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Ideas, layouts, schematics CABINET SWITCHER?

PostPosted: 03 Nov 2017, 00:15
by tedsorvino
I would like to know if there is a safe way to switch between 2 guitar cabinets?
I'm using a 60W tube (fender style amp) and I would like to build an A/B (or even A+B) (foot)switcher box to chose between 2 cabinets (Both 8 ohm).
I know the Radial box but it's way too expensive for me.
I've heard of a switcher that uses relays, but I haven't got any clear information.
I've also read about a passive box with resistors and a switch but it's not exactly what I was thinking since it's working only with the amp bypassed.
Any ideas, info or layouts (or schematic) on how to build such a box would be much appreciated.

Re: Ideas, layouts, schematics CABINET SWITCHER?

PostPosted: 15 Nov 2017, 19:49
by strato56
Any relay that can handle the current ( 60W in 8 Ohm gives 2.7A , so go for 5A ) will do the job. Be sure not to hit the strings when switching, the amp must have no output when switching, because for a fraction of time, your tube-amp will see no load.

Re: Ideas, layouts, schematics CABINET SWITCHER?

PostPosted: 15 Nov 2017, 20:12
by BlueMeany
Just go for it using some decent (well over spec!) relays.

I've used a system like this for years without it ever causing any issues on any valve amp I've been tinkering with. The split second no load thing has never been an issue - and I've had 400W bass amps running through it.

Re: Ideas, layouts, schematics CABINET SWITCHER?

PostPosted: 15 Nov 2017, 20:21
by bmxguitarsbmx
BlueMeany wrote:Just go for it using some decent (well over spec!) relays.

I've used a system like this for years without it ever causing any issues on any valve amp I've been tinkering with. The split second no load thing has never been an issue - and I've had 400W bass amps running through it.


Technically that is quite dangerous. Some years ago someone did a "spark gap" test with a similar setup.

You could easily use a SPDT relay to alternately short out a cabinet and have a "split second Series load" situation. Using a "make-before-break" switch, where the output is shorted, would also be safer.