2. cables
  3. 1150045541

Cable INteracion Question

I am trying a new set of cables, and when I insert them between the preamp and amp, I hear a ton of noise (sounds like the capacitors charging) in the amp at power up. When I revert back to my old cables I hear no such noise. What could be causing the "noise" in the new cables??
ehoehn
ehoehn OP
169 posts
 
I did an experiment this am. I reversed the directionality of the cables between the amp and preamp. Now instead of just doing it at power up, it does it every 30 seconds in a pulsating manner. It sort of sounds like an electric razor that gets gradually louder then just cuts off. It then repeats 30 seconds later. When I put the sonorans back in the system, there are no issues at all.
nsgarch's avatar
nsgarch
2,524 posts
 
I was going to mention the connector(s) too, however I assumed the noise was on both channels which would pretty much (not completely) rule that out.

The pulsating phenomenon sounds to me like digital "hash" (RFI) coming from your CDP (or DAC). Unplug your digital equipment and see if the problem persists. Also, make sure your digital equipment is on a different circuit (if you can) and that it is connected to AC using a shielded power cord.
pabelson
344 posts
 
What could be causing this? Several things, but they all come down to one thing: The new IC is defective. Don't use it. Problem solved.
sasaudio
5 posts
 
The problem is not the "V" ICs, Pabelson. If the sound is like hiss between FM stations, then the problem sounds like an RF oscillation from the amp. The amp was modified, which could easily be the problem. SS amps are very sensitive and one needs care when modifying. I have an IRD amp that oscillates, but gradually dies out at approximately 6 watts output. The preamp will never oscillate. I can also guarantee the ICs are ok.

Steve
SAS Audio Labs
sasaudio
5 posts
 
A further observation.

Whenever a component is modified, extreme care must be taken to make sure the component will not oscillate under ANY conditions. Changing resistor values or ridding of certain components, such as resistors, can cause unexpected problems with the design.

The cable capacitance of the "V" ICs is very low vs other shielded designs, which could easily affect a component's perfomance if that component is not designed properly, or is incorrectly modified.

A simple non-shielded IC is not going to be "defective" under any conditions as long as the wires are connected. They may be more suseptible to RF pickup however; but that is not considered a defect.

Steve
SAS Audio Labs
More to discover