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.

jptenberg1
I have an ARC LS 25 mk I and I am considering an upgrade. Check out the ARC Reference 3. Used prices are at $4500, give or take. This is on my radar. I have a friend who adored his for years. He eventually bought the ARC 40th annevarsary.  Other people say the REF 3 is nearly as good as the REF 5. Either way, I would check into it!
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


+1 jmcgrogan2!
jptenberg1
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...
What makes you certain that the cause of the hum is a ground loop? Typically, a ground loop causes hum in both channels. Have you tried swapping cables from left to right to ascertain the problem isn't in the cable itself?
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.
I too agree with jmcgrogan2. I recently upgraded my preamp from an old Audioprism Mantissa to an ARC Ref 6. I have a Manley Steelhead and as much as I love it, ever since getting the Steelhead I have a ground loop that goes away if I switch back to my Simaudio Moon LP5.3. The Ref 6 sounds amazing too but it did not make my ground loop go away. In fact, it is now slightly worse. You need to solve your ground loop issue first. 

Thanks for the replies so far...So let me go into more detail about my ground loop.

It is only in the right channel-the left is dead quiet. I have swapped all interconnects and speaker cables and is has no effect. (well when switching interconnects from right to left to the amp, the hum changes sides as one would expect) I have tried both balanced and SE outputs from pre to amp.

I have unplugged all sources from the preamp and it goes away. As soon as I connect a source cable to any of the right channel inputs (either balanced or SE) the hum reappears. As I connect more sources to the preamp, the hum gets louder, so it appears to be a cumulative effect. However, the hum is at a constant level and does not get louder or softer with changes in the volume.

I sent the unit back to BAT after talking to Victor on an extensive phonecall and many e-mails. He gave the unit a thourough going over and could not reproduce any hum and sent it back with a clean bill of health. I brought it into my local audio dealer and had their repair guru put it on the test bench and could not reproduce any hum.

I have tried ungrounding all source components as well as preamp and amp. I have tried running a ground wire to all components. I have tried the preamp on another circuit. I have tried plugging it straight into the wall both on the same and other circuits. I have tried the Jensen ground loop isloators--both on balanced and SE between the pre and amp. Currently, all gear is running from a Furman outlet strip on a dedicated 20 amp line. I have also tried with a Monster reference 7000 power conditioner.

I have also switched the tubes from right to left channel, and swapped in a whole different set of tubes.

When I demoed another preamp from my local dealer (the Sonic Frontiers SF1) the hum dissappeared.

So, any other advice on ground loops would be greatly appreciated.

I am still not convinced that this is a ground loop, especially because you report that the Jensen xformers didn't resolve the problem.

Here's what I suggest: Connect to your preamp a battery operated source, such as an iPod or portable radio, using a cable you've already proven is not defective. If the result produces hum, your problem is something other than a ground loop.
EAR 868 is also a pretty safe choice - very musical, great tube sound, natural, good dynamics.  If you get it without the built in phono stage, you can get it around $4k.  I work with a great EAR dealer if you have any interest, feel free message me and can connect you with him to discuss EAR preamps.

cleeds

Good suggestion.  I just tried it with my iPod.  Iplugged it into a SE input and the hum was not there.  As soon as I connected another cable to the right channel, the hum came back...

http://www.libertyaudio.com/products/b2b-2-line-level-preamp-dac

Above you can try out in your room - Built in DAC too :-)

From its maker

Good Listening

Peter




Re: ground loop     I also had a ground loop hum in one channel. The search for the culprit was very frustrating. One time, I was comparing the SQ between a pair of RCA IC’s to a pair of XLR IC’s between my preamp and amp. As soon as I plugged both sets of IC’s in parallel, the hum disappeared. It didn’t matter where the input switch on the amp was set: XLR or RCA. After I decided to keep the XLR’s as the primary IC’s, I simply connected cheap Radio Shack IC’s on to the RCA connections between the preamp and amp. Hum gone! While I was at it, I inserted cheap RCA grounding plugs into the rest of the unused inputs on the preamp. It got even quieter! (If you do this be sure to do it on the inputs only, not the outputs). Hope this helps.

steakster

I just tried hooking up a set of RCA along side my XLR from pre to amp and it made it noticably worse :(  Thanks for the suggestion though

jptenberg1

cleeds

Good suggestion. I just tried it with my iPod. Iplugged it into a SE input and the hum was not there. As soon as I connected another cable to the right channel, the hum came back...

Have you checked the electrical wiring in your house? You might want to verify that hot and neutral have not been reversed anywhere in the house, and that the safety grounds are connected to neutral only in your service panel. Check the integrity of all connections in the service panel to assure yourself that they are tight and clean. If you're not familiar with how to do this safely, call a good electrician.


I have REF 3 for sale at this time.  I'm the original owner and you would love it.  look me up on AudioGon

As far as the ground loop is concerned.  Have you tried the tried and true procedure to find it?

1. Connecting the speakers to the amp only. removing all connections and interconnects, except speaker cables.  Noise?  yes, it is the amp.  No, move on

2.  Connect the pre-amp only to the amp to the speakers.  noise?  yes.  it is the pre-amp or the cables from the pre-amp. 

and so on one element at a time till you find the source.

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.

Hi jptenberg1  I know your price ceiling  as you describe it, but I will share with you briefly

my journey into this crazy hubby. I start it with a Kenwood receiver, move to a separate

power and pre amp it was a David Haffler. I change the pre-amp to Ps Audio 4 after that

I try most of the major brands from MC, Mark Levinson, Pass Lab, Cary Audio, SLP-98 and SLP-05, and final one was the Audio Research LS 27. My search ended when I try the Merrill Audio Christine Reference Pre- amp, it will take your system to the next lever. Merrill has a 30 days try, he is a very nice to deal with, good luck  Juan.        

I'm not convinced this is a ground loop. If that were the case, lifting the ground connections (I assume at the power cords; please correct me if I'm wrong) would have solved it.

Do you have a Digital Volt Meter (DVM)? If so, some simple measurements can put the ground loop issue to bed. On the Ohms scale, with the equipment unplugged, measure from the ground pin of the power cord to pin 1 of the XLR. What is the reading? Is it the same as the ground of the RCA connection? I would do this for the preamp and amp for starters.

BTW we make a tube preamp called the MP-3 that is fully balanced, has dual outputs and 3 balanced inputs (one of which is phono if the preamp is optioned with a phono section, which is also balanced). You might be able to find a used one or a demo at your price point.
I was just about to Recommend the MP-3 Pre-amp from Atma but it seems Ralph is already suggesting it.  I have both the MP-3 and MP-1.
Did you find the root of the ground loop hum? I had hum in my system and picked up a Rolls HE 18 and it removed hum. The less favorable review on Amazon was not my expereince. Also picked up a McIntosh C47 four months ago, May 2017, a wonderful piece. Have not used phono stage as Turntable is connected to a Project DS Tube Preamp and is the connected to one of the C47 line inputs, fabulous. Also have a Tube buffer in the chain so I can go with SS or Tube which is running a pair of Rogers Old new stock 6SN7GTA’s.