Muff Pi (solved)

[Anonymous]

Hi gurus,

so glad I found this site! I have some basic electronic skills and have built several kits (solid state amps and Valve amps) I just built a Muff Pi green russian with a few of the mods and when I bench tested it it worked ok but soon as i mount it into the enclosure PSU read 0V so i figure dead short somewhere. so I remove all PCB’s and switches and the short happens when I connect the output jack. I know it looks a bit ugly but Im sure someone can guide me!
Thanks in advance!!!

 

[Billy]

Difficult to see Stu but you may have connected your output jack ground to the ring connection

If you put a jack in like the image below and trace the connections round to thier solder lugs

The ground lug connects directly to the sleeve like this

Your IN jack which I can see is correct, just an FYI if you’re not using a battery you can use mono jacks for both in and out I notice you have stereo for both which are slightly more expensive and welcome to the forum

[Anonymous]

Do I also see that the input jack ground wire is soldered to the +9V pad on the new V5 3PDT wiring board?

[Billy]

Good spot sir I was looking at that as well thinking could do with a clean up never even noticed the +9v written all over it

I think you’ve reclaimed the ol’ eagle eyes title

[Anonymous]

Thanks for reponse, we will have this nutted out in no time!

This is the wiring diagram I followed, I though it odd that the 9V wired to sleeve

[Barry]

That is an old wiring board. We have upgraded the wiring boards to have symmetrical pairs of 9v / Ground connections placed on either side of the boards as opposed to just way too many grounds. I am still going through the old build documents and updating those that happen to have that particular diagram first.

[Anonymous]

That was it! I must have a newer revision board, you guys are every impressive!

Here it is, had to solder LED to off position due to butchering the solder pad for on oops. MKII will always be better!!

[Billy]

I’m glad I’m not the only one that missed that +9v silkscreen Stu!

Joking aside you can jumper your LED with a wire to have it on when in effects mode just desolder that leg and solder a jumper wire like this from the leg to the 3PDT lug obviously be careful you don’t damage the LED with too much heat

[Anonymous]

I wonder how it worked when I bench tested it? Next build i’ll use a switch with LED, the bezel im using I can’t remove the LED so need to desolder each time I pull the switch out, hopefully I don’t have to do that too many more times

Thanks for all your help

Stu

[Barry]

Here is a bit taken from the 3PDT Wiring Board Build Document

 

[Author]

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