#1
So out of interest id quite like to make the my big muff true bypass. (Yes the newer black one)

http://www.singlecoil.com/docs/russian_muff.pdf
Ive found this, read it. But funnily enough, the switch is allready 3DPT? Its not second hand, so unless they upgraded them? Im dont know much on electronics. So this is all just guesswork.

What does it mean by cut trace? On the PCB of mine theres a bit of a cut in the soldering where its marked on the diagram.

I plan on buying some new jacks/whatnot for when I actually decide to do it. Any idea what jacks will suffice, I understand switchcraft, but which ones?

/totaluttern00b
#2
Quote by beckyjc
What does it mean by cut trace? On the PCB of mine theres a bit of a cut in the soldering where its marked on the diagram.
It means that the copper foil must be severed. If you look at the diagram, the wires to the switch are connected from point opposite of where that trace is severed. When the pole (center lug) on the left side of the switch is connected to the upper throw, the connection is made, just as if the foil was still in place. But when the switch is operated, the pole is now connected to the output jack. If the trace is not cut, the foil will continue to connect the input jack to the input of the circuit.

The easiest way to sever a trace is with a razor knife. Make 2 parallel incisions at a right angle to the trace space them about 2 or 3 mm apart. Cut through the copper, slightly into the board itself. Then take the knife and carefully pry up on the foil between and remove it from the board. Wear safety goggles while you do this. Razor knives are notorious for fracturing. You don't want to take the chance the tip will break off and end up in your eye.

Quote by beckyjc
I plan on buying some new jacks/whatnot for when I actually decide to do it. Any idea what jacks will suffice, I understand switchcraft, but which ones?
I'm guessing the input jack is mounted on the board. Those are the six terminals we see, yeah? That will limit your choice of jacks. It will need to match.

I don't know whether the input or output jack is stereo, but I'm quite certain at least one of them is. That's how the power is switch on when a plug is inserted.

If you don't get more info within a day or two, PM Drew (the ramdom hero). If he's not familiar with the jacks needed on this particular unit, he probably can suggest someone who is.

Quote by beckyjc
/totaluttern00b
stfu. Everybody has to start somewhere. It's great that you aren't just satisfied to let somebody else do it for you. Chicks who do for themselves are awesome.
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#3
I actually guessed so on the cut trace thing, but was just checking. But I actually understood that, thanks for explaining. =) But its just a bit odd because around where the cut trace is marked it looks like somones slipped with the soldering iron

Yeah the jacks are mounted onto the board. I had a look on the switchcraft website, couldnt find any 6 terminal jacks.

I think the Input may be stereo and output mono, not 100% sure though. Can you tell by a schematic?

How about replacing pots? Is that just matching values? They all have 100KM written on them so I assume...

http://www.maplin.co.uk/module.aspx?ModuleNo=2203&doy=19m11

the 100k ones? They seem a bit long though to fit the knobs back on, migth replace the LED for the fun of it too

And thanks
#4
^ Input is stereo, output mono. Stereo has 3 lugs, mono 2. It means you can turn the battery/power on when plugged in.

Are the pots on the board?
The Laney Thread are big and clever. No exceptions.
#5
Quote by beckyjc
I think the Input may be stereo and output mono, not 100% sure though. Can you tell by a schematic?
I looked at the schematic through the link in your OP. The input is indeed stereo. The output only needs to be mono. From the looks of it, the output jack is stereo, but the traces only connect to the terminals for the tip and the sleeve. The ring connection is not used on the output jack.

As best I can tell from the photo, all the important connections are on the right. The tip is the lower lug, the ring the center, and the sleeve the upper. The connections on the left are either to internal switches, or are just dummy lugs to keep the socket stable on the board. It looks like the trace on the output jack goes to the ring rather than the sleeve. This won't matter at all, since a mono plug inserted there will make contact with both the ring and sleeve through the sleeve portion of the plug.

Here are some links to Switchcraft's site that might help identify the jacks:

http://www.switchcraft.com/products/jack-94.html

http://www.switchcraft.com/products/jack-95.html

It looks like any of these will work except for one that's mono. Check the spacing on the pins compared with the jacks you have now.


