Why do I see a stronger left channel?

the mix tape forum
pokearoo
Posts: 2
Joined: 11 Aug 2012 20:29

Re: Why do I see a stronger left channel?

Post by pokearoo » 12 Aug 2012 00:42

In servicing some stereo equipment I have noticed also some small variations in the outputs of pre-amps as the volume control is brought up and down. It seems that the potentiometers can wear (or even be manufactured) with a variance from one end of the scale to other.

I used the same signal in both channels and measured the output on an oscilloscope. The scope inverted one channel and added them, say left (inverted) and right. I adjusted the gain on one side of the scope to null the two signals. The result was to show the difference from one side and the other. A flat line on the scope was displayed when the 2 sides were equal. The dial was changed from one extreme to the other. The output showed a changing difference as the dial moved. Not always the same side is higher at all volumes, if you go and check the individual signals.

This result is typical of a range of equipment from Sony, Marantz and my McIntosh MX-112. Unless you can hear the difference I'm not sure it's worth worrying about it. Maybe adjust the balance or even look for newer higher quality potentiometers.

I like the idea of checking with a test LP. I'll check to see if the one I have can check the balance.

Great site, great Forum

soundssupreme
junior member
junior member
Posts: 14
Joined: 17 Apr 2008 21:39
Location: u.k.

Re: Why do I see a stronger left channel?

Post by soundssupreme » 19 Aug 2012 15:20

What about linking the left and right channels together going into the computer, i.e. making the input mono ? This would absolutely rule out any imbalance of the line in of the computer.
Unless you can hear the imbalance (particularly in the midrange), then I would not worry about it.

Jim Leach
senior member
senior member
United States of America
Posts: 861
Joined: 03 Mar 2010 18:40
Location: Back in CT!

Re: Why do I see a stronger left channel?

Post by Jim Leach » 20 Aug 2012 13:35

Let's ponder this:

This was 1976. Records were mastered with nearfield monitors and/or headphones. You mentioned they sound right and image right, so the engineers did their job with the available technology.

Compare the sound to an all digital release of anything. But the all digital stuff looks better on the screen.

Who cares? The idea is to have good sound in an audio recording. I think you are over thinking it a bit. If it sounds good; it is good!

soundssupreme
junior member
junior member
Posts: 14
Joined: 17 Apr 2008 21:39
Location: u.k.

Re: Why do I see a stronger left channel?

Post by soundssupreme » 20 Aug 2012 15:15

Jim Leach wrote:If it sounds good; it is good!
I agree with that. If it doesn't sound imbalanced and you don'y notice it when you listen to it, why does it matter if the levels don't look right.
Going back to the days when cassette recorders were the order of the day if you wanted to archive (unless that is, you wanted to do it with reel to reel), then you should have seen the variation in channel balance with many records going by the recording level meters, yet they still sounded fine. I would rather have that than the probably perfect channel balance of a modern re-issue on cd.

wordwizard
senior member
senior member
Posts: 466
Joined: 02 Sep 2010 02:24
Location: Los Angeles, CA

Re: Why do I see a stronger left channel?

Post by wordwizard » 20 Aug 2012 17:05

jake wrote:... Balancing issues drive me crazy.
That's why they invented balance controls :mrgreen:

stepaan
Posts: 2
Joined: 15 Oct 2012 10:59

Re: Why do I see a stronger left channel?

Post by stepaan » 15 Oct 2012 11:46

Hello!
I experience slightly different issue. It seems anything above cca 10 kHz is coming louder from the right channel. The rest of the frequency spectrum is "in place". Singing is OK, Snare drums are OK, but Hats, some cymbals and very high FXs come mostly from right hand side. Any help would be great!
Thank you,
Stepaan
Midranger: I would recommend you to try as many record you can. Try different wires, switch them, try headphones, if it's possible ask your friend to play your records on his/her gear, as someone has mentioned – try to obtain a digital copy and compare. Try to obtain another piece of the same record and compare. It helped me a lot. Now I know that error is definitely on my turntable (but still don't know what is it ;-))

soundssupreme
junior member
junior member
Posts: 14
Joined: 17 Apr 2008 21:39
Location: u.k.

Re: Why do I see a stronger left channel?

