Parasound HCA 2003 amp

kevhed72

It just arrived today and the difference between my current amp is literally night and day. It added a dimension of smoothness (if that's a word) to my speakers which I wasn't sure the A9's were capable of.
Now for the "bad" news. It is plugged into my Monster power conditioner and it emits a faint, continuous hum from each speaker...just loud enough to be annoying. Here are my top 3 guesses as to the hum:
A. Power cord too close to IC's or speaker cables
B. It should be plugged directly into wall
C. Something going on internally due to amp's age

Any input appreciated...I would try out A. and B. myself but there is a pretty wicked storm rolling through the greater ATL area, so I just unplugged everything...

domflane

Congrats on the new amp, the A9's are fantastic speakers when properly driven. As for your humming, it shouldn't be an interference issue as most of your cables should be well shielded. Hopefully its not your amp, I would definately try A, not so much B as the power cond. is more than likely not the problem. Good luck and enjoy!

jinjuku

I would leave everything as is and pull the line level input from the preamp and see if the speakers are still humming.

That would be an amp problem at that point if it still existed (most likely).

dekuda

Congrats on a great amp! I have a Parasound HCA1500 plugged into a Monster power conditioner and I do not get any hum. I agree that you should try unplugging your pre and see if the problem persists. If it does then you may have a ground differance between your amp and power conditioner

kevhed72

Well, I tried A and B, and neither did the trick. I hum comes from all 3 channels equally, and increases equally when I turn the gain controls on the rear pf the amp up. Too bad Ben has moved up to Conn., as I gather he is pretty good with this type of stuff. I'll try calling Parasound later today...

cfrizz

Get a 3 prong to 2 prong plug & plug that into the amp cord & conditioner to see if the hum goes away.

kevhed72

Hmmm, I took the AVR out of the equation and hooked my CDP up directly to the amp. And besides the sound being completely mind-blowing compared to what I had before.....NO HUM! So, is this some type of ground-loop issue...and how do I go about fixing if so? Maybe the AVR has so much going on inside of it electronically, with its own internal amp, could be causing the hum? (just throwing out theories....)

kevhed72

cfrizz wrote: »

Get a 3 prong to 2 prong plug & plug that into the amp cord & conditioner to see if the hum goes away.

That makes sense, since the old Adcom amp was only a 2 prong, and the AVR is a 2 prong plug....where as the new amp is a 3 prong, as is the CDP....
let me hit "The Shack" today and pick one up. Thanks much Cathy,

billbillw

Sounds like a typical ground loop. It seems to happen frequently when you you have your receiver hooked with an electrical connection (HDMI, RCA, Dig coax) to a cable box, satellite box, or roof antenna. Those feeds are usually tied to a true earth ground that may be different from your electrical ground. I've experienced it myself. You can use a cheater plug (to remove the ground from the amp), but I think its safer if you get a coax ground loop isolator. Something like this:
http://www.amazon.com/VSIS-EU-Cable-Ground-Loop-Isolator/dp/B0017I3K9M

BTW, those Parasound amps do sometimes develop internal hum/buzz from the smaller secondary power supply caps going bad with age. Not sure exactly how old yours is, but I had to re-cap my HCA2200ii to solve problems like that.

EDIT: I should mention that some ground loop isolators are not compatible with digital cable or satellite. Do your research before you buy one. There may be other ways of eliminating it too, like using optical cable instead of an electrical connection. Also, if you have cable TV, the cable company may provide you one for free if you ask.

kevhed72

Well, it was the 2 coax cables coming in from the Satellite dish...I disconnected both and the hum disappeared. The weird thing is the splicer for the coax cables on the outside of the house is tied in to the same electrical ground of the house. Oh well, at least its not the amp itself...:)