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