Post by soundssupreme » 16 Oct 2012 14:50

stepaan wrote:Now I know that error is definitely on my turntable (but still don't know what is it ;-))
Many things can change balance between channels, and since you are sure the problem is with your turntable, these are some things you can look at :-

Check all cartridge alignment, i.e. Vertical tracking angle (tonearm height effects high frequency content). Azimuth (i.e. the angle of the stylus to record as viewed from the front). This will certainly effect balance, particularly in the high frequencies, and more so with elliptical than, for instance, a spherical stylus.
Check bias. Most cartridges don't actually need as much bias as is often set, i.e. 1 gramme is usually sufficient for playing weights up to around 2 grammes, so you can play around with the bias either side of the playing weight and see if this make a difference, but I would suggest the 1 gramme setting.
Channel balance of the cartridge. If the cartridge is fairly new and you have always had the problem since fitting it, the cartridge could have a low channel. This can happen !
Check all your connections from the cartridge right up to the amp, but especially the cartridge tags for bad connection. Apply some isopropyl alchohol to inside of the tags with a stylus brush and push the tags onto the cartridge pins a couple of times for each pin which should clean them. If is fitted to an SME style headshell, then clean the tags at the other end of the wires as well.
The only other thing that could effect balance that I can think of is either friction in the lateral bearings, or if the internal tonearm wire is twisted, for instance if it has been internally re-wired incorrectly, forcing bias on the tonearm.

I hope this helps you find the problem.

stepaan
Posts: 2
Joined: 15 Oct 2012 10:59

Re: Why do I see a stronger left channel?

Post by stepaan » 16 Oct 2012 16:57

soundssupreme: Thank you very much! It's amazing how many things can affect the quality those 30 years old gems ;-) Since I have bought my turntable at an internet auction site, I'm not sure in what condition the stylus really is. I have ordered a new one. I also have to visit a service, because it's Technics SL3 with a linear tracking tonearm, I doubt I could fix it (or make a proper settings) by myself...
But once again: thank you.

soundssupreme
junior member
junior member
Posts: 14
Joined: 17 Apr 2008 21:39
Location: u.k.

Re: Why do I see a stronger left channel?

Post by soundssupreme » 17 Oct 2012 07:00

stepaan wrote:soundssupreme: Thank you very much! It's amazing how many things can affect the quality those 30 years old gems ;-) Since I have bought my turntable at an internet auction site, I'm not sure in what condition the stylus really is. I have ordered a new one. I also have to visit a service, because it's Technics SL3 with a linear tracking tonearm, I doubt I could fix it (or make a proper settings) by myself...
But once again: thank you.
You're welcome. I hope you get it fixed soon (hopefully the stylus will sort it out for you).

theoaronson
United States of America
Posts: 3
Joined: 26 Feb 2019 01:22

Re: Why do I see a stronger left channel?

Post by theoaronson » 16 Apr 2019 15:20

Old thread I know - but I'm experiencing the exact same issue. New Pioneer PLX 1000, Radial J33 Phono Preamp, Ultimate Analog Test Record. All records are 2.5-3db louder in left channel. But it gets weirder - I only experience this with my Shure M44-7 and Ortofon Scratch cartridges. My Shure M44G is more balanced and leans a little to the right sometimes. All styluses have <20 hrs use. Possible the break in period will improve channel balance?

I've exhausted all trial and error options to rule out preamp, receiver, etc...its definitely coming off the turntable, cartridges, arm, etc...See attached photos of both the MM44-7 and Ortofon needs and peak level I measure in my DAW. Also tried different tracking weights and anti-skip and issue remains the same.

Any ideas for why this is happening? Thx in advance

Ortofon at its worst 2.5db difference:

https://imgur.com/gDQ0fh1

Ortofon at its best 1.75db difference:
https://imgur.com/L5mRo1I

Shure at its worst 4db difference:
https://imgur.com/3TGGtUJ

Shure at its best 2db difference:
https://imgur.com/wU4lrBV
Attachments
Ortofon Scratch 2db.png
(267.78 KiB) Downloaded 30 times
Shure M44-7 4db.png
(275.92 KiB) Downloaded 29 times
Shure M44-7 2db.png
(268.75 KiB) Downloaded 30 times
Ortofon Scratch 2.5db.png
(259.51 KiB) Downloaded 30 times

theoaronson
United States of America
Posts: 3
Joined: 26 Feb 2019 01:22

Re: Why do I see a stronger left channel?

Post by theoaronson » 16 Apr 2019 18:40

PS - these tests were all done via the 1k mono test tone Side A Track 1 on the Ultimate Analog Test LP: https://www.needledoctor.com/Ultimate-A ... mTEALw_wcB

vinylvark
junior member
junior member
Netherlands
Posts: 20
Joined: 09 Jul 2014 15:29

Re: Why do I see a stronger left channel?

Post by vinylvark » 02 May 2019 06:44

theoaronson wrote:
16 Apr 2019 18:40
PS - these tests were all done via the 1k mono test tone Side A Track 1 on the Ultimate Analog Test LP: https://www.needledoctor.com/Ultimate-A ... mTEALw_wcB
I fixed an issue with channel imbalance by taking the needle out, and under a good loupe, look at the angle of the magnets, should be the same angle either side. I could also see my diamond tip was slightly off to one side too. With a small pointly thing, I softly tapped the magnets until they were both at the same angle, I think its 45 degrees (so they are 90 degrees angle on each other). The diamond tip was now also straight up.

This completely eliminated my channel imbalance, audible and measurable.