Friday, 3 February 2012

ZVex Mastotron

A few people have requested a vero of the Mastotron, so here it is.  If you want to make it verbatim then you would put a 100 ohm resistor in series with the input wire before the pot, and a 100 ohm resistor in series with the 9V supply wire, but I personally wouldn't bother with either.  So enjoy your Woolly Mastotron!


72 comments:

  1. Well I did sit down to finally do the Orange squeezer then realized I forgot to order more 1N34A's!...So you can verify this instead :o)

    Just one thing though, the 'PW' wiring needs flipping as it worked backwards.. This is really nice, Especially for people who don't like the noises of the Fuzz Factory..

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    1. This comment has been removed by the author.

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    2. Imageshack removing my pic!!

      http://imageshack.us/f/137/dsc00136yk.jpg/

      I used the case from my 'King Of The Britain's' failure....

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    3. Ha ha, excellent, waste not want not!

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    4. This is also verified by the way :o)

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    5. Forgot to change the tag, cheers mate

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    6. Vince! Your photos are gone again.. :(
      +m

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  2. I have 0 pedal building/soldering or circuit board printing experience.
    How would I get the circuit board that I would need to try and build this or any pedal?

    Thanks

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    1. Check out this guide:
      http://tagboardeffects.blogspot.fi/2012/04/vero-build-guide.html

      Stripboard is sold at almost every electronics component store. Taydaelectronics is pretty good shop, as you can get almost everything you need from there.

      So.. The stripboard doesn't need any printing, but just trace cuts - and those can be done with a knife, drill bit or what have you. There is a tool for that too: http://www.ebay.com/itm/220509678716

      For starting out, i would however suggest something a bit simpler, like ROG Buzz Box:
      http://tagboardeffects.blogspot.fi/2012/09/runoffgroove-buzz-box.html
      or some simple booster, like Catalinbread Naga Viper or EHX Hog's foot:
      http://tagboardeffects.blogspot.fi/2012/08/catalinbread-naga-viper.html
      http://tagboardeffects.blogspot.fi/2012/05/ehx-hogs-foot.html

      I personally started with kits from General Guitar Gadgets and Musikding. Those are good, because you don't have to know all the components when shopping..

      Anyway. Welcome :)
      +m

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  3. There's a photo of Mastotron guts on the web somewhere, and to me it looks like the Pulse Width pot say 500R and not 500K. Anyone else notice this or look into it?

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    1. A 500R wouldn't make much sense in the position it is in so I would doubt it. The PW pot is a modification to the 100K feedback resistor found in the Fuzz Face. In the Mastatron it has a 100K in series with it and so it means the feedback resistor is variable from 100K to 600K. If it was a 500R it would be variable from 100K to 100.5K and I doubt anyone would notice any difference.

      I'd probably experiment with the 100K series resistor and use something lower so you can make the value smaller than the 100K found in the Fuzz Face depending on the PW pot setting. Just so that you can vary it up or down.

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  4. I assumed as much since the math doesn't add up, must be a bad print on the pot in the photo. Thanks for confirming.

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  5. I built one pedal with this layout, and i'm having some troubles in making it work.
    I'm a bit of a newbie, as this is my third project. The other two pedals that i've built are working great, this one is completely dead when i turn it on.

    I've assembled an audio probe to help me debug the circuit (using a Wima 100nf, and a clamp for the ground), and the sound in the audio path is stopping at the first transistor. After that no sound at all. What could it be?

    It's worth noticing that i'm not using this layout literally, one of the caps that i had available for this project was a bit bigger that the space that i had for it, so i used a mini vero board to hold that capacitor in other place. I'm pretty confident that I done that modification correctly, but being a newbie that I am, I'm starting to doubt everything.

    Any hints on how to solve this would be great.
    Thanks in advance.

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  6. I'm starting to think that i connected the power plug with the wrong polarity. If this assumption is correct then i might have fried the transistors right? The electrolytic caps visually seem ok (no dilation etc). And considering that the sound stops at the first transistor it might be that one that fried blocking the signal for the rest of the circuit.

