"Amp Head Switcher"...is it possible?

[Clubman35]

What I have is 2 Amp heads, both are tube. One is 35 watts, the other is 50 watts. I have 1 Marshall 4x12 cabinet that I would like to use for both heads. I know that I could wire the cabinet in stereo and run both amps into 2x12, but that's not what i'd like to do. Is it possible to build a swicher that would select one of the head and seen it to the cabinet, while at the same time, send the head not being used to some type of load? Maybe a large resistor. Is it safe to run and amp's output through a 3PDT stomp switch to a speaker or a dummy load? Many thanks.

Jim




           

[boogietube]

I've never seen one that is DIY, but here's a commercially available one:
I've searched extensively through the DIY forums and have not been able to find a schem or layout.
http://www.tonebone.com/tb-headbone-vt.htm
Sean

[calpolyengineer]

This brings you into the realm of "make before break" and "break before make" switches. The normal 3PDT switches we use around here are break before make (they break contact with the connected lugs before making contact with the disconnected lugs). What this would mean is that your tube amp would have no load connected to it for a split second, thats not good. If you can find some make before break switches then it is possible.

-Joe

[d95err]

Is it safe to run and amp's output through a 3PDT stomp switch to a speaker or a dummy load? Many thanks.

It seems awkward to run the speaker signals from the amps to your pedalboard to a switch and then back again. The pedal board would need to fit the dummy load etc.You should definately use relays for this with a switch box located near the amps and and an external footswitch that triggers the relays.

I think I've seen a DIY schematic for a head switcher somewhere, possibly by Aiken. It used one relay to mute the input of the unused amp and one DPDT relay to switch the speaker signal and simultaneously switch the unused speaker signal to a dummy load.

With the input of the unused amp muted, it will put out very little power (only the hum), and thus the dummy load resistor doesn't need to be able to handle the full power of the amp (still need a fairly large dummy load resistor thogh, just to be safe...)

[Bernardduur]

Anybody knows why they have three versions?
- Tube head switcher
- SS head switcher
- Both (tube as solid state)

Just a way to sell or really a difference?

[JimRayden]

Anybody knows why they have three versions?
- Tube head switcher
- SS head switcher
- Both (tube as solid state)

Just a way to sell or really a difference?

Tube amps need a load on the output transformer (wchich can be either a speaker or a load resistor). SS amps don't have one and can be run without a load. No load - less switching - cheaper.

------------
Jimbo

[bancika]

This brings you into the realm of "make before break" and "break before make" switches. The normal 3PDT switches we use around here are break before make (they break contact with the connected lugs before making contact with the disconnected lugs). What this would mean is that your tube amp would have no load connected to it for a split second, thats not good. If you can find some make before break switches then it is possible.

-Joe

I don't think it's a problem. If amp doesn't have any large signal out while it's being switched it should be fine...

[d95err]

Anybody knows why they have three versions?
- Tube head switcher
- SS head switcher
- Both (tube as solid state)

Just a way to sell or really a difference?

I think solid state poweramps can be sensitive to switching transients. At least, I've heard that plugging or unpluggning the speaker of a SS amp while it's on can damage the output transistors. So, the SS amp switcher may have to be designed to handle that safely.

Tube amps (I assume) are less sensitive to this, but of course require a load or the output transformer will burn as the heat builds up.

[Aharon]

Aiken Amps had schems for a head switcher,don't know if they are still available.
Aharon

[geertjacobs]

The link to the Aikenamps headswitch pdf is dead, but I still have it locally.
Feel free to PM me if you need it.
A friend of mine built one and it worked fine.

[jonathan perez]

i already did this thread a long while ago hahah...search for it, youll find alot of useful information.

Radial has good stuff, and i recommend their head switchers.