Monday 12 June 2017

Silicon Tonebender MKII

I saw a request for a Silicon Tonebender MKII based on a perfboard layout over on StompBoXed's page, which is the modified Tonebender MK II Professional. So after making a layout for it I started searching for other Silicon Tonebenders.The other 2 schematics can be found over at DIYSB.

Silicon Tonebender MKII

Silicon Tonebender MKII Professional

 

Silicon Tonebender MKII Professional Mod

19 comments:

  1. Been wanting to try a silicon tonebender for a while. Gonna try the middle one today, hopefully I'll be able to verify it for you guys.

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  2. the bottom layout is verified. i used bc107b's and a bc109b with hfe's from 200-230. i also used a 10k dual gang pot for the fuzz control and the switch. 10k is definitely too much but oh well. i may put higher gain transistors in but i was an idiot and didn't use sockets so maybe not.

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    1. I dont think you need higher gain transistors for Q1 & Q2, just Q3. Why did you use a dual gang for the Fuzz pot and switch out of curiously?

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    2. Laziness. I had an enclosure drilled for 3 controls and didn't want to clean shavings off my floor. I guess dual ganged is the wrong term. A dual concentric is what i meant. I had it from a failed Boss Blues Driver build. Dialing in that cap is actually pretty nice. And after playing with it for awhile i think the gains are pretty okay I just wanted to see what i was missing with the 5088 and the 3904's.

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  4. So I built the middle layout this evening. It's quite quiet and gated, but then I haven't had the chance to adjust the bias trimpot yet. I'll confirm tomorrow after I've done that (can't do it now or else my neighbours will complain), but since I'm getting sound, I'd say that layout 2 is verified as well.

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    1. Cool man. I marked it verified. Definitely sounds like it needs to be biased.

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    2. Spoke to soon. Decided to try it anyways, couldn't get the bias set anywhere that a usable sound could be found. Granted, I did use a 100k trimmer in place of a 50k as that was what I had on hand, but I would've assumed that I'd have still found a spot where it stopped sputtering if this was working properly. I'll have a go at troubleshooting tomorrow, or else just try the top layout and add a tone control to it since my enclosure is already drilled out for one.

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  5. There's another SI Tonebender mkII here which looks similar to the first layout: http://tagboardeffects.blogspot.se/2013/07/npn-si-tonebender-mkii.html.

    It's next on my build list so it came to mind. It uses low gain si transistors, which might be interesting to try also. It's also suggested there that the Attack pot works better as a 2k lin.

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  6. Did anyone try the first one? I tried it yesterday and I have a problem with the "Attack" pot. It works perfectly on the first half, but when I put it on the second half there's a permanent buzz that sounds horrible, even when i mute the guitar... Any ideas to solve this?

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  7. i made the third along with an SHO booster and mine chokes (stops for sec, and then sound continues, almost like a oscillation error?) at some specs. anyone knows why?

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    1. okay sorted. was an issue with over clipping as ive housed this along with an SHO boost and at max attack and sho boost it gates itself :P
      here's my demo of it:
      https://www.youtube.com/watch?v=mQqtktisWHg

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  9. NEED HELP, IM BEGGING.....ANYBODY!!!

    So I’m trying to build the third one. And all I’m getting is no signal unless I strum REALLY hard on the guitar. Even then, it’s not how the pedal is supposed to sound, but I can hear the guitar. Idk what the hell is going on, I’ve check component values, made sure no strips were touching, all cuts and links were where they are supposed to be, 4 or 5 times over. I’m using the off board wiring on this site for the switch. Everything is where it’s supposed to be, and it’s not working. I’ve tried swapping out trannies...nothing. Idk what else to do. PLEASE HELP ME?!?!?!

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    1. If I were you I'd post this to the forum, then you can post a front and back pic of the board so we can see if anything stands out as a potential problem. Also measure the voltage between each transistor pin and ground and post that as will. It should give a clear indication where the issue is

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  10. Built the top layout, and can not seem to get a single sound out of it, not even a gated farty noise. The component placement and offboard wiring is 100% correct. I have scraped in between the tracks and cleaned off with a brush and rubbing alcohol and looked under a magnifying glass to make sure there are no bridges or wrong connections.

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  11. Built the second layout, and it is verified.
    * From the original layout, the 1N914 diode is in reverse polarity, but I personally prefer this circuit without diode, so I replaced with a jumper. Diode version sounded a bit fizzy to my taste.

    I used slightly lower gain TRs (2N2222 @ hfe 200 & BC550 @ hfe 500). It was possible to get 4.5V bias near the very end of the trimpot.
    Sound great! Powerful and balanced, with an awesome tone-pot. Gives a nice crunchy Led Zepplin-ish tones when plugged into a clean amp.

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