[Neil Mc]

Recently changed speakers from 84 db ATC SCM11 to a pair of Pi Seven corner horns that are 102 db efficient.  With the ATC speakers in the chain, the back ground was completely silent.  With the Pi speakers, there is hiss that can be heard from 12’ away.  I am trying a new pair of tubes for the T10 to drop the noise level.  After combing through the web to find other solutions, I found a couple of possible alternatives.  1. Use of attenuators like Rothwell or Harrison Labs.  2. Have a technician reduce the gain of the preamp.

Has anyone attempted to address the impact of moving to higher efficiency speakers and the hiss that is revealed by doing so?  What are my other options to get back to a “black” background?

Rest of my system:  WiiM Pro Streamer, Merason Frerot DAC, Van Alstine T10 RB Preamp, Van Alstine SET 120 Amp.

[Rusty Jefferson]

I'm 'pretty' sure the SET 120 has a lot of gain, like maybe 33dB. Think I've seen mentioned the gain of the Van Alstine analog preamps being about 15dB? Don't hold me to that but in the ballpark. I think some of their preamps have a high/low gain switch. 45-50 dB of gain is definitely too much for 103dB speakers. You'll likely need both an amplifier and preamp with lower gain if your preamp isn't one that has the gain switch.  I'm not a fan of adding attenuators.

[I.Greyhound Fan]

You could talk to AVAHiFi and see if they can decrease the gain of your amp or preamp. 

Frank once modded a preamp of mine that I needed a delayed start after turning it on.