RichardP Posted January 3, 2008 Share Posted January 3, 2008 I recently purchased the Dayton HPSA1000-R Subwoofer amp (500w), to power one of my Klipsch KW-120 subwoofers, to add to my Belle stereo setup (the other sub and KA-1000 amp remains with my HT system). The main 2-ch amp for the Belles is a vintage 1980's Yamaha 600 "Natural Sound" series. It has pre-amp out jacks, which I thought would be appropriate connection for the sub amp's inputs. The Dayton sub amp only has L,R, and LFE RCA inputs; it does not have speaker level inputs. There are two problems I have encountered. First, I get an elevated noise level, sometimes with occasional static, coming from the Belles (not the sub). It is not the 60 Hz hum common to grounding problems; it is a higher frequency, and clearly comes from the Belle's midrange drivers. It is not quite a sibilant sound, but definitely not a low hum; some might call it a hiss. If I connect the sub amp to the Yamaha's tape rec out jacks instead, there is no noise, but of course with that configuration the subwoofer volume does not change with the Yamaha volume control. I would have to set the main speaker volume on the Yamaha, then separately adjust the sub amp level to match it. I have tried three RCA cables to make the connection, with no difference. They are not monstrous (get it?) gold plated connectors, but I think they are reasonably shielded. Moving the cables away from other connectors and power cords also has no effect on the noise. The next problem is that, when using the preamp out connection, the signal is very low. I have to turn the sub amp level control from lowest to highest just to be able to hear a difference in sub volume during playback. It is as if there is only a 1 or 2 db range of adjustment. When the sub amp is connected via the tape rec output, there is a much higher signal, and a huge range in volume can be heard when changing the sub amp level control. The Yamaha owner's manual lists the preamp output as 775 mV (2 ohms) with a max of 3000 mV; the tape rec out is listed as 120 mV. That doesn't make sense. It seems that currently the preamp out signal is far below what it should be. I have never attempted to use a preamp out connection before, and do not know exactly where to start to try to diagnose and possibly eliminate the problems. I would hate to think that I must use the tape out connection, and have to adjust sub amp level each time I adjust the main volume level on the Yamaha. Can anyone offer any information on this problem? Thanks in advance. Quote Link to comment Share on other sites More sharing options...
RichardP Posted January 4, 2008 Author Share Posted January 4, 2008 bump....anybody?....anybody? Quote Link to comment Share on other sites More sharing options...
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