Ortofon OM20 lousy tracking

[magiccarpetride]

Alex,

Can we run through all the checks you have made:

[1] Is the turntable level, especially the platter?

[2] Is the arm mounting collar and horizontal bearing housing vertical with respect to the platter?

[3] Is the VTF as recommended by Ortofon, or at least not less than the minimum of the recommended range? (I always start with a setting 0.25g below the maximum recommended figure and work from there.)

[4] Do you still have problems if the bias dial is turned to zero?

[5] Is the azimuth correct? (you can use a mirror to check this.)

I still think the problem is with the arm applying too much bias. In my experience the bias calibration on most arms, marked as being appropriate for a given tracking force, are only correct for spherical stylii, for others: elliptical; fine line etc., the bias setting need only be half that of the corresponding playing weight (VTF).

Thanks Barry, here are the vital stats:

[1] Is the turntable level, especially the platter? -- Yes, as level as I could get it to be.

[2] Is the arm mounting collar and horizontal bearing housing vertical with respect to the platter? -- Yes.

[3] Is the VTF as recommended by Ortofon, or at least not less than the minimum of the recommended range? (I always start with a setting 0.25g below the maximum recommended figure and work from there.) -- I now have VTF at 1,67 grams.

[4] Do you still have problems if the bias dial is turned to zero? -- the problems are intermittent (which is what makes this so maddening). Last night started acting up again around 4 - 5 minutes into the playback. Then it suddenly decided to play fine and only start acting up toward the end of LP. Then later on, decided to play fine, beginning to end. So I never know what's going to happen next.

[5] Is the azimuth correct? (you can use a mirror to check this.) -- haven't checked azimuth -- Rega RB300 doesn't have removable headshell, so not sure how to adjust that?

Not sure what exactly is meant by 'bias'? Anti-skate?

[Barry]

Thanks Barry, here are the vital stats:

[1] Is the turntable level, especially the platter? -- Yes, as level as I could get it to be.

[2] Is the arm mounting collar and horizontal bearing housing vertical with respect to the platter? -- Yes.

[3] Is the VTF as recommended by Ortofon, or at least not less than the minimum of the recommended range? (I always start with a setting 0.25g below the maximum recommended figure and work from there.) -- I now have VTF at 1,67 grams.

[4] Do you still have problems if the bias dial is turned to zero? -- the problems are intermittent (which is what makes this so maddening). Last night started acting up again around 4 - 5 minutes into the playback. Then it suddenly decided to play fine and only start acting up toward the end of LP. Then later on, decided to play fine, beginning to end. So I never know what's going to happen next.

[5] Is the azimuth correct? (you can use a mirror to check this.) -- haven't checked azimuth -- Rega RB300 doesn't have removable headshell, so not sure how to adjust that?

Not sure what exactly is meant by 'bias'? Anti-skate?

Yes, by 'bias' I meant 'anti-skate'.

When it's "acting up", does the arm skip towards the certre of the record, or does it skip towards the rim?

[magiccarpetride]

Yes, by 'bias' I meant 'anti-skate'.

When it's "acting up", does the arm skip towards the certre of the record, or does it skip towards the rim?

It first starts distorting (crackly/wooly sound, like radio static). After a second or two it gets stuck in the groove, keep repeating the same second over and over. Like a stuck, broken record.

Then, if I discontinue the playback, and return to it a few hours later, it may or may not behave the same on the same side of the same LP. I cannot detect any pattern, only that it keeps changing over time. Everything else staying the same, only the arm/cartridge sometimes start distorting at the approximately same place on the record and then get stuck, or at another time keep playing without a hitch.

[magiccarpetride]

Yes, by 'bias' I meant 'anti-skate'.

When it's "acting up", does the arm skip towards the certre of the record, or does it skip towards the rim?

Anyway, I'm done with Rega, ordered 10" Jelco tonearm.

