As a first Audio DIY project, I'm trying to build a passive preamp, however I have some basic questions.
Am I correct in thinking that if I want 6 inputs, I need a 2 pole 6 way switch, and then just use 1 pole for the Left channel and 1 pole for the right channel?
Also what kind of signal cable do I need to use? and should it be shielded?
And finally how do I connect the various earths together? Do I just daisychain the input earths or should they all meet in one point? should they be connected to the chassis?
Any advise is greatly appreciated.
James
Am I correct in thinking that if I want 6 inputs, I need a 2 pole 6 way switch, and then just use 1 pole for the Left channel and 1 pole for the right channel?
Also what kind of signal cable do I need to use? and should it be shielded?
And finally how do I connect the various earths together? Do I just daisychain the input earths or should they all meet in one point? should they be connected to the chassis?
Any advise is greatly appreciated.
James
Two poles, six ways will do it.
What kind of cable to use is liable to start arguments. You can use single strand if you like--as long as you use a metal case to shield against RF. However, twisted pair or coax would be an improvement. At that point, in principle, you could use a plastic project box.
A star ground is a good idea for an active circuit, but hardly essential. Since your wires are likely to be comparatively short and there's nothing electronic being added, you can do most anything you like. Just make sure that your grounds have good connections. Assuming that you use a metal chassis, you should ground the chassis. If you use twisted pair or shielded wire in a plastic box there's no need.
One last hint--try to do a tidy job. Sooner or later you will go back into this box for one reason or another. Try to make it so that your future self will be proud of you. Not that it matters to the sound...just to you.
Grey
What kind of cable to use is liable to start arguments. You can use single strand if you like--as long as you use a metal case to shield against RF. However, twisted pair or coax would be an improvement. At that point, in principle, you could use a plastic project box.
A star ground is a good idea for an active circuit, but hardly essential. Since your wires are likely to be comparatively short and there's nothing electronic being added, you can do most anything you like. Just make sure that your grounds have good connections. Assuming that you use a metal chassis, you should ground the chassis. If you use twisted pair or shielded wire in a plastic box there's no need.
One last hint--try to do a tidy job. Sooner or later you will go back into this box for one reason or another. Try to make it so that your future self will be proud of you. Not that it matters to the sound...just to you.
Grey
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