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Preamp switcher?

Discussion in 'Amps and Cabs' started by telewacker, Jun 8, 2006.

  1. telewacker

    telewacker Member

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    I'm looking for something analogous to a head switcher, but switches inputs and outputs from two preamps to a common power amp, as opposed to two amps to a common speaker.

    Anyone know of such a product, or a custom builder who might make one?
     
  2. enditol

    enditol Member

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    You could do that with an AB box I think? For ultimate control get something like the Sound Sculpture Switchblade.
     
  3. waxnsteel

    waxnsteel Member

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  4. telewacker

    telewacker Member

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    You mean two AB boxes? I need to switch both inputs and outputs.
     
  5. drbob1

    drbob1 Silver Supporting Member

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    Well, AB boxes would work, but if you're using preamps, you're using a rack, and a rack based router is designed exactly for this. The Raxess? stuff, the 360 Systems, GCX I think will all get you what you need. You could probably use a looper to do it, but you'd have to think the routing out a bit more carefully.
     
  6. telewacker

    telewacker Member

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    Actually I'm not using a rack. My setup is unusual...I have a channel switching head with a pre amp out/ power amp in with which I would like to switch with the speaker driven line out from a vintage amp that will be run loaded with a 50 watt 8 ohm resistor.

    This way I can run my guitar through either channel of the channel switching amp OR the full vintage amp slaved into the 100 watt power amp of the channel switcher. This gives me more headroom with the 20 watt vintage amp as well as the tone that you can't get with a channel switching amp plus the the modern tones, all with 100 watts of power.

    I need to switch inputs and outputs simultaneously with something analogous to a Headbone with relays, remote footswitch, etc.
     
  7. Tone_Terrific

    Tone_Terrific Member

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    You might just drive both pres at the same time with a simple stereo out chorus pedal (or equivalent) then switch the input to the pwr amp, so you pick the one you want, from the 2 always "hot" signals with an a/b box.
     
  8. telewacker

    telewacker Member

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    I thought about that, unfortunately the vintage amp is too noisy if left on (I run it all the way up and use the guitars volume) so I really do need it's output switched off when not in use. Maybe I'll have to find someone to build this as it looks like finding a device like this might be impossible.
     
  9. drbob1

    drbob1 Silver Supporting Member

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    You could do this with a Yamaha PLS1 (no longer built but about $100 used). It's midi controlled, with 1/4 I/O on each of 8 "channels". You'd go into #1 input and output 1A to the vintage amp, 1B to the modern amp. Return from the vintage amp would go to 2A, effects send from the modern amp to 2B, output from #2 (the single jack, same thing we used as input for #1-these are relay switched and input/output routing can be flexible) to the effects return. Set up midi so that 1A-2A and 1B-2B are the routings and you're done. Leaves you with another 3 pairs to set up as effects loops to run before or after your preamps!
     
  10. Tone_Terrific

    Tone_Terrific Member

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    Maybe I missed something but, if you are dummy-loading the amp, that will provide the line out signal that will only be amplified when it is picked by the switcher.
     
  11. laadeeda

    laadeeda Member

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    Ok, here goes - I do the same thing that you are trying to do. Here is the shortcut - Mesa high gain amp switcher. It cuts the inputs and the outputs simultaneously when selected/deselected. You have four loops, and all can be used in any combination. Here is the key point to what makes it work -
    isolation transformers! if you are using two amps/preamp, you need to intercept one of those with a iso trans, so that you don't get a massive ground loop coming through your speakers. so for everytime that you ad a preamp you need to add a iso transformer. for example, two preamps, one iso, three preamps, two isos etc etc. Now the other way that you can do this is to get a Axess BS-2, which is a stand-alone buffer that has a iso out
    (mario at axess can add a second iso trans to the third output for an extra $25) you plug your guitar into the buffer, take the standard output into the input of a looping device (like a DMC gcx or axess grx4), use the send to the input of pre, output of pre goes to return of loop, out of loop to a mixer of some sort. Take the iso out of the bs-2, do the same configuration as the other loop, but just using your other preamp. This will give you the ability to shut down inputs and outputs, because if you don't you will get a bleeding effect from the other preamp raging away while it is not being used. Hope this helps.
     
  12. telewacker

    telewacker Member

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    While both these suggestions sound feasible I don't want to use any rack mounted gear. I need a small box like a Headbone and a remote FS, plus both the Mesa and Yamaha units are overkill for my application. I think I'm going to need a custom built unit. Anyone know someone who could build something like this, or know where I might inquire further?

    Thanks for all the suggestions and info.
     
  13. lastwinj

    lastwinj Member

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    if you can get me a schematic of the mesa high gain amp switcher, i could build it up for you, for use on the floor.

    germ
     

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