Jump to content

please help if you can: pic of a tb'd vintage big muff 3034 circuit board


CHOUTMUSIC

Recommended Posts

  • Members

I'm trying to true bypass my 1980 big muff (you can hear the fuzz when it's disengaged!!) and the pic on this otherwise helpful guide is an older circuit board than mine

http://www.singlecoil.com/docs/vintage_muff.pdf

 

and being a newb to this,...

 

Can anyone link or post pics of where the wires go from the 3034 circuit board to a 3PDT switch?

 

please!

 

thanks!

Link to comment
Share on other sites

  • Members

A photo would not be as helpful as an explanation. I have a drawing though... (ignore the left row of terminals if you're not planning to add LED)

 

3pdtSwitchWiring.gif

 

Basically, you'll just be taking the wire that goes from the input jack to the circuitboard and disconnecting that. There's your problem.

 

You'll already have a wire going from your input jack to your old switch. You can use the same wire, or you may need to use a new wire, as some of the old EH wires were brittle and crappy.

 

Then run a wire from the spot on the circuitboard where the input jack wire WAS connected to, to the middle lug of that switch (labelled "Board In" on my drawing).

 

The other side of that switch, you'll want to connect to ground. This silences your Big Muff while you're in bypass mode, so there won't be any noise waiting in the pipeline when you kick it on (and it also serves to keep the input cap drained, so there won't be a 'pop').

 

Then, you'll notice that your old switch already did switch the input and output signals properly. Just reproduce that wiring on your new switch.

Link to comment
Share on other sites

  • Members

I'm actually kinda lost...I know this pedal has been tampered with so I'm not sure where to go from here...there's two other wires coming off the input jack to the circuit board.

Any help would be appreciated.

BigMuffInnards004.jpg

 

Study the construction of the input jack. It's got 3 conductors; one is for ground (the "sleeve" connection), one is for the "tip" of the plug (carries the audio signal in this case), and one is for the "ring" of the plug (if it were a stereo plug that is). The "ring" connection actually connects to the plug at its body, which makes it a dead short with the "sleeve" connection when using a mono plug like a guitar cable. This is what switches the power on and off when you plug into the pedal. The ring terminal is connected to the negative battery lead.

 

The wire going from the sleeve to the circuitboard is ground. Notice where the ground is on the circuitboard, there's like a big pool of copper there near the middle. Do yourself a favor and solder another wire over from the input jack's sleeve to the sleeve connection of the output jack as well (otherwise a loose nut will kill your signal there).

 

The other wire going from the input jack to the circuitboard must be the input.

 

If you know where your circuitboard gets its 9v, input, output, and ground, then you can wire it up. Are there any of these 4 things you're lost on?

Link to comment
Share on other sites

  • Members

Skr3ddy - you are the man. I love seeing you come in & help folks with their BMP issues (the same way you did when you helped me figure out what kind of caps to use for my tone stack mods). I've got a ton of respect for a well-loved builder who takes the time to lend a hand. Rock on! :wave::thu:

Link to comment
Share on other sites

  • Members

A photo would not be as helpful as an explanation. I have a drawing though... (ignore the left row of terminals if you're not planning to add LED)


3pdtSwitchWiring.gif

 

Thank you for this. Sorry to be pedantic, but when you say ignore 'left row' do you mean ignore the left colomn of lugs and should solder the ground only to the bottom middle lug? Cheers.

Link to comment
Share on other sites

  • Members

Thank you for this. Sorry to be pedantic, but when you say ignore 'left row' do you mean ignore the left colomn of lugs and should solder the ground only to the bottom middle lug? Cheers.

Correct; I meant left column, and yes, the ground would go to the bottom/middle lug if you're leaving out the LED.

 

BTW, if you're adding an LED, don't forget to add a current-limiting resistor (not pictured). For a bright red (clear lens) LED, 8.2k will work. For an ultrabright LED, you'll want something higher like 18k. For an oldschool or not-so-bright LED, 4.7 or maybe lower, depending on blah blah blah. :)

Link to comment
Share on other sites

  • Members

Well I put the switch in and wired as above (no LED) and it works! Thanks a lot Skreddy, you're a hero. I usually play out with my US reissue but shall now take the old roaring op amp one with me. Cheers again, I owe you a drink!

 

Oh and I can post a pic if anyone would like.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...