LP Physical Standards ?

[valveitude]

Could someone point me to a resource for the industry standards and tolerances for LP's? Such as label height, lead out groove diameter ect.

Thanx,
Casey

[Ghianni]

Hi,

There is an IEC recommendation, Publication 98, 1964 and its supplements, for this matter, but you have to buy it from the IEC web site.

Ghianni.

[Werner]

Here:

http://www.mcc.spacetown.ne.jp/~yosh/

[Ghianni]

Hi,

Try this new one:
http://webstore.iec.ch/webstore/webs.../artnum/018568

Ghianni.

[valveitude]

I found this page linked from the one Werner suggested...

http://www.mcc.spacetown.ne.jp/~yosh...ards_table.htm

.... it covers everything I was looking for except the specification of label height. Does anybody know how far the label area is raised above the rest of the album, and what the tolerance is ?

I am looking at creating a depression in my TT platter to clear the label but I need to know how deep.


Ghianni...I would consider purchasing from IEC, but I haven't been able to find any pricing.

Casey

[EC8010]

One thing that specification didn't mention is that some LPs are flat(ish) and some have a 1 degree angle to them. Have a look and you will see that some have a distinct dip at the run-in groove, followed by the 1 degree slope up to the final groove, whereas others are flat. I have a vague recollection that this "innovation" may have been started by RCA (probably to save vinyl during the 1973 oil crisis).

[valveitude]

One thing that specification didn't mention is that some LPs are flat(ish) and some have a 1 degree angle to them. Have a look and you will see that some have a distinct dip at the run-in groove, followed by the 1 degree slope up to the final groove, whereas others are flat. I have a vague recollection that this "innovation" may have been started by RCA (probably to save vinyl during the 1973 oil crisis).

Lovely

It would seem to make sense then to "bowl" the platter by 1 deg. to ensure a solid coupling to the platter..I think the "flatish" records could stand being deformed this small amount with the record clamp.

Thoughts ?

Casey

[EC8010]

I knew you'd be pleased. Dishing the platter by 1 degree and applying a clamp sounds sensible. You'll need to measure a couple of LPs to see where the 1 degree dish should start from, and put a rather steeper opposite dish before that to ensure that you don't end up supporting the LP by its periphery.

[SY]

The other alternative is a reflex clamp, similar to what VPI has done. It works surprisingly well.

[valveitude]

You'll need to measure a couple of LPs to see where the 1 degree dish should start from, and put a rather steeper opposite dish before that to ensure that you don't end up supporting the LP by its periphery.

This looks like it could turn into a real can of worms...I don't have many albums on hand (yet) to measure. Was this an exclusive RCA "innovation", or did the rest of the industry follow suit ?

The other alternative is a reflex clamp, similar to what VPI has done. It works surprisingly well.

Well I'm all for a simpler solution. But as I picture this in my mind ( such as it is), I see the clamp holding the thicker portion of the record down while the thinner section "floats" above the platter.

What am I missing ?

Casey