"Line level" output help

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ampfab
Posts: 118
Joined: Sun Nov 11, 2012 3:00 pm
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"Line level" output help

Post by ampfab »

I want to build a preamp to use with my peavey 50/50 power amp.
The peavey power amp specifies a "line level" input signal. It also has an input impedance of 250k ohms
I've found that there are different "line levels", consumer and professional. It seems that professional "line level" is approx 1.25v RMS, does this sound right? Is this the "line level" I want to shoot for?
As far as input impedance, assuming my "line level" voltage is correct, should I build a preamp that can produce 1.25v rms with a 250k resister to ground on the output?
Any advice, corrections, or explanations would be appreciated.

Thanks
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Milkmansound
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Re: "Line level" output help

Post by Milkmansound »

The output impedance of a triode is somewhere in the 20-30k range depending on what you use. That means you should be fine with just a t-pad on the output to knock the signal down. I'd put the pad or a pot after the coupling cap and call it done

If you want to get fancy you can add a diode clamp circuit for protection before the t pad
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