So this might be a dead thread….but I recently decided to buy a htm1d3 to use with my 804d4 with a recently purchased mrx520 and utilizing 2 nad m22 v1 amps. The issue is connecting the nad m22 v1 amps to the pre out section of the Mrx 520 produces a hiss from the 804d4 speakers while the htm1d3 is connected to the terminals on the receiver with no hiss at all. Is the gain on the nad to much for the pre out of the 520, if so anyway to fix that….they worked perfectly when I was using 2 channel with my nad m12. I am new but my questions have gone unanswered on avs forum which I’ve been a member of for 15 years and audiogon…which they never really help…unless u own 1000$ snake oil cables lol.
Based on the specifications, the M22's gain is 29 dB, not that high at all. Also, the HTM1 d3's sensitivity is 2 dB higher than the 804 d4 so if gain is the reason it should be more prone to audible hiss. The MRX's gain is likely around 28-29 dB as well. Since you have two M22, you can troubleshoot a little such as (if not yet):
- Swap the amps for the 804 d4 and HTM1 d3 and see if the HTM1 d would hiss. Note: Avoid moving/disturbing the interconnect cables, just do the unplugging and plugging (in case the cables for the 804 d4 may be picking up noise for whatever reasons).
Or you can just unplug the interconnect cables from the MRX pre out for the center speaker plug them into the pre out for the M22. Just choose the FL or FR for this test.
In any case, you probably should try (again if not yet) using a pair of RCA to XLR interconnect for the M22, just make sure you pick a pair that is wired to Hypex recommendation.
Edit: Forgot to ask, have you tried the balanced/unbalanced selector switch at the back.