mine as well. Still following this to see. Bump
Quote from: slacker on March 19, 2013, 07:06:14 AM
Any chance you can draw your changes on the schematic? I still can't understand what you're actually doing.
Never got a concrete answer to if this will work?There's some pic's I posted of the mod close to the top of the page.Sorry for posting one my old thread. :icon_redface:
ok, so it seems like what you did is to take the 10k that is between the input jack 3 and c1 and remove it, moving the brown wire to the other side of r1, so it goes from input 3 to c1 without the 10k, then use the 10k to go between the in jack 3 and ground. this puts 10k to ground at the input.not sure but it could fix any bleed if the bleed is coming from the input.not sure why there would be bleedthrough at all tho...
Quote from: Quackzed on April 25, 2014, 07:30:07 AM
ok, so it seems like what you did is to take the 10k that is between the input jack 3 and c1 and remove it, moving the brown wire to the other side of r1, so it goes from input 3 to c1 without the 10k, then use the 10k to go between the in jack 3 and ground. this puts 10k to ground at the input.not sure but it could fix any bleed if the bleed is coming from the input.not sure why there would be bleedthrough at all tho...
So,in your estimation,this will work?Thanks for your help!
Soupbone, it is still not clear wether you added a 10k resistor from signal to ground at the input of the pedal (but this would eat a lot of signal, so I guess you just messed up words between "tip" and "sleeve"), or you simply "exteriorized" the 10k resistor from the board to "flying". In the latter case, I really doubt that can be helpful.
HOWEVER, this well known issue of the SD-1 has already been SOLVED exactly 9 years ago (!!) by ANALOGGURU.
You can read here (http://www.diystompboxes.com/smfforum/index.php?topic=23903.0) the thread I started that long time ago, where I put down in words all the dozens of experiments and substitutions I tried in vain, before concluding we probably are/were experiencing a layout issue and, most of all, before analogguru posted a schematic of his really clever solution (page 3 of the thread). Now, that schematic appears to be no longer available, but in the subsequent posts I put it down in words for another person, so here you have it (quoting myself):
"You need an SK30A jfet, a 0.1u (=100n) cap and a 1n4148 diode.
Obviously, you have to solder your new components to the top side of the board, because you won't be able to close your pedal anymore if you work on the traces side...!
Watching the front (the flat side) of the jfet, the three legs pointing downwards are named (from left to right) S, G and D (Source, Gate and Drain, respectively).
Yuo have to solder S to D4's cathode (the side with the black ring), G to your new 1n4148's anode (the side without the black ring) and D to one side of the cap.
The other side of the cap must be soldered to the point where R5 and R6 "look each other" (they are connected together at that side, so it doesn't matter if you solder to R5's or R6's leg, choose one!).
Solder the cathode (again, the side with the black ring) of your new 1n4148 to the cathode of D8.
Done!"
This mod takes advantage of the existing switching circuit of the pedal and adds another function to it: lowering the gain of the overdrive to unity while bypassed (you might in fact have noticed that the bleed-through is more evident with the gain of the pedal left at max). By doing so, you don't get any hearable bleed-through (as any eventual bleed would be a clean signal, which we don't care about).
Hope this helps!
Giulio
Quote from: shredgd on April 25, 2014, 06:06:51 PM
Soupbone, it is still not clear wether you added a 10k resistor from signal to ground at the input of the pedal (but this would eat a lot of signal, so I guess you just messed up words between "tip" and "sleeve"), or you simply "exteriorized" the 10k resistor from the board to "flying". In the latter case, I really doubt that can be helpful.
HOWEVER, this well known issue of the SD-1 has already been SOLVED exactly 9 years ago (!!) by ANALOGGURU.
You can read here (http://www.diystompboxes.com/smfforum/index.php?topic=23903.0) the thread I started that long time ago, where I put down in words all the dozens of experiments and substitutions I tried in vain, before concluding we probably are/were experiencing a layout issue and, most of all, before analogguru posted a schematic of his really clever solution (page 3 of the thread). Now, that schematic appears to be no longer available, but in the subsequent posts I put it down in words for another person, so here you have it (quoting myself):
"You need an SK30A jfet, a 0.1u (=100n) cap and a 1n4148 diode.
