pads - inline with patchbay. cct help

[Damien]

i need to make some inline pads. to go after some pres, before my converters. im thinking of cutting some bantom leads in 1/2 and putting a resistor network inline. so i can patch the pad in/out. id like 10, 20 and 30db pads.

does anyone remember how to wire pads with resistors? what values will give me close to this. any pros/cons... etc...

cheers.

damien

[Thirteen]

At the bottom of this page...

http://www.ethanwiner.com/gadgets.html

There is a download link to a pad component value calculator for PC. I haven't tried it as I am in Mac though....

[rob]

always pros and cons.
there is never a free lunch when it comes to electronics
I'd have to do the maths when i've got a calculator in front of me, but the fundamental tradeoff is that you can't create a pad that has a medium input impedance ( say 10K ) and a low output impedance unless you want a pad that drops alot of level ( say 40dB ). So the first question is are your converters happy driving a low impedance, say 600 ohms?
The downside of creating a pad with a higher output impedance is you lose the ability to drive long cables without high frequency loss / or slew rate distortion. However "whats a long cable" and exactly what sort of high frequency loss are we talking about, all become variables in a big equation.
If you had space on the patch bay, what about creating some pads within the bay itself. Bottom row input / top row output. This avoids chopping leads and ending up with a big blob of heatshink in the middle to encase the three resistors you'd need for the pad.

Rob

[Damien]

we discussed pads in the bay, but i ave more leads to spare than patch points.... and a lead with a blob is more obvious that you are changing stuff...

impedance of the converters.. one is a an apogee ad16x, the other is a lynx aurora 16..

ill read manuals again...

[Alastair Reynolds]

Hey Damien, I've got an old AWA Table of attenuator values , I use it to make up all sorts of pads. I'll scan it and email it to you (and anyone else who wants it). It covers T section, Pi, H etc .

send me your email or I'll send it on and someone can post it up .

[Damien]

thanks to all..

Alastair, thank you very much. i now have buckets of info and am off to buy some stuff..

dam its hard to buy components now as compared to years ago... bloody dick smith no electronics stores..

[Futureman]

I avoid Dick Smith like the plague... Jaycar is generally better stocked.

Regards
Mike