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Using Pre Amp Outs


 
4/16/2000 11:28 PM
Shon
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Using Pre Amp Outs
Hello folks,  
 
If I have a combo amp like a Fender Princeton 65 and want to use only the preamp, how can I mute the output section for the combo ? I thought a possible solution would be to disconnect the speaker, but if I did this I would be running the amp without a load. However if no signal is going to the power stage via the effect loop return I would think this is safe (no load needed). Or buy keeping the master volume (the power section volume) to zero, that this would be safe (no load needed if there is no volume) ? I also thought of installing a power amp mute switch. I think Bogner has mutes on some amps. I would also like to use the preamp out on a head like the Marshall DSL. Again do I need a load for a head or can I just not connect the effects loop return, or just keep the master volume to zero. Thank you all.
 
4/17/2000 12:17 AM
dale
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if the amp has a loop, just put a "dummy plug" in the return. a plug with the hot and ground soldered together. this will insure the power amp is quiet as the signal to it is grounded out. then you can take the send as your line out. the regular line out won't work if it's after the loop since you have the dummy plug in the return.  
 
dale
 
4/17/2000 1:02 AM
Shon
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That is a wonderfull solution! It's too easy!Anyway, when I thought through the mechanics of this, I thought it would be best to use a right angle phone plug to keep it from protruding out from the back, to keep it from being accidentally knocked or moved. And then putting a piece of duct tape over it to keep someone from removing the dummy plug accidentally. More permanantly speaking, I assume I could solder the hot to the ground inside the return jack. I think manufacturers could address this trick by putting a little switch in the back, connected in circuit after the return jack.
 
4/17/2000 3:30 AM
dale
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shon,  
 
you could solder it internally, but these are switching jacks, so you'd also have to sperate the contacts that only open when a jack is inserted. if you dont do that the preamp signal will also be sent to ground and you'll have no sound from the send jack.you could either do this by phsically seperating the contacts by putting something between them like electrical tape or something, unless they are closed jacks where you can't get to them. or you could do it by seprating the connection on the circuit board by scraping at the circuit traces to create an open circuit.  
 
dale
 
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