Modifying RIAA playback for 78 rpm/45rpm

[ashok]

I keep reading that it is possible to get better results with a variable RIAA playback curve for 78 rpm records. What do they really adjust ? I guess it must be the corner frequencies but by how much ?
Is this also applicable to 45 rpm plaback ?
Anyone on this forum who does these things ? Any sites that I can check out with such information ?
Thanks.
Ashok.

 

[sreten]

33 RPM and 45RPM RIAA eq is the same.

78's used lots of different curves.

A MM fitted with a 78 stylus will not be right through a MM input.

Sometimes I think for 78's a ceramic cartridge that does
not require any EQ at all would be the easiest option.

sreten.

 

[Havoc]

Read and enjoy: http://www.rfwilmut.clara.net/repro78/repro.html

 

[ashok]

Thanks.

Hi Havoc and Sreten,
Thanks for the info. I think that all I wanted.
It has everything that I was looking for.
Thanks again.
Ashok.

 

[dvautier]

I run the ceramic 78 RPM output right into my sound card. Then I equalize as needed. when I say "as needed" I mean it. The records are wildly different depending on make, model, year and condition.

I have some web pages on this subject. The discussion under technical page may help. hope so.

http://dvautier.home.comcast.net/records/records.htm

 

[hagtech]

What do they really adjust ?

We adjust the corners and turn frequencies, just as you thought. 78s were recorded with many (dozens) of equalization curves. There are three main inflection points, one at a low frequency (50Hz for modern RIAA), a mid-band (500Hz), and upper (2122Hz). More info here:

www.hagtech.com/equalization.html

and

www.hagtech.com/pdf/riaa.pdf

I don't believe 45s have this problem, they don't go back as far. But don't quote me on that.

jh