Tuesday, June 2, 2015

Reducing Monotribe Clicks and Pops

I was playing the Monotribe with a MIDI keyboard, which is a lot of fun, but the nasty clicks and pops during the note on and off are total dealbreakers when the 'tribe is plugged into a big bass amplifier, or your speakers are cranked up.  It's not so much an issue in most sequences, but when you play it like a keyboard instrument, it's a pretty glaring awful sound.

So I watched THIS YOUTUBE VIDEO and figured out what to do.  Basically I soldered a 4.7 uF capacitor from the base (pin 1) of Q24 to a ground pad (negative cap leg to ground).  He suggests you can use a 1 uF all the way up to 10 uF depending on your preference.

The trade off is it does seem to soften the envelope a bit.  It sounds a bit less snappy, so I might go back in and put this mod on a switch.  The volume envelope sounds a little bit compressed now, which tames the acid edge perhaps a bit much.  Of course you can still get the filter screaming or whatever.  But I recommend a switch.

The mod really does work well, the clicks are almost completely eliminated, which makes the monotribe now a joy to play as a monophonic keyboard instrument (see: MIDI mod in an earlier post).

If you haven't cranked this thing up through a guitar or bass amp, you've got to hear it.

Here's the transistor pinout for Q24:


And here's the best picture I could get of my cap soldered in place.  I would recommend cutting the leads to the right length, and tinning them with solder, before installing the cap.  Do the transistor connection last, and as quickly as possible to avoid damaging the part.  Tinning the capacitor's legs helps here because you only need that tiny bit of solder to make that tiny connection, and it frees up a hand to help position the parts.  It really wasn't that bad of a task.  It came together quite easily with the right technique.






12 comments:

  1. Hi,

    Could you post more info about how we could do it? the things we must to have to do it?
    also more pictures if it possible and the instructions to do it

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    1. Hi Caneloni,

      If you look carefully at my photograph, you should be able to see the correct pin, and the correct ground pad to solder to. It would be very easy to destroy the transistor with too much heat or a turbulent hand, so you need to be very precise with the soldering iron.

      Just make sure the + side of the cap is on the correct pin on the transistor, and the - side of the cap, which is usually marked with a colored stripe, goes to the ground connection.

      I'm afraid my blog post is about as clear as I can get, if you read and understand it well it should be a pretty straightforward job. It's only one capacitor, and two solder joints. If you need help, it would be best to find someone with more experience to guide you, locally.

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  2. steep by steep if it's possible

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  3. how many Voltage for the capacitor?

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    1. I used a 4.7 uF 50 Volt capacitor. I think you could probably get away with a lot less, probably anything 16 V or more should be fine.

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  4. This comment has been removed by the author.

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  5. Thanks for sharing a short and precise post! Good picture :)
    I have done several videos with my MidiModded Monotribe with keyboard without noticing the clicks and pops - but they are there VERY loud and clear 8(
    If I were to do this mod with a switch - would you recommend one cap leg over the other for the switch ?
    Thanks in advance! :)

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    1. For the switch I would probably "lift" the positive leg of the cap out of the circuit, the leg that goes to the transistor, and leave the grounded leg of the cap alone. You would only need a simple SPST switch for this. The switch would close to connect the cap, and open to disconnect it.

      Also I've gotten used to the slightly changed sound now, it doesn't bother me at all, it didn't change all that much really. I don't even think I'm going to bother with a switch at this point.

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    2. Thanks for the reply and the good explaination!! I'm pretty sure I can do this :)

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    3. I did the mod - and it works great! There is still some clicking on the more high pitched notes but the overall effect is very significant! I did it with a switch, and I can confirm that that is unnessesary as I won't ever turn the effect off again! Thanks for great guidance!
      I put some pictures on facebook but didn't know where to find you there. It in the 'Synth DIY' group :)

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  6. Yes, I can confirm that the mod works well. It also does so when the capacitor is not directly soldered to the pcb, but wires are added in between so it is easier to add a switch: http://karg-music.blogspot.de/2015/12/monotribe-removing-clicks.html

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