Is there a way to use one extension speaker on two different amps?

**PaulW10** · 08-02-2018, 06:38 PM

Hi All,

May I ask for the group's help with a question?

I have an outdoor solo guitar gig coming up (mood music for a farmers' market. I call it vegetable buying music!).

I have a Quilter 12" extension cabinet with a 1/4" input. I'd like to use two different combo amps with it....one is a Quilter Micro Pro (solid state) for my amplified nylon string, and the second is a Mesa tube amp for my archtop. Both combo amps have 1/4" extension speaker outputs and both will also be plugged into their own speakers in addition to (hopefully) the extension cabinet. I'm trying to spread out my sound a little.

I will only be playing the amps one at a time of course, although if it works I may have a mic plugged into the Quilter amp as well (not for vocals, but for announcements and possibly to mic my guitars if it works)

Am I able to do this with some kind of Y connector speaker cable? Any precautions? Any suggestions on which type/brand cable connector to use?

I know I could switch the cables when I switch amps, but I'm hoping I could avoid that.

Any advice will be sincerely appreciated.

Thanks in advance!

Paul

**blille** · 08-02-2018, 07:14 PM

Radial Headbone is a purpose-built switching device that lets you toggle between two different tube amp heads while using a single speaker cab.

Radial Headbone VT - Tube Amp Head Switcher | Sweetwater

**PaulW10** · 08-02-2018, 08:46 PM

Originally Posted by blille

Radial Headbone is a purpose-built switching device that lets you toggle between two different tube amp heads while using a single speaker cab.

Radial Headbone VT - Tube Amp Head Switcher | Sweetwater

Thanks for your reply. Since each amp head will already have its own speaker ( as they're combo amps), would this kind of device still be necessary for them to share an extension cabinet?

**blille** · 08-02-2018, 08:57 PM

Originally Posted by PaulW10

Thanks for your reply. Since each amp head will already have its own speaker ( as they're combo amps), would this kind of device still be necessary for them to share an extension cabinet?

Sorry, I can’t answer authoritatively.

You usually need to have the right load for tube amps, this is a unique situation since there’s partial load.

**sgosnell** · 08-02-2018, 09:11 PM

It depends on the amp, but there is a definite risk of blowing the output fuse. With some amps, it happens every time two amps are connected to one external speaker. With a tube amp, you can blow the output transformer. Don't ask me how I know this. I wouldn't try connecting both at the same time.

**Jimmy Mack** · 08-02-2018, 11:19 PM

I would never have 2 outputs connected at the same time, to a speaker. You're not just addressing a remote speaker, you are (in effect) connecting 2 separate amps' output transformers! And the power tubes! #$^%&*&()* Ouch.
Try to find another way and good luck.

**KirkP** · 08-03-2018, 12:16 AM

The Y-cable idea is a no-go. You’ll either need a switch box or do it manually. Make sure the parallel impedance of the speakers is within the specified range for each amp.

**PaulW10** · 08-03-2018, 01:44 PM

Thank you everybody for your help here. After reading all your posts it dawned on me I need to quite being lazy and just get myself a second extension cabinet for the second amp.

The logic of my little brain first told me a Y-cable makes sense, but something also told me I should really ask here first. I'm glad I did. Thanks again!

**Woody Sound** · 08-03-2018, 03:04 PM

I would think any good quality A-B switch box would do it, but ICBW. Do NOT use an A-B-Y box. You don't want to accidentally combine them. Here's an example. If you're not sure about the speaker load on it, send them a note asking.

Invisible Sound Invisible Sound guitar small A B switch box | Reverb.

**John A.** · 08-03-2018, 03:35 PM

Originally Posted by PaulW10

Thank you everybody for your help here. After reading all your posts it dawned on me I need to quite being lazy and just get myself a second extension cabinet for the second amp.

The logic of my little brain first told me a Y-cable makes sense, but something also told me I should really ask here first. I'm glad I did. Thanks again!

No, lazy would be bringing only 1 combo amp and using it for both guitars. You're well into diligent/ambitious territory just by asking the question.

John

**PaulW10** · 08-03-2018, 04:05 PM

Originally Posted by Woody Sound

I would think any good quality A-B switch box would do it, but ICBW. Do NOT use an A-B-Y box. You don't want to accidentally combine them. Here's an example. If you're not sure about the speaker load on it, send them a note asking.

Invisible Sound Invisible Sound guitar small A B switch box | Reverb.

This is an intriguing little gadget. Just to be able to easily use two guitar with one amp would make this a real nice thing.

Anyway, I did ask them about how it would work for this particular situation. I will report back what they say. Thanks very much for suggesting it.!

**PaulW10** · 08-03-2018, 04:06 PM

Originally Posted by John A.

No, lazy would be bringing only 1 combo amp and using it for both guitars. You're well into diligent/ambitious territory just by asking the question.

John

Thanks John!!

If I could pull my car right up to where I'm setting up, I wouldn't care too much about the load in. However, I have to hoof everything I bring a block or two so I'm trying to go as easy as I can.

**ccroft** · 08-03-2018, 09:15 PM

Oddly enough, I did this with a Mesa Combo, Quilter Aviator 8 and.... you guessed it... a Quilter extension cabinet. Just comparing sounds.

I used a basic AB box. Can't remember the name. I got a bad ground loop hum which made it totally useless. The specs for the other far more costly box that was linked to talks about a ground isolation circuit to avoid exactly this.

No damage as long as you have the internal speaker on the Mesa connected. If not, when you switch to the Quilter you're running the tube amp with no load. Not good. That expensive stomp box also has a circuit to switch in a resistor in place of the speaker to keep a load on the circuit. I can see why it costs so much more. Might be worth it.

**Duotone** · 08-05-2018, 11:30 AM

Originally Posted by blille

Radial Headbone is a purpose-built switching device that lets you toggle between two different tube amp heads while using a single speaker cab.

Radial Headbone VT - Tube Amp Head Switcher | Sweetwater

Delisle and Palmer build similar switches.

de Lisle Amp-Speaker Selector V1 – de Lisle Guitar Co.

PTINOS Palmer MI TINO SYSTEM - Switching System 2 Guitar Amplifiers to 1 Cabinet with Remote Input

Still, all these solutions are pricey, it seems.

**DRS** · 08-07-2018, 09:32 AM

I know this is low-tech but why not just turn off one amp, and move the 1/4" out to the extension cab to the second amp, then turn the second amp on. If you are playing mood music for a farmers market, nobody's going to care. Do you really want to spend $300+ on a second cab?

**Greentone** · 08-07-2018, 10:37 AM

Lots of good advice here. Just remember, DO NOT HAVE TWO AMPS TRYING TO FEED ONE CABINET AT THE SAME TIME. This will cause electrical problems for the two amps. You will need to switch between the amps and the cabinet with a switch box, or by going back and forth with a cable.