HydrogenAudio

CD-R and Audio Hardware => Audio Hardware => Topic started by: MedO on 2008-01-08 00:52:17

Title: Turntable calibration
Post by: MedO on 2008-01-08 00:52:17
I recently got a Technics SL-J1 turntable (tangential tonearm), and I'm now trying to get it working correctly. Now, when I play discs, I sometimes hear a distortion in loud parts not completely unlike clipping. You can get a sample here (http://www.uni-koblenz.de/~smaxein/nova%20cantica.flac) (the LP should be in mint condition).

I've tried adding a small weight to the tonearm to increase the tracking force, because I read that these distortions might by caused when the needle is not pressed strongly enough against the vinyl. It did seem to reduce the problem, see the second sample here (http://www.uni-koblenz.de/~smaxein/nova%20cantica%202.flac).

Should I just increase the weight until the problem disappears? Or might I damage the vinyl because of too high pressure?
Title: Turntable calibration
Post by: AndyH-ha on 2008-01-08 03:05:05
Cartridges come with specifications for recommended and maximum tracking weight. The recommended is the neighborhood of where you can generally expect the best results; the maximum is that which, when you exceed it, damage starts.

There are a number of other cartridge and tonearm parameters. Any of of them being off will produce poor quality playback.
Title: Turntable calibration
Post by: AndyH-ha on 2008-01-08 04:17:18
Attached to the second post here
http://www.hydrogenaudio.org/forums/index....mp;#entry540058 (http://www.hydrogenaudio.org/forums/index.php?showtopic=54879&st=0&gopid=540058&#entry540058)
is your first sample after some declicking. Does this address your complaint with the recording?
Title: Turntable calibration
Post by: digital on 2008-01-08 08:03:12
.
(http://www.vinylengine.com/images/model/technics_sl-j1.jpg)

That’s an oldie!  It may be malfunctioning, or it may be simply that the needle is worn out.  The unit you have on hand is a 1984 / 1985 model year product.  This makes it more or less 23 years old.  If that’s the original needle (or even the second replacement!), I'd throw out a wild guess that a new needle would work wonders.  You should be able to pick up a replacement needle for less than $30.00 or so.

Here is the TT's manual:

http://www.vintagetechnics.stereomanuals.c...ables/index.htm (http://www.vintagetechnics.stereomanuals.com/turntables/index.htm)

Here is another link with general data about the TT

http://www.vinylengine.com/library/technics/sl-j1.shtml (http://www.vinylengine.com/library/technics/sl-j1.shtml)

Here is a Technics User's Forum:

http://technicsforum.com/Main/index.php (http://technicsforum.com/Main/index.php)

Andrew D.
www.cdnav.com


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Title: Turntable calibration
Post by: MedO on 2008-01-08 09:45:33
That’s an oldie!  It may be malfunctioning, or it may be simply that the needle is worn out.  The unit you have on hand is a 1984 / 1985 model year product.  This makes it more or less 23 years old.  If that’s the original needle (or even the second replacement!), I'd throw out a wild guess that a new needle would work wonders.  You should be able to pick up a replacement needle for less than $30.00 or so.

The needle is new, I've bought a replacement that only arrived yesterday, because the old one was broken.
Quote
Cartridges come with specifications for recommended and maximum tracking weight. The recommended is the neighborhood of where you can generally expect the best results; the maximum is that which, when you exceed it, damage starts.

There are a number of other cartridge and tonearm parameters. Any of of them being off will produce poor quality playback.

I just checked, the recommended weight is 1,8g. I'm pretty sure I can figure out a good way to measure that.
Quote
is your first sample after some declicking. Does this address your complaint with the recording?

Thanks, but I think it's best to try to get the best quality from the turntable first, so that I have to do less restauration afterwards. Also, too small weight can damage the vinyl as well as I've read, and I certainly don't want that.

I'll check the weight and tell you how it went.
Title: Turntable calibration
Post by: MedO on 2008-01-08 17:25:32
Ok, I tried to determine the tracking weight with a block of sticky notes, a kitchen scale (1 gram resolution), and a ruler (edit: and of course a calculator). My result was 1,25 grams, but it might be off a bit because of the measurement method. Since I didn't find an easy way to correct the weight, I sellotaped a few small lead weights to the tonearm. The resulting sample is here (http://www.uni-koblenz.de/~smaxein/nova%20cantica%203.flac). I'd call it a success