Re: line level pad

First check your sound card driver. I've had this problem and solved it by
rolling back to an earlier version of the sound card driver. The input
range that you can get a soundcard to accept is very much driver-dependent.
Try all the versions you can get hold of; the newest is not necessarily the
best (at least with Sound Blasters, which is where I ran into this
phenomenon).

I believe Radio Shack sells 20 dB pads built into RCA plug adapters.

If you want to build a pad, it's simple. For each channel, you need two
resistors (wattage does not matter since they're each handling far less than
1/10 watt). Here's how to wire it up (for one channel):
- Input ground to output ground.
- Input center pin to 22k resistor to output center pin.
- 4.7k resistor from output center pin to output ground.
That should give you 15 dB of attenuation. If you want less attenuation,
change the 22k resistor to 10k. If you want more attenuation, change the
22k resistor to 47k. Build all this in a shielded metal box with the shield
connected to the cable shields (signal ground).

Pro-Ject MKII
Input impedance 47k ohms
(irrelevant since we're connecting to its output; the output impedance of
any modern preamp is going to be quite low, like 1000 ohms or less, even
though it's designed to drive a 10k amplifier input)
Output voltage 300 mV @ 1kHz
Max. output 9.5 V (1kHz)
(those two seem to contradict each other, but the second one indicates that
it could indeed overdrive a sound card, even one with pro audio level
inputs)

M-Audio 2496
Peak Analog Input Signal +2dBV
(meaning it will take up to about 1.3 volts input)
Input Impedance 10k ohms minimum
(meaning its input impedance is at least 10k ohms and may be higher; that's
why we used a smaller resistor, 4.7k, on the output of the pad. Output
impedances should always be lower than the input impedance of the thing
being driven.)

Of course, if you believe one of the people who have posted on this group
recently, electronics has *nothing* to do with audio and you should just do
everything by ear.


.

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