[jonners]

  I've been setting the bias on my Technics SL1210/Denon DL110 with a test record. I'm finding that in order to remove mistracking in the R channel with a +15dB modulation I'm having to set the bias dial to at least 2.5. Tracking force is 1.8g.

  From what I've read it seems more usual to have the bias set lower than the tracking force so I'm just wondering if this is OK?
  Btw I'm using the KAB fluid damper and a Sumiko headshell.

  John

[royphil345]

Unless the anti-skate dial is not calibrated correctly (which can happen) that setting is pretty far away from your tracking force to be optimum. It could cause a slight channel imbalance and increased record / stylus wear.

I'd check to make sure the turntable is level, the cartridge is aligned properly and the headshell azimuth is correct. I find very small azimuth adjustments are sometimes possible due to just a little "play" in the headhell connection.

EDIT: I didn't catch you had the Sumiko headshell which is probably adjustable for azimuth. Another thing about these test records is that every track can't be located at a null point where your cartridge is perfectly aligned... and the pressings may not be perfect... I'd take the results with a grain of salt. After awhile, you'll be able to pinpoint the optimum tonearm settings with your ears.

[jonners]

  royphil -

Thanks for your reply. I've checked azimuth etc. and all seems OK so I guess I'll just play safe and reduce the bias setting somewhat, and then try to fine-tune by ear over a period of time.

  John

[Wayner]

I'm tracking at 1.5 grams and my anti-skate is dialed in at 2.75. I use a blank disc to set it (the arm will sit and not move in or out at any playback position.

IMHO, the Technics anti-skate is off. Their VTA is also off. The original mat thickness was less in the old days then stock one now and I really don't think they've fixed that either. The counterweight for setting VTF is very close. I use a feeler gauge to set arm height anyway.

Wayner 

[jonners]

  Wayner-

  It's interesting that you have arrived at pretty much the same bias setting as me, but is a blank disc going to give an accurate result? The forces on the arm/cartridge when the stylus is in a groove are going to be different, aren't they?

  John

[Wayner]

I've been doing this for years. I have had a few folks argue a point, but to no avail. Yes, there is a slight inward push buy the outer groove, because the record is a sprial 2D screw thread, if you wil. And it is also weird that the natural tendensey of the arm inertia to fling towards the center (with out anti-skating compensation). I use to use a test record, but I like this technique better. If some mechanical engineer told me to lean it a little, I probably would. The point here is that leaned or not, we are very close to the right spot.

Wayner

[jonners]

  I tried setting bias again, this time using the blank vinyl method. It came to around 2.5, as before.

  John

[Wayner]

Good John,

Your ears will tell you if something is wrong. The LP should center itself right between the speakers and shouldn't lean to the left or right. Both channels should have equal amounts of volume and the stylus shouldn't look like its getting tugged at from on direction or another.

Happy spining!

Wayner

[jonners]

 

[jonners]

 I think I've finally resolved this problem. I noticed that the stylus was not exactly aligned with the cartridge body. When I took a lot of trouble to align the stylus shank with the protractor lines, I found that the mistracking in the R channel disappeared at a much lower bias setting, which is now around 1.8.

    John

[royphil345]

I think I've finally resolved this problem. I noticed that the stylus was not exactly aligned with the cartridge body. When I took a lot of trouble to align the stylus shank with the protractor lines, I found that the mistracking in the R channel disappeared at a much lower bias setting, which is now around 1.8.

    John

Glad you figured it out ...

I wasn't going to argue, but I've found the anti-skate calibration to be surprisingly accurate on my Technics tables. Very close to dead on at lower tracking forces and maybe just a smidge off at higher tracking forces (or it's just my ears... lol). VTA setting seems to end up pretty close to "0" with the stock rubber mat for most cartridges too.