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Preamp Noise with High-Efficiency Speakers

I have Avantgarde Duo Classic Speakers, I hear a very audible buzzing noise whenever I insert an analog preamp. If I run my DAC (AMR DP-777) directly into power amp, the noise disappears. I have tried 4 different preamps (tube and SS), 3 different amps, a bunch of RCA and XLR interconnects, the problem persists. I have tried dedicated power line and two power conditioners (with Multi-wave options) and various high-quality power cords, so far nothing works, and I am forced to run DAC-direct into power amp. The buzz is not very loud but certainly audible enough to be annoying. There's no noise running the same equipment and power source into regular speakers, I am pretty sure it's just the Avantgarde (104dB sensitivity). Please share your solution if you have had similar situations. Thanks!
yingtonggao
roscoeiii's avatar
roscoeiii
1,155 posts
 
But it should be noted that the passive preamp offered by Pass is no mere volume control. It is a buffer design that attempts to eliminate impedance issues that afflict many passive designs, IIRC.

I will also add my 2 cents:

Cent #1: I agree that attending to the gain structure of a system is a very important part of achieving system synergy. With speakers like the OP's, too much gain is likely to be an issue.

Cent #2: I have also never found a passive preamp that doesn't impact dynamics and oomph, compared to an active pre. Of course to get both the drive of an active and the level of detail of a passive you need to spend a good deal. So for some budgets you may need to choose one or the other. I found my perfect balance in the Musical Fidelity kW linestage.
grannyring's avatar
grannyring
6,484 posts
 
My active voodoo sounds more like music. My voodoo ways confirm my active sounds more like the instruments sound live. Oh well, live music cast a spell on me causing me to enjoy great active, tube preamps!

Tried passives and George's LS on three different occasions! Purchasing the unit on two of those occasions..... Installed in passive friendly systems it was very good, but missing the cues that equate to the sound of live instruments and voice. Nice for sure, but the overall tone, natural weight and scale of music was simply absent. No voodoo at all, just reality to my ears.

Others will have a different experience and I say great! You're not a victim of voodoo, but just a different opinion and preference. Enjoy
georgehifi's avatar
georgehifi
10,312 posts
 
Sorry Roscoeiii, you need to read Nelson Pass's quote more carefully.

"just an input selector and a volume control.Hardly any noise or distortion added by these simple passive parts"
His B1 buffer is active

"no worrying about what type of capacitors – just musical perfection."
His B1 buffer is also capacitor coupled.

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
Also just to let you know that Nelson Pass originally designed the B1 buffer back in May 2008
http://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-new-passive-preamp-137.html#post1521766
to be on the output of the Lightspeed Attenuator so it could then drive low input impedance amps of 20kohms or less that some of his amps have that people want to use the Lightspeed with.
You can read all about it on the Lightspeed thread on diyaudio.
After that he released it in diy form with a passive pot for diyer's who wanted to use just a potentiometer as the volume control.

Cheers George
roscoeiii's avatar
roscoeiii
1,155 posts
 
No need to apologize George. I have found what works best for me in my system and am quite content. That happened to be an active pre in my case. Please do not take it upon yourself to put down what I have found to work best for me in my system.
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