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Bouncing my head against the wall and hoping you guys have some insight / advice for me.
I've just treated myself to a RC-1590 preamp for my music listening setup. The rest of the setup is a Rotel RB-1090 power amp, my old but still great and trusted Bowers & Wilkins DM640 floorstanders and a REL Quake MK2 subwoofer to complement the low end (sub's crossover is set to 40 Hz).
Before the RC1590 I used an Onkyo AVR as preamp (TX-SR705).
The difference in sound is AMAZING. However, it has an awefull lot of background hiss. The Onkyo had barely any background hiss, I had to put my ears against the tweeter to hear any at all. The Rotel, however, has A LOT of it! I can hear the tweeters hissing from 3 feet away, which quite frankly shocked me... It's even worse if I use XLR cables instead of unbalanced. I can reduse the hiss by flipping the switch on the RB1090 from unbalanced to balanced while still using the unbalanced inputs. This lowers the level of gain, which reduces the hissing considerably. However, there still is some.
The reason to chose the RC-1590 over the RC-1572, and pay the hefty premium that comes with this choise, is that I had read that the RC-1590 suposed to have a much better SNR and lower noise floor.
This hiss does not change with the volume, between 1% and 85%. At 0 the amplifier switches off the relay and all hiss is gone. At ~85 and above the hiss rises with volume. Until that point the hiss is at a constant level, independent of volume.
I've tried disconnecting all sources from the preamp, including my mac that's connected to the USB DAC. Even with just the preamp, power amp and speakers connected there's a verry prominent hiss. I've tried switching inputs, but on all inputs except bluetooth it produces hiss. The only reason it doesn't on BT is that it seems to turns off the output relay when no device is connected or playing while BT is the selected input.
I LOVE the sound of the preamp, it's much smoother, less aggressive, than the Onkyo. It's buttery smooth, very 'open' and more 'full boddied'. However I'm shocked (and disappointed) by the level of hiss and wonder if maybe there is something wrong with my unit... How can it be that my old Onkyo has a better noise floor than the Rotel. It's suposed to be the best audiophile unit Rotel has to offer (except for the Michi) and has three times the retail price of my old Onkyo - a entry level surround receiver from yesteryears. :huh:
Are there any others on this board that have this amp and can shed some light on this issue? Does your preamp also hiss or is it just mine?
I've just treated myself to a RC-1590 preamp for my music listening setup. The rest of the setup is a Rotel RB-1090 power amp, my old but still great and trusted Bowers & Wilkins DM640 floorstanders and a REL Quake MK2 subwoofer to complement the low end (sub's crossover is set to 40 Hz).
Before the RC1590 I used an Onkyo AVR as preamp (TX-SR705).
The difference in sound is AMAZING. However, it has an awefull lot of background hiss. The Onkyo had barely any background hiss, I had to put my ears against the tweeter to hear any at all. The Rotel, however, has A LOT of it! I can hear the tweeters hissing from 3 feet away, which quite frankly shocked me... It's even worse if I use XLR cables instead of unbalanced. I can reduse the hiss by flipping the switch on the RB1090 from unbalanced to balanced while still using the unbalanced inputs. This lowers the level of gain, which reduces the hissing considerably. However, there still is some.
The reason to chose the RC-1590 over the RC-1572, and pay the hefty premium that comes with this choise, is that I had read that the RC-1590 suposed to have a much better SNR and lower noise floor.
This hiss does not change with the volume, between 1% and 85%. At 0 the amplifier switches off the relay and all hiss is gone. At ~85 and above the hiss rises with volume. Until that point the hiss is at a constant level, independent of volume.
I've tried disconnecting all sources from the preamp, including my mac that's connected to the USB DAC. Even with just the preamp, power amp and speakers connected there's a verry prominent hiss. I've tried switching inputs, but on all inputs except bluetooth it produces hiss. The only reason it doesn't on BT is that it seems to turns off the output relay when no device is connected or playing while BT is the selected input.
I LOVE the sound of the preamp, it's much smoother, less aggressive, than the Onkyo. It's buttery smooth, very 'open' and more 'full boddied'. However I'm shocked (and disappointed) by the level of hiss and wonder if maybe there is something wrong with my unit... How can it be that my old Onkyo has a better noise floor than the Rotel. It's suposed to be the best audiophile unit Rotel has to offer (except for the Michi) and has three times the retail price of my old Onkyo - a entry level surround receiver from yesteryears. :huh:
Are there any others on this board that have this amp and can shed some light on this issue? Does your preamp also hiss or is it just mine?
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