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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
grannyring's avatar
grannyring
4,637 posts
 
An isolation transformer can indeed fix or sort out the noise issue mentioned by the poster. I have used them with good results.

Yes, the LS passive attenuator is easily one of the best buys in audio history. It does sound very nice and if I had a very low budget it would be high on my list. Both Charles and I are talking about best in class active tube preamps that cost many times more.

I, like Charles, simply wish George would stop saying we like Voodoo etc..That simple.

I also thank George for his unselfish DIY giving. I am a very active DIY guy and kind folks like George make it possible for me to play.
clio09
2,978 posts
 
The OP is going to have a hard time sorting out the noise issue with 104 dB speakers. I do not think line conditioners or isolation transformers are going to solve the issue. He has already said going direct with his CD player has worked. Maybe this is the solution. Based on this if he feels he needs to insert something in between I would have to recommend something that will not add gain. I would recommend either the LSA or a very good TVC (Bent Audio and Music First come to mind), and if there is a need to increase flexibility to have longer cables or to have peace of mind regarding impedance matching then something like the Pass B1 or Burson Audio buffer could work. An MP-3 set up as a tube buffer could work as well.
georgehifi's avatar
georgehifi
4,966 posts
 
My whole argument is for the OP to go direct with his DP777 dac and use the inbuilt passive in it.

And yes if you want to drive 30ft of interconnect an active is the way to go.

My comments on voodoo are just that some believe that an active preamp can actually add real musical information that the source isn't providing, this shatters me that some can believe this.

Cheers George
grannyring's avatar
grannyring
4,637 posts
 
George, no need to be shattered. The source you use or anyone uses is not perfect so fidelity to the source is not the goal. The end result of the music out of the speaker is.

An isolation transformer can and has in my experience removed ground related noise that no other method would. Sometimes this happens with certain gear - that is this unwanted noise. I had a noise issue that I could not get rid of until I used an isolation transformer.
georgehifi's avatar
georgehifi
4,966 posts
 

He has tried all that and more.

Quote from the OP:
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.

Cheers George
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