PCS-Electronics

I run my XM (FOX news mono) audiio into my pcimax2005. I notice that when I put this into stereo mode the recieved sound (which was very good under mono operation) got lots of white noise (hissing) but the stereo light did turn on on my receiver.

So why is this??? Is it due to freqencies greater than 15khz getting into my transmittter?

Does anyone have an insight for me?

If I remember correctly from my usage of it, the 2005 has problems with stereo and I'm not sure how to fix it. I know the newer 2006 works great though.

Whilst it's true you wouldn't want freqs. above 15khz being transmitted, if the hissing is there regardless or audio source and levels then that wouldn't be the problem.

Thanks, I hadn't read anyone else having problems with their 2005. I had am original pcimax that was very noisey running inside my pc then upgraded to the 2005 and built it as a stand alone transmitter. It either came with a blown final transister or I did something to blow it out but after getting that sorted out (self repair) it is used from my car to listen to my xm radio inside my building from the parking lot...
This is when I found that the signal was noisy in stereo mode and I had to run it in mono mode for acceptable sound. I would like to know a/the fix if any besides spending another $200 on another version.

My other dissapointment is that the 2005 version takes quite a high input to get acceptable output. In fact, my mp3 player at full volume doesn't quite "get it". I am considering building a pre-amp (and maybe a filter to cut out freqs above 15K if that would help the stereo hiss).

Oh, my final blew out again strangely while using this last winter. I'm not sure if it was sudden death or gradual decline in power......I have a matched antenna on this but since this is such low power I didn't think it mattered. I'm running the board at a regulated 12V so I'm not pushing it. The only thing I can figure is that I "sparked" the antenna during winter use and it blew my final (are these chips pretty fragile like that?)

Care to comment on any of this Marko?

Sir Nigel wrote:If I remember correctly from my usage of it, the 2005 has problems with stereo and I'm not sure how to fix it. I know the newer 2006 works great though.

Whilst it's true you wouldn't want freqs. above 15khz being transmitted, if the hissing is there regardless or audio source and levels then that wouldn't be the problem.

Hi! Could anybody remove the high-frequency noise in stereo mode for PCI MAX 2006?

Perhaps try an external power supply. I don't have that problem on my 2006 PCI max.

Sir Nigel wrote:Perhaps try an external power supply. I don't have that problem on my 2006 PCI max.

I have already removed the noise by changing external power supply. Thanks. I used PC AT power supply earlier.

Using PC power supply for this is a very bad idea.
It produces a "beat" frequency with the other PSU inside the PC
which can be heard as a tone with constant or varying frequency,
depending on the type of PSU. Or it could manifest as a noise.

The proper PSU would be a stabilized 12-15V type, preferably
not a switcher, but a well done and filtered switcher will do also,
especially if its switching frequency is sufficiently far from the other
frequencies used in stereo signal generation.