Custom BB Big Mud for a friend

I got into the workshop yesterday a little deflated and procrastinatory (is that a word?) so I decided to make this custom Black Bubble Font Big Mud for Imogen who works in my shop/studio.



She mentioned how she'd like a Black Bubble for bass to play in her bands so I started out making one. Then realised I didn't have artwork for the enclosure so I thought "I'll make a custom stamped one"

That was a mistake.

I spent the next six hours (and 2 PCBs) fine tuning the Tym Black Bubble using all my favourite black Russians for reference. I'm a huge fan of the Black Bubble Font although I have played some terrible ones (it's a Big Muff....) but my beaten up BB here is the best one I've heard. Very similar to my Civil War. The other one here I have always kept as it's different, but great. 



The other big and medium box black Russians here are also my favourites for other reasons so I sat down and went down that rabbit hole. My Black Bubble Font Big Mud is based on my favourite one and although I've sold a few BBs I haven't been able to get rid of this one. 



This custom Mud is one of my Black Bubble Font Big Muds with NOS Russian KD522 diodes like the original Civil Wars with a toggle for a mix of LED and silicon clipping kinda like my Bass Black Mud. It also has a toggle for mids which gives more, but not flat mids as I'm not a fan of flat mids in these Russians.



It also has a low and hi input like my Black Mud (it has a switch) for high output or active pickups, or just to clean up the gain, and a couple of components changed slightly. In the high input with both mini switches down it's essentially my Black Bubble Font but with two inputs and two mini toggles the options open up.

I ended up using high gain 5088s instead of the original lower gain NOS Russian KT3102s I use in my BBs as these higher gain ones just sounded better to my ears. As I've said before the type of transistor used in a BM circuit has very little (or no) effect on tone but the gain of each stage does slightly. Changing one of two key components has a MUCH bigger influence on tone than transistors. Some of the best sounding Big Muffs out there have the most common transistors in them. 



This is in one of my custom stainless steel big box enclosures which is essentially the same size as the original triangle or smaller later 4 screw black Russian. I stamp these by hand to suit and then hit them with the wire brush to give them some texture and bring the lettering out.

These projects are always fun and the time is well worth it to get to know this wonderful circuit even more. 

Feb 14 2020 Written By: Tim Brennan