Tuesday, 3 May 2022

Lastgasp Art Laboratories GM2 Green Monster

 Schematic is avaiable at Deadend Fx.





15 comments:

  1. This comment has been removed by the author.

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    1. The schematic or the layout?
      Or should we be waiting for the Deadend Fx Zilla build docs?;-)

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  2. Thanks for all the layouts Anders. I hope your surgery goes well. I built this one last night and wasn't getting any output. I only probed it for a few minutes and was planning to take a look at it again after work. Is there a known issue with the schematic/layout?

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    1. I tried building this a few days ago and had the same issue :/ a few things i caught...

      looking at the schematic, i believe the top leads of d1 and d2 need to go down a row (onto row D, next to the 10k resistor) so that they are connected to pin 3 of IC2. Then there needs to be a jumper or something to connect pin 6 of IC1 to pin 2 of IC2. I took a piece of wire and used it to connect C1 to H1. still no output, but i think that's schematic-correct now. i haven't ruled out a build error on my part. thinking might breadboard this one since it's small to double-check the schematic before i try to build it again.

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    2. Were you ever able to get this one sounding right? https://dirtboxlayouts.blogspot.com/2021/12/devi-ever-hounds-tooth.html

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    3. sadly, i never did :/

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    4. Same here - no sound, I hear a pop when connecting power, but this is it.

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  3. finally got around to breadboarding, and I think there may be something off with the schematic. having the same exact issue as the vero build. could just be i screwed something up on the breadboard, too. eager to see if anyone on FSB ever verifies the schematic.

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  4. The feedback resistor value was wrong, last gasp obvs wanted to throw everyone off. Wanted to check our theory out before commenting. Should be 470k

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    1. Yeah the Zilla build doc is up. As you mentioned, in that schematic the 47 ohm FB resistor has been replaced with 2 switchable resistors; 470k and 4.7m. There are some other changes as well. https://www.deadendfx.com/build-doc-links

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    2. I know, I'm one half of deadend fx

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    3. My apologies. I was unaware.

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  5. I removed the 47 ohm resistor and replaced it with a dpdt with 470k on one side and 4.7m on the other. This circuit sounds awesome! (If you are into broken sounding fuzzes.) Thanks for the layout Anders!

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    1. Cheers!
      Thanks to both of you. The layout is updated and tagged. I will add a layout for the gain switch mod later on but it is a n easy mod to do with the stock layout, just as Echowreck did.

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  6. I used to have an original Green Monster, and am the one who sent the pictures to Deadend FX for tracing. Deadend sent me a free pcb as a thank you, which I've built and compared to the original GM: they sound identical! Plus the clone has the gain blast switch, which is a super cool mod!

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