Adding an external cab socket to a combo.

[The_Theramist]

This could be a massively dumb question.

I have a Mk1 Line 6 Spider, 50w 1x12 version and I'd like to add an external speaker port onto it.

Now obviously the easy way would be to just have a switched socket that turns of the internal speaker but I'd like to find a way to do it with keeping it running as well.
I have a 2x12 that I want to use at the same time and/or end up with a 4x12 eventually plugged into it.

I'm sure I'll hear a bit of Line 6 Spiders suck here, but the first versions if these amps are way better than the newer ones. I love the sound of it and I'd like to use it with more.

So the question is, is there a simple way to accomplish this without messing up the rating that I'm attaching to the amp with 3 speakers?
I am now wishing I had the 2x12 version but you work with what you have.

Failing this I'm not far off selling all my amps and just buying a head and 4x12 cab.


Marc

!m!

[Zozobra]

Is it open or closed back? If it's open backed then you should be able to get to the input terminals on the speaker easy enough. All you need to do is then add a jack socket in parallel to it on some flying leads. Lamp cord is fine. Be sure to observe the polarity so that the speakers in the cab are in phase with the combo speaker.

A word of caution here; this will change the load the amp sees. Say the amp is expecting to see an 8 ohm load from the internal speaker and that is the minimum load the amp can safely drive, if you add an 8 ohm 212 cab in parallel the total load is then 4 ohms which may damage the poweramp. Alternatively you could get a bit fancier and add the cab in series to make a 16 ohm load but then you'd reduce the power output by a factor of approximately 0.7, leaving you with 35W. I suspect that you aren't adding the cab to make it quieter! In this case you may be better off bypassing the internal cab and just using the 212. This can be achieved with a switching cliff jack easy enough.

Can you post a picture of the back of the amp? Hosting it on imgur is the easiest option.

Also what impedance is the 212?

[The_Theramist]

The combo has a 16 ohm speaker, open back and my 2x12 is 8 ohm, looks like 2x4ohm in series.

Not gonna work I think.

Thanks for the response.

!m!

[satchmodog]

I have a cheap orange crush 20 I use for traveling. It sounds flat and lifeless through that 8/inch speaker, so I ran a guitar Jack and a two way switch out the back. It sounds amazing now through a 212

[Riffraff]

Remove the wires from the speakers and solder them to a jack making sure to connect the positive wire to the terminal for the tip and the negative wire to the ring terminal. You can use a small plastic job box or even something as simple as a small strip of metal bent in a 90 degree angle to mount the jack in the back of your combo. Next take a length of speaker wire and mount a 1/4" plug to one end and attach the other end to your amps internal speaker. Plug the amps speaker into your new jack to use as normal. To use with an external cab unplug the amps internal speaker and plug a speaker cable into the new jack and run the other end to your external cab.

I used a job box to install jacks wired to the 4 ohm and 8 ohm OT taps in one of my 1482's so I can swap 4 ohm or 8 ohm speakers or external cabs. I've added speaker jacks like this to all but one of my combo amps.

[zaxxon]

if it's ok to jump in on this thread,
i'm wanting to add an extension cab socket to my 1x12 combo (the combo has an 8 ohms speaker), and the extension cab has an 8 ohms speaker also. the minimum ohms the amp safely supports is 8 ohms, so the two speakers would need to be running in series (to make 16 ohms total load). i don't mind losing some power, it's a 100w amp and i don't need all that volume.

is there some way this can be done, using a socket? if it can be done, what kind of socket do i need and what would the wiring be for this setup please?

[clipless bumper]

I added a series jack to one of my combos.
You need to use a shorting jack - like this
https://www.mojotone.com/amp-parts/Jacks_1/Switchcraft-J12A-1-4-Shorting-Jack
so the amp will run without the extension speaker plugged in.

you need to install this jack in-line with the existing speaker cord.
here is a wiring diagram:

[zaxxon]

thanks so much clipless bumper, really appreciate it

i'm thinking i could also use one of these types of jack sockets, is that correct?

[clipless bumper]

yup - just pay attention to which side you solder to to keep the connections correct.

[zaxxon]

excellent thanks again, i think i already have one of those sockets here,
i will be careful and use my multimeter to check everything is correct before switching on amp