Sunday, 9 June 2013

Knight KG389 Fuzz Box

Originally sold as a kit, this seems like a nice adaptation of Sam Ash/Astrotone fuzz. Not sure about the original transistors, but my best bet would be on the 2N2222 and other relatively low gain devices. Original also has 50n caps, but i think most of you have stock of 47n caps...

Andrea notes on the comments that the transistors in original ktis are likely to be the ceramic BC108C with golden leads. Updated the layouts transistor notes accordingly.

Update: The transistors in original unit are in fact 2N3391As, as clarified by the awesome Tonemachines blog. And by looking at the datasheet, those are rated at 250-500 hFE, so 2N2222s should be just fine - unless, of course, you can find a batch of 2N3391s somewhere...




12 comments:

  1. The transistors looks like these :
    http://www.ebay.it/itm/171052776357?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1586.l2649#ht_500wt_949

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    Replies
    1. I think those could be anything TO106 package. BC108 would be a very good candidate.
      +m

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    2. The white ceramic with the black rosin hat and gold legs are very distinctive :
      http://files.effectsdatabase.com/gear/pics/knight_kg-389_003.jpg
      I've hundreds of them, the hfe starts from 150 arriving at 550 just like unselected BC108.
      P.S. the transistor is labeled CIL 108

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    3. DIYSB build report stating the 2N2222:
      http://www.diystompboxes.com/smfforum/index.php?topic=99677.0
      Analoggururu's shots of the original:
      http://www.phpbbserver.com/phpbb/viewtopic.php?p=165&sid=66799886c918b5095c65d82e45180234

      Couldn't find original build documents, so i can't say for sure. Here's an example of some possibilities what those could be (mainly, anything in TO106 package):
      http://www.datasheetarchive.com/indexer.php?file=Scans-0018370.pdf&dir=Scans-000&keywords=TO106+transistor
      +m

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    4. Well I can tell you this much, it works fine with 2n2222s. If anything there was probably a little too much gain (if there is such a thing :D). I've just been out for food and over-indulged a little so I needed something to ease me into building before I finish off boxing the last couple of builds I've done. Nice and easy but probably not as good as a Fuzz Face, a little thinner and more brittle but upping the input and output caps would probably solve that. Nice symmetrical layout too.

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    5. Quick! Cool thing dude! I'll tag it.
      +m

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    6. No problem dude, I've been trying to stop hogging the verifications but I needed something to pull me out of my food coma so I didn't mess up a pedal I'm boxing for someone. This certainly did the trick seeing as I've managed not to arse up the decal on the box :D

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  2. Build, works fine but the amount of distortion isn't enough with an hfe less then 300/350, more it's useless nothing canges.
    A right choice permits to have a quiet clean boost with the gain at zero, and a quiet good distortion at maximum.

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  3. Kröhm....
    http://tonemachines.blogspot.fi/2013/07/a-new-friend-arrived-today.html
    +m

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  4. Hello,
    Maybe i miss something, but if someone have a video of this, i will be very thankfull !

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  5. In my search for obscure old fuzz circuits I built this bit with luciferstrip mods which improved it to being boxable.
    http://www.freestompboxes.org/viewtopic.php?f=10&t=20090&p=207154&hilit=knight+fuzz#p207154.
    Jumper the 470k resistor. Replace both resistors at q2, 2m2 to 560k, 100k to 8,2k.
    As for the caps, lower all the 47nf to 22nf, the 1,5nf to 220pf.
    As for transistors I used a metal can 2n222 and for q2 I used a russian ge, 1T311I, hfe around 150. I also tried mp38a but didn't like it.
    It's now a great fuzz with a distinctive own flavour. I added a ground lift through a 20k pot for chaotic synth sounds.

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  6. Video: https://www.youtube.com/watch?v=5Xsh-bdzyqs

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