This is Mic Tester’s 21st Century Big Muff. Its the standard big at it’s heart but updated. It uses an op-amp for the input and output stages, a James tone stack, and adds an interesting gain control to the clipping stages along with a diode lift switch for the first stage.
I’m a Big Muff fan so I had to build this and give it a try. I designed a PCB in Eagle and had some boards fabricated at PCBWay.com. To keep the costs down I combined this with a couple other orders.
The boards came out well. So the next step was to mill an enclosure. Put some art together really fast. Some times it’s better that way. If you think about something too long you can over think it.
Next I soldered the boards. I built this with a 3PDT PCB and a ribbon cable. Soldering this outside the box was quick and easy.
Then I put everything in the box and soldered the jacks and switch.
Last, sign the box and put some knobs on it!
How does it sound? Sounds like a big Muff. That’s funny thing about Big Muff circuits, they all sound the same. This one has a wider range of tone adjustment. Rather than a single pot you can dial the treble up or down, and do the same with the bass.
It also has a wider range of gain settings. The gain pot gives you sounds of Muffs with different emitter resistors, though this control is really adjusting the collector resistor. There is a lot of interaction between the Sustain, Gain, and Volume.
There is a also a diode lift switch that removes the clipping diodes from the first clipping stage which gives you another option.
With all of these options it still has the character and quality of a big muff.
Would I build this? I suppose I would because I did! Should you build it? If you’re a Big Muff fan and you don’t care how many Big Muffs you own and you want to own them all, build this one! If you just want a more flexible muff, build this. If you own a Big muff or two and you’re happy with those, you might not need this one.
| Part | Value |
| R1 | 2M2 |
| R2 | 1k |
| R3 | 100k |
| R4 | 22k |
| R5 | 1M |
| R6 | 1k |
| R7 | 1k |
| R8 | 10k |
| R9 | 82k |
| R10 | 100r |
| R11 | 470k |
| R12 | 6k8 |
| R13 | 100k |
| R14 | 10k |
| R15 | 82k |
| R16 | 100r |
| R17 | 470k |
| R18 | 6k8 |
| R19 | 100k |
| R20 | 100k |
| R21 | 22k |
| R22 | 22k |
| R23 | 1M |
| R24 | 1M |
| R25 | 22k |
| R26 | 22k |
| R27 | 180k |
| R28 | 10k |
| R29 | 1k |
| R30 | 22k |
| R31 | 1k |
| BASS | A1M |
| SUSTAIN | A100k |
| TREB | A470k |
| VOL | A470k |
| GAIN | A100k Dual Gang |
| CLIP | SPDT |
| D1 | 1N914 |
| D2 | 1N914 |
| D3 | 1N914 |
| D4 | 1N914 |
| D5 | 1N5817 |
| D6 | LED |
| C1 | 100n |
| C2 | 10n |
| C3 | 100n |
| C4 | 100n |
| C5 | 560p |
| C6 | 47n |
| C7 | 560p |
| C8 | 47n |
| C9 | 100n |
| C10 | 100n |
| C11 | 1n |
| C12 | 10n |
| C13 | 500p |
| C14 | 5n |
| C15 | 10µ |
| C16 | 100µ |
| C17 | 10µ |
| C18 | 10µ |
| C19 | 10µ |
| C20 | 100n |
| C21 | 100n |
| C22 | 10µ |
| Q1 | 2N5089 |
| Q2 | 2N5089 |
| IC1 | TL072 |
Leave a Reply