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1st November 2009, 09:46 PM  #1 
diyAudio Member
Join Date: Oct 2009

Attenuation
Hello,
I've tried attenuating my cd input using a 10k restistor as a jumper and a 6.8k to ground, it attenuated the input but not enough. Anyone know what values will double the above attenuation? Thanks. 
1st November 2009, 10:08 PM  #2 
diyAudio Member
Join Date: Feb 2002
Location: Western Sydney

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Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency 
1st November 2009, 11:08 PM  #3 
diyAudio Member
Join Date: Oct 2008

"Twice" as much attenuation
If we assume that the load driven by the attenuator is kind of high, then your current attenuator (10K series, 6.8K shunt) has 7.86 dB of attenuation. To get "twice" as much attenuation, psychoacoustically, you add another 10 dB of attenuation. Your can do that by keeping the 10K series, and changing the shunt resistor from 6.8K to 1.5K. That attenuator, 10K series, 1.5 K shunt, gives 17.7 dB of attenuation, or about 10 dB more attenuation. This will sound about 1/2 as loud.

1st November 2009, 11:16 PM  #4  
diyAudio Member
Join Date: Oct 2009

Quote:


3rd November 2009, 12:16 AM  #5 
diyAudio Member
Join Date: Dec 2006
Location: Overtaxed Long Island, NY

In order for your CD player to sound its best you need to keep the players output impedance in mind. Specifically if its 47,000 ohms the attenuator should also have a 47,000 ohm impedance. With a resistor setup as you are playing with my guess its loading down the op amps and causing problems with distortion and excessive output current.
My elderly Sony CD player sounds it's best feeding into an attenuator that has a 100,000 ohm impedance. Even though it has LM4562's as the op amps and on paper they can drive a 600 ohm impedance. Look on line for attenuator calculators where you input impedance along with attenuation, lots of them out there. 
3rd November 2009, 07:13 AM  #6  
diyAudio Member
Join Date: Oct 2008
Location: Vancouver

Quote:
Last edited by cbdb; 3rd November 2009 at 07:17 AM. 

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