Saturday, 5 January 2013

Mid-Fi Electronics Random Number Generator

I've always wanted to get more layouts with 7 rows of height :)




28 comments:

  1. The early 90's called, they said the wanted their modem sounds back :D

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    1. :DDDDD

      I may have a treat for you tomorrow or so :)
      +m

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  2. Any way you can do a layout for the mid-fi electronics demo tape fuzz?

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  3. Any hint about the 2 knobbed version?
    maybe the second control is a voltage control for some of the transistors?

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  4. I can't find a schematic for the demo tape fuzz :(

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  5. I read somewhere that the 2nd knob was a pot in place of one of the 100k resistors.

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  6. Breadboarded this last night, fun little circuit definitely gonna put this one together. Any advice on swapping out the volume for a clean blend?

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    1. Use this as a daughterboard:
      http://tagboardeffects.blogspot.fi/2012/01/mini-blend-jfet.html

      Probably the easiest way...
      +m

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    2. Worked out really well as a mostly clean blend, which I think I like better than if it totally cleaned up given the character of the unit.

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  7. Tried this last night and i think it needs just exactly the listed transistors. I didn't have 4401s, and subbed that woth 3904 - Only 2222s i have are metal can 2N2222 and plastic 2N2222A, plus some MPS2222As.

    With those it tries really hard to sing, but it just doesn't get it - resulting in gated fuzz.

    I think this one needs exactly the correct transistors...
    +m

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    1. I've just put this together using just 2n3904's as they were all I had and it's working just fine. That is if you class fine as some sort of unholy noise that sounds like the offspring of a dial up modem and a detuned radio. Right now I've got the volume killed on my guitar and it's just talking away to it's self making some of the most insane noises I've heard in a long while, it's even better when you're actually playing :D

      I'd tag it, the layout's definitely correct but it'd be interesting to see if different trannies make it sound even more wild. I had a look at the datasheet for the pn2222's and at least in terms of hfe they seem pretty similar to 2n3904's. I got the best results playing high up the neck with single notes but power chords worked ok if you let them ring out.

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    2. I'll tag it...

      I just think that the PN2222 is something that starts the singing more easily.

      Thanks again Madferret! You're becoming quite an animal when it comes to verifying!
      +m

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    3. Yeah you could be right there, it definitely needs a heavy pick action to get the low E string really twitching out. Maybe a 2n5088 instead of the 4401? Or perhaps some higher gain mpsa18's to get it really freaking out? :D

      I found mine liked having the volume set high on the pedal and low on the amp to get the best (worst) sound.

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    4. Just what i thought.. Still believe the magic combination of PN2222 and 2N4401 that makes it sing. Could be a long process to find alternatives...
      +m

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    5. Well RS Components stock both and they just happen to have a branch in Stockport. I think it I may have to pay them a visit tomorrow so we can find out if they're have the magic in them.

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  8. This through the Nurse Quacky - insane. That is all.

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  9. Is the 1m resistor a pulldown or should I go ahead and add another 1m on input to the ground?

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    1. No, you will need to add another resistor if you want a pull down.
      Cheers
      Dave

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  10. Hi

    If, for purely presentation reasons, I built the LED dice circuit linked and drilled the LEDs into the top of the enclosure, would 9v give me enough power to drive this circuit as well as the number generator circuit and would I be able to wire the push-button wire of the LED dice circuit into the 3PDT switch so that each time I turned the effect on, a random dice number would appear on the enclosure?

    Apologies if this is too off topic a question to ask.

    http://www.electronicsclub.info/p_dice.htm

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    1. The voltage will always be fine, it's the current that you have to worry about, but to be honest there is nothing in either circuit which is particularly power hungry and so it should work fine even with a battery. With a power supply you obviously will have no concerns at all.

      I'm not sure whether you could use the 3PDT to replace the push switch in the dice circuit. It says that you press the push switch to throw the dice and start the numbers cycling, and then the number is displayed when the push switch is released. Switching on the effect with the stomp would start the cycling process but based on that description it won't stop on a number until you turn the effect off and that would obviously make it all a little confusing. Number shown in bypass, cycling numbers when the effect is on.

      So I suspect the circuit will need altering so that you can cycle and settle on a number by making a single contact, so you may want to ask the designer of that circuit if it can be easily adapted to do that.

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  11. That's great, thank you, I'll tinker, read and ask.

    Thanks for your help

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  12. Unfortunately, for me, its just distortion, no random things :(
    All 3904s...

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  13. Hey guys, just built that circuit and its great, its constant oscillating even with the volume down like madferret said.
    It is even cooler when just turn around Q2, it sound almost flangerlike.

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  14. anyone get this working like the video sounds?

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  15. soooo freaking loud... i tried 50k audio for volume and it still has the boost of a boost pedal maxed out. i'm about to skip 25k and go straight for 10k for the volume control. For those of you out there I'd say start with 25k if you like a lot of volume, but 10k or even 5k will probably be the sweet spot for me

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  16. Built this today using 2N2222As for all four transistors. It sounds great, but doesn't give the same level of multi-pitch oscillation as the video. As someone else pointed out, high notes respond most dramatically and it kicks in as the note dies away.

    Currently I have a lot of noise when not playing, but I think that mat be the nature of the beast. It doesn't sound like a grounding issue but I'll experiment and see if I can clean it up at all.

    I added a battery starve knob, which produces interesting some variations and makes the oscillation sort-of tunable (though the pitch drifts pretty severely).

    The volume control really interacts with the circuit, making it feel more like a drive control, so I added a second volume control after it that literally just sends the output to ground or to the out jack. As GoldenMonkeycolor said, this pedal is off the chart in terms of volume.

    I socketed the transistors so will try some others when I have them. The only suitable alternative I have in right now are MPSA18s, and they seem to perform exactly the same as the 2222s.

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