Left / Right Balance – Am expecting too much?

Discussion in 'Audio Hardware' started by JayH, May 18, 2021.

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  1. JayH

    JayH New Member Thread Starter

    Location:
    Chicago, IL
    I just purchased a Rogue Audio Cronus Magnum III integrated amp. I’ve always been a fan of tube amps and the sound of this amp didn’t disappoint me. In my opinion, the sound is fantastic! The only complaint I have is that the left / right balance is a bit off. By “a bit” I mean ~ 0.4 db (measured into a non-inductive load) 50 – 15kHz. To correct this, I have to set the balance pot to about the 1-o’clock position. Part of me says I’m being too critical, another part of me says that for the cost of the amp (~$3,000), something as simple as a balance pot ought to be right on the money.

    What do you think?
     
  2. Rick58

    Rick58 Forum Resident

    Location:
    Eagle, ID, USA
    I think anything with tubes especially might suffer from this malady? For the past 10 years or so I’ve insisted on having a remote balance control, first in a McIntosh C220 preamp and now my Parasound P 7.

    I like to tweak individual records or songs as needed, I sometimes have it centered but other times one or two clicks to one side or the other, these are about 0.5dB per click.

    I think individual recordings can need a tweak one way or the other just to get the soundstage just so.

    I don’t know if swapping tubes around left to right would achieve a better balance or not. If it really bothers you that much it might be worth a try. Maybe it’s other aspects of the circuit though. If it just needs to stay at 1 o’clock that doesn’t seem so bad to me.

    I guess if it really bothers you you could send the unit back but it seems a bit extreme to me to do so. Maybe call or correspond with rogue and see what they say.

    I guess another question is do you hear it as a shifted soundstage? If so could you leave the balance control centered and move one speaker forward or back by an inch or so. I used to do that all the time before I got a remote balance control. Actually I didn’t have a balance control for quite a while. I moved the speaker back-and-forth to achieve the best soundstage.
     
    Old Rusty likes this.
  3. vinylontubes

    vinylontubes Forum Resident

    Location:
    Katy, TX
    At this point I wouldn't be concerned. You have to put a few hours on the tubes before you know where you're at. I honestly wouldn't swap the power tubes as the first thing to try. They've been paired buy Rogue and your bias setting should adjust for balance on the power side. You could swap the two pairs of preamp tubes, though. You also have the center tube to swap into the mix as well. But, I would center the balance and adjust speakers, myself.
     
  4. Thorensman

    Thorensman Forum Resident

    Could you build a passive pre.

    2 single pots.
    Purely as an evaluation tool.
    This way you will know if the pre is the problem.
    I have little faith In preamps.
    My Leak is definitely better with my
    Home built passive 10 ,K tokos pots.
    Many preamps years ago had input trimmers.
    You set vol at 12 o clock and adjust
    Input trimmers. The advantage being
    Perfect channel balance.
    My old Naim 42 pre had its balance
    Nearly all the way to the right.
    Maim said it was normal.
    Never happy with this.
    Best active I have is the AV1 S2000
    Relays no switches on input.
    Excellent channel balance.
    Good luck
     
  5. Razakoz

    Razakoz Forum Resident

    Location:
    Utah
    With tubes things usually won't be perfect, it's simply how they work. Something like this could be caused by something as minor as the tubes not being perfectly matched in gain. If you love the sound I'd say not to worry too much.
     
  6. Helom

    Helom Forum member

    Location:
    U.S.
    It uses a single dual-triode tube for the 1st gain stage and it’s far from a dual-mono layout. I’m surprised the imbalance isn’t greater.
     
  7. JayH

    JayH New Member Thread Starter

    Location:
    Chicago, IL
    After a bit more testing, I think the problem, at least in part, is due to slight volume control mis-tracking at low volume settings. I found that if I attenuate the input and turn the volume pot up to around the mid-point, things improve considerably. In fact, I was able to find one point where the balance was near perfect. For what it's worth, I did swap and rebias the power tubes, as well as the preamp tubes, with no change in performance. I spoke to Mark at Rouge, who was most helpful. He told me that the amps are tested for balance after assembly, but before a 1-hour burn in. After the burn in they are subjected to a critical listening test before they leave the factory. I suppose it's entirely possible that there was a slight drift in one of the components during the burn in. In any case, the amp makes me smile every time I listen to it and based on your comments, I don’t think this is something I’m going to worry about.

    Thanks!
     
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