Obviously, you have to solder your new components to the top side of the board, because you won't be able to close your pedal anymore if you work on the traces side...!
Watching the front (the flat side) of the jfet, the three legs pointing downwards are named (from left to right) S, G and D (Source, Gate and Drain, respectively).
Yuo have to solder S to D4's cathode (the side with the black ring), G to your new 1n4148's anode (the side without the black ring) and D to one side of the cap.
The other side of the cap must be soldered to the point where R5 and R6 "look each other" (they are connected together at that side, so it doesn't matter if you solder to R5's or R6's leg, choose one!).
Solder the cathode (again, the side with the black ring) of your new 1n4148 to the cathode of D8.
Done!"
This mod takes advantage of the existing switching circuit of the pedal and adds another function to it: lowering the gain of the overdrive to unity while bypassed (you might in fact have noticed that the bleed-through is more evident with the gain of the pedal left at max). By doing so, you don't get any hearable bleed-through (as any eventual bleed would be a clean signal, which we don't care about).
Hope this helps!
Giulio
Thanks!I also found a "Bleed Fix Mod" by Brian Wampler(Indyguitarist) He used J201+.1uf+1N4148.I've never tried it,so not sure if it works or not?Thank you for your help!-s.b.
Here's a diagram of it in case anyone is interested. Super simple mod. http://brianwampler.com/downloads/boss-sd1-bleed-fix.pdf
Did anyone ever get to the bottom of this? Other than the wampler/ old analog man mod that involves the floating fet?
Quote from: rosscocean on March 27, 2016, 05:08:21 PM
Did anyone ever get to the bottom of this? Other than the wampler/ old analog man mod that involves the floating fet?
You can try this one. It only adds one new part to the original circuit. Though myself I would put the source towards R3 instead of towards the cap, since it's the source voltage that the Vgs references for turn off. YMMV
I'm not sure what you mean by "this one"?
Quote from: Groovenut on March 27, 2016, 06:35:19 PM
Quote from: rosscocean on March 27, 2016, 05:08:21 PM
Did anyone ever get to the bottom of this? Other than the wampler/ old analog man mod that involves the floating fet?
You can try this one. It only adds one new part to the original circuit. Though myself I would put the source towards R3 instead of towards the cap, since it's the source voltage that the Vgs references for turn off. YMMV
Oops!
My apologies.... forgot the link
Here you go!
https://sites.google.com/site/cctsim/home/boss-sd-1-bleed-fix
i know this is an oldish thread, but figured i'd post this as my 'sd-1 bleed fix' searching always brought me here so others with the same search will probably see this too...
i just read an unrelated thread that solved this issue by swapping out the 1n4148 diode in the (d7 i believe) jfet switching path to a different 1n4148. same part # swapped and fixed the problem.mr. mark hammer said the possible reason was that different 1n4148s will have a slightly different turn on threshold, so when you swap in a different 1n4148 it COULD have a slightly lower threshold which can fix the issue. its the difference between turning the fet 'mostly' off (bleed) and turning it 'fully' off (no bleed)
so grab a handfull of 1n4148's and swap 'em into the d7 spot till you find one that stops the bleed.
If that solution works it is probably better to place a resistor across R18.
I'm thinking 330k but extreme units might need 100k.
The "best" thing is to find the largest resistor that works with a small safety margin.
You should check with low and high battery voltages.
Use 1M or 500k pot across R18, adjust it until the problem is gone then use the next smallest resistor.
Since it is so fine, changing R18 and R19 to 10k's might even work.
Sorry to reply on an old topic, but I just attempted this fix using 2 different transistors (J201 and 2N5457) and it works well as long as I pick lightly...... the minute I dig in then I have kind of a "hard knee compression" effect, where notes swell in almost like if I was using a volume pedal. I have tried with 2 different pcb's and it's the same, so I've had to return it to stock .
Anyone else has experienced such an issue ?
EDIT: I can see there's 2 different mods.....one involving 2SK30 / 0,1 mF cap / 1N4148 diode (Analogguru), and another one -the one I have tried- involving a J201 and the existing C2 cap, no extra diodes. This is the one that doesn't work for me. I assume Analogguru's one is the right one ?