The Secret Society of Lathe Trolls

Nitrocellulose "lacquer" discs are not inherently dangerous or explosive by themselves. Professional cutters use heated cutting styli on them as a regular, standard operating procedure. But the "chip" or "swarf" thread that is cut from them can be highly flammable due to its high surface area. Profe...

B&W, your first picture is essentially correct at its right side. I should have been more careful in my description. There is no large, loose ball roller. The sled or carriage on the Scully is suspended on conventional ball bearings (rather than sleeves or bushings) inside of V-shaped rollers or whe...

I don't have pictures of any of this, but I have used and can remember how the cutter traversed over the lathe bed on some of the Neumann and Scully models. On the Neumann AM-32b (and on the VMS-70, if I remember right) the upper carriage structure rolled on ball bearings over two long flat, ground ...

Advance balls were anachronisms already by the 1970s, if not earlier. The Neumann suspension box worked so well that it was widely adapted and used on many other lathes, including Scullys. So far as I can remember, none of our lacquer channels at RCA Records still used cutter suspensions with advanc...

Correct. There are two dashpots - the turntable drive is fluid coupled to filter out the power pulses coming from the synchronous motor to keep flutter to a minimum. The dashpot right at the front of the cutter suspension is designed to reduce the bounce of the cutter caused by slight irregularities...

Generally speaking, there are two essential sources of service information for consumer electronic devices. Prior to model year 1947, the source was the Rider's Perpetual Troubleshooting (PPT) Manuals. These are MASSIVE binders of reprints of manufacturer's service data collected by the Rider group ...

Hi Kirk, there were only a few CD-4 modulation systems installed worldwide. JVC made most of them. Theirs included the Mark I which was the so-called "one third speed" system which actually operated at 1/2.7 real time. There was one of these in the RCA Records studios in NYC and one or maybe two in ...

Yes, Steve, you're making too much out of this tonearm bizness. First of all, unless you are cutting soft lacquers with professional grade cutters like Neumann or Ortofon, the tonearm doesn't need to be cutting edge quality. Playback of lacquer cuts without inflicting too much damage to the lacquer ...

Steve, I'm just now discovering your post and quotation from the wikipedia description of the RIAA compensation. Yes, there are errors in this description. The history of the various attempts to equalize recording and playback thru the early years of electrical recording are probably fairly accurate...

Doug, the original article that contains the above RIAA graph was printed in the Journal of the Audio Engineering Society (JAES) July 1959, Volume 7, number 3, titled "Automatic Plotting of Cartridge Response" by C.P. Germano. Germano worked for the Clevite Brush Corporation which was one of the ear...

Yes, you can use pink noise as a test source and measure your result on an RTA. But the results will be more ambiguous and imprecise because of the noisy character of the signal. This would be a good way to start your process to get the response "roughed in". But I would suggest using the sinewave t...

I recently received an inquiry from Doug6N about the RIAA recording pre-emphasis. Although I responded to him, I think this topic still needs some further airing out because I'm sure there is still confusion about it. So I'm repeating most of what I said to him for everyone who's interested. As I've...

Steve, those spectral plots look interesting. I've been looking for a cheap spectrum analyzer program. What software are you using?

All American-made equipment made before about 1980 used SAE or "English" standard threads on their machine screws. You might have a problem finding SAE threaded screws and nuts anywhere in europe, even England :? . If these thread into plates or other equipment parts such that you can't substitute m...

The professional cutting electronics from Neumann and Ortofon already contain electronic circuit breakers to help protect the cutter from overdrive. They are much faster acting than a fuse. But even with these, it's still possible to blow the drive coils. There's no substitute for paying attention t...

Once again, the discussion regarding the purpose of RIAA equalization given in the 'plattenspeler.com' link is WRONG, WRONG, WRONG !!!. Bass frequencies are NOT REDUCED during recording to get more level on the disc and highs are NOT BOOSTED to improve signal to noise ratio. It's just the opposite, ...

Steve, depending on how old your machine is, you may not be able to get there from here. Old acoustic reproducers (no electrical amplification, such as Victors and Victrolas) used steel or tungsten wire needles. These needles were DESIGNED to wear into the groove shape very quickly to distribute the...

I'd like to correct what is apparently a GROSS misconception regarding the RIAA equalization curve that is applied to all modern analog disc recordings. The sited article in EM magazine just perpetuates this myth. This quotation from the article heading titled "The RIAA EQ Curve" is just plain WRONG...

Depends on whether you want to replicate the old acoustic 78 groove geometry or intend for your new cuts to be pressed in vinyl and playable with modern pickups. Nobody presses shellac anymore (well, maybe in India), so you just about have to have your records pressed in vinyl. So you can use a conv...

Well, too bad you had to learn about cutter feedback the hard way. I hope this wasn't a really good head. Repair of a Neumann or Ortofon stereo head was a multi-thousand dollar proposition 20 years ago. I can't imagine what it must cost these days. Setting the feedback on one of these heads is the t...