    What do you think?
    And how should i connect the power socket? Negative to ground, and positive to feed the circuit?

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    1. Very possibly, that's why I always socket transistors so it's a quick and easy fix if anything happens. For the supply negative goes to ground along with all other points of ground, i.e board ground, socket sleeves, stomp switch for LED circuit, pots etc.

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    2. Well... it wasn't that, and it was such a simple error that i'm a bit embarrassed for not realizing it before. I had one of the pots cables misplaced on the board, creating a path that isn't supposed to happen, and was obsessed that the error was in the power supply part of the circuit.
      Once i realized what was wrong it was a quick fix.

      Well thanks anyway for the quick answer.
      The pedal is working fine and today I will try to rock it a little bit.

      Continuation of the good work on this site, I stop by every day to see the new stuff.

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    3. Glad you got it going Pedro. Everyone makes these errors from time to time. I spent hours fault finding a TS type pedal once before realising that I hadn't put the IC in the socket yet.

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    4. Yep, done that, also spent hours debugging a build only to find I hadn`t turned my power supply on. I have numerous nominations for idiot of the year, fortunately there`s always a politician can trump me. :-)

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  7. Hi, what types off caps are used for the 220n, 33n, & 10n. Also are the transistors npn? Should the caps at least be 16v?

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    1. Use whatever caps you have that are suitable for the 2 or 3 row spans required. I used all polyester caps when I built this, but I wouldn't worry too much about type. Some people swear by polyester, some will only use ceramic caps in fuzz pedals but the effect is so extreme in this case that any differences are subtle at best and not worth worrying about. Yes the transistors are 2N2222A which are NPN.

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  8. Would someone help me out by writing up a quick list of all the components used for this build? 1:1 as possible. This would be my first major build and want to double check I'm reading the schematic correctly.

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  9. I would also like some help putting together a parts list. I was wondering if the 220n capacitor and similar looking ones are mylar or some other type?

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  10. is this a correct list?

    1/4 jack (2)
    9v jack (1)
    3 pos DPDT switch (on-off-on)

    100k Lin Pot
    5k Rev Log Pot
    500k Lin Pot
    10k Lin Pot (2)

    Transistors NPN 2N2222A (2)

    -Cap-
    100u (4)
    220n (2)
    33n (1)
    10n (3 span) (1)
    10n (2 span) (1)
    68n (1)

    -Res-
    56k
    22k
    100k
    2k2
    5k1
    10k

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    1. does it really matter what types of Caps i use for a one off build? (like mylar, etc..)

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  11. Hey Guys

    I Just got the inventobox module by Zvex and am very much looking forward to building the mastotron effect. however like Dragon Ninja, I have no experience with building a pedal effect or any experience with circuit building. I check out the tutorial given to Dragon Ninja, but it seems they are building it without a breadboard.

    The inventobox comes with a breadboard built in already and I am not sure but I think im looking for the mastotron module or at least a breadboard friendly schematic for this module. Can anyone give me some advice?

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  12. so i accidently ordered a 500k revese log pot for the fuzz instead of the 5k. will this make an extreme difference? can i get away with using the 500k or should i order the 5k?

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    1. The 500K will be useless for this, you really need the 5K. Don't worry though, there are plenty of other things you could use the 500K for so it won't go to waste.

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  13. i built this and when i press the switch i dont get anything. i get the bypass signal when its off. i used a 5k linear pot for the fuzz and used the offboard wiring from this site. any ideas on what went wrong? is it a problem with my switch wiring?

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    Replies
    1. or maybe a jump on the veroboard that shouldnt be there?

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  14. now i have a very low signal. i can very faintly hear it when i crank my amp and slap the pickups but i am getting some sound now. any ideas?

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    1. i am having the same problem as Ben....did you figure it out?

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    2. This is usually caused by either incorrect component placement, incorrect component values or solder bridges, I'd double and triple check these things before asking for more help.
      Cheers
      Dave

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    3. so so i had the transistors backwards...would that damage them? after turning the around i got audio and all the knobs worked but it didn't sound as tight and huge as the stock mastotron i had with me. is that just this build (the way it sounds) or did i damage something.

      to clarify it sounds like a fuzz just not as unique as the mastotron sounds...

