John Curl's Blowtorch preamplifier part II

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I don't tend to go old enough to need variable EQ, although there is an archival phono stage design in LA. As far as my research goes, anything after 1955 is RIAA.

Not really.
Just because there is a norm, it is not sure the norm is used everywhere.
In fact, there are many records with non standard EQ.
FM delivered a paper with many sheets, which EQ has been used by which company.
Stereo records started sales in 1958.

Today we have some remastered records and don't know what happened while remastering. Furthermore todays cutting machines are the old ones, nobody knows if they are still good in shape, its hard to get good acetat discs and the process to metalize them and so seems to be not so easy due some lack of wisdom and material . We also never know which kind of Mastertape has been used.

And BTW, Cutting heads amplifier used Feedback to control the Resonance of the head. So how did those amps sound, which were used? :t_ache:
 
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Not really.
Just because there is a norm, it is not sure the norm is used everywhere.
In fact, there are many records with non standard EQ.
FM delivered a paper with many sheets, which EQ has been used by which company.
Stereo records started sales in 1958.

I know there is a lot of rubbish spouted about alternative curves and when they were used, often by the people selling phono stages with adjustments! And of course the internet copies it until 'it must be true' :) Hopefully a definitive list will come. Most agree that from 1955 nearly all recordings adhered to RIAA. http://www.arsc-audio.org/journals/v20/v20n1p14-23.pdf gives a good list. My monos are post 1955 so I think I am ok. If I start collecting earlier Mono microgrooves i will think again :)


I think you are confusing the equalisation curve for the cutting with general EQ. There are always things you might want to adjust in the FR to get around some limitation in process, but changing the RIAA network may not be the best way. But that is a whole other topic for discussion!
 

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Right. Sure. That must be what i am measuring. :rolleyes:
THx-RNMarsh

Since there are no 24 bit DAC's or ADC's you are measuring their particular performance, you are NOT making any measurement that tests the mathematical underpinnings of dither. I cease to understand the point dither is based on first principles and it has been used even in mechanical systems to prevent cogging for decades, considering your background I am surprised.
 
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I know there is a lot of rubbish spouted about alternative curves and when they were used, often by the people selling phono stages with adjustments! And of course the internet copies it until 'it must be true' :) Hopefully a definitive list will come. Most agree that from 1955 nearly all recordings adhered to RIAA. http://www.arsc-audio.org/journals/v20/v20n1p14-23.pdf gives a good list. My monos are post 1955 so I think I am ok. If I start collecting earlier Mono microgrooves i will think again :)


I think you are confusing the equalisation curve for the cutting with general EQ. There are always things you might want to adjust in the FR to get around some limitation in process, but changing the RIAA network may not be the best way. But that is a whole other topic for discussion!

You mean something like this:

http://linearaudionet.solide-ict.nl/sites/linearaudio.net/files/recording emphasisv10.pdf

Jan
 
Jan, Why was the low frequency pole left off of this list? It also varied.

The Manual of FM 222 has also no information abouth this and Jan's list is more complete. Thanks Jan.

FM Manual mentionend that RIAA was established not before 1958, that some records were made with wrong Pre-emphasis thereafter since the cutting machines were not so good above 10 Khz until 1968 , thus some manipulations in the frequency response before pressing and that some records in the 70's and 80's had excessive HF (Brightness) and need some attuenation.
 
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Hi John,
To achieve reasonable performance, a CD player (SACD / DVD) has to be aligned properly. This includes both mechanical and servo adjustments. The minimum price point for a CD player that sounds good has been about $2,500 CDN list price over the years. Setting these things up can make an amazing difference. It is entirely possible you haven't heard a good CD player yet. Do they have some problems? Sure they do, but they don't normally sound bad unless you are using the lower end products.

-Chris

I have two players with different CD drives..... one player with common consumer drive and the other uses a computer drive to play CD's. Which is better and why?


THx-RNMarsh
 
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