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Full sized Schiit amps - Channel imbalance?

post #1 of 18
Thread Starter 

I've been working hard to construct a legitimate A/B testing environment for source gear.  Combined with my co-workers, we have a huge number of amps, including all 5 Schiit amps.  After A/Bing sever Schiit units, we've found that our Lyr and our Asgard exhibit a pretty sharp channel imbalance (the left channel is very low compared to the right).  Interestingly, the Magni does not seem to have the same problem.  We haven't compared the Valhalla to anything but the Asgard, and no imbalance was observed there, so I assume the Valhalla has the same imbalance.

 

I've tried swapping every single components in the chain, as well as using a Fiio HS2 instead of my wooden switch box.  In all configurations, the only difference is in the immediate output from the amps.  For the comparisons, I am using the Sony SA-5000 in the picture and a set of Senn HD 700s.

 

So, has anyone else observed this?  I found this note on the 'Amp Problems' page on the Schiit site: 

 

"Channel imbalance is completely normal on all amps with very small potentiometers, (volume controls) at low listening levels. This includes Magni. The channel imbalance should not persist above 8:00 on the volume pot."

 

All of my tests have the volume pot at around 9:00pm.  I also have not observed this behavior in any of the other amps we have examined.  Is this a design flaw in the full size chasis Schiit amps?  Is there any way to fix it?

 

post #2 of 18

I suggest you to contact Schiit Audio to see what they can do. There's always a threshold for channel imbalance. 

post #3 of 18
Thread Starter 

I'll have to take a more detailed stab at this again on Monday.  I need to test if the imbalances really go away at higher levels on the volume pot, and compare all 3 amps again.

post #4 of 18

How do you measure channel balance? We should start there.

post #5 of 18

Well, shouldn't be that hard: just listen some music with different gears just like the OP starter did. For example my Vaio S15 developed a small but noticeable channel imbalance in contrast with my dac/amp. (Not exaggerating I hear the difference). Then you compare headphones with different sources. My grado sr60i also present imbalance, but due to a difference measured between my left and right ears I find the imbalance to be harmonically pleasing. 

post #6 of 18

There is a ton of potential problem with measuring channel balance with a headphone and your ears. Both of these "instruments" can be mistaken, and the headphone postion on your head is CRITICAL. Also, if a pad is slightly more used  or has a slightly different shape, it will alter your results. Just be aware of that before writing any conclusion with such a, may I say,  "subjective" test.

post #7 of 18
Thread Starter 

With the rig in the image, one source is playing music into a splitter, through two separate amps, then into the wooden switch box.  The switch box toggles between the two amps.  The channel imbalance is perceived in two ways:

 

1.  Listening to actual music, throwing the switch changes what I can best describe as "center of gravity" of the music.  Everyone who listened agreed that when toggling away from the Schiit amps, the sound was more "centered".

 

2.  Slightly more scientifically, I have a calibration track that pumps out a single tone noise for 30 seconds.  I use this to manually level (imprecise, i know) the two amps for all of these tests.  Using this tone, wearing only the left ear cup, I can I can toggle between the amps without any noticeable difference.  Wearing only the right cup, toggling to the Schiit is very noticeably lower volume.

 

Also, if I plug into the amps' outputs directly, I can alternate listening to one side and the other by pulling one ear cup away from my head.  The Schiit amps also clearly produce a different volume level on my calibration track, while the Magi and the A1 in the pic do not.

 

If anyone can recommend a good way to measure the actual decible level of each cup, I can do that.  I'm positive the difference is objective at this point.

post #8 of 18
Quote:
Originally Posted by Rem0o View Post
 

There is a ton of potential problem with measuring channel balance with a headphone and your ears. Both of these "instruments" can be mistaken, and the headphone position on your head is CRITICAL. Also, if a pad is slightly more used  or has a slightly different shape, it will alter your results. Just be aware of that before writing any conclusion with such a, may I say,  "subjective" test.

Let say you're right, but what if the imbalance is still present after testing different headphones? or inverting the cups L-R? I understand well that even drowsiness, sickness or allergic reactions affect the sound but still there's a subjective part we can't ignore. 

post #9 of 18
Thread Starter 
Quote:
Originally Posted by squallkiercosa View Post
 

Let say you're right, but what if the imbalance is still present after testing different headphones? or inverting the cups L-R? I understand well that even drowsiness, sickness or allergic reactions affect the sound but still there's a subjective part we can't ignore. 

The imbalance is present with different headphones, and again, the second amp connected to the cans does not have the imbalance when active.  Like I said, I've tried swapping every component in the chain.  The only time the imbalance changes is when I change the inputs into the switcher, at which point the side with the imbalance switches (indicating that the problem originate at the output of the amps)

post #10 of 18

I've heard some people pop off the knob and clean the potentiometer with deoxit or alcohol and it fixes it.. if it's still really bad, yeah definitely contact shiit for a possible exchange/repair

post #11 of 18
Thread Starter 

Alright, I just tested my amps with a monotone sound with the pot at 12:00.  I used the left ear cup only, and leveled the sound by hand until I couldn't tell the difference flicking the switch back and forth.  Then, I tried the same using only the right ear cup.

 

The channel imbalance is still blatantly present at 12:00.  I think I need to contact Schiit.

post #12 of 18
Quote:
Originally Posted by morph2k4 View Post
 

Alright, I just tested my amps with a monotone sound with the pot at 12:00.  I used the left ear cup only, and leveled the sound by hand until I couldn't tell the difference flicking the switch back and forth.  Then, I tried the same using only the right ear cup.

 

The channel imbalance is still blatantly present at 12:00.  I think I need to contact Schiit.

That's quite strange.... Keep us updated on the issue.

post #13 of 18
Thread Starter 

I've confirmed that 2 separate Lyrs and one Asgard all have the exact same behavior.  I've compared to an iBasso d3, a Maverick A1, and a Schiit Magni, none of which have the imbalance.  All of this testing was configured to run the volume nobs at 12:00.  I'll try to get my hands on the Valhalla floating around my office again to confirm if it is also affected.

post #14 of 18

It's interesting how headphone amps manufacturers can be so incompetent to not get rid of channel imbalance. I've had the same problem with pretty much every headphone amp I've owned so far, including the quite expensive Musical Fidelity M1HPAP which costs 900 dollars, as well as the Nuforce HDP, Little Dot mK5, mKIII,  Musical Fidelity V-CAN II, etc. Interestingly, my very cheap laptop (like 400 dollars) doesn't have any channel imbalance, Asus essence st doesnt either,  neither does the iphone 4s, or samsung galaxy s3, or a 20 year old philips receiver, or an onkyo integrated amp or a Panasonic plasma tv headphone output.  But headphone amps, designed to do one thing and one thing only, do have imbalances. Makes you wonder why you'd pay for them if they can't even do the basics right.

post #15 of 18

In most cases it is not the fault with the amp. It can be a problem with a difference in impedance between the left and right headphone driver. This then affects the rms voltage to the drivers. It is especially noticeable on low volume levels.

But more surprisingly, it can be a hearing imbalance. I am one of those who has such a problem with my hearing and need to use a headphone amp with a gain offset.

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