When I saw gmoon's Instructable for the original ValveLiTzer, I decided to make two guitar pedals based on his design - one for a friend of mine (the ValveLiTzer Redux), and one for my father-in-law (the ValveLiTzer Trifecta). Both are guitar players (obviously) and I wanted to give them something unique.
My first version, the ValveLiTzer Redux, features a prominent "figure 8" design with the tube sticking out the top, etched aluminum plates, and a glowing blue base.
This Instructable will describe how I built the second one. The guts are the same, but as you can see the case is very different. It's also made of Baltic Birch plywood, but the case is a rounded square with the tube inset and mounted sideways. There are aluminum plates on all the sides, and the knob labels glow when the pedal is plugged in.
If you want to make one of your own, you don't have to use gmoon's exact schematic. You could fit a lot of different pedal designs inside this 5x5 inch case, changing the labels and knob locations as necessary.
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Step 1: Design, Materials and Tools
Both gmoon's and my first ValveLiTzer feature a vacuum tube sticking out the top of the case, unprotected from feet, cables, and damage in general. I wanted this version to be smaller, more streamlined and most importantly, to protect the tube.
I used one of my favourite materials, Baltic Birch plywood (aka Russian Birch plywood) to build the case. The case is actually several layers stacked together. The main case is a layer of 1/4" plywood glued to a 3/4" piece. The bottom of the case is a single layer of 1/8" plywood. The top is the most complicated. It is made of a 1/8" plywood bezel, with 1/8" polycarbonate hidden inside. A layer of aluminum duct tape is applied to the plastic, and acts as a mask for the component labels. The top is laminated with a wood veneer to conceal the plastic and the label mask.
The sides feature inlaid aluminum, with the front panel etched using electrolysis.
It's... kinda tricky to make, but I'm sure you can do it. With the right tools, that is!
1 6x6" piece of 3/4" Baltic Birch plywood
1 6x6" piece of 1/4" Baltic Birch plywood
2 6x6" pieces of 1/8" Baltic Birch plywood
1 5x5" piece of 1/8" transparent polycarbonate, acrylic or Lexan plastic sheet
about 25 square inches of 1/8" thick aluminum plate (brass or steel would work, too)
a few flat head 1/2" wood screws
20 inches of aluminum duct tape
Two-part Epoxy (the longer the set time, the better)
packing tape (optional)
clear acrylic finish (I used Minwax Polycrylic)
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
5 blue 5mm LEDs
1 amber 3mm LED
2 1000uF 25V electrolytic capacitors
2 1M resistors
1 470k resistor
1 220k resistor
1 47k resistor
1 510 ohm resistor
1 120ohm resistor
1 220 ohm resistor
2 0.01uF polyester, mylar or ceramic capacitors
1 0.1uF ceramic capacitor (or replace with a 33uF electrolytic for more boost)
A variable-speed scroll saw
A good scroll saw blade for wood (I use Olson reverse skip tooth PGT blades)
A crown tooth scroll saw blade (for cutting plastic)
A drill press and assorted bits (a hand drill would work in a pinch)
A band saw (or a scroll saw with metal cutting blades)
Lots of sandpaper
A sharp knife (use a fresh blade for this - you'll need it!)
A computer and laser printer
An electrolysis bath
A clothes iron
Step 2: Print the Patterns
Attached below is the pattern I used to make the pedal (in both Illustrator and PDF formats). Print out four copies of the case pattern on cardstock or regular paper (I like to use cardstock because it holds together better during cutting). Print one of the label pattern on regular paper. Print the electrolysis-resist pattern on glossy photo paper using a laser printer set to its darkest setting.
Using spray adhesive, paste one pattern on the 6x6" piece of 3/4" plywood. Paste one pattern on each of the 1/8" pieces of plywood. Depending on the spray adhesive you use, you may have to let the glue dry for a minute or so before sticking it onto the wood, or it will be too difficult to get off later.
