Me and the dog are building an 18 watt amp

[Dolamike]

Hey all, new member starting a build thread here to document progress and get advice / help along the way.

My plan is to build a classic 18 watt and build as much as I can from scratch with the exception of the chassis.

I have started with the cabinet, I’ll be making a head unit for this amp. Progress so far in the photos below.

Thanks for any help / advice along the way, appreciate it.

[Crabman]

Nice job on the head cab. Is than pine plus ply front and back?

I built a head can that looks almost identical except it’s s oak. Im considering adding a vent along the top next to the strap but concerned I may botch it. Im curious to see how others may go about these types of things.

I see a slight rounding of the edges. Would like do the same to mine .. what type/size router bit did you use for that?

Wood grain or tolex?

[Dolamike]

I used pine for the box and plywood for the back and front. For the edges I used a 3/4 roundover bit in a handheld router. For the box joints I used a jig from Rockler and a router table.

It's been fun to do some woodworking. Never been my strong suite. The right tools definitely help.

I'll be adding tolex to the outside. I didn't include the top vent either, I see some Marshall heads have it and some don't. Felt risky to add it, don't want to mess up now. Hahaha.

While I was at it I built up this amp cradle as well. Always wanted one.

[Bieworm]

Nice job on the head cab. Is than pine plus ply front and back?

I built a head can that looks almost identical except it’s s oak. Im considering adding a vent along the top next to the strap but concerned I may botch it. Im curious to see how others may go about these types of things.

I see a slight rounding of the edges. Would like do the same to mine .. what type/size router bit did you use for that?

Wood grain or tolex?

I wouldn’t bother making a top vent. There’s plenty of air inside the cab to dissipate heat with an open back. Top vents are pretty difficult to tolex

[JMPGuitars]

If you're not going to tolex, and it's a head cab, a top vent might be a good idea. Measure a lot.

[Crabman]

I did an oak head cab with half blind dovetails so no tolex on this one. I struggled with the front and back … tough to get straight lines on the cutouts using a jig saw. Strangely the corners look good, just the long straight edges not perfect

So to put a decent vent on the top of the cab would require some practice on blanks and also some advice on how to get the lines dead straight. Any ideas when using a jig saw?

[JMPGuitars]

I did an oak head cab with half blind dovetails so no tolex on this one. I struggled with the front and back … tough to get straight lines on the cutouts using a jig saw. Strangely the corners look good, just the long straight edges not perfect

So to put a decent vent on the top of the cab would require some practice on blanks and also some advice on how to get the lines dead straight. Any ideas when using a jig saw?

Generally speaking, you measure the heck out of it, and draw straight lines. Use a drill to drill out the corners (holes need to be drilled a little larger than the jig saw blade), and then you follow the lines as best you can with the jigsaw.

The trick: KEEP THE LINES.

After you cut out the hole with the jig saw, you're going to need to use other tools to fine tune then sand down to the lines you drew for the cutout.

Besides that, if you are going to route the cutouts, then you use a router with guides, or a router table with a fence and limiting guides.

Thanks,
Josh

[Bieworm]

I know what you mean Josh, but even if the line is kept it all will boil down to how good you are in shaving off the excess material. That is especially hard to do in the corner areas.
When I didn't have the proper tools to cut straight lines I always made an assembly of rectangular pieces. So fro the front panel one wide panel and two small panels to glue on each side of the faceplate cutout area, aligning with the sides of the wide panel. If you watch out for the direction of the wood grain it will afterwards be very hard to see that it's an assembly. When the assembly is glued well with the necessary pressure it's very strong.
I can make a tutorial for this if you want. There are preferably some easy toolings to be made in advance to get the best result.

[JMPGuitars]

It's a good idea to practice on other wood. If you do a great job, you can use it as a template for a router. That's the easiest thing to do. Template!

Speaking of which, for me, I would make a router template using my laser. Then there's exceptionally little effort in lining things up well.

[Dolamike]

I definitely agree with practicing on something. When building the cabinet I started by making this little box. I'm going to practice tolexing this as well.

[Dolamike]

A little more progress on the build to share. First time creating a turret board myself. Fun project. Hardest part was mapping the chassis mounting holes to the turret board.

[JMPGuitars]

A little more progress on the build to share. First time creating a turret board myself. Fun project. Hardest part was mapping the chassis mounting holes to the turret board.

That's exactly why I made those drawings 1:1.

Nice work BTW.

[Dolamike]

Worked great to print it out as guide for drilling. Thanks for the extra effort in making the layout true to proportion.

I’m building a BOM now, need to start ordering some parts.

I’d also love to find a few photo examples of a well done wiring job for this amp as inspiration. If anyone has some please post a link to the photos or thread. I’d love to learn from others experience with lead dress.

Also wondering if everyone is using CE can caps, I’ve heard mixed reviews but do not see an alternative.

[Bieworm]

here's a guideline thread for wiring layout etc..
the pics are from a PCB version of the tremolo TMB, but you'll get the idea..

viewtopic.php?p=252047#p252047

And here's an 18W Superlite TMB build on a turretboard circuit..

viewtopic.php?t=25914&start=20

[Dolamike]

Parts are starting to arrive. A little bit of progress to share. Started with heater wires. Going to wire the power supply next.

[JMPGuitars]

That's a nice start; however, you should have mechanical connection support in addition to solder whenever possible.

[Dolamike]

I totally agree.

[Bieworm]

pretty neat filament wiring! that will definitely avoid heater hum.
I wonder though how you're going to connect the wiring to the filament wires of the PT. Best practice would be to remove the green/white wires of the last EL84 socket and directly solder the (twisted) heater wires from the PT to the socket. Another option would be adding a terminal strip and join the wires at the lugs of that strip. That would be the easy route, but IMHO less desirable. The terminal strip would be positioned in a spot that's already crowded by other wires (DC) and there's a chance that there would be hum induced because at the terminal the heater wires would be lifted from the chassis.

Tip: connect the center wire from the heater to the cathode of the EL84 instead of grounding that wire. That will elevate the filament wiring by +-12V and, even though it is not that much, will be beneficial towards heater hum. Take note this is only beneficial on cathode biased output circuits. On fixed bias circuits there are other ways to elevate the heaters, but that's another discussion..

[Dolamike]

Hey thanks for the feedback, I really appreciate the tips! I think I did that same trick with the heater center tap on my 5E3 and it did make a difference. I'll try it here as well once I get the amp up and running.

I have already grounded it to the chassis, easy change though.

For the heater wires I did actually already add a terminal strip to transition from transformer wires to my twisted wires. The twisted pair flies over the wires below like a fender until it get's to the edge of the chassis. I hear ya on the chance for hum there as well, I may need to tweak that later as well.

Thanks again for the input and advice! Blue dog says thanks as well!

[Dolamike]

A little more progress to share. Hoping to do an initial start up in a week or two.