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Pre amp ruining analog

I recently obtained an Audio Research Ref 6 which works wonderfully well for digital but creates such a whine and hum when I try using it for vinyl I can no longer listen to it. I've spent a lot of money on my analog set up and enjoy vinyl enormously so you can imagine how frustrating this can be.

I've tried all the known remedies; cheater plugs. grounding from the tone arm to all components, unplugging my cable box and wireless router(which of course cannot be a long term solution), using different inputs, switched rca and balanced interconnects... I don't have a lot of room in my apartment so I can't go moving components far away from each other. I could go back to ss but I'd prefer to keep the arc because digitally it creates such beautiful music compared to the ss pre I had before. And it would be a hassle to sell needless to say.

My amp is a vtl s200(shortly switching to a Pass 350.8) which created a slight hum for vinyl which was masked by the music but the tube pre makes lps intolerable. My phono pre and head amps are allnics(when replaced with a Shiite the hum was still there. When I had a ss pre amp and amp the allnics created no hum at all.)  Turntable is a vpi superscout with 3D tonearm and koetsu blue lace.

Any ideas before I am forced to go back fully to ss? Tubes are so musical and warm but they seems to come at too high a price.
vindanpar
6 responses Add your response
lostbears's avatar
lostbears
538 posts
 

 The fact that you have no hum with digital leads me to think the problem is somewhere in the analog front end and not the preamp. Do you have any dimmer switches, compact florescent or LED light bulbs? These can cause hum in your system, especially with analog. Do you have your turntable motor plugged into the same place as the rest of your system? This can also create a problem.

 I have both a Ref 5se and Ref Phono 2se and they are dead quite. I had problems with some phono preamps causing hum before I got my Ref Phono 2se. Anything with a battery caused hum including  a ClearAudio power box for my turntable. I have also had problems with compact florescent bulbs on the other side of the house creating hum in my preamp. This really confused me because it was intermittent. It took a while for me to realize the hum was only there when the dining room light was on. I now have everything in my front end plugged into a power conditioner except my turntable motor.  


salectric
755 posts
 
Have you tried plugging the phono preamp into other inputs on the ARC?  Perhaps unplug the digital input and plug the phono preamp into that input since you know it works fine.  The fact that the hum was still present with the Shiite phono preamp says to me that the phono preamp itself is not at fault.  If you still have hum when the Allnic phono is plugged into the digital inputs, then I would suspect a ground loop issue.  I would try a cheater plug on the AC line for your Allnic.  Back when I had an ARC linestage, I recall a recommendation that if there was a ground loop problem the linestage should be the only component with its AC plug connected directly to the wall outlet; all other components should use cheating plugs to float their chassis grounds.
lostbears's avatar
lostbears
538 posts
 

 That was a long time ago when ARC gear was mostly single ended. There was sometimes a ground loop between the amp and preamp. ARC recommended grounding the preamp and floating the amp.

 Are using balanced or single ended cables from the  phono preamp to the Ref 6?


roberjerman
4,319 posts
 
Your Allnic tube pre-pre amp is the likely culprit. Get a good step-up transformer!    Any tube gain stage will be inherently noisy when trying to amplify a mc cartridge's typically low voltage (<1 millivolt). Yet the mc cartridge has adequate current output - making it an ideal match for a transformer! I have been using step-up transformers with my mc cartridges for 40 years with NO problems! Perfectly quiet backgrounds to the music from LP's! I'm presently using a Denon 320 with a Denon 103R. Since you have a Koetsu you might consider a Koetsu step-up transformer (after selling the Allnic!) Or for less money a Bob's CineMag would be a good choice! Check out Art Dudley's writings on this subject on the Stereophile site (under "Listening") He believes (as I do!) that NOTHING beats a good mc cartridge and transformer! That is why I have always preferred analog over digital playback!
roberjerman
4,319 posts
 
I have yet to hear an active gain-stage that can equal a passive transformer's quiet backgrounds AND dynamic contrasts when used with a mc cartridge!
atmasphere's avatar
atmasphere
11,841 posts
 
A whine is often caused by a microphonic tube.

But this problem only shows up on the phono input, and as I recall all the Ref series preamps are line stages. So the problem sounds like a microphonic tube in the Allnic.

Try swapping the interconnect cables left for right at the input of the ARC for the phono. If the problem moves, the ARC is off the hook and the Allnic is suspect. I'd be tapping the tubes to see if the whine shuts up even for a little bit.
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