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L/R Channel Imbalance

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L/R Channel Imbalance

Postby okaycpu » 15 Jul 2018 23:39

I have a channel imbalance issue with my turntable. Left channel is slightly louder than the right. My setup is a Rega P7 with a Dynavector 20x2L (retipped by Soundsmith). I initially noticed the imbalance once I bought a headphone amp. I noticed that when I turned the volume down, the right channel would go completely silent at very low volume and the left would still give me some soft sound. I think I have made it better by doing a cartridge realignment. But it’s still bothering me.

As you can see in the pictures, when I test the left channel at -20dbs I get very little noise from the right channel and hit right at the -20dbs on the left like I’m supposed to. Whereas when I test the right channel, I get much louder noise from the left channel (about -10dbs?) and the right channel is like -2 or -3dbs shy of hitting the -20dbs mark.

https://imgur.com/a/tNGX6AP/

Does anybody have any idea what could be causing this? I have realigned my cart with the MINT LP Tractor several times now and when I use the Hi-Fi News year record I’m able to pass up through the 8th band on side 1 for the bias setting and all 3 of the tracking bands on side 2. I just can’t seem to get the channel balance correct.

I know it isn’t the preamp (Jolida JD9 MKII) or the tubes because I’ve tried another input source and swapped tubes. So I’ve narrowed it down to either the cartridge or the turntable’s wiring. The leads going into the back of the cart look very clean but I could be wrong.

Also, I mounted a different cartridge that I had lying around (some cheap groovetracer) and the issue was essentially non existent. It’s a much less accurate cart and seemed to pick up a lot more noise so it was hard to tell. But I wanna say that the problem was still there, albeit very very minuscule.
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Re: L/R Channel Imbalance

Postby ChrisfromRI » 16 Jul 2018 05:19

Can you set the stylus down on a mirror and sight it from the front to make sure the Azimuth is reasonably correct?
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Re: L/R Channel Imbalance

Postby Solist » 16 Jul 2018 10:43

There is always gonna be a small channel imbalance. Some cartridges will have worse channel balance than others. But it really should not be audible. With that said it can be poor azimuth adjustment as ChrisfromRI already mentioned. A poor azimuth setup will cause the stylus to have more contact on one side of the groove which will cause channel imbalance. Use a magnifying glass and make sure that the needle is _!_ to the record. Some manufacturers do a better job at fitting the stylus to the cantilever than others, but you should always check for that no matter how much you spend on the cartridge :D

The other possible cause is antiskate. Antiskate is used to counter the force which is pulling the tonearm torse the center of the record. Too much or too low antiskate will cause the stylus to ride one side of the groove more than the other, which will cause channel Imbalance. Now, its impossible to set the antiskate correctly for the whole record, since the amount of pull will vary from the outer groove to the inner groove. Its a matter of trial and error and when you find a sweet spot thats it.

There are also test records which will Help you set up the cartridge correctly, recently someone wrote on another thread that he uses mono LPs to set up the cartridge.
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Re: L/R Channel Imbalance

Postby Solist » 16 Jul 2018 10:58

Regarding the protractor I would suggest to use the Conrad Hoffmans protractor generator. Its free and you can try different alignments. All you need is a decent printer :)

viewtopic.php?f=19&t=16849
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Re: L/R Channel Imbalance

Postby okaycpu » 16 Jul 2018 18:08

Solist wrote:There is always gonna be a small channel imbalance. Some cartridges will have worse channel balance than others. But it really should not be audible. With that said it can be poor azimuth adjustment as ChrisfromRI already mentioned. A poor azimuth setup will cause the stylus to have more contact on one side of the groove which will cause channel imbalance. Use a magnifying glass and make sure that the needle is _!_ to the record. Some manufacturers do a better job at fitting the stylus to the cantilever than others, but you should always check for that no matter how much you spend on the cartridge :D

The other possible cause is antiskate. Antiskate is used to counter the force which is pulling the tonearm torse the center of the record. Too much or too low antiskate will cause the stylus to ride one side of the groove more than the other, which will cause channel Imbalance. Now, its impossible to set the antiskate correctly for the whole record, since the amount of pull will vary from the outer groove to the inner groove. Its a matter of trial and error and when you find a sweet spot thats it.

There are also test records which will Help you set up the cartridge correctly, recently someone wrote on another thread that he uses mono LPs to set up the cartridge.


I believe you’re onto something here with the azimuth adjustment. Problem is this is a Rega arm so adjusting the azimuth isn’t exactly easy to do. After looking over the waveform again I think what I’m seeing is that the left channel is getting a nice clean reading with out bleeding over much to the right, whilst with the right channel, the sound is bleeding over to the left channel which is causing an imbalance. Correct me if I’m wrong but azimuth as I understand it, is the tilt in the cartridge and/or cantilever.


Basically what I need to do is tilt the cart within the head shell slightly more to the right so I’m getting a more even signal.

Also I have played with anti skate and it had no effect.

Thank you for your Help. Please correct me if I’m wrong anywhere.
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Re: L/R Channel Imbalance

Postby ChrisfromRI » 16 Jul 2018 20:09

Azimuth is stylus tilt to the left or right as viewed from the front. I suggested setting the stylus down on a mirror (preferably front surface mirror if you have a choice) and looking at it from the front which will exaggerate the visual tilt when you see the reflection as well as the primary view. With the naked eye you will easily see if the cartridge body is tilting which MAY be an indicator of the azimuth being off at the stylus - where it really matters. In that your cartridge was re-tipped this could be only at the attachment of the stylus to the cantilever being a little off, and the body will not indicate this.

Even though your headshell is not adjustable for azimuth you can always shim one side of the cartridge body away from the headshell by inserting a washer or shim of some sort between the cartridge body and the headshell on ONE side only (trapped by either the left or right screw). You can try this and if the cartridge needs more washers even add more, and then you can ultimately measure the thickness of the required shim on the one side. Then in the workshop you can make a better tapered shim from a plate later with the same delta between the two side but maintaining uniform contact between the cartridge body and the headshell all the way across. Maintaining full uniform contact is more important with lower compliance cartridges and less so with higher compliance cartridges. Lower compliance cartridges tend to apply more energy into the arm that the arm needs to sink away, which your arm is very good at doing - but I have not used your cartridge so am unfamiliar with its requirements.
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Re: L/R Channel Imbalance

Postby Patrice Brousseau » 16 Jul 2018 20:54

It could the potentiometer on your amp, there is some tolerance, particularly at low level...
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Re: L/R Channel Imbalance

Postby Solist » 17 Jul 2018 01:39

The easiest way that I could find and it does wonders is to use pieces of electric tape and
medical tape (the white thing, for even more precise adjustments since its thinner) to use it in between the cartridge and the headshel. If you want you can also do a 3 or 4 point thing, where the 2 points in the front (where the screws are) are for the azimuth and the 1 or 2 on the back of the cartridge are for vta adjustment.
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