Hovland pre-amp susceptible to A/C line noise?

Not only did Stereophile have humming problems but the Absolute Sound had a low level buzz in there review model.
My advice is to send it back the problem is in your pre-amp. It seems they have a problem and are not doing anything to solve it and they know it.

I have an HP-100, too, and am experiencing the same problem. I spoke to Alex @ Hovland and he claimed to not know what I was talking about. I will forward the URL of this thread to him.

Many thanks to all of those who responded to this thread.

Hovland, to their credit, was immediate in their response and identified the problem. As I understood the explanation, the Hovland is a wide-bandwidth design that has little RFI shielding. Between the Hovland and my VAC amp, I am using a long, unshielded Kimber Select interconnect which itself is known to produce buzz/hum in certain installations due to the lack of shielding, the problem usually arising when the IC is used in long lengths. The combination of the two causes noise to enter through the preamp's output. When I threw in a shielded interconnect, the Hovland was basically fine, but the problem returned as soon as I went back to the unshielded Kimber. Hovland reports that this problem exists in 1 of 150 installations and they have a ready-made "RFI filter kit" that they Fedexed to my dealer the day of my call (impressive). I previously ran a CAT preamp, and never had any noise problem using this Kimber interconnect. I do not yet have the pre-amp back from the dealer, but have my fingers crossed that the RFI filter retrofit will solve the problem. As for Kimber, they were quite helpful as always, and discussed perhaps doing a special shielded version of their TAK tonearm cable as a substitute for the unshielded, all-silver Kimber Select that is currently part of the problem. If the RFI filter kit does not work, I will surely consider the Kimber idea.

A couple of comments about your above comments. I cannot speak for Stereophile, but I understood Michael Fremer to write that the hum he experienced came from the MC phono stage in his Hovland review sample and that it was remedied when Hovland sent him a later-generation unit. I have the line stage only and the problem is present at all times that the mute button is disengaged, regardless of the level of the volume control and regardless of the choice of input. Again, the noise largely, if not totally, disappears when I substitute a shielded interconnect as the output interconnect.

Hovland and Kimber have been great about the problem thus far. Alex Crespi reports that the RFI filter usually solves the problem.

Thanks again for your input.

I would return the pre-amp. It sounds like a major design flaw. I would not accept any band-aids fies. In this price range you should expect dead silence..
I had the hovland for a trial period and found it noisy and that it smoothed over too much of the music making it less dynamic than other preamps..
mike

Dear MikeM:

Thank you for your post, and I know you are trying to help me, but I respectfully disagree.

Hi-fi equipment in the league of Hovland or Kimber Select is state-of-the-art and cannot be expected to operate perfectly in every single environment. My guess is that the decisions to not shield the Kimber Select interconnects and to not equip the Hovland with a standard degree of RFI shielding were made intentionally because, it most installations, the designers found that those two products sound better that way, all while knowing full well that, in certain installations, these design characteristics will not be practical. Some street Ferraris have only four inches of ground clearance, and, the motors in those cars demand high RPM's -- drive one here, in manhole-rich, broken pavement Manhattan, and the undercarriage will occasionally bottom out and the plugs will foul due to the engine being lugged down at low RPM's. If you want "practical", you get a Buick or a Rotel. But if it's real glory that you seek, my experience has been that things will likely get complicated.

In short, I do not think it is a design flaw to make a preamp that should be used with a shielded interconnect, or, to make an unshielded interconnect that should be used with a preamp featuring RFI shielding. As for your own experience with Hovland, I'm sure it is as you report -- again, a product like this is not going to work perfectly in every environment.

The problem is not a big deal for me and something that I almost expect at this level. I'll see how the RFI retrofit works and go from there.

Thanks again