Pad
Q: What is a Pad?
A "pad" is short for an "Attenuation Pad".
This is a device used to lower the signal level between two other devices.
Contents
Padding PS1 Power Stand (Classic) / Model I Inputs
We use pads with our PS1 Power Stand (Classic) / Model Is when running a pro level +4 dBu signal (e.g. output from a mixer) to the XLR inputs on Channels 1 or 2. We want to do this because the input sensitivity for these inputs is set for microphones. To get a better match for levels between the source and our inputs, we can use a pad.
Pads can also help when connecting the PS1 Line Outs to semi-pro or consumer recording devices. If the PS1 Line Outs are too hot for the recorder's inputs, a pad can be used to prevent overdriving those inputs into (clipping) distortion.
A -20dB pad is also a good choice when connecting the PS1 Line Outs to a house PA, or other off-stage system. This would ensure that the house mixing console's inputs can handle the signal level without being overdriven into distortion, especially if the house console has insufficient built-in pads, or none at all. (Beware of the potential for Ground Loops here.)
Daisy Chaining PS1 Power Stand (Classic) / Model Is
Another application (although relatively rare) is if you want to connect the output of one PS1 Power Stand (Classic) / Model I to input of another. Sometimes called daisy chaining, you can connect the Line-Out of one PS1 Power Stand (Classic) / Model I to Channel 1 or 2 of another. In that case you probably want to have a -20 dB pad inline, between the Line-Out of the first System and the Channel 1 or 2 XLR input of the second. See PS1 Powerstand / Daisy Chain for more information.
You can find separate attenuation pads like this:
Cost: $20-30 on the web
Sources:
- http://www.proaudiosolutions.com/product_p/impad20.htm
- http://www.musiciansbuy.com/WHIRLWIND_IMPAD20_IMPEDANCE_CONVERTERIMPAD20.html
- You might find something like this in a local music store if they have a Pro Audio department.
This an example, and you will want to look into the details to determine if you need a pad, and the kinds of connections that are appropriate for your input device.
More Formal Definitions
"attenuator or attenuator pad Electronics. A passive network that reduces the voltage (or power; see usage note under gain) level of a signal with negligible distortion, but with insertion loss. Often a purely resistive network, although any combination of inductors, resistors and capacitors are possible, a pad may also provide impedance matching."
Do It Yourself
A quality inline pad can be easily soldered [makes no sense to spend extra money here]: Insert 3 resistors into your mic cable:
- 2x 470 ohms, inserted into line 2+3 [absolute value +/- 10%, but matched to less than 1% tolerance]
- 1x 470 ohms, inserted between pin 2+3 on the console side.
Source: Martin Schneider / neumann Mic. Development
References: