I was fascinated by gmoon's design for a super-simple guitar pedal, the ValveLiTzer, that used a tube as the heart of the effect. Unfortunately I don't play guitar myself, so I built one for my friend's birthday instead. Here are the results of my design. The circuitry is virtually the same, but the case is much different.

To build my version of the ValveLiTzer, you will need everything listed in gmoon's instructable. I bought nearly everything at Antique Electronics Supply, except for the LEDs (eBay), resistors and capacitors (local electronics shop), and wire.

EDIT: Be sure to check out an alternate version of this design, which I call the ValveLiTzer Trifecta. Same circuit, very different case!


1 12FQ8 tube
1 9 pin miniature socket
2 1/4" mono jacks
1 50k linear potentiometer
1 500k audio (logarithmic) potentiometer
1 SPDT (on/on) footswitch
2 blue LEDs
2 1000uF 25V electrolytic capacitors
2 1Mohm resistors
1 470k resistor
1 220k resistor
1 47k resistor
2 470 ohm resistors (for LEDs)
2 0.01 uF capacitors
1 0.1 uF capacitor
24 AWG stranded wire


about 2 square feet of 17mm thick Russian Birch Plywood (aka Baltic Birch)
about 1 square foot of 2-3mm thick plexiglass, Lexan, or polycarbonate plastic sheet
about 1 square foot of 3mm thick aluminum or brass plate
7 3/4" countersunk wood screws
some rubber stick-on feet
wood stain (your choice of colour, I used "Cabernet" red oil-based stain)
wood finish (I used Minwax Polycrylic water-based finish)


A band saw
A scroll saw
A drill press
A belt sander (or a sanding belt for the band saw) - optional, though good to have!
A Dremel tool with a drill press attachment
A 1/8" milling bit for the Dremel
A polishing bit for the Dremel
200 and 320 grit sandpaper
a 1/2" wide paint brush
A 1/2" wood chisel
assorted drill bits
and countersink bit - optional, you could also use a 3/8" drill bit
soldering iron


A variable output (up to 12V) DC power supply capable of 3 amps
a piece of scrap aluminum
a tub large enough to hold the cut aluminum pieces
salt water
a clothes iron
a laser printer
a sheet or two of glossy photo paper

Step 1: The Case

I decided to craft a very unique case for this pedal. It is roughly in the shape of a figure-8, with the single valve emphasized at the top. The case itself is made of two layers of 17mm thick Russian birch plywood - a very special sort of ply with 13 layers. Its side profile is unique and very attractive (IMO).

Plates of aluminum are set into the top, providing a strong stable surface to mount the switches, jacks and pots. The aluminum is etched with the names of the various components.

The bottom of the pedal is made of diffused (sanded) polycarbonate plastic, which is illuminated from the inside by two LEDs.

I started by drawing the case in Adobe Illustrator. Using the diameter of the valve as a starting point, I drew circles and arcs accordingly until I came up with the design below. There are a few concentric cutouts visible, that indicate the various profiles of the pieces. I also marked the locations of the various components that would be mounted on top.