Rega is a fantastic tonearm for the price, but it is super hard to work with. I've tried to replace the cartridge on it, and it is super tight and the connection wires kept falling off while I was trying to adjust the cartridge with the protractor. Too much hassle, I think I'm ready for a more civilized tonearm. Jelco has been receiving warm reviews, I'm hoping it will be a step up from RB300.

[hifi_dave]

You don't get easier to set up and use arms than the Regas. All very straightforward, positive and easy.

If your arm was working previously, your first step should be to replace the OM20 and try again.

[walpurgis]

Have you examined the diamond stylus tip under magnification? It occurs to me that the problem described could be due to dirt contamination or even a damaged stylus.

[hifi_dave]

Exactly. If the arm was working with the previous cartridge, it is the OM20 or the set up.

[Svend N]

Alex, the max VTF for the OM20 should only be 1.5g (this is from Vinyl Engine database). If you're at 1.7 that's a bit high. Remember, this cart is high compliance at 30, so needs a lighter touch. Have you tried it at 1.25g?

Also, you mention bias (anti-skate) dial....the RB300 does not have a bias dial, but rather it is set on the slider on the bracket below the arm, upon which the arm lift also sits. The numbers are hard to read (black on black) -- are you SURE you have it set correctly? What happens when it's at zero?

Finally, I think I asked this before, but how does the arm behave when you drop the needle into the lead-out area of a record? Have you tried this on an LP with a wide lead-out section? This can be very telling about AS behaviour, and is a quick easy test. Does is pull out or in? It should, if set more or less correctly, slowly move to centre before slipping into the groove. You will have maybe 1 second to observe this, so you may have to repeat a few times 'til you twig it.

Check these out and let us know what you find...

Hang in there man!

[Svend N]

Anyway, I'm done with Rega, ordered 10" Jelco tonearm.

Rega is a fantastic tonearm for the price, but it is super hard to work with. I've tried to replace the cartridge on it, and it is super tight and the connection wires kept falling off while I was trying to adjust the cartridge with the protractor. Too much hassle, I think I'm ready for a more civilized tonearm. Jelco has been receiving warm reviews, I'm hoping it will be a step up from RB300.

What the heck? Wires falling off? It sounds like you may have a couple of problems here. In addition to your tracking issue, it sounds like you need to give the cartridge lead tips a gentle little squeeze with a pair of fine needlenose pliers to snug them up a titch. That's where the crackle is coming from, is the loose leads.

Back to tracking,- you mention that you tried to align this cartridge....was this before or after your tech did it? If the former, have you checked the tech's work? Is it aligned correctly now?

[magiccarpetride]

Alex, the max VTF for the OM20 should only be 1.5g (this is from Vinyl Engine database). If you're at 1.7 that's a bit high. Remember, this cart is high compliance at 30, so needs a lighter touch. Have you tried it at 1.25g?

Also, you mention bias (anti-skate) dial....the RB300 does not have a bias dial, but rather it is set on the slider on the bracket below the arm, upon which the arm lift also sits. The numbers are hard to read (black on black) -- are you SURE you have it set correctly? What happens when it's at zero?

Finally, I think I asked this before, but how does the arm behave when you drop the needle into the lead-out area of a record? Have you tried this on an LP with a wide lead-out section? This can be very telling about AS behaviour, and is a quick easy test. Does is pull out or in? It should, if set more or less correctly, slowly move to centre before slipping into the groove. You will have maybe 1 second to observe this, so you may have to repeat a few times 'til you twig it.

Check these out and let us know what you find...

Hang in there man!

Thanks Svend, will try this experiment later today.

What's really confusing to me is the sporadic occurrence of the mis-tracking. If the setup was incorrect in any way, then the symptoms would be consistent, no? But the symptoms emerge at random intervals, making me think that something else must be the matter here. Otherwise, why would the arm/cartridge work smoothly on some occasions, and then stop working on some other occasions, etc.?