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bob olhsson

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Posts: 3,353 Member Since:25/01/2011

#24 [url]

May 18 13 2:20 PM

Unusual?

That bottom RCA or the 7" 45 version is what we and everybody I know used as our reference for cutting systems during the '60s and '70s. I assume the blue one is just a newer pressing of the same.

There was an audiophile market for test records during the '60s and '70s. Many labels sold a variety in the stores that were uniformly all over the map. I only saw the RCA one bought directly from RCA in use for cutting systems.

www.audiomastery.com Bob's room 615 562-4346 georgetownmasters.com Georgetown Masters 615 254-3233

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bodyslam

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#26 [url]

May 24 13 2:57 AM


That bottom RCA or the 7" 45 version is what we and everybody I know used as our reference for cutting systems during the '60s and '70s. I assume the blue one is just a newer pressing of the same.

-bob_olhsson


I have both a red label and a blue label RCA. I think they are from the same stampers, only the labels are different.


Paul Stubblebine
serious student of the audio arts

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bodyslam

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#28 [url]

May 24 13 10:33 PM

Paul, didn't you use the RCAs at Columbia too?

-bob_olhsson

Bob,
Yes, that's what we used when I was cutting for CBS in San Francisco...and I still use them.

Of course, I have a lot of other test records too. Some for their weird appeal, but some useful for various things. That current one from Acoustic Sounds is very good. And of course the old standard, the NAB record, for level.

Paul Stubblebine
serious student of the audio arts

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bob olhsson

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#29 [url]

May 24 13 11:47 PM

I was wondering because somebody claimed only CBS test records had been used and I distinctly remembered my big grin seeing that RCA hanging in your CBS room. I'm curious, was that cutting room pretty much what Bill Putnum had installed before selling the studio to CBS or did they bring in their own gear like they had for the big studio?

I think a lot of people would be stunned by how accurately a  properly calibrated cutting system reproduces a master tape. For our readers benefit, the RIAA standard was in fact that record and not the various published curves and filter co-efficients that described it. I've always been amazed more hi fi manufacturers didn't use it for designing their cartridges and preamps.

I even wonder if the audio quality of tape deteriorates over time. My former boss Mike McLean sent me a CDR of some obscure Motown singles he made playing  a Shure V-15 into a sound blaster card with a Radio Shack preamp. It sounds exactly like what I remember the tapes sounding like while CD reissues mastered from those tapes decades later sound lots worse.


www.audiomastery.com Bob's room 615 562-4346 georgetownmasters.com Georgetown Masters 615 254-3233

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bodyslam

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#30 [url]

May 25 13 12:34 AM

I was wondering because somebody claimed only CBS test records had been used and I distinctly remembered my big grin seeing that RCA hanging in your CBS room. I'm curious, was that cutting room pretty much what Bill Putnum had installed before selling the studio to CBS or did they bring in their own gear like they had for the big studio?

-bob_olhsson

The CBS studio in SF was leased from Putnam. Coast Recorders was the name of the SF branch of Putnam's studio empire, first on Bush Street, then they built a big new facility on Folsom Street: 3 studios, a voice-over room, dupe room, mastering and offices. Within months after the grand opening CBS approached him about leasing space there. This was the beginning of the SF rock explosion and several labels wanted a foot on the ground there. CBS made a deal with Putnam for two studios, the cutting room and a couple of offices. Coast continued to operate the rest of it. A lot of the gear came from Coast, a lot was shipped in by CBS. They shared a lot of staff too: George Horn, in charge of cutting and maintenance, had done the same thing for Coast before being hired by CBS. Mike Fusaro came over from Coast too.

The equipment in the cutting room belonged to Coast for the most part. The lathe was already theirs. They built a console--actually in vertical racks, but functionally the console--to CBS's specs. It was put together by Bob Bushnell, working for Putnam in LA. It included a couple of proprietary pieces that were built by the console shop at CBS in New York. (Ironically, I eventually bought an almost identical system that had been installed in the CBS Records studio in Hollywood: vertical racks, Scully lathe, even the proprietary gear. Even more ironically, the lathe has a property tag from CBS Records in Stamford, CT, indicating it may be the lathe they used to cut the CBS test records.)

