Class D Amps - FM reception

I use shielded power cords and an Exactpower EP-15A. The antennas I have used are a Magnum Dynalab ST-2 and a large Godar. I remember trying each in the same room as the system. In the case of the ST-2, the eAR amp was in use and the H20 with the Godar.

There was no noise problem. The reception is better with the antenna in the attic through.

I am doubtful of of typical filters curing a noise problem of sufficient magnitude. I wonder where the FCC stands on components generating noise...

Bob

The review of the H20 M250SA amp over at Ultra Audio compared the effect on FM of the H20 amp (none) with that of the Nuforce Reference model. The Nuforce caused interference in other rooms of the reviewer's home. It sounds as if the Nuforce choke is optional and that makes me wonder if it has an effect on the sound.

I have had no FM issues with either my eAR Two or H20 S250. This with my vintage tuner placed 6 inches above the amp. I use RG6 quad shield to connect to the attic-mounted attenna using a balun-free adapter to the tuner's 300 ohm connection.

The eAR has a thin stainless steel chassis and the H20 has a heavy metal chassis. Both use the same B & 0 module. And, both amps can be powered up with no load without endangering the amp.

BTW, the reviewer did not find a tremendous difference between the Nuforce and H20 amps soundwise - more of a flavor preference. I am not sure that the higher bandwith equates to wonderful sound theory holds water. High bandwidth designs have come and gone over the years.

Bob

The Nuforce is the only brand I recall as having the reported noise problem as well as turn on noise and the no-load vulnerability. These strike me as implementation issues and not reflective of class D amps in general.

It may be that only the Nuforce models have FM noise problems to solve.