Pedal project: Modified double muff

timhulio · Post by **timhulio** » Thu Jan 06, 2011 12:04 am

You've connected the bases of the transistors. The collector of Q1 should be connected to the base of Q2.

wilrecar77 · Post by **wilrecar77** » Thu Jan 06, 2011 12:10 am

timhulio wrote:You've connected the bases of the transistors. The collector of Q1 should be connected to the base of Q2.

Turns out that was an MSpaint error, looking at the unedited photo (and the board) the jumper is going collector-base like it should be.

Bill Oakley · Post by **Bill Oakley** » Thu Jan 06, 2011 12:12 am

Well, I don't see anymore errors. Did you use 2n5088's and did you check the datasheet pin configuration for YOUR 2n5088's. The can vary from manufacturer to manufacturer.

wilrecar77 · Post by **wilrecar77** » Thu Jan 06, 2011 12:14 am

Bill Oakley wrote:Well, I don't see anymore errors. Did you use 2n5088's and did you check the datasheet pin configuration for YOUR 2n5088's. The can vary from manufacturer to manufacturer.

They're the 2n5088's off of small bear, so I'm guessing it's correct. I can't find the manufacturer name on the transistors themselves.

Bill Oakley · Post by **Bill Oakley** » Thu Jan 06, 2011 12:17 am

What's on them?

wilrecar77 · Post by **wilrecar77** » Thu Jan 06, 2011 12:30 am

i can barely make out a 2N, 5088, and what looks like a -k47. thanks for the help guys, this isnt working yet but at least i layed it out right.

Bill Oakley · Post by **Bill Oakley** » Thu Jan 06, 2011 1:36 am

Just checked it again and as long as that jumper is right, everything looks right.

Only things I can think of.
1. 5088's have a different pinout.
2. Bad part
3. Hooked up battery wires to the board wrong.
4. Bad connection on your breadboard.

I checked the schematic and your layout with another schematic on the web just to be sure there wasn't an error there. It's right.

Oh, and are you sure you're plugging your guitar in the input and amp in the output. I've mixed that up before and took me hours to figure out what's going on because everything looked right.

If you still can't get it going, I'll try to breadboard it tomorrow and see if it works.

Post by **Mike** » Thu Jan 06, 2011 9:49 am

I think the problem might be that on your breadboard the continuity is in horizontal chunks, not vertical ones as you seem to be under the impression of, given the way you've aligned the transistors. So currently all your transistor pins look to be connected together.

wilrecar77 · Post by **wilrecar77** » Thu Jan 06, 2011 11:13 pm

Mike wrote:I think the problem might be that on your breadboard the continuity is in horizontal chunks, not vertical ones as you seem to be under the impression of, given the way you've aligned the transistors. So currently all your transistor pins look to be connected together.

I'm fairly sure that isn't the case, here's a picture of the full board.

For now I think I'm going to borrow my grandpa's multimeter (I should have began with that, but his house is on a hill with a road that is mostly iced over during these months) and see if I have a faulty part. Given how precise current production techniques are I would have never guessed a part would be to blame, but being that I've cross checked my layout with you guys and checked the schematic against others I'm pretty sure that's what it is. Luckily these parts are common enough to pick up at the local radioshack.

Bill Oakley · Post by **Bill Oakley** » Thu Jan 06, 2011 11:35 pm

You are hooking a battery up to this and the battery is good. Right?

wilrecar77 · Post by **wilrecar77** » Fri Jan 07, 2011 12:16 am

Bill Oakley wrote:You are hooking a battery up to this and the battery is good. Right?

Fresh battery with a battery clip.

Bill Oakley · Post by **Bill Oakley** » Fri Jan 07, 2011 12:29 am

Ok. Just checking. I haven't seen one in any pictures is why I asked.

Bill Oakley · Post by **Bill Oakley** » Fri Jan 07, 2011 2:15 am

Just threw it on my breadboard using the Beavis Audio layout and it worked fine.

Can you take a non-blurry picture straight above your breadboard and not at an angle?

My advice would be to take it all off and start again and do it on a different section of your breadboard in case you have a dead spot on your board.

Post by **Mike** » Fri Jan 07, 2011 8:12 am

wilrecar77 wrote:
Mike wrote:I think the problem might be that on your breadboard the continuity is in horizontal chunks, not vertical ones as you seem to be under the impression of, given the way you've aligned the transistors. So currently all your transistor pins look to be connected together.
I'm fairly sure that isn't the case, here's a picture of the full board.

So you're sure it's vertically connected? Test this as the first thing you check with your DMM.

Bill Oakley · Post by **Bill Oakley** » Fri Jan 07, 2011 8:20 am

Mike wrote:
wilrecar77 wrote:
Mike wrote:I think the problem might be that on your breadboard the continuity is in horizontal chunks, not vertical ones as you seem to be under the impression of, given the way you've aligned the transistors. So currently all your transistor pins look to be connected together.
I'm fairly sure that isn't the case, here's a picture of the full board.

So you're sure it's vertically connected? Test this as the first thing you check with your DMM.

Or you can hook up your input and output jacks to the board and see which way signal passes through.

Post by **Mike** » Fri Jan 07, 2011 8:33 am

Yeah that. Plus just build one stage at a time if you're having issues.

wilrecar77 · Post by **wilrecar77** » Fri Jan 07, 2011 2:08 pm

I just figured out the problem, no parts failure or anything. It turns out that the power rails were split across the board, they aren't connected halfway on the board. I jumpered it and now it works like a charm.

Post by **Mike** » Fri Jan 07, 2011 2:16 pm

Ah yes that's another gotcha.

wilrecar77 · Post by **wilrecar77** » Fri Jan 07, 2011 2:40 pm

Ha, I assumed that they would have been connected. I suppose you can't assume anything when it comes to building pedals. Thanks for the help guys, I would have never guessed it to be that simple. After I get everything soldered and drilled I'll try to get a demo up.

wilrecar77 · Post by **wilrecar77** » Sat Jan 08, 2011 10:37 pm

Update: Because the muff fuzz alone was lacking in sustain and crunch, I breadboarded an LPB boost to run infront of it and WOW it is much more usable. Way crunchier and with big muff-like sustain. Unless the incoming snowstorm prevents me from borrowing a drill, I should have it in a box by the end of the week. It's like a superfuzz but less gainy and more crunchy with better sustain.