The Secret Society of Lathe Trolls

Firstoff, Kevin, I will admit that this subject has been confusing. Partly because I didn't completely explain the realities of the whole scene in one single post. If you bother to do a search of this forum, you will find that I have addressed this RIAA subject in several posts on different threads....

I believe the SRC logo that you are referring to is the logo of Specialty Records Corp. which pressed the Warner catalog in the 1970s. It's not a signature of the cutting engineer. Specialty started out as an independent pressing plant but was later bought by Warner. FYI, the cutting engineers at mo...

Moss, I don't recall RCA Indianapolis or the USA studios employing a "sweating" process for lacquers. During the glory days of 45 and LP record manufacturing, there was almost no need to deal with "old" lacquers - lacs were cut within days of their being shipped out from Apollo, Transco, Pyral or wh...

Moss - Yes, the cutting-in-copper technology was developed at RCA Indianapolis (not at the RCA Princeton laboratories - they were still using electron beam recorders). Of course, it was developed specifically for use in the shallow groove application for CED mastering. At the time, Teldec had their ...

Moss - Yes, I worked at the Indianapolis pressing plant and engineering department of RCA Records from 1973 to when we turned the lights out on the press floor at the end of 1987. The SelectaVision CED cutting and disc manufacturing technology was a spinoff (pun intended) of the RCA Records Division...

See my other postings about CED records. RCA designed and built nearly ALL of the manufacturing equipment as well as most of the consumer playback equipment. That includes the lathes, the PZT recording heads, the recording styli and the playback styli. RCA made their own copper recording blanks and ...

The RCA CED (Capacitance Electronic Disc) videodiscs were manufactured on specially-modified Toolex Alpha record presses. The disc material was a special vinyl filled with a very high carbon content to make it electrically conductive. This was required to form one plate of a capacitor, the other pla...

The playback styli used in the RCA CED videodisc players are NOTHING like those required for audio disc recording or playback. They are extremely tiny by comparison. The CED records turned at 450rpm and were recorded at about 9,000 lpi and the styli are appropriately small. Yes, Virginia, this is mo...

Capps made a unique cutting stylus shape in the pre-stereo era. The cutting face was curved rather than being flat or planar as are all other styli. Capps called this the "Cappscoop" and it did indeed function as a scoop to curl the chip as it cut. The scoop shape was not so well suited for cutting ...

Moss, I'm not quite sure I understand your description of the Edison "gold molded" cylinder record process. Prior to that, a mechanical duplication process was used by most cylinder makers that involved the use of a completely mechanical duplication system known as "pantographing". The process invol...

TEE HEE, chuckle, chuckle. Reading all this commentary just makes me laugh. If this isn't a prime example of the old expression "those who don't know history are condemned to repeat it", I don't know what is. EVERYTHING commented on here from overcutting, cutter lift, and kissing grooves was OLD NEW...

Hi Bill, It sounds like you're referring to Randy Kling. I remember when he moved from the Chicago studios to Nashville. Our engineering manager at the RCA pressing plant in Indianapolis, Joe Wells, used to manage the Chicago studios when Randy was there. I used to keep up with Randy over the years ...

Ed Roys was an engineering manager at the Indianapolis record plant of RCA Records. He retired a little before I went to work there, so I never got to meet him. Yes, the "pre-distortion" technique written about in the Woodward paper was employed in the original RCA Dynagroove records. In fact, it wa...

CC, the whole issue of increased media linear speed is much the same for analog disc recording as it is for analog tape recording. It is mostly the matter of making the recorded wavelength sufficiently long even at the highest desired signal frequencies that it can be accurately scanned by the playb...

Mark, your links to the technical paper on scanning loss are interesting. This is indicative of the thinking going on in the late 1950s and early '60s when mono records were still popular. People were more concerned with high frequency LEVEL loss than distortion at that time. The term "scanning loss...

Thanks for those links, CC. Roger Russell has some good info on his website. I met him at an Audio Engineering Society convention in NYC once. I told him that I had built his circuit for a dynamic volume expander which was published in an electronics magazine back in the 1960s. He blushed and didn't...

CC, your plan to make a piezoelectric transducer (PZT) cutter isn't really anything new. That's what all the crystal cutters of the 1930s and '40s were. I suspect that places like WestTech that now rebuild the old crystal cutters are doing so with modern ceramic materials rather than trying to resur...

Mark, your interest in trying to decode CD-4 records by playing them at half-speed and then doing the processing in a computer is interesting. But it will probably prove to be more trouble than it's worth. You will need to do A LOT of number crunching. There are two carriers - one on the left channe...

Mark, that article by Burstein is very good. I have built my own ceramic cartridge preamp using the principle of very high input impedance, and it works wonderfully well. Most people have no idea how good a GOOD ceramic cartridge can sound because they've never heard one used with a proper amplifier...

Mark, those textbook pages are very interesting. And informative. As I said earlier, I have no experience with moving iron type cutters and cutters without feedback, so I was surprised to learn that they typically have a much higher resonance than is found in dynamic (moving coil) designs. The analy...