I then worked out a separate template for the text that would eventually be etched onto the aluminum. I picked a font that matched the aesthetic of the case - you can use virtually any font in the world using the etching method!
thank you for the instructable i'm trying to etch a smd stencil from aluminium and this is getting me crazy could this method be used to etch, say, about .5 mm holes ? the board is approx .1 mm thick, i ve tried the ferric chloride so far, but the etching is very not so precise
Hmmm, it might work. I haven't tried etching holes straight through aluminum before, though. I think the biggest problem you'd run into is that the edges of the holes might be a little jagged, due to undercutting. Can you cut a smaller piece of aluminum and do a test to see what kind of precision you can get?
Great Instructable Jeff-o ; your write up is great as I&nbsp;was already planning on building a version of the ValveLitzer. <br /><br />Just a couple of questions:<br /><br />On the C1, C2, C3 - the capacitors ; are they 600v, or 400v? &nbsp; Did you use the 4 pin 1/4 mono Marshall jacks found at Antique Electronics supply?&nbsp; Where did you obtain the 16v 1000uf capacitors ; and are they absolutely necessary as I&nbsp;don't see them in the original schematic ; and I see you added another (2 instead of 1). <br /><br />Again, awesome stuff and THANK&nbsp;YOU!!<br /><br />
C1,2,3: It doesn't matter, since the circuit is running on 12V!<br /><br />Yes, I think I used the Marshall jack. You can use whatever you want, though.<br /><br />I got these caps at Sayal, a somewhat local electronics components chain. They shouldn't be hard to find, though. These filter the power supply and should be used if you're using a wall-wart ac/dc converter. If you're using a battery they aren't necessary.<br />
Thanks Jeff. Great work ; the LED lights and translucent bottom are a nice touch.<br />
&nbsp;Thanks. &nbsp;Most of the stuff I build lights up in some way... &nbsp;;)
you can use Thinner to take the toner off, it's almost instantaneous
Cool, I'll try it next time I use this method.
Hey, here is my finished work, thought you may like to see it:<br/><br/><a rel="nofollow" href="http://www.facebook.com/photo.php?pid=3685285&l=44bc234cf1&id=630911404">http://www.facebook.com/photo.php?pid=3685285&amp;l=44bc234cf1&amp;id=630911404</a><br/><br/><a rel="nofollow" href="http://www.facebook.com/photo.php?pid=3685287&l=ab4f4be9f3&id=630911404">http://www.facebook.com/photo.php?pid=3685287&amp;l=ab4f4be9f3&amp;id=630911404</a><br/><br/>Wiring:<br/><a rel="nofollow" href="http://www.facebook.com/photo.php?pid=3685303&l=6effc23467&id=630911404">http://www.facebook.com/photo.php?pid=3685303&amp;l=6effc23467&amp;id=630911404</a><br/><br/>It has amber LEDS underneath the valve and the case, so it gives a lovely glow when on, can't get a good picture of it in the dark though:<a rel="nofollow" href="http://www.facebook.com/photo.php?pid=3685297&l=88ea6fafb6&id=630911404">http://www.facebook.com/photo.php?pid=3685297&amp;l=88ea6fafb6&amp;id=630911404</a><br/>
Very nice indeed! I like the "hammered" metal on top. Have you had a chance to use it much?
Yeah hammerite paint is wicked! I have used it a bit, not loads though, I'm bringing my studio back online after a forced absence (electrical problem) so I have lots of things to check and troubleshoot right now. It sounds WELL good though, the middle pot selects 1st/2nd stage of the valve, I replaced R3 and R4 with a 2 Mpot, and under advice from Gmoon connected a couple of resistors to make sure there would never be no load, and the wiper of this pot goes between the plates. It's very dynamic, there is a lot of control over the sound like this. You can read a more detailed expl. from Gmoon in the Valvelitzer (never rolls off the keyboard that word does it?!) comments
if theres a hole in the middle of the socket for the tube it would be cool to put an led in ther and hook it up so the leds only glow when its turned on.
Hi stevie1, I'm almost finished building a second ValveLiTzer clone, and this time I installed an LED in that little hole in the socket. It looks great! Thanks for the suggestion!
no prob, i look for that stuff sometimes. i'm kindof obsessed with leds. i convinced my dad tto put leds on his mortorcycle and my moms bike too.
Wow, both your parents ride!! You're one lucky guy!! Dm
sortof... my dad dropped his first bike a couple years ago and now i cant get one till im 40! it sucks
Oh man, that stinks. He shouldn't project his failures onto you. <br/>It's not a matter of dropping the bike...it's just a matter of when. Everyone drops their bike eventually.<br/><br/>=p<br/>Dm<br/>
Ha, nice!
Good idea! There is indeed a hole in the middle of the socket that's just the right size for a 3mm LED. Perhaps I'll try that the next time...
people probly think my dads a pimp cuz i convinced him to put purple on his!!!
thanks a CAD is something you can print onto a paper transfer it onto copper clad, etch it and make a pcb out of it.. I was thinking of using a clear case and this would look much more professional.
