Amp to Speaker Selector

[jp_nyc]

I don’t really want to buy another cabinet right now. I want to hook multiple amps up to the one I have. There are switches for this but many of them are complex beasts for people who want to switch between huge stables of guitars and amps and cabs which isn’t what I need. I just need a switch between multiple amps and one cabinet. KHE gear looks good but it’s more complex and expensive than I really need. I think that this selector by de Lisle would work, or this one. Help me do this without blowing up an amp!

 

[xStonr]

Will this work for you? Also available on amazon.

 

[jrockbridge]

Either of the de Lisle switchers should work with some caveats. You have to observe proper impedance matching between amp and speaker, or you can blow an amp output transformer on a tube amp. Also, you can’t simply turn on all your amps, ready to output to the speaker, and use a passive switcher to switch between them, because that will blow some output transformers on your tube amps. You have to observe a specific procedure, doing things in the correct order, to keep from blowing up your amps.

Tube amps need to have a speaker-type load or they blow an output transformer. Therefore, with a passive switching box, amps have to be put in bypass, or off, before you change the switcher to a different amp.

If you get mixed up, with the switcher, select the wrong amp, it’s pretty easy to blow up an amp. If you forget to switch an amp to bypass, or off, before using the selector to switch amps, you will likely blow up an amp.

You have to be careful about impedance matching between amps and cab. Tube amps are very sensitive to impedance mismatches. If you use the 16 ohm output of an amp head into an 8 ohm cabinet, or a 4 ohm cab, it can blow the output transformer. If you use the 8 ohm output of an amp into a 4 ohm cab, it can blow the output transformer. Impedance mismatches the other direction are safe, example, 4 ohm amp output to 8 ohm cab, or 16 ohm cab. Also 8 ohm amp output to a 16 ohm cab is safe.

I thought about getting a passive switcher to make it convenient to switch between different amps and different cabs. However, the convenience also makes it easier to blow up an amp by making a simple mistake. The active boxes, with protections built into them, are safer, but more expensive.

I opted for adding labels with cab ohm ratings to my wires. I have to turn amps to bypass, or off, manually unplug, and plug in wires, to change amps, and cabs, but it forces me to pay attention.

I have not blown an output transformer since labeling the wires. Years ago, I blew the output transformer of an Epiphone Valve Junior with an impedance mismatch. Thank goodness I learned that lesson on that cheap POS amp.

 

[Bob411]

Either of the de Lisle switchers should work with some caveats. You have to observe proper impedance matching between amp and speaker, or you can blow an amp output transformer on a tube amp. Also, you can’t simply turn on all your amps, ready to output to the speaker, and use a passive switcher to switch between them, because that will blow some output transformers on your tube amps. You have to observe a specific procedure, doing things in the correct order, to keep from blowing up your amps.

Tube amps need to have a speaker-type load or they blow an output transformer. Therefore, with a passive switching box, amps have to be put in bypass, or off, before you change the switcher to a different amp.

If you get mixed up, with the switcher, select the wrong amp, it’s pretty easy to blow up an amp. If you forget to switch an amp to bypass, or off, before using the selector to switch amps, you will likely blow up an amp.

You have to be careful about impedance matching between amps and cab. Tube amps are very sensitive to impedance mismatches. If you use the 16 ohm output of an amp head into an 8 ohm cabinet, or a 4 ohm cab, it can blow the output transformer. If you use the 8 ohm output of an amp into a 4 ohm cab, it can blow the output transformer. Impedance mismatches the other direction are safe, example, 4 ohm amp output to 8 ohm cab, or 16 ohm cab. Also 8 ohm amp output to a 16 ohm cab is safe.

I thought about getting a passive switcher to make it convenient to switch between different amps and different cabs. However, the convenience also makes it easier to blow up an amp by making a simple mistake. The active boxes, with protections built into them, are safer, but more expensive.

I opted for adding labels with cab ohm ratings to my wires. I have to turn amps to bypass, or off, manually unplug, and plug in wires, to change amps, and cabs, but it forces me to pay attention.

I have not blown an output transformer since labeling the wires. Years ago, I blew the output transformer of an Epiphone Valve Junior with an impedance mismatch. Thank goodness I learned that lesson on that cheap POS amp.

"You have to be careful about impedance matching between amps and cab. Tube amps are very sensitive to impedance mismatches. If you use the 16 ohm output of an amp head into an 8 ohm cabinet, or a 4 ohm cab, it can blow the output transformer. If you use the 8 ohm output of an amp into a 4 ohm cab, it can blow the output transformer. Impedance mismatches the other direction are safe, example, 4 ohm amp output to 8 ohm cab, or 16 ohm cab. Also 8 ohm amp output to a 16 ohm cab is safe."

Pretty sure that's true for solid state amps and backwards for what a tube amp needs. Also, only one step, not two.

100% agree the convenience isn't worth it. At least for me. I'm sure I would forget to turn an amp off.

 

[jrockbridge]

"You have to be careful about impedance matching between amps and cab. Tube amps are very sensitive to impedance mismatches. If you use the 16 ohm output of an amp head into an 8 ohm cabinet, or a 4 ohm cab, it can blow the output transformer. If you use the 8 ohm output of an amp into a 4 ohm cab, it can blow the output transformer. Impedance mismatches the other direction are safe, example, 4 ohm amp output to 8 ohm cab, or 16 ohm cab. Also 8 ohm amp output to a 16 ohm cab is safe."

Pretty sure that's true for solid state amps and backwards for what a tube amp needs. Also, only one step, not two.

100% agree the convenience isn't worth it. At least for me. I'm sure I would forget to turn an amp off.

Impedance mismatches work the same with solid state amps as they do with tube amps. If the ohm of the speakers is a lower number than the output of the SS amp, you can damage the amp.

What is different is the speaker load requirements. Solid state amps do not typically have output transformers, so they do not require a speaker load the way a tube amp does. It’s easy to blow a tube amp output transformer if there is no speaker hooked to the amp. You can turn a SS amp up without any speaker attached and it will be fine.

If you wanted to use a passive switcher and all the amps were typical SS without output transformers, you could leave them all powered up and switch between amps to your hearts content. No need to put the SS amps in bypass or turn them off before changing the switcher.