I thought I'd share something I found out about my cartridge today. I've been suffering worsening channel balance for sometime. I'd blamed all sorts of things as sometimes it seemed to respond to "treatment". It got so bad last week that I sent my Kontra B to Henley Designs to be checked. The coils measured fine, when they looked at the stylus under a powerful microscope they found some welded on crud, it was wrapped around the tip but was built up much more on one side than the other. They reckon this correlates with what I was hearing. Henley managed to remove the crud without removing the tip as well. I'm now waiting for the Kontra to come back.
How did this happen? I'm guessing I'd cleaned a record but not ensured it was 100% dry. Some dirt then dried onto the stylus.
Channel balance
#2
I have my Kontra B back now. Certainly the channel balance is a lot better. It does seem that the crud on the stylus tip did push the balance to right but the channels are still not quite in balance. It's not far out but I would prefer better.
Henley measured the dc resistance of the coils, they said they were within spec. So now I've measured them, the right channel coil is just 2% higher resistance than the left (5.4R vs 5.5R) - a more accurate meter might show 5.35 vs 5.55, but that's pure conjecture.
Extra resistance I assume equals extra voltage, at least I know that more turns equal extra voltage. The higher reading coil is indeed the right channel.
Is it reasonable to expect better than 2% match between channels? Can anyone calculate what this is likely to equate to in db matching between channels for a 0.47mV output cartridge?
BTW, I realise that I'm probably being rather "picky".
Henley measured the dc resistance of the coils, they said they were within spec. So now I've measured them, the right channel coil is just 2% higher resistance than the left (5.4R vs 5.5R) - a more accurate meter might show 5.35 vs 5.55, but that's pure conjecture.
Extra resistance I assume equals extra voltage, at least I know that more turns equal extra voltage. The higher reading coil is indeed the right channel.
Is it reasonable to expect better than 2% match between channels? Can anyone calculate what this is likely to equate to in db matching between channels for a 0.47mV output cartridge?
BTW, I realise that I'm probably being rather "picky".
#4
Thanks Nick. I should be able to live with -39db!
Since I posted I've be re-aligning the cartridge to the cantilever, not the body. It's close to correct now and it is sounding better. I should tweak it a little more but I've had a beer and am about to have another. Alcohol and cantilevers don't mix so I finish the setup tomorrow.
Cheers!
Clive
Since I posted I've be re-aligning the cartridge to the cantilever, not the body. It's close to correct now and it is sounding better. I should tweak it a little more but I've had a beer and am about to have another. Alcohol and cantilevers don't mix so I finish the setup tomorrow.
Cheers!
Clive
#5
I don't imagine anyone's too interested but I should close this off properly. My channel imbalance was caused by a combination of the crud on my stylus (70% of the problem) and by my canilver being 4 degrees out. Now that the crud is banished and I've properly aligned to the cantilever, I now have fully corrected the channel imbalance.
Clive
Clive
#6
It's not that we're not interested Clive, just difficult to add anything?
How do you align the cantileaver?
How do you align the cantileaver?
#7
Hi Darren,
It is difficult for others to add anything as this is setup for my cartridge. Hopefully someone may find my experience with this useful one day. It is surprising (to me) how much difference 4 degrees error make, I suppose that 4 degrees is actually quite a lot.
I aligned to the cantilver by using the HFN cardboard setup disc. I used the part that has a line drawn though the spindle hole to the edge. There are lines drawn perpendicular to this. I lined up the cantilver with the perpendicular lines whilst looking along the cantilver. I hope this makes sense!
I worked out the cantilever is 4 degrees out by attaching an allen key to the side of the cartridge and marking the 2 end points on the perpendicular lines. Then I used a protractor to measure the angle.
It is difficult for others to add anything as this is setup for my cartridge. Hopefully someone may find my experience with this useful one day. It is surprising (to me) how much difference 4 degrees error make, I suppose that 4 degrees is actually quite a lot.
I aligned to the cantilver by using the HFN cardboard setup disc. I used the part that has a line drawn though the spindle hole to the edge. There are lines drawn perpendicular to this. I lined up the cantilver with the perpendicular lines whilst looking along the cantilver. I hope this makes sense!
I worked out the cantilever is 4 degrees out by attaching an allen key to the side of the cartridge and marking the 2 end points on the perpendicular lines. Then I used a protractor to measure the angle.
#8
Silly me, of course that's how you did it.
I for some strange reason had a picture of you forcing or bending the cantileaver against the cartridge body !!!
I just knew that couldn't be the case, and now I feel silly for asking !!!
I for some strange reason had a picture of you forcing or bending the cantileaver against the cartridge body !!!
I just knew that couldn't be the case, and now I feel silly for asking !!!
#10
For the record .... and to be fair to Ortofon I should say where I'm up to with getting a good channel balance with my Kontra B. I have found out that Ortofon deem 2.5 degrees of stylus skew as being the maximum acceptable. My 4 degrees of skew has resulted in the cartridge being replaced even though it's out of warranty. This is my 4th Kontra B, in other words my 3rd warranty replacement!
Number One developed a skew of about 10 degrees after a couple of weeks, it suffered no accidents and as it has a ruby cantilever I expect it would snap, not bend, if it did get knocked.
Number Two soon became a "low rider", scraping its underside on some records.
Number Three lasted longest but the 4 degree skew developed, I could tune out most of the channel imbalance with setup but it the end it went back.
Number Four is playing now.
Maybe I've just been unlucky. Maybe the first 3 cartridges were from the same batch. If there has been a quality problem I hope it is now fixed. At least Ortofon have not argued and simply the replaced the cartridges. On another positive note, I originally purchased the Kontra B in Oct 2003 and I now in 2007 have a brand new cartridge so that is compensation for my hassle.
Clive
Number One developed a skew of about 10 degrees after a couple of weeks, it suffered no accidents and as it has a ruby cantilever I expect it would snap, not bend, if it did get knocked.
Number Two soon became a "low rider", scraping its underside on some records.
Number Three lasted longest but the 4 degree skew developed, I could tune out most of the channel imbalance with setup but it the end it went back.
Number Four is playing now.
Maybe I've just been unlucky. Maybe the first 3 cartridges were from the same batch. If there has been a quality problem I hope it is now fixed. At least Ortofon have not argued and simply the replaced the cartridges. On another positive note, I originally purchased the Kontra B in Oct 2003 and I now in 2007 have a brand new cartridge so that is compensation for my hassle.
Clive
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#11
Good to hear that Ortofon are giving you good customer service Clive. I got my Kontra B before I heard of your woes. So far there's no skew, and although it does appear to ride a little low for my liking it does just clear the record surface. As mine came from Hong Kong I don't know how much support I would get if it does develop a crab-like stance so fingers crossed (for you and me!).