If the plastic sheet you have still has a layer of protective film, you can glue the pattern right onto it. If not, stick down some packing tape and glue the pattern onto that.
The aluminum plate can be cut on its own, but I recommend sandwiching it between two layers of scrap (low-grade) plywood. This makes it much easier to cut.
Allow all the patterns plenty of time to dry, so they don't accidentally peel while you're cutting them out.
Step 3: Cut Out the Wood and Plastic Patterns
I use a DeWalt DW788 variable speed scroll saw. It's really fantastic. But enough about my favourite tool in the workshop.
The easiest piece to cut is the base. Simply cut around the outside line, ignoring all the extra lines that show where the metal plates and components go.
To make things easier, the main case is cut in two parts. Start by cutting out the holes where the in and out jacks and the power jack will go, from the 3/4" plywood. Don't cut anything else. Next, glue the 1/4" plywood to the bottom of the 3/4" piece, being mindful not to get any glue on the cutouts. Clamp the pieces together no minimize any visible seam.
When the glue is dry, drill a pilot hole for the interior cuts. Then carefully cut out the inside and outside edges of the main frame. Take note of where the aluminum pieces will be, and cut out the notches for them. Also be aware of the support pieces on either side of the switch.
Cut out the top panel bezel carefully. Do the outside first, then drill a pilot hole and do the inside cuts.
Finally, install the crown tip blade into the scroll saw and turn the speed down to about 1/4 (setting 3 on the DeWalt 788). This will allow you to cut the plastic without melting it. Cut around the very inside lines. The plastic piece should fit perfectly inside the wood bezel. Finish the plastic piece by drilling 3/32" pilot holes for the switch and two adjustment knobs.
Step 4: Cutting the Label Mask
The pedal is designed so that the labels for the knobs and pots are illuminated from inside. This is accomplished by using a plastic top, so that the light can shine through. A wood veneer is applied on top of the plastic so that the wood itself appears to glow when turned on.
In order to just have the labels illuminate, a mask must be placed between the plastic and the wood. The mask must block all the light so that even in complete darkness only the labels glow.
The thinnest, cheapest, most opaque and most readily available material for the job is aluminum duct tape. It is backed with a strong adhesive that sticks very well to the plastic, and it can be cut with a sharp knife.
Start by laying a layer of duct tape on the top of the plastic. It should be absolutely flat with no wrinkles. The edges should line up perfectly with no seam - hold up the plastic to a light source to make sure no light leaks through. Trim the duct tape flush with the edge of the plastic. You can use a blunt, smooth object to further flatten the duct tape against the plastic. I used the handle on a pair of scissors.
Print out the label template and position it on the duct taped side of the plastic. Using masking tape, secure it to the plastic on all sides. It should sit perfectly flat.
Now, here comes the most fiddly part of the build. Using a fresh blade, cut out the letters through the paper and duct tape all the way to the plastic. Be careful at corners and small curves. Using the tip of the knife or a small pair of tweezers, peel off the cut out letters. It pays to really, really take your time with this, because if you screw up it's very hard to fix. I was lucky and didn't make a mistake - I encourage you to do the same.
With all the letters cut out, remove the paper template and carefully flatten any raised duct tape edges. Only push down, not side to side - otherwise you may tear the aluminum.
Finish the piece by sanding the bottom of the plastic with 220 grit sandpaper to give it a frosted appearance. This will help diffuse the light.
Step 5: Glue the Case Together
The case goes together in a few steps.
Start by gluing the top bezel onto the main frame of the case using wood glue. Make sure that the rounded corners line up as closely as possible (though they may not be perfect just yet!) Set a weight on top of the frame as it dries.
With the bezel in place, pop in the label mask plastic layer. In my case, the plastic was actually about half a millimeter thinner than the wood, causing a visible edge at the transition. I fixed the problem by gluing narrow pieces of wood veneer all the way around the inside ledge. Hopefully, the plastic you get will match the thickness of the wood veneer and you won't need to do this.