Quote by beckyjc
How about replacing pots? Is that just matching values? They all have 100KM written on them so I assume...

http://www.maplin.co.uk/module.aspx?ModuleNo=2203&doy=19m11

the 100k ones? They seem a bit long though to fit the knobs back on, migth replace the LED for the fun of it too
Resistance value, physical size, pin spacing, bushing diameter, and shaft diameter are all very important here. Check what you have now against the specs from the maplin site.

1 - If the shaft is too long, that's easily remedied. A dremel with a saw blade (my favourite) or a cutoff wheel will cut through an aluminum shaft like a hot knife cuts through butter.

2 - The M probably indicates the taper, but I have no idea what M indicates.

3 - The wrong taper, will still work, but your knob positions will be bunched at one end or the other if you exchange a log (audio) taper for a linear, or vice-versa. I wish I could help more with this, but sadly, I have no experience working on the EHX pedals, Russian or American.

No reason to not change the colour of the LED to make it more personal to your taste while you're in there. Remember that polarity is important here. Install it backward and it won't illuminate.

Quote by beckyjc
And thanks
You're welcome, dear.
The girls on this site are always so pleasant and cordial. I'm glad to help where I can.
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#6
Thought so, =) -is getting the hang of this slowly-

The er pots are mounted to the casing...

Having a look at the PCB now, spacing between the pins is about 5mm, yeah the only contacts that are actually leading anywhere are the 3 on the right and on the out jack just two leading to random places. So couldn't I technically just get a 2 contact jack? But then I suppose it mightent fit properly.

That cut trace marked is DEFFINATELY allready there... Weird.
Im gonna have a good look at that schematic because I think its allready TB.
It'd be a good chance to upgrade parts though.

I have no idea about the pots though, msot of what you just described mean nothing to me.
All I can get from the pots are written on it Cn3-4am - T1A - 100KM for both tone and sustain and Cn3-4am - R8B - 100KM for volume and I have no idea what id be measirung for anything else.

As for the LED is short end positive? I think from what I can remember, one of the er metaly stick bits leads to the switch and one to the PCB. ANy idea which way around id stick that then?
Last edited by beckyjc at Nov 19, 2007,
#8
Quote by beckyjc


So this is basically whats going on with the PCB/switch, if you can make sense of it.

That might just be TB already, I can't tell exactly but if there's a 3x3 switch on there it's probably TB. Try and see if it is by putting it as the only one in your chain, playing bypassed and comparing it to having nothing in your chain?

So by that it'd seem the tone and sustain are audio taper and the volume linear taper, I think... It doesn't make much sense though, unless, does the volume jump up quick on low settings like on Fender amps but then the increase gets lower as you turn it up?
The Laney Thread are big and clever. No exceptions.
#9
Quote by beckyjc
As for the LED is short end positive? I think from what I can remember, one of the er metaly stick bits leads to the switch and one to the PCB. ANy idea which way around id stick that then?
The long lead is positive. Use a multimeter to determine the polarity of the voltage on the present LED before you replace it. Worst case, if you get it backward it won't damage anything, it just won't light. Swap ends in that case.

As far as the rest goes, if the pots only mount to the chassis, but not to the board, that makes things a bit simpler for selection. I can't make heads or tails of the numbers on the pots. I suspect they're all the same and the "T1A" and "R8B" might just be production lot numbers.

You could take them out, and set them to the center of their rotation. If you measure about half the total resistance from the wiper to each outer lug, it's linear. If you measure about 10% to one lug and 90% to the other, its logarithmic.

I hope your soldering skills are better than your drawing skills.

cba to check the entire wiring against the schematic and the other mod drawing, but it looks like the input jack is connected to the pole bottom center. (this switch is turned 90 degrees from the on in the other drawing) It only connects to the input of the muff circuit when the contact is made to the throw on it's right. The output jack (pole dead center of the switch) is connected to the volume control on the right, or to the input on the left. That fits perfectly with the true bypass scheme. I dunno what's going on with the top row. obviously the led on the right, but I have no idea about the "sust" on the left.
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#10
Hmm, i actually have no idea what you mean by measuring the resistance, and i cant get the pots out, theyre held in too tight and i dont want to be ripping any of the wires out just yet... =(

My drawing skills are incredible, soldering, not so much. I have a tendancy to grab too far down... Which doesnt end well.

Well, will save me a bit of solder work then if its allready TB.

I just copied the way they installed the switch. And sust, is sustain/distortion pot.