Interconnect Inductance vs. Capacitance


How do the inductance and capacitance of ICs impact the sound? I have seen some ICs that have low inductance but high capacitance. On the other hand, some ICs have high inductance but low capacitance. One manufacturer even claims that his higher models have higher capacitance.

So can someone explain to me how they impact the sound?
vett93

Showing 4 responses by shadorne

High capacitance can be a tough load for consumer grade gear - best to stick to short runs or low capacitance IC's. You can lose dynamics and in some extreme cases you get distortion.
Let me give an example to illustrate my point. I had a DIY preamp project recently. I used 0.68uF for the output coupling caps. Since my power amp has an input impedance of 500K, it yields 0.5Hz 3db cut-off freq. Then I changed the output caps to 10X value; i.e., 6.8uF. The 3dB freq. is now 0.05Hz. Interestingly, I can hear better bass. A couple friends can hear that too.

Interesting. 500K is pretty high for input impedance. Did you ensure their was a return path for input bias current on the power amp? (Charge can build up in coupling caps if you aren't careful)
No, as far as I am aware no one sells interconnects with capacitance high enough to "grossly" affect high end frequency response. But under extreme circumstances (high component output impedance, long cable length, high cable capacitance per unit length), it could become marginally significant. So in that sense it is potentially a system-level issue, that the consumer should be aware of.

For less than 6 foot IC's no worries but once you get to 12 feet or more then you would be surprised at how poorly some RCA line level gear will perform. I don't think the high end roll off is the most noticeable - to me there often seems to be a loss of dynamics when using very long runs - I'd avoid long RCA runs and go with XLR balanced if that is your need.
Shadorne's example of dynamic and lively sound is a good one. I am not sure what electric characteristics can be used to describe it.

I am not sure either but I suspect it has to do with the current drive capabilities of the output stage of the line level component. I have observed it many times and it is quite audible on long runs of say 30 feet or more. If the current is insufficient to drive the higher capacitance of long interconnects then the slew rate of the signal will be less (at least that would be my guess)