interesting phenomena in the cutting room


We've (my friend Bob and myself) been working on an LP cutting lathe for some years. Its been a while refurbishing the lathe itself, finding parts and solving problems/puzzles, rebuilding the electronics, etc.

The lathe itself is a Scully, the cutterhead a Westerex 3D and the electronics the 1700 series built for the cutterhead by Westerex.

About 6 weeks ago we finally hit upon the magic combination of stylus temperature, vacuum, depth of cut, etc. It works beautifully! So we have been playing with parameters, including different amplifiers. The stock amplifiers were built about 1972 and are solid state.

Now those of you that know me know that I am all about tubes. But the stock amps worked quite well! As we gained familiarity with the system, we found out why: the Westerex cutting system is a high efficiency cutterhead- it does not take a lot of power to make the head work. It can easily cut grooves that no cartridge could ever keep up with, and do so without breaking a sweat. So the amps, which can make 125 watts, are loafing through the most difficult passages.

I had a Dyna ST-70 that I had rebuilt so for fun we swapped that amplifier in and it did quite well. Our next step is to use a set of our M-60s, as the cutterhead is an easy load relative to most loudspeakers.

What is interesting about this is that we can make cuts that literally demonstrate the audible differences between amplifiers, something that can be demonstrated on any playback system.

Its also apparent that the cutting process is relatively unlimited as a media compared to any other recording system. The dynamic range is well beyond that of analog tape or any digital system- like I said, it can cut grooves with such range that no cartridge could possibly keep up, yet is dead silent (if the lacquer is OK, that is). The real limitation in LP recording is the playback apparatus, not the cutters.

There is a fun little forum website for more information called 'Secrets of the Lathe Trolls'. Here's a post on that side made by my friend Bob (Bob has run a recording studio for some 20 years and was a roommate of mine in college):

http://lathetrolls.phpbbweb.com/viewtopic.php?p=19435&mforum=lathetrolls#19435
128x128atmasphere
I also think this is a very interesting thread.
Ralph, I hope you will continue with this discussion and your findings. It would also be nice if and when you actually have a product to sell, that you provide us with a web address or phone number to order!
Regards,
We master LPs for other labels. Most of our work has been for Nero's Neptune, which is a local label in Minnesota. We've also done a number of independent projects. Most of them have not been what I would call audiophile, for example we mastered a reissue of a Spider John Koerner LP called 'Folk Songs Like they Used to'... The label was happy because we got it sounding better than the original. Fortunately in that case we had the master tapes which were in excellent condition.

That does not always happen. We did a project for a punk band that was recorded in mono on an old Ampex 300 tape machine, which should have turned out spectacular, but I don't think the mics used in the recording were all that good. We also figured out that the tape machine must of had a microphonic tube as we could see an intermittent signal in the grooves that was at about 16KHz.

So we've been pretty happy about the results- but so much depends on the master tape or master file!
As a recording engineer I have some very interesting and audiophile recordings that might be of some interest to you. I would love to discuss this with you. Feel free to pm me.

Ray
Do you have one you want mastered to LP?

For some reason I can't do a PM to you via your moniker.