I just hooked my RCA RP5008 DVR to a Johnny Stewart Power Pro Convert-A-Caller, and can't get very much volume. I think the DVR doesn't have enough power output to drive the amp in the JS. However, the DVR works great with the RS mini amp and an old 12 watt Burnham Bros. speaker. The JS Power Pro works with a Sony Walkman, but not with the digital voice recorder. Anyone else have any ideas what the problem might be?