Using Combo amp Speaker as Cab

[MartyVega]

Hello everyone -- new here. I tried to search the forum for an answer, but no luck... or I didn't use the proper search terms.

Here's my situation. I have an Epiphone Valve Jr. combo, which has a speaker output/jack for its own internal 8" speaker, which is too small for my needs. The output is rated a 4 ohms.

I also have a Line 6 Spider combo with a 12" Celestion speaker -- also rated for 4 ohms.

I want to use the Line 6 as a cab for the Valve Jr. My thought is I should be able to attach a jack to the speaker itself and just plug the Valve Jr. into this. Am I correct?

Do I need to detach the Line 6's speaker wires -- or can I leave them in place and just use the second set of lugs for the added jack? In the photo below (of a Celestion but not the one in my amp), I've labeled the second set of lugs as 1 & 2 (with 2 being positive on the Line 6's speaker). I don't want to make a permanent change the Line 6, I just need a temporary solution for a one-off gig, until I've found a different amp.

Thanks for any help!

[loudthud]

You must disconnect the wires going to the Line 6 amp. Otherwise you will damage the amp.

[MartyVega]

You must disconnect the wires going to the Line 6 amp. Otherwise you will damage the amp.

Hi, that's what I needed to know. The Line 6 has quick connects and when I first looked at them, I thought they'd been soldered on, but they're not, so I'm all set I think.

I have a new Switchcraft jack lying around, and speaker wires harvested a long time ago from an old cabinet.

Thanks!

[R.G.]

Better yet, get a jack that switches contacts when a speaker is plugged in. Even a mono jack with a tip shunt will work in this case. Hook the Line 6 speaker to the jack with the "common" wire to the sleeve, and the "hot" wire to the tip shunt. Wire the tip contact to the speaker "+" and the sleeve contact to the speaker "-". Wire the VJ cord with "+" to tip, "-" to sleeve. When you plug in the jack, the jack connects tip to tip, and disconnects the tip shunt.

Be aware that having this switching connection in the speaker path may make the Line speaker intermittent as the jack gets old, worn and dirty, but it'll work great while it's clean and the contacts are making and breaking well.

[MartyVega]

I found one of those jacks in my parts box, but went with the standard mono instead.

I tested it out today -- it sounds great if you're into super-saturated tube overdrive (which I am, sometimes). But I'm going to need a much cleaner sound for most of our songs, so I'll have to borrow an amp from a friend.