How to get rid of 'Hiss' from preamp

H

Howiebrou

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Apr 16, 2013
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I just got a Dartzeel Preamp tp demo at home with a pair of Analog Magic Apollo monoblocks. I swapped out another demo preamp from Synastec (which was silent) and the Dartzeel is a HUGE improvement.

However, there is a loud audible hiss from the speakers, a little like tape hiss of old. It is so loud that i can hear it over quiet passages. This preamp sounds fantastic so i want o get rid of the hiss. I was told to move the power supply for the Dartzeel further away from the preamp which i did but it didn't help. In fact when i moved it away i swapped the Kondo PC for a Crystal Ultra PC which was longer. The hiss turned into a buzz! I'm not quite sure why the buzz occurred considering both PC are plugged into the same Furutech power distributor.

Should I try connecting the preamp to the wall? Also plugged into the Furutech is my CH Precision C1, AR Ref 2 phono and Avid Acutus power supply. The hiss remains whether it is my C1 dac playing or vinyl.

I understand the Dartzeel power supply needs careful positioning but have no idea where to put it or where to plug it in.

Thanks

Howie
 
Try plugging the preamp straight into the wall.
 
The hiss you describe is most likely the noise floor of the preamp, not a power or shielding issue. I have high sensitivity speakers (96 dB/Watt), and it can be a frustrating struggle to find a preamp that sounds great and dynamic but also remains dead quiet - even units advertised as "dead quiet" can be quite noisy here. The problem is all the gain you have from preamp and amp's active stages downstream of the volume control. You're probably not even using anywhere near all that gain, but you're certainly hearing all the noise from it, with no help from the preamp's volume control to cut it back down. Many preamps have way too much gain. If you insert say 10dB attenuators between preamp & amp that would cut the noise floor and you simply raise the preamp volume to bring back your usual listening level. That said I don't like the idea of inserting attenuators - I'd keep looking at preamps.
 
Problem solved. The Analog Domain power amps have two gain settings on the back. One is 26DB and the other is 'full'. I thought is was on 26DB so i didn't presume that was the cause. Of course it wasn't and the amp is now quiet. Phew...
 
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