Monday 25 April 2016

Madbean Sharkfin (Maestro FSH-1 Filter, Sample & Hold)

Here is Brian's modified version of the old Maestro FSH-1.
You could buy his PCB here and find all infos about this project here.


45 comments:

  1. Holy crap Aex, that layout looks amazing. I've built this on one of Madbean's PCBs, and that only just fits in a BB box, so to get your layout as compact as this is just stunning.

    ReplyDelete
    Replies
    1. This comment has been removed by the author.

      Delete
  2. Going to have to give this one a go at the weekend. Built Madbeans version but never managed to get it working. Never understood why but the 13700 was just not getting any power. I eventually gave up and put it down to either a dodgy PCB board or a mistake i just couldn't see. Probably the latter.
    If anybody else attempts this just be aware lots of people have had problems with the PCB version, so take it slowly if you do.
    Let you know how it goes soon.

    ReplyDelete
  3. I was planning on buying Madbean's PCB for this, but this layout looks so good I think I'll just build this. My only concern is clock noise since this one tends to always have a little tick. I'm hoping it's not too bad on the stripboard

    ReplyDelete
  4. I built the Madbean PCB version a while back, and the LFO does, indeed, tick. It's not really noticeable when you're playing, though - just in the silences. Solution: never stop playing.

    Frank Zappa's Ship Ahoy is a good example of the S/H setting in action: https://www.youtube.com/watch?v=SFTJ8V2T0nM

    ReplyDelete
    Replies
    1. Mine ticks too, but it's not a major issue. There's a warning on the build docs from Madbean about this, and they say you can't eliminate it. I used shielded wire on mine which is supposed to help.
      Like the Vox repeat Percussion, I think it's part of the character of the pedal which actually adds something, rather than just being a bad thing.

      Delete
    2. I read about the ever-present tick. I'm fine with it but also hoping it's not much louder on the stripboard compared to PCB. You know how these LFO driven builds can be sometimes..

      Delete
  5. Fun little effect.. not really something I'd ever keep on a touring pedal board or anything. Kinda hard to get going properly somehow. The Madbean PCB wasn't just one you could throw together.

    ReplyDelete
  6. Alex, Attack 1&2 should connect directly to F/SH Sw 3

    ReplyDelete
    Replies
    1. Thanks Michael!
      I've fixed that.
      If you've already built that version, just disconnect the link between Decay 1,2 and F/SH Sw3 and connect F/SH Sw3 to Attack 1,2.

      Delete
  7. How to read footswitch 3pdt pin numbers?

    ReplyDelete
  8. Built this but think i may have my 3PDT toggle wired up wrongly. Should it be the same as the footswitch Travis posted above when the solder lugs are horizontal? Seem to have brain freeze today.

    ReplyDelete
  9. It is like Travis wrote.
    You can use a toggle or a footswitch.

    ReplyDelete
  10. Cheeras Alex. I did wire it up wrong then. Been one of those days, must have woke up on the wrong side this morning. Think i'll leave the correction until tomorrow. Let you know if i get it working.

    ReplyDelete
  11. You can tag it! Worked at first try! Sounds, erm, crazy!

    ReplyDelete
  12. Thanks Guilherme!
    Does it tick?
    If so, is it loud?

    ReplyDelete
    Replies
    1. It ticks only in the sample mode, and also, clicks when in bypass, when in this mode (and I wire my 3pdts grounding the effect input when in bypass and all.

      Delete
    2. Maybe another IC instead of LM741 (the bottom right corner one)?
      TL061?

      Delete
    3. I'll try it! Probably I'll just use buffered bypass in this one, since I didn't used sockets, and build another one from scratch

      Delete
  13. I'm having a problem with my build. Not sure what the problem is. I get ticking in sample mode but thats it. I need to look over it again. I seem to be making silly mistakes recently.

    ReplyDelete
    Replies
    1. Gavin, it's a pretty big circuit, but keep the faith, it works (the circuit, not the faith)!

      Delete
  14. This is an amazing Effect! I built the vero of the oberheim vcf published by Harald Sabro on sabrotone.com a while ago. I was reeeally lucky with it, as it worked right away, had no issues with ticking (only a tiny bit, I used Tl022s) etc.
    Used 245As for JFETs and 2n2222 for that noise transistor. That one's a bit tricky, you have to try out different NPNs to see which one gives you the best sound. I might try a 5088 as well in the future, maybe thats even better.

    ReplyDelete
  15. Ok, got mine up and running. Had not cut a trace properly. Love this effect. Definitely one for boxing. Thanks as always guys/girls.

    ReplyDelete
    Replies
    1. Thinking i would like to wire the rez so i can use it with an expression pedal as the filter on this seems like it should work well with it. Maybe even seperate the filter and stick it in a wah pedal. Any thoughts?

      Delete
    2. Hi Gavin!
      If you want I can eliminate the Sample & Hold part of the circuit and draw another layout for it.
      That's not too difficult.

      Delete
    3. http://guitar-fx-layouts.42897.x6.nabble.com/Madbean-Sharkfin-Filter-without-Sample-Hold-tp30635.html

      Delete
    4. Sorry Michael!
      I've missed that.

      Delete
  16. Few notes...

    Ticks like a ticky thing ticking! Even when bypassed before a high gain pedal. Going to try our usual tricks and see what happens.

