Newer Fender Schematics - Input Test Signal

[Gibsonman63]

I have been repairing some newer production Fender amps for friends recently. The schematics for the Blues Deluxe and Hot Rod Deluxe show a test signal of 4mV AC. I am finding this to be ridiculously low. My florescent bench light puts out more than that just being in proximity. Am I missing something here?

[Cliff Schecht]

Yeah that's a bit low. I'll use anywhere from 100mV to 1V at 1 kHz to test amps out, this is more typical of what a guitar puts out.

[teemuk]

Using such a low level of input signal might be about accurately testing that gain stages have proper amount of gain, producing proper amount of output signal swing. Higher amplitude input might just result into overdriving things, making consistent testing difficult.

As you might have noticed, usually the quoted input signal isn't even close to input sensivity rating of the amp.