This is my take on Tim Escobedo’s Ugly Face. I replaced the LM386 with a dual op-amp and and added a mix control.
The LM386 is a great chip but its gain is limited to 200. A single op-amp can easily generate a gain of 200 and more! This way I can replace the 386 with another 8 pin DIP and use the extra op-amp to create a summing mixer.
Here is a schematic:
Parts List
| C1 | 220n |
| C2 | 1n |
| C3 | 10n |
| C4 | 100n |
| C5 | 100n |
| C6 | 470n |
| C7 | 100n |
| C8 | 220p |
| C10 | 100n |
| C11 | 100µ |
| C12 | 47µ |
| C13 | 100µ |
| C14 | 2µ2 |
| C15 | 10µ |
| D1 | LED |
| D2 | 1n5817 |
| ENVELOPE | B1k |
| FREQ | C100k |
| THRESH | B10k |
| VOL | A100k |
| MIX | B10k |
| IC1 | TL072 |
| VACT_1 | LED/LDR |
| IC2 | 7555 |
| R1 | 1M |
| R2 | 470 |
| R3 | 100K |
| R4 | 56K |
| R5 | 1K |
| R6 | 47k |
| R7 | 2k |
| R8 | 10K |
| R9 | 10K |
| R10 | 1M |
| R11 | 200K |
| R12 | 1K |
| R13 | 15K |
| R14 | 15K |
| R15 | 15K |
| R16 | 15K |
| R18 | 15k |
Yow. Got all my parts lined up! I know you’re familiar with the uglies, maybe you can help me out. Have you fiddled with the optocoupler much? I wonder if an nsl32 will suffice or if I should go for the real deal vactrol. Also, I know about the deadair face disaster, but I recently saw another variant somewhere that wasn’t as transparent about the Escobedo influence, but can’t remember what in the hell it was. Ring a bell, maybe? Thanks
Great! Let me know about the results when you’re done!
You can use any LED/LDR combo. The pot allows for some adjustment to compensate. The biggest differences will be heard in decay time of the LDR. I like the sound of a fast decay.
Thanks for pointing out the Dead Air PCB I had t seen that.