Moo-Tron Auto Filter

NOTE: There are a limited numbers of kits avaialble with the required vactrols - they're now obsolete so stocks will become very difficult to source.

All the funk in the universe, compressed into a 1590BB and unleashed on your signal. Dig out any of your 70's vinyl with whakka whoop wha filtering on it (Zappa, Bootsy, Wonder, Santana....) and you can bet your bellbottoms its coming from the original box this is based on. Bass, guitar, keyboards... they all love this pedal.

Lots of controls to play with in this modernised version, including a Gain control to get your input signal just right (as auto filters like the signal just so) and a master volume to balance your level once you've messed with the gain. Volume can be set with an internal trimmer instead of a pot, but you'll have a strange control layout unless you wire up your pots instead of using vertical-pin board-mounts.

We've tried our best - really - but we've not been able to find a roll-your--own vactrol that works well with this. Most of the LDR-LED combos we've tried will produce good results across some of the settings, but nothing works across the full range of the circuit's capabilities. You really need a pair of VTL5C3 vactrols to get the best from this box. Kit is offered with or without the vactrols in case you want to try to get hold of some cheaper. We won't lie - they're becoming harder to source, especially at reasonable prices, but the results are worth it. Thonk are your best bet in the UK. 

If you opt for vertical-mount pots they have round shafts, so you'll need knobs that fix with a set screw. Feel free to wire in 'normal' pots if you prefer a splined shaft. The rotary switch requires a knob with set-screw fitting. Pot spacing is 20mm, so you'll need knobs smaller than that.

Partial kit: PCB, all board-mounted components, pots.

Full kit: As above, plus footswitch and appropriate daughterboard/components for your selected bypass type (see Downloads section for details of those), jack sockets, DC socket, battery snap, hook-up wire, LED.

Enclosure (pre-drilled) is only available with full kits, and will not take a battery. Knobs are not included.

Difficulty: Medium

PCB size: 80 x 60mm

Knobs required: 4/5

Enclosure: 1590BB

Direct-Connect compatible (4- or 6-way)

Please do not attempt this build unless you're confident in your building and troubleshooting abilities. We cannot offer any support with this kit.



Pedal Parts


£48.00 inc. tax

£40.00 ex. tax
? Tax based on United Kingdom.

Customer Reviews

8 review(s) posted (write review)
Got da funk! 5 product stars
"Typically brilliant Fuzzdog kit. Used a pair of Vactrols from Thonk as were out of stock with Fuzzdog at the time." Alan Seeley - 03/03/2018
Vactrol substitutes 5 product stars
"A company name Macron provides Vactrol replacements, I've just seen it at Banzai!" Iznogoud - 25/02/2018
5 stars- Eventually... 5 product stars
"Took 3 attempts at this before I bit the bullet and shelled out on genuine NOS Vactrols. Finally the sound I was looking for. There are Chinese vactrols available which are far cheaper but just don't work properly . Honestly, just buy the legit ones and save yourself hours of ball-ache." Tom - 15/02/2018
With regard to the review below.... 5 product stars
"We have no facility to reply to reviews, so here's a workaround. We've sold over 50 of these kits and have heard of two people having problems. The circuit and components have been identical in all cases. Go figure. As for support, we make it very clear on the site that we cannot offer build support, and it's your choice to go ahead with a purchase with that knowledge." FuzzDog - 01/11/2017
Look elsewhere 2 product stars
"This is a good looking kit that is easy enough to put together. The charge pump means it only needs a regular 9v supply, which is a bonus. However, the circuit just doesn t perform as it should. It does the filter thing to a degree, but the effect is weak and just doesn t work at all across a range of settings. Fuzzdog offer no support on this pedal, so buy it at your peril. I paid (on top of the already significant cost of the kit itself) to have it fixed by a professional audio electronics engineer, only to be told it would be cheaper to start again - too many circuit changes were required to make it function as it should for it to be economical. To be clear - this is due to the kit design and not my building skills - I have built a lot of pedals! Buy a Q Tron instead." Michael - 30/10/2017
disappointing 2 product stars
"Bought it to build it and give it to my brother as a birthday present. cannot compare with my personnal Q tron.. or with any Mu tron or other filter. don't know if I did something wrong with it. it works for sure, but cannot give any interesting sound. without any sound example on the site or any help provided, it's money i have thrown out the window. next time i'll buy the real deal, and i'll be sure to get what i want." rodolphe - 03/02/2017
Let there be funk... 5 product stars
"Wow. My wife bought me this kit as a Christmas present, and I'm absolutely loving it! I've built a couple of FuzzDog kits before, so knew what to expect - build was pretty straightforward, and it worked first time. Still working out all the sounds I can get out of it, but it's pretty wild (in a good way!). Shame the band went on hiatus before Christmas - I can't wait to gig with this! I replaced the LED with a blue one (it seemed fitting, somehow!) in a more sturdy chrome bezel. Now just deliberating whether to leave the enclosure as bare metal or to decorate it somehow..." Jim - 12/01/2016
Funking awesome!!!... 5 product stars
"Bust out the glass platforms with the goldfish swimming in the soles!... Da funk is here... Great kit, easy to build not so easy to stop playing with it... Usual fuzz dog quality... Clear concise instructions, an hour with the soldering iron and you will be funking out in every way... Shame to only give it 5 stars, should be at least ten stars!... Buy one now!..." Poopot - 02/10/2015

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Full kits DO NOT include enclosures unless you select them in the 'Kit Type' drop-down menu.

Don't forget to download the appropriate daughterboard build document for your kit:
Standard 3PDT