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    4. Potentially, you might want to try swapping out the transistors? Did you socket th transistors?

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    5. i will see if my local radio shack has some so i don't have to wait for them to ship from Thailand ;)

      no i didn't socket them...i will try that too. I'm pretty handy with a solder iron (i work for a live audio company) but I'm guessing these things are pretty fragile.

      also would the use of Film box Caps over Mylar greenies make a huge difference?

      thanks for responding so quickly!

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    6. ALSO how much would this affect the sound of the build?

      "If you want to make it verbatim then you would put a 100 ohm resistor in series with the input wire before the pot, and a 100 ohm resistor in series with the 9V supply wire, but I personally wouldn't bother with either. "

      this was in the opening description....

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    7. Yes, it's always a good idea to socket transistors as they are easily damaged by heat, and it's easier to correct orientations.
      Using film boxes will be fine and make very little difference. The 100ohm resistor just brings down the input gain slightly, but it is such a small amount that it makes hardly any difference. I built mine without it and it sounds exactly how it should.
      Cheers
      Dave

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  15. Here's my build of the Mastotron with some audio clips of guitar and bass. Doom metal and stoner rock is written all over this one.

    http://fuzzquest.blogspot.com/2013/04/fuzz-testosteron.html

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  16. right every time I build this circuit it turns out all splatty and biasy and kinda crappy. first time i have tried this layout over the other with different trans. still won't work.... wtf am i doing wrong.

    http://www.youtube.com/watch?v=SFiGVtqlnGE

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    1. What voltages are you getting at the transistor pins?

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  17. how would I test this? just attach negative from my multi meter to ground and then probe the pins with positive and take a reading?

    if so

    C1 1.23v
    B1 .57v
    E1 (not sure how to measure this as its at ground... so....0?)

    c2 2.77v
    b2 1.23v
    e2 0.63v

    sorry if im totally barking up the wrong tree here. I'm pretty handy at the old soldering and boxing up of these band boys... but ask me to diagnose a circuit issue then Im stumped.

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  18. I'm having a problem. My pedal suddenly made a pop (through the amp) and now the gain control significantly reduces the volume over about 2 o'clock. After fiddling about with transistors it started working again (but it wasn't a broken transistor as I have tried various combinations of original and spares and they all worked, for a bit) but it suddenly stopped functioning as normal again. The reduction is noise comes with spitting and gating sounds, and the other controls all still work as usual. Any ideas what this could be? I could really use some suggestions. It sounds lovely at lower gain, but that's not really the point of the mastotron.

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    1. Well if you heard a pop on the fuzz knob it points quite strongly towards that right hand 100u cap. I'd try swapping that and see if it was the culprit. Apart from that a pop could be caused by an poor connection somewhere or maybe an intermittent unwanted bridge that is barely touching. So first port of call would be to knife the gaps, and redo all the cuts to make sure there are no unwanted burrs in any of the holes.

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    2. Thank you, you were right, it was a dodgy connection. I had already reflowed the board but not the connections to it. On to the next project! Thank you for all your hard work on this site, it is such an incredible resource and it's taught me so much.

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  19. Does anyone know if it makes a difference using a 2N3904 instead of the 2N2222 for the transistor? the place I normally order from does not have the 2N2222

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    1. Should be fine, they're both low to medium gain NPN silicon

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    2. also do you have to measure the hfe of the transistor on this one as some mentioned in the mammoth build?

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  20. hey, i own a wholly mammoth with pcb clone :) and i play an active bass. so, i need a push and relax scematic, and how to solder it, can you give me dat schematic? just send to atha.bayu@gmail.com

    thanks :)

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  21. Quick question...
    ...With the tone witch in the center position, I have no output. Any suggestions on what to look for? It is an on/off/on dpdt switch correct?

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  22. I'd look first at that 33n in the bottom right corner. Make sure it's soldered in correctly and not defective

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    1. Many thanks!! I got it. I have a Woolly Mammoth too, but wanted to try this. I will A/B them soon.

