Madbean Pig Butt

[Alex]

VERIFIED!
Madbean's version of EHX Op-Amp Muff.

[Hozy31]

Nice one Alex, Will have to give this one a try. Love Madbeans stuff built 14 so far and have another 4 boards on their way. Glad I hadn't bought this one yet.

[Hozy31]

Built this today and its very quiet. Been through it several times to check for shorts etc but can find anything. Any ideas?

[Alex]

Hi Hozy.
The layout matches the schematics.
Check your ICs voltages and compare them to Brian's at the bottom of the PDF:
http://www.madbeanpedals.com/projects/PigButt/PigButt_2015.pdf

[Beaker]

Sorry to go off topic, but have you got your Sharkfin sorted out yet Hozy?

[Hozy31]

Hi Alex,

thanks for the info. Will check these later and post any oddities.

[Hozy31]

Hey Beaker,

No still not managed to figure out what is wrong with my Sharkfin. I am using UA741 which i presume shouldn't be any different from LM741. I wonder if its my charge pump, i used a L7660SCPA. I have just received some TC1044SCPAs this morning so will see if that makes a difference. Also still haven't looked at voltages which i will also do later before i replace anything in case its a stupid mistake but nothing is obvious. Let you know how i get on. Got so many projects on at the moment.

[Beaker]

Hopefully it will come good with the new charge pump.

I got lucky with mine - it fired up first time, but I did use all the specified parts, and I was ultra-cautious when building it. Everything got double-double checked.

They do have a reputation of being completely unforgiving if you don't use the right parts, or if you make a build error.

[Hozy31]

Alex,

It works like a charm. Found the tiniest bit of copper shard crossing two tracks being held in place by rosin right at a one of the cuts. it must have missed the cuts i do as standard to all builds. Call it verified. I am liking this a lot slightly different to my 24/7 and also better gain.

Thanks for these layouts you do Alex, much appreciated. Especially all the big filter and modulation type stuff thats what really floats my boat.

[Hozy31]

Thanks for the heads up Beaker. I have received a 100k 3362P in the post this morning which  i swapped with a cheap cermet and i have some some 10k 3362Ps on order. I have removed the cheap 10k trimmer already, stupidly before trying the TC1044 so will wait until they arrive as don't want to kill any pads.

How do you like your build and is it as good as i am hoping it to be? I have been so impatient to get this working.

[Alex]

Thanks for verifying this!
I'm glad it works and that you like it.
We should thank Brian for his "free to use" projects.

[Muadzin]

I built one today and it works. Sweet IC muffin' goodness. I made a few changes though.

- Volume pot changed from log to linear, unity gain is now at 12:00. AS IT SHOULD!!!

- I eliminated the tone bypass. A muff without a tonestack just isn't a muff in my book. To do so I eliminated the DPDT on/on switch and the right bottom two 47K resistors and the 1uf cap.

- Instead I added a Skreddy style mids switch. To do so you have to add a link between the rows labeled Sw2 and Sw3, preferably between the 1uf and 100n cap. Then run a wire to lug 2 of an on/off/on DPDT switch and from lug 5 to lug 3 of the tone pot. With normal muffs I usually put a 4n7 cap on one end of the switch and a 10n at the other. 4n7 will give you flat mids and 10n boosted mids. The IC muff has a totally different tonestack though, with for one bigger value caps. In this case I experimented with using 47n and 100n. 47n gives a marked increase in perceived volume. 100n on the other hand was hardly noticeable. Maybe a smaller value will work better. I'm thinking either 22n, 33n or 68n. Then again 100n might work wonders in a mix.