Post by cooksferry on Sept 16, 2019 7:43:03 GMT 12
Got my vinyl setup running again and once again noticed a slight channel imbalance favouring the right speaker. This is something that has been there through three cartridges and several years and for much of the time I've put it down to my hearing as my left ear is not as good as the right. However yesterday I did a swap from the Project arm to the Wand and immediately everything became focused as it should which leads me to believe that there's a very small tilt on the Project arm. Now in theory this arm should be able to be rotated by loosening a small grub screw at the rear of the tube but I do remember trying this some time ago and the tube appeared to be stuck. I've not be brave enough to try any sort of force with the possibility of damaging the arm.
When I use the HIFI News test record in mono Azimuth appears pretty good but this imbalance during listening is starting to annoy me.
I don't think it's the cartridge, Dyna XX2, as the same result was there with my two previous carts(Dyna DV20XL).
My next step is to try and shim the cartridge although looking at the stylus from the front the amount needed would be quite small.
Anyone any hints or advice before I proceed.
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Post by cartridgeguyonline on Sept 16, 2019 7:52:00 GMT 12
So when you play a mono LP everything is fine ? (Do you have a mono switch on your amp ?)
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Post by cooksferry on Sept 16, 2019 8:10:26 GMT 12
So when you play a mono LP everything is fine ? (Do you have a mono switch on your amp ?) From memory everything is fine and centred in mono. I have a dedicated box that does left/right/mono/stereo with a four position switch built for me in Canada.
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Post by Owen Y on Sept 16, 2019 9:26:02 GMT 12
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Post by cartridgeguyonline on Sept 16, 2019 17:25:40 GMT 12
First I would try taking out the grub screw and putting a small amount of lubricant in the hole. Its probably never been moved since it was made....
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Post by michaelw on Sept 16, 2019 18:11:38 GMT 12
grub screw ?
project tonearm iirc,
also
try a direct feed, i.e. take the switching box out of the chain.
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Post by cartridgeguyonline on Sept 16, 2019 19:19:24 GMT 12
Sorry I dont know the project tonearm but cooks said there was a grub screw holding the arm position ?
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Post by colinf on Sept 16, 2019 19:29:45 GMT 12
So....is the mono test record centered in the soundstage with the amp set to stereo, or does that happen only when you use the mono switch on the amp?
AMR-iFi R&D
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Post by michaelw on Sept 16, 2019 19:52:22 GMT 12
Sorry I dont know the project tonearm but cooks said there was a grub screw holding the arm position ? fyi most project tone arms have a very small set screw at the rear of the armtube, loosen (do not remove !) this and you can twist the tube to make small azimuth adjustments.
tbh i have never seen a project arm that needed this adjustment.
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Post by cooksferry on Sept 17, 2019 7:19:18 GMT 12
Thanks for the replies gentlemen. Yes, the Project arm does have a small grub screw that secures the arm and in theory you can loosen this and rotate the arm. How ever I can remember trying to do this not long after I purchased the TT (10years ago, maybe more) and even completely removing the screw, the arm refused to budge. As I said above I am very reluctant to apply any real force in case I damage the arm. Over the years this imbalance has occasionally been enough to spur me into some sort of action rather more than just moving the listening chair a bit more to the left. Since this has been around since day one I can discount phono stages, been through 3, cartridges ditto, speakers ditto again, and room position as it has been the same whether the speakers have been firing up the room or across and the amount of free space around the speakers doesn't appear to be a factor either. If we have a wet weekend I will dig deeper chasing a theory of two and will try shimming the cartridge if all else fails. Manual for the arm, mine is the 10cc version www.henleyaudio.co.uk/shop/product/viewfile?FileId=508&ProductId=130
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Post by colinf on Sept 17, 2019 7:26:40 GMT 12
Perhaps first see if you can use a different turntable and tonearm...?
AMR-iFi R&D
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Post by cooksferry on Sept 17, 2019 7:36:18 GMT 12
Perhaps first see if you can use a different turntable and tonearm...? Using the Wand arm on the same table balance is as it should be which leads me back to the Project arm.
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Post by colinf on Sept 17, 2019 8:41:05 GMT 12
Ok, the Wand, being a unipivot, should be easy to change the azimuth on. See if you can simulate a channel imbalance with this arm by fiddling with azimuth. Otherwise, if you have a multimeter, measure the resistance on each channel output on the tonearm lead rcas. It should be the same or very close on each channel. Can’t remember exactly but I think the XX2 has 12 ohms resistance.
AMR-iFi R&D
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Post by Owen Y on Sept 17, 2019 9:23:02 GMT 12
colinf - do you mean, measure the series resistance of ea ch phono cable across ea RCA plug +/- ? ie With cartridge connected - they say that modern multimeters are safe with MC cartridge coils, because their meter current is too small to risk any coil damage...?
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Post by Owen Y on Sept 17, 2019 9:54:33 GMT 12
In this video, which is in Polish  , you will see the Pro-Ject grubscrew & arm tube rotation at 1:03. (screenshot) 
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Post by Owen Y on Sept 17, 2019 14:53:42 GMT 12
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Post by cooksferry on Sept 17, 2019 15:51:12 GMT 12
In this video, which is in Polish , you will see the Pro-Ject grubscrew & arm tube rotation at 1:03. (screenshot) Yes, that's the one I've removed before. Wonder how a little gentle heat from a hair dryer might work to free up the tube? Might be worth a try if all else fails.
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Post by Owen Y on Sept 17, 2019 17:43:45 GMT 12
Should be safe to withdraw the grubscrew a fair amount (easy enough to find in your room if it drops out  ) Or shim the cartridge if all else fails.
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Post by michaelw on Sept 17, 2019 17:49:07 GMT 12
does the channel imbalance change if you switch channels ?
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Post by colinf on Sept 17, 2019 19:29:20 GMT 12
Owen, yes, digital multimeters measure with low current. Cooks, you could also do another version of MichaelW’s channel swapping. Just swap the channels at the cartridge end, and also at the rca outputs of the tonearm. That way only the tonearm wiring will be swapped and not the stereo from the record as well. If the imbalance shifts to the other side, suspect the tonearm wiring. If not, you might indeed have a setup problem. If you know someone with Analog Magik software that would make fiddling with azimuth much easier. Otherwise just level the tonearm at the headshell (the turntable must also be level...check it on the platter at several locations.
AMR-iFi R&D
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Post by cooksferry on Sept 18, 2019 7:15:21 GMT 12
Thanks for all the ideas, plenty for me to look at over the weekend , appreciate it.
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, you will see the Pro-Ject grubscrew & arm tube rotation at 1:03.
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