When the bezel and plastic are the same thickness, you may glue in the plastic label mask. Apply wood glue or epoxy to the inside ledge and pop in the plastic. Place a weight on the case so that the plastic is held flush with the bezel while the glue dries.
The last thing to glue on for now is the wood veneer. Start by preparing two flat pieces of wood slightly larger than the case, and two or more clamps. Cut a piece of veneer larger than the case itself, and set the veneer and case side by side. I used strong spray adhesive to stick them together. Spray both the top of the case and the veneer, wait a minute or two, then stick them together. Immediately clamp them using the flat pieces of wood on the top and bottom of the case. Let dry for a few hours.
When the spray adhesive is dry you may remove the clamps, and carefully cut away any excess veneer with a sharp knife.
Step 6: Drill the Component Holes
Previously we drilled three pilot holes in the plastic. Flip the case over so you can see them from the inside. Some glue may have squidged through the holes - yank it out now. Find the correct size drill bits for the components you're mounting. In my case, the switch was 1/2" and the potentiometers were 5/32". I used regular drill bits, not Brad point or Forster.
It's very easy to tear up the veneer, splinter the plastic, or rip apart the aluminum duct tape if you drill improperly. Drill from the inside of the case* using the pilot holes to help align the bit. The key here is to go very slowly, clearing away debris, and prevent the case from moving while pressing it firmly onto a scrap piece of wood. It would probably be a tremendously bad idea to use anything other than a drill press for this task. You've been warned.
Watch as the bit cuts through the various layers and adjust your speed accordingly. If at any point you can't see what you're doing, stop and clear away any debris. When you get to the veneer layer, go very very slow to avoid tearing it. The veneer's bond to the plastic is OK, but it's not as strong as if it were glued to wood.
Hopefully, you'll end up with nice, clean holes. Hopefully, you won't have to do repairs or start over...
- One thing that I ought to have tried is drilling the pilot hole through the veneer, then drilling the larger holes from the veneer side. Feel free to make a test piece to try it this way, and be sure to let me know if it works!
Step 7: Attach the Bottom Plate
Before doing any sanding, staining or finishing, the bottom plate will be aligned with the top and screwed in place (temporarily). This way, we can sand the whole thing as one piece, ensuring a seamless transition between the pieces when the pedal is finished.
Tape the bottom plate onto the case with masking tape, getting the alignment as close as possible. Note the size of the screws you'll be using and choose a drill bit to match - I used a 7/64" bit. Drill a pilot hole in each of the four corners. Then, add a countersink to each of the holes with a countersink bit.
Screw in all four screws. They should sit flush with the bottom of the case. When you're satisfied, remove the masking tape.
Step 8: Sanding
With the bottom plate temporarily in place, you may sand the top and sides of the case. I used a belt sander to do the round sanding of the edges, then did a finish sand by hand using 320 grit sandpaper. Since all the layers including the veneer, main case and bottom plate are all being sanded as one piece, they end up perfectly flush with each other. Nice!
I sanded the top of the case with 320 grit sandpaper until it was silky smooth. I did the same with the bottom plate. You can use even finer sandpaper if you wish, but it really isn't necessary if you're using softwood products to build the case like I did.
When the sanding is complete, wipe the case clean with a lint-free cloth. I used the T-shirt off my own back. Well, an old T-shirt that had been turned to rags. ;)
Step 9: Applying Finish
I decided not to stain the case, worried that the LEDs wouldn't sine through as well. I probably could have used a light stain of some sort, or brighter LEDs, but in the end decided to just go with a glossy finish. I used Minwax Polycrylic, my fave water-based finish.
First unscrew the bottom plate. If you paint the case with the plate attached, you risk gluing it to the case, without any electronics installed yet!
