|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
118.148.253.70
In Reply to: RE: AT3482P tracking force? posted by KanedaK on March 12, 2017 at 03:14:33
Hi
I would suggest that you get yourself a digital force gauge to verify what you are actually setting! The VTF scales on an arm counterweight are not the most accurate especially as it relies on you having the correct balance for setting "0".
Without a test disc, "Correct VTF" is a subjective thing. However, you could say it is achieved when all your records sound clean and clear no matter how "loud" the record was cut. If you have 12" maxi singles (esp. those cut at 33), that is a pretty tall order for even the most expensive cartridges. Low compliance MCs have a very limited tracking ability despite the high prices being commanded so price is also no guarantee of technical perfection.
Vinyl Mastering, especially for 12" singles is going to result in a very different sound to the CD, even if it is being correctly tracked. Given that they are intended for Club play, they are mastered to provide as much punch and excitement as possible. Given the high SPLs normally encountered in a club, the top end is rolled off not only to make the sound balance more appealing at high volume, but also to protect the cutting head which will easily be damaged at the large amplitudes to be used to get the "loudest" cut.
I have a lot of electronica and 12" singles like Aphex Twin (although I don't have the 12" you have to help confirm what is actually going on with the cut) and they are cut at the very limits of the cutting head power dissipation so it doesn't surprise me that you are hearing distortion with your 3482P. Clean tracking may not ever be possible if the cutting head was overdriven - I have a few examples of 12"s cut at The Exchange by Graeme Durham or Nilesh Patel (Look for "Grazz" or "Nilz" in the leadout) and those cuts should never have been unleashed on the public due to the appalling HF distortion. One was so bad that it sounded like the cutting engineer had left off Dolby EQ! I know it wasn't my alignment or cartridge which was/is able to achieve 100um tracking and has a low tip mass which puts it at the upper echelon of technically capable cartridges. The other consideration is that your cartridge has a spherical tip and that will be also adding its own distortion although as your record is running at 45rpm, that is less of a problem.
A little background information that you may already know, but otherwise may find helpful:
1.25g is the default VTF for P-mount turntables - P-mount was intended to be a completely plug and play solution and not all arms were adjustable. The onus was on the manufacturer of the cartridge to ensure that the cartridge parameters met the P-mount specification (for mass and various dimensions) so that "correct" geometry and VTF was assured no matter what brand of cartridge you bought.
Now here's where that is relevant! You have a linear tracker. Every dimension will have a tolerance and the "overhang" is unlikely to be absolutely "perfect". There may even be a slight skew in the cantilever. Consequently, you find that there is an inherent distortion due to a consistent tracking error. Also, in many cases, a cartridge manufacturer would adapt an existing design that had a suitable compliance or in simple terms it means that the VTF range for the cartridge would sit in the target range for P-mount. At the default 1.25g, tracking ability is not going to necessarily be the same as for the standard mount cartridge. Very often the manufacturer might downgrade the tracking ability specification to reflect the 1.25g default since the tracking ability spec might only apply at maximum VTF.
Tracking ability is specified typically at 300Hz and the highest recording level that might be cut is typically taken as +18dB which is equivalent to about 90um. Records can be cut louder than that, but the distortion levels from both the cutter and the replay cartridge starts to go through the roof at that stage. That requires an EXCEPTIONAL cartridge to perfectly track! Cheap cartridges are limited to about 55 to 60um (about +14 to +15dB) at nominal VTF although some might do up to 80um but the tip mass is high enough that they are mistracking on the HF tones that electronica would have even if they can track a 300Hz tone at high amplitude. In this situation you would have a very "coarse" sound even if the low end is sounding punchy and controlled.
Also, your phono stage may have an insufficient "overload" margin and is therefore adding its own distortion to the mix. The overload margin is the headroom above the reference level given in the "sensitivity" specification. If your cartridge has a higher output than the reference output used in the phono stage design, then you lose a corresponding proportion of the "headroom" originally provisioned for to track a louder cut. Your AT is specified at 5mV but I'm not sure if this at 5cm/s RMS or 3.54cm/s RMS which is 5cm/s peak. This is relevant if you want to check the input sensitivity specification of your phono stage relative to the maximum output.
Regards Anthony
"Beauty is Truth, Truth Beauty.." Keats
Follow Ups:
That is an awful lot of useful information for a newbie such as me :) thank you!
II'm sure I can fine-tune the VTF on my table (not easy, all I have access to is a recessed screw next to the arm assembly, with a + and - markings. There is also, I'm afraid, not enough space for a digital weight controller. I can only rely on what I hear and, given I don't have anything to compare to (except CD, that is) it is very subjective. I do have pretty good hearing tho :-))
However, I'm pretty sūre there is a problem with that particular 12inch (btw it is a 45rpm cut).
I do have quite a few friends who are amateur or professional "disc spinners" and I've never heard such distortion even on lousy dj turntables with less-than-stellar cartridges (not everybody plays with SL1200MKII) but it's comparing apple to oranges considering the very different technology. I guess I might borrow a couple more vintage electronica and house records from a friend and see what happens with those!
I'll post my findings. It's all making me very curious (even tho it is a little bit frustrating).
I agree that using some kind of gauge on that table would be tricky. You'd have to be able to make sure the platter did not come on while you move the arm out and drop the stylus. That's if you can get it in there at the right height after removing the mat.
You can pull the plug to stop the platter!
However, it's probably not necessary to spend the money on a stylus force gauge. Just increase tracking force until it tracks, assuming that's the problem. It might just be the record.
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: