Using cables to filter frequencies.
Apr 26, 2011 at 2:19 PM Thread Starter Post #1 of 9

cswann1

Headphoneus Supremus
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I did quite a few searches here and on the internet and couldn't really find anything on this so: Here's my situation. I have a new hp rig that I really like but I'd just like a little treble roll-off. I was thinking that a simple low pass filter built into the interconnect cables would be a simple and cheap solution. I just want about a 3db/octave roll-off above 10k. After a little reading a simple resistor and capacitor filter would do it. Maybe the components would even fit inside the barrel of the RCA connectors between my source and preamp. Is this a bad idea? If so why? Yes, I know that many will say that if you don't like the sound, get different cans. And I'd usually agree. However I'm working with a Stax rig which makes that not so much an option.
 
Apr 26, 2011 at 4:32 PM Post #3 of 9
What you are describing is patented & in use by MTI cables.
 
I dont recall if MTI cable owns the patent on an equalizer network IN the cables, or just licenses its use but with a few searches you should find it.
 
If audiophiles weren't so anti-EQ they could save themselves many many dollars and do the same thing (better) with a purpose built EQ. Remember when pretty much ALL preamps had "treble" controls? Maybe there was something to say for treble controls after all.
 
STAX can be beat. Easily. 
 
On that note:
If you are interested in building this FOR YOUR OWN PERSONAL USE (IM not a lawyer, but I think you can build patented rubbish for yourself without liability {check if you really care}) it is not very hard, and at worst the network could be built into a small project box. BE SURE to include the load impedance in your calculations. The input impedance of the amp you are driving WILL load this circuit, and it wont work the same on an amp with a 10K or 100K input impedances.
 
Apr 28, 2011 at 4:20 PM Post #7 of 9
Thanks for all the feedback guys.Well I have all the tools I need to build my own filter and I'm certainly a fan of doing things legally so......
...using the formula
 

 
I can use a 3.4kohm resistor and a 4.7nF capacitor to create a simple first order low-pass filter that cuts off at about 10khz (9959hz).
However when I went to see about ordering these components I was a little disheartened to see that these values aren't all I need to consider.
 
So for line level voltages can someone give me advise on what specific component values (specifically power rating) and types I should look at?
 
TIA.
 
 
 
 
Apr 28, 2011 at 4:46 PM Post #8 of 9
In a line level application (with ~2v signal & Very high {more than 1Kohm} impedance resistors) the power and voltages at hand are basically negligible. Dont worry about it.
 
I would suggest getting a few values of resistors around what you expect to need so you can adjust it a bit by ear before you solder it all up.
 
Apr 28, 2011 at 4:48 PM Post #9 of 9


Quote:
In a line level application (with ~2v signal) the power and voltages at hand are basically negligible. Dont worry about it.
 
I would suggest getting a few values of resistors around what you expect to need so you can adjust it a bit by ear before you solder it all up.



Sounds good. Will do thanks.
 

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