My first R2R was a ReVox B77 Mk-II, bought in July, 1990. I was told that it was equalized in CCIR, not the usual NAB equilization in north America.
I did a frequency response test on that B77 and found the recorded square wave was not as beautiful as it supposed to be. I wrote a letter to ReVox and got a reply from its technical director Mr. Korowski. Detail reason for the square wave response was given and "phase compensation" was clearly mentioned in second paragraph. Then I ordered a new service manual from ReVox's authorized dealer in Nashiville, TN to study what was going on.
20 years later, I started to collect my first professional R2R, a STUDER A807 Mk-I; two months later an A810 , then an A807 Mk-II, HS, all in 2011; followed by an A820 in 2014.
The audio section followed from A810, A820, A812, all the way to A816; thus "phase compensation" was all embedded within. Later version of record amp and HF driver included HX-Pro and skimming, found only in A812 Mk-II, A820 Mk-II and A816.
STUDER A807 Mk-I/II and ReVox C270 were two models developed outside this rim.
I wonder how much the "STUDER" sound was reflected by this feature?
http://www.recordist.com/studer/Phase_compensation.pdf
AP=All pass; BP=Band pass (@20kHz?)
http://lab2104.tu-plovdiv.bg/index.php/2016/01/25/ph_compensation/
Additional bonus of googling was the reel-to-reel project@LAB2104, dated around March 2016. It seems to me that the scope of the new R2R project was quite vibrant, much advance than Ballfinger's M063?! There was no update information ever since.
http://lab2104.tu-plovdiv.bg/index.php/2016/03/03/r2r/
I did a frequency response test on that B77 and found the recorded square wave was not as beautiful as it supposed to be. I wrote a letter to ReVox and got a reply from its technical director Mr. Korowski. Detail reason for the square wave response was given and "phase compensation" was clearly mentioned in second paragraph. Then I ordered a new service manual from ReVox's authorized dealer in Nashiville, TN to study what was going on.
20 years later, I started to collect my first professional R2R, a STUDER A807 Mk-I; two months later an A810 , then an A807 Mk-II, HS, all in 2011; followed by an A820 in 2014.
The audio section followed from A810, A820, A812, all the way to A816; thus "phase compensation" was all embedded within. Later version of record amp and HF driver included HX-Pro and skimming, found only in A812 Mk-II, A820 Mk-II and A816.
STUDER A807 Mk-I/II and ReVox C270 were two models developed outside this rim.
I wonder how much the "STUDER" sound was reflected by this feature?
http://www.recordist.com/studer/Phase_compensation.pdf
AP=All pass; BP=Band pass (@20kHz?)
http://lab2104.tu-plovdiv.bg/index.php/2016/01/25/ph_compensation/
Additional bonus of googling was the reel-to-reel project@LAB2104, dated around March 2016. It seems to me that the scope of the new R2R project was quite vibrant, much advance than Ballfinger's M063?! There was no update information ever since.
http://lab2104.tu-plovdiv.bg/index.php/2016/03/03/r2r/
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