Preamp Noise with High-Efficiency Speakers

After almost a month the buzz remains with any preamp, and luckily I can still enjoy music running source-direct. The buzz is audible both above and below 140 Hz, I know this because my Avantgarde Duo Classic speakers have active sub crossed over around 140 Hz, and I hear the buzz from both midrange horns AND the sub. I may be able to hear a little hizz close up to the tweeter horn, but it's much less intrusive, and "normal" for almost any speakers. The buzz is independent of the volume setting on the preamp, so it's not source-related. Tuning preamp volume all the way down doesn't diminish the buzz, turning preamp volume all the way up does add a little more noise, but when I listen I rarely go beyond 10 O'clock. I should mention that I did take some wires to connect the chasis of the pre and power amp (common grounding), nothing improves. I did not buy a Ground Zero.

Yingtonggao, did you try using a ground cheater on the power cord of the preamp? If it works it is not a solution, but an indicator.

Ok you tried to give all 4 preamps a earth with no joy, but you have not said if the mains lead on them is earthed?, if so disconect it, if this still is not a fix, "luckily you can still enjoy music running source-direct." which in your case is a good impedance match and you still have an abundace of gain.

Cheers George

Finally got a noise-free pre/pwr combo! Audio Mirror T-61 preamp + Cary 300SE monoblocks. I don't know why but this combo is free of noise/buzz/hiss. Sounds wonderful too! The best I've heard with Avantgarde Duo.

Substituting either pre or pwr with another brand and the noise comes back.

Unfortunately Cary discontinued the 300SE. Does anybody know the sonic difference between 300SE and 300SEI?

Active tube pre with 300b SET, you`re good to go. Congratulations with solving the problem.Now just enjoy your music.