    The floating base has to be wrong. I've read thru every FSB post (Nocentelli's included) and can confirm that there must have been a schematic error thats been continuously copied from one version to the next. Tying the Base to -9V (the collector socket in this layout and float the collector) gave instant results! People here and on Madbean have constantly reported that tuning this thing was a nightmare....but with the collector now floating it's a breeze.

    The Top trimmer now seems to set the range of CV that will be triggered (i.e. how low and high the filter will open) and the right most sets where within that range it will open (kinda like a depth range). Instant results with every BJT I tried. The gain does have an effect but like I said, you can redial the operating range in quite easily.

    Don't use multi turn trimmers....it'll break your heart!

    All in, a great sounding effect. Cheers lads

    ReplyDelete
    Replies
    1. I just wanted to add more support to the noise transistor being set up wrong in the official build. Float the collector, not the base.

      Here's a little article on the subject:
      http://aquataur.hilpold.net/aquataur/musicstuff/fsh-1.html

      Delete
    2. I also tied the base to -9v and floated the collector, and it's much easier to dial in. With more range than I remembered vs the original pcb.

      Thanks for the tip Ciaran and Rory!

      Delete
  17. Anybody know how to incorporate the up/down switch that GGG's design has for the sample/hold? Looks like just a 12k resistor in/out of the circuit, but I'm never sure with this kind of stuff.

    ReplyDelete
    Replies
    1. You got it. Using a DPDT on/on...
      12K between 1 and 4
      Filter 2 to lug 2
      Hole next to top of 22K to lug 5

      You could also use a SPST but you'd need to fly the 12K or squeeze it into the top left and make a cut next to the diode.

      Delete
  18. Great filter, fired up straight away. Any ideas how to add volume knob to boost it slightly above the unity level?

    ReplyDelete
    Replies
    1. Ok, done. Decreasing the value of r4 (100k to 56k) increases output and response. Now it shines even more!

      Delete
    2. Great tip on R4 Piotr, thanks!

      Delete
  19. If I want one closer to the original (VCF-200/FSH-1), could I just replace the potentiometers with fixed resistors? Is there anything else I should do?

    ReplyDelete
  20. If you are getting ticking when bypassing the sample/hold side, try this countermeasure.

    Instead of connecting the usual ground wire to bypass stomp switch lugs 2,3 and 6, just attach the ground wire to lugs 2 and 6. Then run a wire from the speed pot lug 3 to the now vacant bypass stomp switch lug 3.

    The idea is to ground out the speed pot's lug 3 when the bypass switch is engaged.

    This eliminated 100% of the tick in my build when bypassing the Sample/Hold effect. (There wasn't any ticking when bypassing the Envelope side, only when bypassing the Sample/Hold)

    ReplyDelete
  21. I've only got B1M pots on hand, but that seems to work fine for the resonance pot (I usually leave it wide open anyway). Would that really make enough of a difference to make it worth sourcing a B2M?

    ReplyDelete
  22. The REZ control is wired like a rheostat, and it injects between 0k to 2M resistance between the Q2 jfet and the negative input of the 13700.

    So if you use a 1M, you're literally cutting the REZ control in half. Instead of going from 0-10, you'll only have 0-5.

    You can easily test whether or not you want or need the "missing" 2nd half of the REZ control. Just swap out the 100k resistor at REZ 1 pcb connection with a 1M. This would simulate the 2nd half of the REZ control's rotation. (5-10)

    If you don't like the "5 thru 10" settings with the 1M resister, then put the 100k back in and just use the 1M pot.

    If you ONLY like the settings with the 1M resister installed, then leave it like that with the 1M pot. (You could also use a resistor somewhere between 100k and 1M, like 470k and that would be like having just the settings "3 to 7" on the REZ control.)

    But, if you do like the control with both the 100k and the 1M resistor, then you will need to use a 2M pot.


    BTW, you can make a 2M linear pot by getting a 1M dual linear (from Tayda) and wire the 2 wafers in series. Connect lug 1 to the pcb as usual, connect lugs 2 and 3 to lug 4, and connect lugs 5 and 6 to the pcb's lug 3 connection. It will function exactly like the 2M linear pot.

    ReplyDelete
    Replies
    1. Thanks Mao! In the end I found an extra B2M and just used that. I'm not sure if the difference is great, but at least I won't wonder anymore. There are so many variables with this circuit (noise transistor choice, opamps, offboard wiring, etc.) that I figured it best to not insert different component choices too.

      Delete
  23. When I was first testing this pedal I ignored the LEDs, and when I finally put it all together I suddenly started hearing the ticking that everyone was talking about. Turns out a big contributor to the ticking is in fact something to do with the Speed LED and most likely some other things involving the LFO and the SH footswitch, but I haven't dug too far into it.

    I also added a wet/dry blend (the mini JFET blend layout by IvIark) on a daughterboard because I found the SH mode obscured the input signal a bit too much. Definitely ground the speed pot through the bypass switch as described by MAO, it's perfect for getting no ticking in bypass, but the blend makes the ticking even more obvious when engaged.

    If the ticking is bugging you when actually using the SH mode, just add a capacitor between the "Speed LED +" strip and ground, the simplest form of a low pass. I used a non-polarized 68nF and it got rid of the ticking without noticeably touching the actual audio signal (which it hopefully shouldn't in the first place).

    I think the reason it helps is because it is smoothing out the square wave from the LFO so when it affects the audio signal, however it is doing that, it is less noticeable.

    All in all, really awesome pedal. Tons of fun figuring it out and reading the comments here.

    ReplyDelete