Version One Big Muff Pi Build

[HNB]

I got this enclosure and circuit board from Jay and got to work on it today. I use photoshop and a picture of a V1 Muff to get the basic positions of the pots and switch. I printed it out and taped it to the enclosure. I used a sharpie to make a dot in the center of each place I needed to drill. Then center punched it and drilled it out to size. Holes are not perfect, but I think they will be just fine. When the parts are in with their washers, it looks totally ok. I also did the same process with the back to make holes for 9v power and the jacks.

IMG_20200605_104213 by Christopher Louck, on Flickr

IMG_20200605_104401 by Christopher Louck, on Flickr

IMG_20200605_114325 by Christopher Louck, on Flickr

IMG_20200605_104152 by Christopher Louck, on Flickr

IMG_20200605_114332 by Christopher Louck, on Flickr

IMG_20200605_114357 by Christopher Louck, on Flickr

[Jay]

Following!

[daydreamdelay]

So cool to see these again! I built one up years ago using same pcb and enclosure. Did all carbon comp resistors, gold lead 2N5133 transistors, and huge ceramic caps. It turned out killer and was easily one of the best Muffs I’ve had. My bassplayer has it now and loves it.

Good luck with your build, looks like you got through the worst of it. I nearly died drilling that sheet of steel, my step bit sent it spinning violently. It’s definitely not quite the same as drilling aluminum.

[HNB]

Drilling it wore out my hands even with a drill press. LOL

Tomorrow I get to work on the board. I am going slow to make sure I don't screw up hopefully. LOL

[Jay]

I had to get stitches once when I stupidly tried to put a hole in a metal plate while holding the plate.

I didn't remember it being that hard to drill the enclosure, but it probably was.

[HNB]

I got to wiring today. I hooked up the resistors.

IMG_20200606_150816 by Christopher Louck, on Flickr

Then I did the transistors. (2N5962)

IMG_20200606_151728 by Christopher Louck, on Flickr

Then I did the caps and diodes.

IMG_20200606_155035 by Christopher Louck, on Flickr

Next I added the wires for input, output, power, and pots.

IMG_20200606_161253 by Christopher Louck, on Flickr

I hooked all the stuff I had up.

IMG_20200606_171643 by Christopher Louck, on Flickr

When I went to test it out, bypass worked, but when the pedal was clicked on, it just goes thump thump thump thump. Any ideas? Below are the values I used and the schematic.

V1 SCHEMATIC TEMPLATE_polarized electros by Christopher Louck, on Flickr

V1 SCHEMATIC TEMPLATE_NPN_no electros by Christopher Louck, on Flickr

10e5378bec9fc6dfc1dcac360371a456 by Christopher Louck, on Flickr

Only thing I did differently than the pictures is I didn't use an led and resistor to the switch. I just ran a plain wire. Also on the board there wasn't a hole for resistor 12 so I soldered that leg to resistor 15 since it went to the same pad.

I did have two 500k pots hooked up to tone and sustain because I didn't have the other two 100k pots to connect. I just wanted to check if the circuit worked. Hopefully I didn't blow it. LOL

[HNB]

Oh and one of the four diodes was a little bigger physically than the other three I ordered from mouser, but they were all supposed to be the same part.

1N914
ON Semi Diodes

[HNB]

Just for kicks I tried using a battery vs my one spot power and it doesn't thump.

Any ideas?

[jvin248]

.


..... the parts are on the wrong side of the board. They go on the un-traced side, leads poke through to the trace side, and then are soldered.
Verify any can-type caps have the + side to the correct voltage and diodes are not reversed. Open up any pedal you currently have and see how it's soldered.

You see the traces here but that is just read through on the board.


Most circuit problems are solder blobs bridging, wrong parts in the wrong place, overheated and cooked parts (which soldering on the same side as the parts can do), or cold solder joints. Check that the pots are wired so you have 'max' when you think you do (check the full range).

You can disconnect the output hot wire from the board and then with a looper pedal playing some input you should be able to probe through the stages on the board with the output wire to see where there is or is not signal. Don't use your best amp and don't have the volume up too loud.

.

[HNB]

I populated the board as the picture looked of a vintage one.

If I flipped the board it would have had everything backwards as far as location?

[HNB]

Is it possibly because this needs a center positive power and my one spot chain is center negative? I looked at a ehx power adapter and it was center positive. That could explain why it is ok with the battery but not with my one spot cable.

[Jay]

If you’re not using an led, you do not need to connect anthing to the switch there. If you connect power to the switch without the LED, you’re shorting 9V directly to ground when the pedal is turned on. Also, the wiring diagram posted is for a center negative power supply input. Parts on the wrong side might be ok as long as everything is where it’s supposed to be but it makes wiring things a bit trickier and your pots will be swapped sides in the enclosure.

[HNB]

I disconnected the hot from the switch and ran it straight to the power adapter and no more thumping noise. The volume pot works. If I touch the leg and turn it, the buzz from touching the pot gets quieter. Once my other two pots come in, I will be able to tell for sure if everything is a-ok. At least the thumping noise stopped.

[ElephantDNA]

If you’re not using an led, you do not need to connect anthing to the switch there. If you connect power to the switch without the LED, you’re shorting 9V directly to ground when the pedal is turned on. Also, the wiring diagram posted is for a center negative power supply input. Parts on the wrong side might be ok as long as everything is where it’s supposed to be but it makes wiring things a bit trickier and your pots will be swapped sides in the enclosure.

If you need an LED to tell you the big muff is on I think you have a problem

[HNB]

Right? Lol