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  23. This was my first build and It worked! It is a christmas present for my girlfriend, but Im ready to build mine.
    Im thinking on getting a little bit crazy and try something like the "magnavibe" circuit to add depht/rate control to modulate the pulse width in order to get modulated synthy sounds.
    http://tagboardeffects.blogspot.com.es/2012/01/bigfoot-fx-magnavibe.html
    I could wire the circuit needed , (resistors, caps, led and lcr), on a different vero, wired to the 2 extra pots, (depht/rate), and then to the PW knob.
    What do you think¿
    Best regards.

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  24. I forgot to say that I am just getting some gain from the fuzz pot from about 80 percent of the running in advance. Below that, nothing but nothing. I purchased a standard 5k log pot for that: May be a lower value¿
    Best regards.

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  25. This is probably really obvious but, how do I add a bypass stomp switch to this? I am guessing that it is just not shown because it is so obvious. Thanks

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  26. http://tagboardeffects.blogspot.co.uk/2012/02/offboard-wiring.html

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  27. Hi there, this is my first build, I used the layout above and the off board wiring diagram from this site. I put it all together, plugged in the power supply, pressed the footswitch and I got a quick flash of the LED and then nothing at all. When I tried to switch it on again I get absolutely nothing. When I switch it off I get the dry guitar signal. Does anyone know what might have caused this? Thanks.

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    1. I just used the Beavis Audio off board wiring, the LED still doesn't come on, but I'm getting some really high pitched squealing / oscillating noises that seem to change when I mess with the PW knob. There is also a loud pop between positions 1 & 2 on the toggle switch, 3 seems to be fine. Any ideas?

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    2. I'd bet you have a short in there somewhere that's causing a feedback loop. Possibly in the switching. This could also explain the toggle behaviour.
      +m

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    3. Thanks man, I checked all my wiring and I can't find any touching. Could this be caused by solder bridges / cuts not properly done?

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  28. Hi,
    I have the same problem as above, but it is a loud percussion-like oscillation that varies turning pw clockwise. And frequency is doubled with 3rd position of the switch...
    Last but not least: sustain is quite short, with high notes particularly.

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  29. I forgot to say that at turning the effect on , it can be quiet. But cycling pops begin after playing a note or a chord.
    Sometimes, sustain ends in a sort of tremolo way. :-S

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    1. Hi ,
      Found what was wrong with my build !
      I compared my voltages with those posted by Mark for the Wooly Mammoth build. Q1 was OK but Q2 collector was starved to 0.9v...
      Swapped 22k resistor with a trimpot and tuned it for a decent voltage.
      That could be a mod idea: replacing 22k with a external pot could be a sort of gate/glitch control.

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  30. Old layout i know, but i cannot get it to work.
    How would you test this before boxing it up? with all the pots etc.. i am used to all the connections are on the board but here it just goes from the input at the pot right? so that the board input is the input wire at the first pot? i tried boxing it up, but i dont even get bypass, so something it definately off.
    greetings from Denmark.

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  31. So I build this originally a couple months ago, and when I did, I didn't have any 2n2222a's on hand, but in the comments I saw someone asking about 2n3904's, and I did have some of those, so I built it with them and I loved the way it sounded! Super thick and farty (playing bass through it.
    Now, I just recieved some 2n2222a's and swapped them into it and tested it out, and I gotta say,I don't like the sound at all! I have to turn the fuzz all the way up to get that thick farty sound, but then it gets all choppy and cuts in and out. I swapped the 2n3904's back in and it sounds awesome again!
    I know they're not to spec with the original, but give them a try if you have some laying around! You won't be disappointed!

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    1. Did you check the pinout? I also tried 2n2222a's and had the same problem. Then I realised the pinout was different and I had to flip them around :)

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    2. http://electro-music.com/forum/phpbb-files/figure8_1_165.gif

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  32. Hi, this is my first build from this site and I've bought tantalum 220nF capacitors. I have no idea which way round to put them! Can someone advise? Thank you.

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  33. You should use film caps instead

    The 220nf on the left will have the + side facing down, the one on the right will have the + side facing up

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    1. Thanks Travis - I'll know for next time.

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