The first layer of finish should be very thin. The acrylic finish soaks right in and basically prepares the wood to accept additional coats of finish. Don't bother applying finish behind where the metal plates will go. After about two or three hours the finish is dry enough to be sanded. Use 220 or 320 grit sand paper, sanding until the case is smooth again. Again, wipe with a lint-free cloth.
The second layer of finish can go on a bit thicker, and will end up looking a little glossy once it dries. It will also feel a little rough. Once dry, sand with 320 grit sandpaper and wipe clean.
By the third coat you'll start to see a much nicer looking finish. In fact, you may be able to stop here. I only applied three coats to the sides. If you decide to add a fourth layer, sand again with 320 sandpaper and wipe clean.
The fourth coat will probably be all that you need. Once it dries you're done - don't sand it!
Step 10: Cut the Metal Plates
I'm fortunate to work at a company that has a metal shop. I can get small scraps of aluminum for free, in various thicknesses. I decided to use 1/8" 6061 aluminum to make the plates. You can use whatever you've got, as long as it's strong enough to support the input and output jacks. Aluminum, brass, copper, steel or even some plastics would be fine.
The least expensive tool a hobbyist is likely to have that can reliably cut 1/8" aluminum is a bandsaw. I happen to have one that I scored on Kijiji for a good price. You can also use a scroll saw, but blades don't last long and it's hard to control (especially with 1/8" metal!)
Measure out the plates using the template as a guide, noting the positions of the drill holes. The power jack can be centered on the width of its plate, but the input and output jacks are offset a bit. Measure carefully! Mark the cut lines using a fine tip marker, and be sure to recall which side of the line you need to cut on. Otherwise, you may end up with a plate that is slightly undersized.
Before cutting, drill the holes using a regular drill bit. The input and output jacks I used needed 7/32" holes. I the power jack was 5/32". Since you may use different parts than me, measure the parts you've got to get a perfect fit.
The hole for the socket is too large to use a regular bit. Use a step bit if you have one. I really ought to buy one someday. I used a metal-cutting blade on my scroll saw instead. It worked, but it's very hard to control. 1/8" 6061 aluminum is pretty tough!
With the holes drilled you can cut out the parts. Work carefully, and be aware that the metal will heat up pretty fast. By the end of the cut the heat radiating from the metal was near my pain threshold. Dumb, I know! Use gloves to cut the metal if you need to.
The edges will probably be a bit rough and will have burrs. They may not even fit perfectly. Sand them smooth with sandpaper on a flat surface. Test-fit the pieces into the case often so that you don't over-sand.
Now sand the face of the plate that faces outward. I started with 320 grit sandpaper, sanding in a single direction at a 45 degree angle. I found that this looked nicer than circular swirls. Simply place the sandpaper on a flat, sturdy surface and rub the plate on the sandpaper.
Once the plate is smooth with an even pattern, replace the 320 grit paper with 2000 grit automotive sandpaper. Sand with the same motion in the same direction. The 45 degree pattern will still be visible, but the finish on the plate will be super-smooth and shiny.
Once the sanding is done, wash the plates under running water and dry them off immediately.
Note that sanding makes a lot of very fine aluminum dust. Not only does it get all over your hands, it can also contaminate the pristine finish on your case. Wipe the plates clean or wash them off before test-fitting. Also, don't eat or inhale the dust. It's probably really bad for you.
Step 11: Etch the Metal Plates
To etch aluminum plates you only need some basic materials, a 12VDC power supply (a modified computer power supply or a car battery charger), a laser printer, an iron, some packing tape and some nail polish.
I used the toner transfer method to make a "resist" layer for etching. I started by creating a graphic in Illustrator (attached below). I put multiple copies of the same stencil on one page, because the printing step makes a lot of defective stencils. The patterns are mirror images so that they appear correct when transferred to the metal.
