Epiphone Valve Jr: adding an 8 ohm output

I only found hints and brief mentions about modding a Valve Jr combo for 8 ohm output. So here's a step by step.

Disclaimer: Tube amplifiers are dangerous. It's quite possible that a lethal voltage remains in the capacitors for weeks. Don't do this if you don't know anything about amps.

Ok, got that out of the way. So the output transformer in the combo version looks like this:

The 4 ohm output to the internal speaker is wired to the brown and black wires. To add an 8 ohm output all you have to do is stick in a jack that's wired to the red and black wires. That's it!

That's what the standard jack is wired to. Note the red wire that isn't connected to anything. Epi was nice and left plenty of wire so anyone could use it if they wanted to.

Here's what I recommend:

1. Install a 1/4" jack in the back of the amp close enough to the 4 ohm output that the red wire will reach it.
2. Solder the red wire to one terminal.
3. Cut the black wire in two. Strip both ends of the cut.
4. Run a heavy gauge (18 AWG speaker wire should be fine) wire from the free terminal on the jack to both ends of the black wire. Twist all three conductors together and solder.
5. Put some electrical tape over any exposed conductor and box that bad boy back up.

That's all there is to it. You can test it by running the 4 ohm internal speaker briefly using the 8 ohm output. Now you can drive an 8 ohm cabinet for when you need a bit more oomph.

DIY bottleneck slide

Intro

Slides are cheap, but finding one you like isn't easy. Here's one method to make your own from a wine bottle.

DISCLAIMER: You'll be using power tools and glass in this project. Eye protection is mandatory. Gloves are recommended. A dust mask is required when you're using the dremel tool on the glass. If you chop off a lung while doing this it is not my fault.

Find a Bottle

The thicker the glass the more sustain you'll get from it, but mainly just find something you like and fits your finger as close as possible. The neck needs to be straight so it fits your guitar neck profile (which for slide purposes is mostly flat). Angled is ok, but flared is bad.

For this demo we'll be showing a Yellow Tail 2005 Shiraz, a very good year for $8 wine. This was too big for my pinky but I made it for a friend.

Note: I've only had success with this method with blue and green glass. They're harder than clear glass and that probably has something to do with it. The clear glass always cracks in a bad way.

Tape it up

You don't want to scratch any of the sides of the neck so tape it up with masking tape or whatever.

It's personal preference how long the slide is. Most bottlenecks are straight for just about the right length. The blue slide shown at the end is 2.25" in length and is just right for me. Having a slide shorter than the width of your neck isn't a huge handicap since you rarely play all 6 strings at once.

Score the cutting lines

This helps get a really straight line when we go to the dremel tool in the next step. I use a triangle file but any file with a sharp edge will do.

Say hello to my little friend

Ok, whip out that dremel tool. You want the big cutting disc (I think it's 1.5" in diameter). Start on the tip of the bottle and go round and round, following your scored line. Start with the slow dremel speed. Once you get a good cut in there, kick it into high gear but keep going around the bottle. The glass will turn red-hot where you're cutting and eventually the lip of the bottle will pop off.

Repeat for the body-end cut. This is more touchy and is where you're most likely to have a devestating crack.

There's a possibility that either cut will break in a bad way. That's ok because you can always find another wine bottle and you only spent about 10 minutes so far doing this. See the end for the reliable, slow way to do this.

Finish it up

It's unlikely that you'll get a clean break. Even if you do you want to file the ends smooth enough you won't cut yourself and that it's comfortable. Your tools are files, sandpaper, and the buffing wheel of your dremel tool.

The palm-end of the slide doesn't need to be too smooth but the tip-end does. The tip should be rounded off so that you can use it on single strings and so it doesn't catch on neighboring strings. Note the rounded tip (on the right side of the picture):

Making it comfortable

The last thing I do is take some adhesive velcro tape and cut some of the fuzzy side up and use it to make a cushion inside. This helps it to fit better. If the bottle diameter happens to fit your finger very well then you don't need this.

You can also round the spot where your finger sits on the palm-side of the bottle. You can see this in the below picture.

The slow way

If you've got a lot of patience you can keep the dremel in slow speed the entire time and actually just grind away the glass until you cut thru it all the way. This will give you a nice clean break... but it will take many hours, especially with blue glass. I've done it. It wasn't worth it. Just grab a few bottles and keep trying till you find one that works. I'm 2/2 with the blue glass, but it's hard to find.