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Precision, or not....

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Re: Precision, or not....

Postby Poinzy » 11 Jan 2017 16:36

If I didn't have access to a turntable with a removable spindle, allowing me re-center off-center records, the wow would often be intolerable. So I have 2 turntables on my equipment bench. Obsessive? I have no idea.
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Re: Precision, or not....

Postby analogaudio » 11 Jan 2017 17:28

The LP is an imperfect medium which was the best that could be done using analogue engineering.

At it's best it can be very good quality. To achieve the best requires attention to detail as you have noticed and the purchase of good quality components (costing hundreds but not thousands of US$).

I agree, the LP itself is probably the weak link in the chain. Self-centering platters were made (Nakamichi Dragon) and vacuum hold-down made (SOTA and Audio Technica) to overcome two of the problems. Nothing can overcome the decrease of groove velocity as playback progresses, nor the subsonic resonance of the cartridge+arm combination (although the Morch anisotropic arm minimizes this problem).

Regarding precision/obsessional aspects of the hobby these are things that entertain some people more than others and seem to me to have little to do with the enjoyment of music.

In the late 1970s it was realized that LP had reached the end of the road and the solution was a new medium, the compact disc, which does not suffer from any of the problems mentioned. I stopped buying LPs in the early 1990s and switched over to buying CDs, I haven't regretted the choice.
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Re: Precision, or not....

Postby Mike 33 » 11 Jan 2017 19:01

Warpage and decentration are flaws that should not be accepted, they are manufacturing flaws or storage flaws.

For used records it is all down to your tolerance for imperfection.

The Nak was a terrible thing since it allowed the industry to put out more trash.
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Re: Precision, or not....

Postby tlscapital » 11 Jan 2017 22:05

NOT for me... I'm not looking for precision nor perfection. I'm likely in the minority here, but it's all to do with my love for my music, I have to have the original pressings and they are mainly USA singles from the 6T's and 7T's. Not all have a perfect mastering and some even the pressing plant's work makes you wanna go Hmmmm ! But it's them I collect and play them as they are. Jut like they were first played that way.

But I'm looking to get a sound that gives my beloved 45's justice with depth, power, dynamic and balance both in soft and hard, highs and lows. So I'm still tweaking my phono set-up to reach there on my "humble" budget. I'm more of a RI (ght) -FI (delity) than the regular HI (gh) - FI (delity) guy. I'm looking for a sound that will bring the most of my 45 (and when I play LP's the sound is still rather descent IMHO) and that is pleasant to my ears as to my guests.

It started with a love then a passion for music and original records. It should remain the same for me. I understand the other trips about techs and so forth but then it's most likely to do with performance than with music as such.
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Re: Precision, or not....

Postby nat » 12 Jan 2017 01:02

MIcro Seiki and Luxman (if memory serves) had vacuum hold down (and, I think, before SOTA). I'm happy that Mike 33 is satisfied with his choice, but I have found CDs much more fragile than records - often scratches on them are intolerable and there is no way to nudge the laser, and no record has ever died from internal corrosion (CD rot) -- and I'm exceedingly annoyed by the lack of room for album art, liner notes, and lyrics (yes, some manufacturers do provide booklets, but too many don't), and the seemingly purposeful leaping of CD cases to the floor where the top of the case would lose one or both tabs that kept the top on the holder. I also haven't noticed any consistent superiority of CD sound compared to records on good turntables, though I also haven't noticed an consistent inferiority, either, even if I do find records more relaxing to use, and to listen to.
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Re: Precision, or not....

Postby Copperhead » 12 Jan 2017 03:04

nat wrote: and the seemingly purposeful leaping of CD cases to the floor where the top of the case would lose one or both tabs that kept the top on the holder.


Those tabs surely must feature in in the top 20 design disasters, they break as soon as you look at them.

The scratches on discs I polish out with jeweller's rouge, have had some success with it.
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Re: Precision, or not....

Postby analogaudio » 12 Jan 2017 18:13

The point about LP having reached a dead end is not because of how good or bad LP sounds in an individual case, rather it is because there is inconsistency in sound quality that depends on the quality of playback hardware and its adjustment. Good LP is very good. Bad LP is very bad. Too inconsistent.
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Re: Precision, or not....

Postby analogaudio » 13 Jan 2017 03:12

CTV what you are noticing visually, but not sonically, is the subsonic behavior of the system, stuff that is happening below the lower limit of audibility around 20Hz.

There is nothing much of musical interest down there and LPs deliberately have very little musical energy below 40Hz, the lowest string on a bass.

LP playback has a resonance in this subsonic region due to the combined behavior of the stylus suspension (a spring) and the arm mass (a weight) and as weights on springs tend to do they bounce, the bounce frequency is around 10Hz on a well tuned system that has cartridge compliance and arm mass matched to one another. The warps and eccentricity of the disc occur below this resonance frequency and cannot be heard, nevertheless these very low frequency signals are present in the preamp output (unless a filter is used to remove them) and are often also present at the output of the power amplifier and can be larger in size than the wanted musical energy.

This can cause distress to the woofers of some speaker systems, when this occurs and the woofers are visible the cones can be seen fluttering sometimes called woofer flapping. This is not good for the woofers and may have an effect on musical sounds higher up in the audio band, a form of interference that may be heard as distortion.

The point is that what you are seeing is real and can reach the speakers. We don't hear 2Hz, but we can hear the distress of the loudspeaker that is attempting to reproduce 2Hz and being pushed into distortion while doing so.

When this kind of trouble occurs and the resonance has been fine tuned to 10Hz then it may be time to experiment with a high pass filter in the preamp (also known as a rumble filter because it can reduce the noise of low quality platter bearings) they can be found on some preamp units.
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Re: Precision, or not....

Postby analogaudio » 13 Jan 2017 17:37

You are welcome

When the maker has not published a value it is difficult to arrive at one because there are so many variations possible in the details of the arm and headshell and they all have an influence. One can make estimates if a weighing scales is available and the parts can be removed to be weighed. The largest two contributors to effective mass are the counterweight and the headshell, both can often be removed and weighed. Then a calculation is made. This topic has been discussed and can be found using the forum search, some of the threads go into detail on how to do what you wish for.

Another approach is to simply measure the resonance using the resonance test track of a test LP, the HiFiNews disc 2 has such a track, there may be others.
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