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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
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atmasphere's avatar
atmasphere OP
11,931 posts
 
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!
raymonda
855 posts
 
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
atmasphere's avatar
atmasphere OP
11,931 posts
 
Do you have one you want mastered to LP?

For some reason I can't do a PM to you via your moniker.
r_f_sayles's avatar
r_f_sayles
872 posts
 
I would love to hear how this project of transformer-less vacuum tube cutter system is progressing Ralph. 

PS. I could not be more pleased with my Mk.3 updates! Thanks. 
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rauliruegas
13,103 posts
 
Dear atmasphere: "  The real limitation in LP recording is the playback apparatus, not the cutters. " 

That I remember in this forum I never read a post where some one saids that cutters were the problem with the LP recordings/playback.

The normal recording process has several characterisitcs that in one way or the other puts its own limitations to the LP playback.

I'm not and expert on this subject and don't know for sure the whole recording process till the LP is for sale.

With out importance level in that process and with out know almost nothing about I list some limitations on that normal process ( not " audiophile " but normal. ):

- quality level of microphone.
- microphones place during recording.
- use of limiters, equalizers, reververation or other electronics artefacts.
- quality level of monitoring system.
- bias of the recording engineers or recording producer to some kind of sounds.
- edition work.
-dubbing.
-mastering and platting.
-quality level of all the electronics surrounded the recordings: microphone amps, cables, connectors, amps and preamps, overall recording consoles, etc, etc.
-quality of pressing.
-and many other " characteristics " where you can put some light to ignorants as me trying to learn.

and yes, the LP playback whole process is surrounded with faults any where.

So, IMHO both process are far away to be " perfect " or that permits that the LP be the best medium to listen music at home.
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