How to link up amps?

[AlanMcKillop]

Sadly my days of heavy lifting are a thing of the past, and I've had to sell all my rack gear and 1959 AC15 Roger Allcock special. All have gone to good homes and Gary (The Runaways) will do the amp proud.

I've got a Fender Super Champ XD which I use at rehearsals and not only is it a great sounding amp, it's very light and portable. However, if we have a larger venue, I'd thought about buying another XD if they could be safely linked together. I'm sure others do this (I can only think of Brian May at the moment) and was wondering what the best way to do this would be and also of any dangers that I should be aware. Look forward to any help /advice on the matter.

[RayL]

The simplest (and cheapest) way to increase the level from your amp is to use an extra speaker cabinet (your amp has an External Speaker socket).

Your amp does not have a line level output for feeding the input of another amplifier. You can use the signal from the external speaker socket, but it needs to be reduced in level and isolated. To do this you will need a D.I. (Direct Injection) box, one with jack sockets for In, Out, and Mixer out. You don't need one of the powered variety, just a simple 'passive' one with an isolating transformer inside. Link External Speaker to the box's Input and take Mixer Out to the input of the second amp.

Ray

[AlanMcKillop]

Thanks Ray, I'll have a look at your suggestions.

I had another thought, would an A/B/Y box work? it would mean sending the guitar signal to both amps, but I don't know if the input level would be reduced as it's splitting the (guitar) signal into two.

[bob t]

If I remember correctly the 60's way of doing this was to connect a lead from the amp using the second input, the first being your guitar lead, and connecting it to the input of the second amp

Hope that's clear

Bob T

[RayL]

would an A/B/Y box work?

It would mean adjusting both amps if you wanted to make a change to volume or any of the other controls. By slaving one amp to the other, you only adjust the Master amp.

If you decided to use a Y cable it shouldn't make a noticeable difference to the level from the first amp (for the same reason that if you have a light bulb across the mains supply and you switch on a second bulb the first one does not go dim). It is possible though, that you would get a hum from both amps because you would be setting up a hum loop. A DI box with an isolating transformer (these boxes also have an 'earth lift' switch) prevents hum loops.

Bob, it doesn't look as if the Fender Super Champ XD has a suitable double input socket (and, again, it would mean adjusting both amps and the possibility of a hum loop).

Ray

[Didier]

Using an external passive speaker will not increase the volume, unless if the additional speaker has a higher sensivity. When two speakers are used in parallel, the amp's 15W electrical power remains the same and is divided between the two speakers. Anyhow, it's likely that using the socket for an external speaker disconnects the internal speaker (the user manual is not very clear about that).
You'd have to test your amp with an external speaker to check.

The AC30 was designed with two speakers only because each speaker could only withstand 15W.

On the Super Champ XD, there is a line out socket which could be used to feed a second amp, but an attenuator might be needed to avoid overloadind the second amp input.

Didier

[JimN]

Just connecting the Super Champ XD to a bigger and better speaker makes it louder (even if that disables the internal speaker).

I tried mine with a Carvin 1x12 cabinet (fitted with a Celestion Vintage 30). The available volume was much improved immediately.

JN

[Didier]

Just connecting the Super Champ XD to a bigger and better speaker makes it louder (even if that disables the internal speaker).

I tried mine with a Carvin 1x12 cabinet (fitted with a Celestion Vintage 30). The available volume was much improved immediately.

JN

The Celestion Vintage 30 has a 100 dB sensivity, which is certainly much higher than the Super Champ XD 10" internal speaker...

Another solution : use an active splitter like this one : http://www.thomann.de/gb/millenium_hx_3.htm

Didier

[RayL]

On the Super Champ XD, there is a line out socket which could be used to feed a second amp, but an attenuator might be needed to avoid overloadind the second amp input.
Didier

The Specification on Fender's own fender.com site does not list a Line Out socket, though it does list the External Loudspeaker socket.. Perhaps Alan could tell us if his amp does or does not have a Line Out?

Ray

[dave robinson]

It does have a line out, all you need to do is go from the line out to the next amp, I can't see what all the confusion is about as that's the way it's designed - it's what I do with mine if I want it louder, although I use the PA system rather than a second amp.