2. amps-preamps
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Thinking of a new preamp and looking for advice...

So, I am currently running a BAT VK30 into a Parasound A21 to Golden Ear Triton 2 speakers.  Sources are a Sony Z1ES and a Linn LP12 to a Parasound JC3+ phono stage. Green Audioquest cables all around. Most of my listening is vinyl--lots of jazz and 70's-80's rock and female vocals. I love the sound of my system, but the BAT is very finicky about power, and I have a ground loop that I cannot find...It works fine at other locations, but has a hum in only the right channel in my listening room...It's driving me bananas!

I demoed a Sonic Frontiers LS1 and the ground loop was gone, but it didn't have the open airy sound that my BAT does.  I am looking into an Audio Research LS-27, and also a McIntosh C47.  My must haves for a new preamp are at least 2 balanced inputs and balanced outs, and a remote control.  I may like to stay with tubes, but I'm not opposed to SS either.  Price-wise my ceiling is around $4000.  I would love to here from anyone who has either of these preamps as to what they like or don't like about them.  I am also open to suggestions. 

Thanks for your input.

128x128jptenberg1

Showing 3 responses by jmcgrogan2

jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
I would first try a little harder to eliminate the ground loop hum. I know they can be frustrating, but I have even heard $12K preamps have this issue until the culprit is found.

As is, your system appears to be quite well balanced. Adding a better preamp may or may not eliminate the ground loop, and may or may not make your system sound better.
A more transparent preamp like the ARC LS-27 may just highlight flaws in your source or speakers.

http://www.audioholics.com/home-theater-connection/ground-loops-eliminating-system-hum-and-buzz


jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
Typically, a ground loop causes hum in both channels.

I have had a ground loop hum in one channel before. It can be very frustrating. I tried changing cables, cords, etc. It came and went for no apparent reason. 
The only fix was when I unplugged my cable F Type connector from the cable box and plugged it back in again, the hum was gone for good. I was planning on trying a Jensen Isolator, but didn't need it.

I didn't suspect this because the TV and video system is on a different circuit altogether. Ground loop hums are strange animals.
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
1) I have unplugged all sources from the preamp and it goes away.

2) cleeds

Good suggestion. I just tried it with my iPod. Iplugged it into a SE input and the hum was not there.


I think this is all the proof you need to know that the BAT VK30 is not the problem, as well as VK’s assurances.

I went through this 20 years ago with a Cary preamp (my 1st tube preamp). I sent it back to Cary twice, and both times they found nothing wrong with it. I eventually gave up and went back to a SS preamp (Classe?).
SS preamps are less susceptible to ground loop hums, but IMHO, they are less susceptible to musical nuances.
I cannot live without a tube preamp anymore, though occasionally I have to fight through a grounding issue.

I’m rather surprised to hear that you tried Jensen ground loop isolators on RCA and XLR audio inputs, as I was thinking of the video device.

http://www.jensen-transformers.com/videos/

Do you have no video cable in your home/apartment?
If you do, try simply unplugging the cable input, and see if the hum goes away.
It makes no difference if the video system is on a different circuit, or in a different room.
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