Friday, 15 April 2011

MI Audio Crunch Box

Version 1 of the Crunch Box

24 comments:

  1. Hello. What diodes would suggest on this one? Thanks

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  2. They're red LEDs, one each way

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  4. Ah, that makes sense now that I actually look at the drawing! Sorry about that.

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  5. IvIark - verified this layout. Used 3mm red LED for the diodes. Think I read someone it was 5mm, but what the heck.

    Thanks for the great work.

    Ian

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  6. Thanks for verifying mate.

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  7. OH yeah I used a TL072 also, as I heard this was a good sub.

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  8. what about 1n4001 as the original schematic?

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  9. Have you got a link to the schematic you're talking about? It was probably used for reverse polarity protection for the supply and so would be optional and wouldn't affect the sound.

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  10. http://www.matsumin.net/diy/bunkai/MI_audio_dist/MI_audio_dist.jpg

    yes you're right.it used for the power supply!!!!

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  11. ok tried my hands at this one and having an issue with it. I have my bypassed signal. When activated I get nothing. I broke out my audio probe and the last place I have a signal is at pin 3 on the IC. Now I didn't have a LM833, is it ok to substitute a TL072? Also, I did notice a faint signal on the upper leg of the 10k resistor, but fizzles out. The clipping LEDs stay lit. Ready to pull my hair out on this one.

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  12. I built this a few days ago, with no issues. Used a TL072 in place of LM833. The clipping LED's should flicker to match the guitar signal and seem to be most influenced by the Gain pot. If they are on constantly, there must be a stray signal from somewhere it shouldn't be. You may want to check wires to your pots, or run a blade down each of the non-copper grooves to be sure there are no shorts, just a thought. As for me, I am fresh out of hair after troubleshooting Echo Base, Umble and now TransMORGrifier. Good Luck.

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  13. Got it!!!
    I left out the 22k resistor to the left of the op amp. Doh!!! Now I'm wondering how I could really make those clipping LEDs brighter since I mounted them on the enclosure.

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  14. Hello Mark could tell me the polarity of the LED d1 and d2 from top to bottom? It 's the same layout v2? thanks

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  15. The left one is top + bottom -, right top- bottom + or vice versa

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  17. Hi, anyone has an acoustic feedback on this?
    I encounter some difficulties to fix it.

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  18. Hi I'm having some serious problems with this pedal! It has no sound, but when I wiggle the pcb around, sometimes there will be little snippets of sound. For example, when I pull the pcb upwards, I get a burst of distortion, then it crackles and fades away. Then there won't be any sound until I try wiggle it again to find the "sweet spot" where the distortion turns on. I also changed the pots to see if they were giving trouble. The wiring on the enclosure looks good, and I already spent many hours trying to swap parts and wires around, and even resoldered most of the pcb. What could the problem be? Help is appreciated! :(
    I've even checked the pcb for any unwanted bridges - none! All solder joints are good and shiny. Thanks!

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    1. I've had those symptoms on many occasions. It's always a bridge or bad joint. Bad joint is more likely suspect, as moving the boards makes a difference.
      +m

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  19. Thanks for the reply. I've checked my connections with the multimeter - no bridges, and bad joints were corrected. However, the voltages on my LM833 look weird, and I also replaced it.

    1: 4.77
    2. 4.77
    3. 2.37
    4. 0.00
    5. 4.49
    6. 0.61
    7. 1.36
    8. 9.05

    I also note that sometimes the LED diodes turn on and off when I test with the multimeter. Is that weird? Thanks again.

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    1. Pins 6 and 7 look a bit low, otherwise those should be ok.

      I'm still saying that it must be a bad joind if the symptoms still occur.
      +m

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    2. Thanks for the help. I still can't get it to work. This project's frustrating and is now dead!

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    3. Ok I fixed it! Figured out a stupid mistake where I connected one of the jumpers wrongly! Argh feel so dumb...

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  20. Hi check out my demo of this pedal here https://www.youtube.com/watch?v=tdONTd2HCDc

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