Print the stencils using a toner-based laser printer or photocopier, onto glossy photo paper. Note that it must absolutely be glossy paper (not satin finish!) or the toner won't transfer to the metal very well. I know. I learned this the hard way! Check the printout and select the best one. Chances are, you'll get maybe one or two that are actually usable. The others will have spots here and there where the toner didn't stick to the photo paper. Be careful when you handle the stencil, as it will flake off very easily (if it doesn't flake off easily, you won't get a good transfer)
Cut out the best stencil and place it face-down on the metal plate. I used Kapton tape (a special heat-resistant tape) to hold it in place, but it's not necessary. Then, place a sheet of ordinary paper on top. Some photo papers have a plastic backing that will melt onto the iron if allowed direct contact, which is why the regular paper is important.
With the iron set to medium-high (cotton setting in my case), apply heat to the stencil and metal for 4-5 minutes. For the first two minutes just hold the iron in place without moving it. After that, alternate moving and holding the iron. Try dragging the edge of the iron along the stencil to put extra point pressure on it, which will help the transfer process and squeeze out air bubbles. Make sure you cover the corners too; I found they were the hardest to get a good transfer.
When you're done fusing the stencil to the metal, turn off the iron and place a large, flat, heat-resistant object on the stencil and metal as they cool. This is to prevent the photo paper from buckling before the toner has re-set. I used a glass 9x13 baking pan.
When the metal is cool you may peel off the photo paper. It should leave behind a shiny layer of black toner, hopefully with no voids or errors. Inspect the transfer carefully and correct any places where the toner did not transfer properly using nail polish.
To protect the back and sides of the metal plate from etching, cover them with ordinary packing tape. I like to stick a stripped wire to the back of the plate, so that I have someplace to attach the positive lead.
Now, head over to your etching tank. I used a plastic ice cream container filled with ordinary tap water and about 2 tablespoons of salt. You may also use washing soda; either will work. Place a piece of scrap aluminum on one side of the tank and attach the negative (black) lead to it. Then place the plate to be etched on the other side with the positive (red) lead attached. Connect the negative lead to the negative or ground connection on the power supply, and connect positive to the +12V line. When you flip on the power, you should see a cascade of bubbles emerge from the negative plate, and a smaller amount from the plate being etched. I assume these are hydrogen and oxygen, so please do this away from sources of spark and flame!
In 3-4 minutes the plate will be etched with a quarter-millimeter deep permanent pattern. Its gray matte finish contrasts nicely with the polished background. Peel off the tape, and clean off the nail polish and toner using nail polish remover. Wash in water, and you're done!
Step 12: Glue on the Metal Plates
Once the metal plates are complete (and etched), you may glue them in place (except the socket plate, more on that later). I used JB-Weld because it sticks very well to both aluminum and wood. Regular epoxy may work just as well.
Mix up the JB-Weld and apply a thin coat to each of the metal plates. Stick them down and hold in place for a few minutes. Make sure that the etched plates are facing the right direction! Immediately wipe off any squeeze-out that may impact fit or finish of the pedal later on.
The plate holding the socket is a bit different - don't glue it in place with the rest. Start by modifying the socket by cutting off the screw tabs. I used a band saw, but a dremel or bending them off may work just as well. Glue the socket onto its plate using epoxy or JB-Weld. When the glue is dry, solder the various components and wires onto the socket tabs as shown in the Wiring step. Once that's done you can come back and glue the socket and plate in place on the frame.
Step 13: Install Components
It's a tight fit for some of the components. Some will need wires soldered onto them before mounting them in the case.
Start by soldering wires onto the input and output jacks, the power connector, and the switch. These are the hardest to reach when the components are installed. The wires should be long enough to reach to the opposite corner of the case, just in case.
Insert the input and output jacks first. You will have to bend flat the leads closest to the jack's opening so that it will fit in the case. Fasten the jack using the included nut.
Install the switch next. Try not to over-tighten the nut too much, or you may risk cracking the top of the case.
