Saturday, 22 January 2011

Tonebender MKI

Updated 31st January 2014:  A lot of people have mentioned that the trimmers in this aren't as important as finding the correct transistors, so I'd recommend building this version which omits the trimmers entirely and puts the fixed resistors back.
Make sure you use sockets for the transistors and prepare yourself to audition plenty! :o)
 
 
 

25 comments:

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    1. It's a positive ground effect so just do everything you would normally do but swapping the -ve connections to +ve. The positive ground will still connect to the anode of the LED and then simple put the current limiting resistor in series from either +ve or -ve.

      Like this: http://www.generalguitargadgets.com/diagrams/switch_lo_3pdt_tb_dcj_pnp.gif

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    1. Was the circuit working before you added the offboard wiring? You really want to test these circuits before adding bypass switching or you're adding another potential point of failure to the equation. Once you know the circuit is working, then any problem after that has to be down to the switch or installation and so it narrows things down. Are you getting -9V between supply and ground, just to check that you are getting power to the board?

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  5. Ive finished this pedal now ,I got rid of the cc resistors and fancy big capacitors ,the transistors are nos stock oc75 and ac125s the only thing I changed was the trimmer for q1 I used 100k and q3 50k. Ive also used a led. and the 50k trimmer pot is external. The transistors needs to be no more than 80 hfe other wise its get all sorts of wizzing noises etc.The bigger value trimmers make it easier to bias according to the BYOC forum, and I agree ,this didnt take long to get a nice vintage sound.Next pedal univox super fuzz hopefully that goes smoothly

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  6. This circuit really is a pain in the butt to get sounding good but I think I've finally done it (after like 2 months of failure).

    My build consistently produced a pleasant fuzz tone with pretty much every transistor I tried, but no matter what it had this terrible hissy fizzle to the decay. I'm not talking about gating but a fizz that crept up as the note decayed..

    Finally I tried some of these 60s RCA 2N217 I got for really cheap on eBay and they sound really great. I'm not getting that fizz and the fuzz is really smooth and nice

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    1. Good info, thanks. I've made two MK1's and have no plans to ever make another, they're too hit and miss for me, no matter how good they can sound if everything clicks into place.

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  7. It was a frustrating build because I had pretty high expectations for it and of course you know how challenging it can be to get this circuit to sound really good. Thankfully your layout did make transistor swapping very simple since theres no need to twist legs or anything!

    I think I'll try to squeeze another one or two of them out of this bag of 2N217. They're really noisy in a Fuzz Face type but sound perfect in the MKI

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  8. I had mine working ,and decided to change the 10n cap to get a pedal that wasnt so bright by trying different caps , then I couldnt get it to work again so I etched a zonk machine pcb from fuzz central substituted the right parts and now I have a pedal that I could call brilliant very 60s sounding I do get a little motor boating like Travis did but if you adjust the trimmers you not only change the tone but you can get rid of the motor boating as well [95%],I may look for 2N17 on ebay.

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  9. This effect is great. Sounds really fine, and you can get an use for this load of leaking and useless germanium trannies. My leaking AC180 and AC184 work like a dream in the MKI / Zonk, so, If you're bored and got the time, I recommed this pedal.

    Just to comment, trimmers are useless fot this build. Even gettin the recommended voltages, doesn't mean that the pedal will sound ok, so my advise is puttin the stock values, use the voltages as a sheer reference, and try some (or many) of your 300-500 leaking / +- 60-90 hfe pnp trannies.

    May the force be with you :P

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    1. I feel really satisfied today. Have just received a MKI trannies set from Small Bear. Was quite sure about my trasistors selection, but have it confirmed, so ordered from Small Bear, as I needed too a bunch of small chicken heads knobs for my MKII series.

      Well, the set from SB sounds really great, but my selection sounds even better :)

      Finallly I'll be able to provide a good client with his fancied Zonk Machine!!!!

      Really, really happy today :)

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  10. Does anyone know where to score one of those angled MKI type enclosures?

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    1. http://www.pedalenclosures.com

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    2. I tried to order from them and they wouldn't respond to emails or Facebook messages so I had to open a paypal dispute to get my money back.
      Not recommended.
      I ended up buying a clone of the MKI enclosure on ebay from Pigeon FX that comes predrilled.

      On another note, this circuit sounds amazing and the trimmers really do allow fine adjustment to minimize the fizz and feedback and get the tone just right.
      I built mine with a MAX1044 for negative ground.
      Thanks!

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  11. Here's a question, does anyone know if using a 22uf instead of the 25uf electrolytic would have any effect on this circuit?

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  12. I've finally gotten around to throwing this one on the breadboard after being kinda disappointed with my last build eventually

    So far it's going surprisingly well. I used some random 2n404 and an MP20A that I had sitting on my desk simply as place holders on my breadboard so I could make my layout. When I plugged it in I was surprised by a glorious sound

    Only very slightly gated with great sustain and no shitty crackling artifacts like my last attempts. I'm going to set this trio aside and experiment more, but wow, maybe I can finally get it now that I have a better selection of germs

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    1. A good selection is a must when building a MkI. Bloody horrible pedals to build.

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    2. Actually I don't know what's going on it's like the fuzz gods have smiled on me today.

      I'm just getting great results.. I'm still shocked at how good the random low leakage transistors sounded but did some experimentation and settled on some AC125s.

      Right now I have a circuit very worthy of getting boxed up. I think I'd like to experiment a bit more to maybe get a slightly "stickier" fuzz.

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  13. http://i825.photobucket.com/albums/zz176/Dub-T-123/4B7016CC-F7E4-4CC7-A49C-3565F05FC97C_zpsdbanavv8.jpg

    Hopefully I'll have time to box this tomorrow. I have a nice 1590P1 to put it in

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    1. Great job, that looks bang on the money!

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  14. my Tone Bender, great sound, but took some time to really get the trannies to merry with eachother: http://s12.postimg.org/g5yobs0fh/IMG_0413.jpg

    now it nails early cream and led zep like a dream :)

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  15. Template used:
    http://s17.postimg.org/wuhshp4rz/Tonebender_Sola_London.png

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