After four or five years Coast moved over to Mission Street, David Rubinson moved in and took over the remaining studio, naming it The Automatt, and we moved the cutting room into larger quarters across the hall. I continued to cut in there even after CBS left and The Automatt took over the whole operation, until 1983 I think.

Back to your point, I kept the RCA test records that we had at CBS, used them to keep the system aligned in The Automatt, and use them to this day at my own shop. Don't tell George Horn, he probably wonders where they went.

Paul Stubblebine
serious student of the audio arts

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zmix

Aqua Marine

Posts: 4,288 Member Since:20/01/2011

#31 [url]

May 25 13 12:06 PM




 For our readers benefit, the RIAA standard was in fact that record and not the various published curves and filter co-efficients that described it. I've always been amazed more hi fi manufacturers didn't use it for designing their cartridges and preamps.

-bob_olhsson


I find this statement very confusing.  

Could you please elaborate, i.e. how is this record the standard rather than the circuit used to create the curve on the record? 

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gold

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Posts: 1,532 Member Since:27/01/2011

#33 [url]

May 26 13 2:59 PM

Flat response from that record is the standard. Just like a tape machine you line playback up to the record and then align record to that calibrated playback system. You do whatever it takes with circuitry to get you there.

-bob_olhsson

Huh?

In the Neumann SAL74 rack there is no provision to alter frequency response. There is a trim at 20k and 20Hz but it is normally switched out.

On the VG66 thee is provision for altering frequency response. There is 40Hz, Level, 9k and 12k. You would never alter the frequency response using phono playback as a metric.

The feedback monitor is what you would listen to or measure to adjust frequency response. That is to be trusted.

Do people use phono playback to align a Westrex head to the drive electronics? I'd assume you would use the feedback monitor as well.

Paul Gold Salt Mastering

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gold

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#35 [url]

May 26 13 7:42 PM

My point is that to use a phono cartridge as if it was a calibrated reproducer is a grave error. That is why the light beam method or the microscope method was developed to check the frequency response of a disc.

If you want to check the frequency response of a cutting system you use the feedback monitor. Although that won't tell you what's on the disc it is a very good indicator of the performance of the electromechanical cutting system from input to stylus tip.

The early mono Westrex, Neumann and Ortofon cutter heads all had electrical damping and the ability to use feedback monitor. All common stereo heads have this ability. Every cutting system I've seen that was supplied no matter the manufacturer included this provision.

Paul Gold Salt Mastering

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bob olhsson

Aqua Marine

Posts: 3,353 Member Since:25/01/2011

#36 [url]

May 27 13 3:02 PM

We obviously also double-checked the light beam and feedback monitor but we made matching the RCA test record a priority. I imagine this was partly because we knew radio was setting their systems up to it plus we were cutting our 45s at half speed which required correction.

www.audiomastery.com Bob's room 615 562-4346 georgetownmasters.com Georgetown Masters 615 254-3233

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Hermetech Mastering

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Posts: 389 Member Since:22/02/2011

#37 [url]

Jan 29 15 3:48 AM

Sorry for thread necromancy and slight OT, but have just bought a new TT (Rega RP6). I want to upgrade my cartridge to something better (currently have a Goldring 1042), looking to spend around $500-750, any recommendations? Will be used mainly for pleasure listening but also the odd archival project.

Gregg Janman, Hermetech Mastering

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Hermetech Mastering

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Posts: 389 Member Since:22/02/2011

#39 [url]

Jan 30 15 4:09 AM

Thanks Greg, I will add it to my "too look at" list. I very much trust your ears. I asked here because I know I could rely on a straight answer, asking on the audiophile/TT forums only brings you a seething mass of subjective hyperbole. :)

Gregg Janman, Hermetech Mastering

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mark chalecki

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Posts: 496 Member Since:04/03/2011

#40 [url]

Apr 16 15 2:46 PM

not sure if this has been answered here, I intend to read through, could someone tell me what level the ref tone (1k) on the CBS record should play back at dBu?

_m

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