-20dB pad values at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > All Things Audio

All Things Audio
Everything Audio, from acquisition to postproduction.


Reply
 
Thread Tools Search this Thread
Old November 3rd, 2009, 06:10 PM   #1
Trustee
 
Join Date: Aug 2008
Location: New York
Posts: 1,844
-20dB pad values

I need to construct a simple 'L' pad within a special connection cable. The primary is unbalanced at about 0dBu nominally. Can someone tell me what the R1 & R2 values should be to get approx. 20-25db of attenuation. Unbalanced to unbalanced. Thanks.
Rick Reineke is offline   Reply With Quote
Old November 4th, 2009, 11:19 AM   #2
Regular Crew
 
Join Date: Mar 2006
Location: Leesburg, Fla
Posts: 86
20db Pad

20 dbv = a gain of 10. You want to have 1000 ohms as R1 & 100 ohms as R2. The resistors should be 1/4 watt 5% tolerance; these are carbon film resistors. You might see if your local radio shack still carries resistors.

signal in __1000________ Signal out.

100

ground

The 1000 ohm resistor is in series with the incoming signal; the 100 ohm goes from the secondary side of the 1000 ohm resistor to ground. This will give you a 2o db loss in signal voltage.
Bill Wilson is offline   Reply With Quote
Old November 4th, 2009, 12:07 PM   #3
Trustee
 
Join Date: Aug 2008
Location: New York
Posts: 1,844
Thanks Bill,
I've built many pads, I just can't seem to figure out the resistor value equations. Duh.
-----------------
I had a 1k and 100 ohm in my collection of odds & ends already so a trip to the Shack O' Shame was unnecessary. Soldered them in.. works great. Thanks again.

Last edited by Rick Reineke; November 4th, 2009 at 03:59 PM. Reason: Addendum
Rick Reineke is offline   Reply With Quote
Old November 5th, 2009, 11:39 AM   #4
Regular Crew
 
Join Date: Mar 2006
Location: Leesburg, Fla
Posts: 86
20 DB Pad

Hi Rick: Glad to hear it worked out for you.

Bill W.
Bill Wilson is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > All Things Audio

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 02:14 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network