Matchless Hotbox

[gators81]

Any body out there have a PCB layout for the Matchless Hotbox? My band's lead singer wants me to build him a clone. I have the schems and know how to breadboard, just figured i'd check here first.

[Transmogrifox]

Hmmm... not sure I have ever seen a layout.  However, it's a relatively simple build.  I usually build things directly from a schematic and let the layout be whatever it is.  As long as all the right points are connected you're good.

Be careful on this one because it does use a high voltage on the plates
Have fun.

[gators81]

He wants this as a pedal. Told him this was a schem for an amp, not a pedal. Not sure if anyone has tried to design the circuit to go in a pedal enclosure.

[Mike Burgundy]

It actually *was* a pedal. Big one though, but it came with it's own footswitch on the box and everything.
It does carry high voltage - if you have any doubt whatsoever on dealing with that - don't. DC at tube plate voltages can and will kill, potentially even when the unit isn't plugged in.
Knowing Matchless this thing was built pojnt-to-point. Turretstrip is probably the easiest way, and incredibly sturdy too.
hih

[gators81]

Thanx for the info. I assumed it was an amp because of the voltage level and the tubes. Never built an amp before, just pedals. Not sure I want to attack this one. The schem doesn't look that hard, and I figured it was probably point to point, but the voltage level kinda frightens me. I might decide to try it eventually.

[Guitartoma]

It is a point to point wired unit, runs on 110V. Great unit, high gain, although tends to add a lot of brightness. It is never really bypassed; it has two channels, like an amp: clean and dirty. There is no indicator (other than screaming distortion) to tell you which channel is on. It is big, 1/8" chromed steel chassis, weighs a ton.

But to answer the initial question, there is no PCB layout as it has no PCB!

[phil]

Here's a link to JD. Sleep's site with schematic, bill of materials and an eyelet/turret board layout. As Mike Burgundy mentioned, you could just use turretstrips or even Terminal strips instead of a board.

http://www.generalguitargadgets.com/projects/17-distortion/96-hotbox

Hoffman Amps actually has a Tube pedal chassis that looks like it would work for this as it has hole for 2 tubes and a metal guard for the tubes.
(Scroll down to about the middle of the page)

http://www.hoffmanamps.com/MyStore/perlshop.cgi?action=template&thispage=Chassis&ORDER_ID=286411742

It does run at high voltages though....

[zambo]

I have had some pretty good luck building high voltage designs and then just undervolting them actualy. You might try to build one and use just a simple voltage doubler so you can use a 12volt dc walwart for the heaters and then run the doubler leads to the plates at 24. I may not sound like the actual hot box but it might sound really good... I will try to build the low voltage version for fun. I need more caps....

[MartyMart]

Why not go this route ?
http://www.diystompboxes.com/smfforum/index.php?topic=46806.0

ROG J-Fet emu amps can be great and give the "Flavor" of the real thing, you may need to make a few adjustments
for the "Hotbox" version.

MM.

[gators81]

Damn. Didn't even think of checking at GGG. I've never built anything with tubes yet. Kinda been shying away from it because of my lack if experience with tubes. I just finished the Dr.Boogey layout from Atlantic PCB (gaussmarkov) and still have to bias it. Might tackle the Matchless next.

Another first for me is biasing. Can I assume it is similar to biasing the channels on an old 2", 24 track tape machine?