Next install the potentiometers. Be mindful of which goes where - use the schematic as a guide and install the 500k audio pot in the "volume" position and the 50k linear pot in the "drive" position. Orient the pots so the pins face away from the jacks.
Last, install the power jack. It might be a tricky fit (in fact, you could even install it in the panel before gluing in place).
The tube socket won't be installed until some components are wired up first.
Step 14: Wiring
Start with the tube socket.
By suggestion from an Instructables member on my other pedal, the ValveLiTzer Redux, I decided to fit a small 3mm amber LED into the hole in the middle of the socket to illuminate the tube. Do this by soldering a 510 ohm resistor to one of the LED's pins, close to the body. Fit the LED into the hole, then solder its pins directly to the contacts on the socket, with the LED anode going to V+ (pin 4) and the LED cathode (through the resistor) to ground (pin 5).
Pins 1 and 3, and 6 and 8, are connected together. Run a short jumper between them.
Several components can also be soldered directly from one pin to the other. Follow the schematic and solder some of the resistors and one of the capacitors in place, making sure there are no shorts.
Finally, solder long wires to pins 8 and 2, for connecting inside the case later on.
With the socket wired up, you can install it into the case. Make sure that pins 4 and 5 remain accessible!
Next up are the big filter capacitors. The ones I used (1000uF, 25V) happened to fit perfectly in the space on one side of the switch. Twist together the positive leads and solder them together. Connect the two ground leads together with a short piece of insulated wire. Then, hot-glue the caps into the space. Run the leads from the power jack to the capacitors, connecting the negative wire to the negative leads on the capacitor, and the positive lead to the twisted positive leads on the caps.
From there, proceed according to the schematic, running wires as neatly as possible to their respective destinations. The few components that still need to be added can be soldered directly to potentiometer pins or 1/4" jack pins, where necessary. Don't forget to run wires from pins 4 and 5 (V+ and GND) on the socket to the pins on the filter capacitors.
Quadruple-check your wiring, and use a multimeter (if you have one) to look for shorts and check for continuity.
Step 15: Wiring - LEDs
The pedal will work now, but in order to actually see the nifty backlit labels painstakingly carved into aluminum foil you'll need to add some more LEDs.
I added a total of five blue LEDs, one for each label. I chose blue because the intended recipient of the pedal is colorblind can't see red or green - otherwise I may have used green instead. White LEDs would actually look quite nice, come to think of it.
I wired the LEDs in two series chains, one with 3 LEDs and the other two. Each chain has a current limiting resistor. I used a 120 ohm resistor for the three LED chain, and a 270 ohm resistor for the two LED chain. You could of course add more LED, but there isn't much point.
Select one LED from each chain and solder the resistor onto one of its leads. It doesn't really matter which one, but take note of which lead it's soldered to (anode or cathode) so you can wire up everything with the correct polarity later.
Glue the LEDs in place, so that they point in the general direction of one of the labels. Then run wires between them, being aware of polarity. Make sure each chain eventually reaches ground on the cathode side and V+ on the anode side.
Check for shorts throughout the circuit, then try plugging it in. The LEDs should all turn on. If they don't re-check your wiring until they do!
Step 16: Finishing Up
With the wiring done you can screw on the bottom of the case.
Install the tube, if you haven't done so already.
Add rubber feet to the bottom if you like, to prevent the pedal from sliding around on the ground.
Now plug it in and test it! Fiddle with the Drive and Volume knobs to make sure they do what they're supposed to. Test the Bypass switch to make sure it, um, bypasses. Listen for noise or hum from the output. If it's above an acceptable level, look for grounding problems or change your adapter. I found that a smaller switching-type AC adapter introduced far less hum into the output than a regular bulky transformer type.
When everything works perfectly, be sure to show off your new home-built tube based effects pedal, emphasizing how cool you are because you have one and they don't. Before they get too jealous, point them towards this Instructable so they can make one one their own. ;)