Ah, you want PCB artwork. Sorry, I didn't design a PCB for this. I think you're on your own. I suggest downloading Eagle from www.cadsoft.de - it's free and easy to use.
i have eagle, i just can't use it. Well thanks anyways.
That's a problem then. I have the benefit of having learned it in college, but it's not that hard. Look up some online tutorials, there are some great free ones out there. It's a great skill to have!
well i'm still in middle school but i will look at some tuts
Sounds like a good rainy-day activity while school's out for the summer!
i guess
has any one made a cad for this if so please post if not what is the cheapest tube amp kit(doesn't have to be guitar). thanks
CAD? I've included the template I made in Illustrator, can you use that? As for the cheapest tube amp kit, do a search on Google. There are a few kits around, that include a board and all the parts you need.
Great instructable!
Thanks! Glad you like it. :)
I know it's picky but can you remove the blue bar on the schematic? It covers part of the wiring making the circuit difficult to read:)
Blue bar? I don't see anything on the schematic. Have you tried opening the schematic on the original ValveLiTzer Instructable? I copied it directly from there (with permission, of course!)
OK, this is weird. I tried again, didn't change a thing & the schematic is perfect!!!! Sorry if I've wasted anyone's time. John.
No worries. Acrobat can be weird sometimes.
Ummm - I love the overall look and design, but isn't leaving the tube exposed somewhat risky, given the kind of environment where this will likey be used? In use, this is gonna get kicked. During setup and take down, not to mention storage and transport, well, that tube just ain't gonna survive... It looks great - don't get me wrong. Its just that it needs to be inside unless you want to be buying a new tube after every gig. Rock on!
Not to worry! I built this for a friend of mine, who is very protective of his equipment and doesn't really take it outside ever. I've got a version 2 in the works that will feature a protected tube!
Awesome looking pedal, dude. I will add that I think the valve/tube should have a cage or something around it, as if it were used at a dark gig, a misplaced foot could easily shatter it. Most pro pedals that use tubes normally have simple metal bars above the tubes to prevent an accidental stomp, or they hide it in the bodywork. But other than that, I can't fault it! Great work! Looks gorgeous!
Thanks! My next version will have the tube more protected. My friend isn't really the "play in the dark at a gig" type, so I figured the tube would be safe enough. But yeah, if the intent is to bring the pedal to gigs then it should be protected in some way.
Please can you give a more detailed explanation (perhaps a revision of the wiring diagram?) on how you wired in the caps to filter the power supply? Thanks! I'm going to make the original build but I may include this. Good job with the case build, it's very nice
I pretty much wired everything up according to the schematic. The power supply filter capacitors are each wired up between +12Vdc and ground (positive lead of the capacitor to +12V, negative lead to ground). The LEDs (if you choose to use them) are connected in series along with a current-limiting resistor (anywhere from 470 ohm to 510 ohm) between +12V and ground. I will try to update the posted schematic when I get a chance.
Thanks Jeff, I'm just getting into projects like this so your comment is very helpful. I think I'll leave off the LEDS, but I haven't fully decided on my case yet, so maybe they will go in there. Thanks again, I love this site it's amazing!
No problem! One other thing you can try to get more gain is to change C3 to a higher value, say 33uF or 47uF.
it's virtually the same as the original, with some engraving, but other than that the led's are nice
It is, indeed, exactly the same circuit as the original. Why mess with a good design? ;)
Much too beautiful to stomp on.
Sort of a cruel gift then, isn't it? Hmmm, I must admit I hadn't considered that when I made it. ;)
Great job, Jeff! <em>Really</em> well documented. <br/><br/>I especially like the etching section. I've tried &quot;toner transfer PCBs, and never had much luck. <br/>
I've yet to try it on PCBs, actually. When I get around to actually making something electronic again, I plan to try <a rel="nofollow" href="http://www.dipmicro.com/store/PNPB">&quot;Press-n-Peel Blue&quot;</a> transfer paper. Since it's actually purpose-made I expect better results than photo paper.<br/>
Out of 4 or 5 attempts, only one transfer worked well enough to use. Good link. Pre-sensitized boards work great and aren't really expensive, so I've used those since... I don't think any "oops" spots hurt the labeling etching, though--they give it a serendipitous, artsy look.

About This Instructable


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Bio: By day, Jeff is the Jack of All Robots at Clearpath Robotics. By night, a mad scientist / hacker / artist / industrial designer wannabe!
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