Input & sensitivity

[Jan]

The inputs of the amps, should optimally be selected so thet the signal is around 4V peak to peak at maximum volume. By selecting the input and feedback resistor combination you can vary the input sensitivity.

First thing is then to determine what signal your source has. I will try to collect some data here or under Masurement techniques, but please feel free to add some values / standards / conventions...

- My Soundblaster Zen MP3 player outputs at most 1.6V ptp.
- My Juli@ soundcard peaks well above 10V ptp.
- Stationary CD players, 2V RMS / 5V ptp

more coming...

[gychang]

Jan: how do I get a potentiometer installed to get a integreted amp config on Amp3?

Irvine, CA
sunny place to be

[longitude]

Measured by cheap oscilloscope:
- MPIO FG200 MP3 player: 0.8V ptp
- Prodigy 7.1 XT soundcard: 2.9V ptp

[Reverie]

I'd quite like to know the ouput of my two most common sources if anyone can help out:
An M-Audio Audiophile 2496 Soundcard
and
An Ipod in an Ipod dock.

If I find the values elsewhere I shall add them .

[thomaseliot]

I collected other values for input gain fine tuning.

Somebody measured other sources?

[Reverie]

Good Work ThomasEliot!

But er, isn't it better to change RFdb rather than Rin? Because Rin is involved with the input filter...

And why have you calculated some to come out at 2 Vpp?

just curious...

[Reverie]

I had a quick play in Excel, based on a few tests of the output from my soundcard:



Is it better to be slightly under or slightly over the 4Vpp?

[longitude]

Sorry I made a mistake when I measured the output of prodigy 7.1 XT sound cards.
What I input is -6db signal...so the correct output is ~5.9V peak-to peak.

I also measured the analog output of Creative X-Fi xtreme music: 6.6V peak-to-peak

[Reverie]

May I ask your techniques/outputs you're measuring?

[thomaseliot]

Table updated. I found that Audiophile has +2dBV output or -4dBV.