Eeyore
August 18th 06, 05:39 AM
flipper wrote:
> Building my nephew's guitar amp raised a question for me. Looking at
> fender schematics I noted their test criteria (and measured voltages)
> were with all pots 'centered'. Not a problem for the guitar amp as I
> used the first rule of engineering: plagiarize.
>
> It did make me wonder what position on the volume knob people design
> their 'Hi-Fi' power amps around. Nominal power (whatever that means)
> at 'mid scale'? Max power at pot maxed? And vs what input level?
>
> Makes for a significant gain issue as 'mid scale' to full open is
> 20dB.
17dB for the JIS A taper ( 15% ) actually.
> Of course, there's also 16-20dB of content above the nominal
> 316mV CD input level too.
What 316 mv ? CD output FSD should be 2V. That is 16dB above 316mV it's true.
Graham
> Building my nephew's guitar amp raised a question for me. Looking at
> fender schematics I noted their test criteria (and measured voltages)
> were with all pots 'centered'. Not a problem for the guitar amp as I
> used the first rule of engineering: plagiarize.
>
> It did make me wonder what position on the volume knob people design
> their 'Hi-Fi' power amps around. Nominal power (whatever that means)
> at 'mid scale'? Max power at pot maxed? And vs what input level?
>
> Makes for a significant gain issue as 'mid scale' to full open is
> 20dB.
17dB for the JIS A taper ( 15% ) actually.
> Of course, there's also 16-20dB of content above the nominal
> 316mV CD input level too.
What 316 mv ? CD output FSD should be 2V. That is 16dB above 316mV it's true.
Graham