Saturday, 6 February 2021

Lastgasp Art Laboratories 88 / Super Oscillo Fuzz

 


 



 Modified for 3PDT bypass switching.

Correct schematic avaiable at Deadend Fx
 
 

 

27 comments:

  1. Fuzzhead, you're on fire lately! Once I'm done the byoc harmonic trem, I'm jumping straight to this.

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    1. Well, this is what happening when you are forced to social distansing....:o)

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  2. That's a lotta o switches xD

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  3. Can't get mine to work. I can get different oscillation noises by flipping switches and turning pots but there's no guitar signal. I double checked my components and cuts. I'm only counting 16 cuts.

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    1. Yeah, it is 16 cuts.
      I think I will upload the schematic as well so more fresh eyes can compare it to the layout.
      It has some copyright markings, though and if the owner want me to delete it, I will do so.

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  4. Another experimental/noise fuzz! *rubs hands*
    Added to the to-do-list.

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  5. This comment has been removed by the author.

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  6. I think all is correct except label Q2 and Q3, and the bypass switch will not work like this (input to 3 and 6, when output is 5. But with all these switches its hard to see...

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    1. Yes, footswitch wiring looks a bit odd...

      @ Mike Legris.
      Do you have a test box? If so, connect "Bypass Sw 2" wire to input and wire from lug 2 of the Level pot to output.
      Then we would know if it is a problem within the circuit or simply the bypass switch.

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  7. I still have it hooked up, ill experiment with the switch tonight

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  8. It works with the different input and output wiring. What a crazy effect, reminds me of a fuzz factory but the switches all interact differently with each other. Now to figure out footswitch wiring to get a bypass sound

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    1. Cool!
      We might get away with normal bypass wiring by getting rid of one of the poles of the 4PDT switch. Do you have any oscillation bleedthrough in bypass mode?

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  9. Currently I'm getting nothing unless I turn the volume pot way up and then I'm getting faint bypass.

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    1. Ok, I have updated the layout for normal bypass switching just to make things easier and it doesn't affect the behaviour of the circuit. And tagged it as Verified. Thanks a lot!

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  10. Like as it is I got it working...ish, but not like how it should be (as in youtube demos). A lot of feedback or no sound at all... I think there is something odd between switch two and five, but then the schematic is not correct and my electrical knowledge stops here to figure it out.

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  11. I used the new layout with a 3pdt footswitch, and I love this thing. The switch combinations and oscillation sounds are seemingly endless. The only odd thing I found is sometimes switching off switch 3 can kill the sound, but only when switch 2 and 6 are also off.

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  12. I've tagged this "On hold" until we solve the issues with some of the switches. Hopefully there is a simple bug that is fairly easy to debug.

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  13. Hey guys. Why us there a "clear" resistor? What is it?

    Greetz
    Toby

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    1. CLR stands for Current Limiting Resistor. It is usually 2,2k or more depending on desired brightness and type of LED.

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  14. Dead End traced and released the Super Oscillo Fuzz as "Switchblade": https://www.deadendfx.com/product/switchblade

    Perhaps it has the correction for the switch issue? Worth comparing the schems (here's the build docs)
    https://drive.google.com/file/d/1Sj8dGH0vky2Nc5BnUtE8xApDpqCEeAEo/view?usp=sharing

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    1. Thanks Sesh!
      I'll take a closer look when my mind is clear and sharp since you need to be careful with all those switches...
      But a quick look reveals that Q2 is PNP silicon, not a NPN.

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    2. Checked the new vs the old schematic and it appears that the switching was correct but Q2 should be a PNP silicon, not a NPN silicon as stated in the old schematic.

      I have updated the layout and added a link to the Deadend Fx Switchblade build doc.

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    3. Awesome.. gonna build it now. Had the board all ready with cuts, but dropped it when it became "on hold".

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  15. I've built the LAL88, using the PCB by Dead End FX!

    For the transistors I used 2SC1518 for Q1 and Q3 (I follow Dead End schematic for part coding), and the PNP in Q2 is a BC327.
    For Q1 and Q3 I have also tried some BC337 as suggest by Deadend, but I didn't hear a great difference. The sounds I get are similar to the demo videos you find online, and it's indeed a very cool oscillo-fuzz pedal!

    Now the well known problem: if I turn up/on SW3 and SW5 there's no sound at all. The sound comes back when I switch up SW2.

    I had a chat with Dead End FX and they told me this issue is normal: Also the original one they used to trace the circuit has the same problem!
    And a friend who also owns an 88 confirmed the "problem", and told me it's stated in the Lastgasp manual as well!

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  16. Hi Anders, I double checked the schematic with the board and noticed a missing link between Switch 2-1 and Switch 5-2 . My build works, I used 2N3904 and 2N3906

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