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  3. 169310-128706

Channel Imbalance Mystery

I’ve been experiencing a channel imbalance for awhile now that I cannot seem to solve. I’m only running a turn table so I cannot troubleshoot with a digital source. I have ruled out the TT and cart as the problem because I had it tested in another system and it sounds great there. I’m running a Herron VTPH-2A phono pre into a Cronus Magnum II integrated amp with brand new KT120 power tubes. (The imbalance was present with older power tubes too). My channel imbalance is left leaning. When I swap the tt inputs into the Herron preamp the imbalance is fixed. Vocals are dead center but my stereo orientation is flipped. No problem, just swap my preamp outputs to get me back to the correct channel orientation but doing so shifts the center image back to the left a bit but soundstage is correct. It’s not nearly as bad as when my tt inputs were in the correct L/R positions. What the hell is causing this?! I’ve tried different interconnect cables with the same results so I don’t think it’s a cable issue. Could it be unmatched signal tubes in the Herron? Signal tubes in the integrated? Super frustrated. Thanks for any help. 
paulgardner
elliottbnewcombjr
5,944 posts
 
Get a GOD**** Tube Tester! 

I cannot imagine loving tube sound and denying myself the ability to have confidence or find problems in active and replacement tubes.

Test the tubes, short? good or bad? go from there. Have the tester for the rest of your life! Get or download the manual. It's not rocket science. I test new matched tubes when I receive them.

https://www.ebay.com/sch/i.html?_from=R40&_nkw=tube+tester&_sacat=0&LH_TitleDesc=0&_...

this little tester has given me confidence and found problems for over 40 years. I have a big fancy one, they always agree, I don't bother with the big one anymore, I'm gonna give it away or sell it someday when I get around to it. 

https://www.ebay.com/itm/165066777164?hash=item266ebf224c:g:h-IAAOSw96BhPXpQ

I would take it apart, hose it's guts with contact cleaner/lube, twirl the controls this way and that, blow it dry, wait overnight for further drying, and get right to it.




mijostyn's avatar
mijostyn
8,570 posts
 
Paul, it is probably an illusion created by room acoustics and imbalances canceling each other. 

My system has always run 3 dB hotter on the Lt in my current room. There is an alcove on the left side wall. In preparation for a new turntable I finally completed the built in cabinet for that alcove. My left channel now runs 1 dB hotter. Now if my right channel electronics had 0.5 dB more gain switching channels like you did would cancel out the imbalance. This is what a balance control is for. Unfortunately, that imbalance is hardly ever equal across the audio spectrum so your frequency response curve is being shifted. This is where room control is very effective. For reference a 0.5 dB imbalance is just noticeable. A 1 dB imbalance is obvious. 
elliottbnewcombjr
5,944 posts
 
This will solve things until you ascertain what is going on. Gives you remote balance as well as remote volume.

https://www.ebay.com/itm/234116696552?hash=item36827149e8:g:FOsAAOSwhNlgmIqc

Then, after you 'fix' whatever is going on, you have it, it is noise free 120db s/n and neither I or my friends can hear whether it is in or out of my systems.

I love having remote balance from my listening position for the few tracks that need a balance tweak. A small adjustment can make a large difference, so much ’opens up’ when the balance is spot on.

It also has automatic ’Loudness’, progressively engaged ONLY for low volume listening, the primary benefit is retaining bass presence, a big part of maintaining involvement at low level listening for me.


paulgardner OP
183 posts
 
@mijostyn it’s not room acoustics. There was a time when I had beautiful channel balance in this same room with the same system. It’s gotta be the tubes or something else. 
sns
4,025 posts
 
May be tube related or not. It may also be a recording issue, I hear many early stereo and some mono recordings have left of center bias. Sometimes this is intended bias created by engineers/producers, other times poor remastering and or duplication.
What about your ears, ear wax can cause this, or maybe some other reason for loss of hearing.
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