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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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r_f_sayles's avatar
r_f_sayles
827 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
9,123 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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rauliruegas
9,123 posts
 
of course!: quality of the tape recorder and kind of tape they choosed.


Regards and enjoy the music,
R.
atmasphere's avatar
atmasphere OP
7,068 posts
 
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.
Of the things listed most have nothing to do with the LP except the mastering, plating and the resulting quality of the pressings. IME the quality of mastering means a lot more about the pressing quality than the work of the actual plant.

We did one job where the customer was doing the pressing at United, which is not known for pressing quality. I knew some people that got a project done there and the finished LP seemed kind of .... compressed. But in our case when we got the finished pressings back they sounded fine. We didn't add any compression to the recording- usually with LP there's no point to it.
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rauliruegas
9,123 posts
 
Dear Atmasphere:  "  Of the things listed most have nothing to do with the LP except the mastering, plating and the resulting quality of the pressings. "  

WOW!, I'm totally an ignorant because my thought is ( ? ) that different icrophones have different quality level performance and that it's not the same to make the recording of the 1812 with only three micros than with 8 or 25.

Please let me know, because according with your statement I'm totally wrong, if the audio signal that goes throught the micros, cables/connectors of those micros and micro amps is the audio signal used throught all recording process that at each single link of that process the original audio signal was and is modified/degraded  or it's that at each single link on the recording process only is used the audio signal coming from the micros in original status?  and how is that the quality level on the open reel tape deck used for the " masters " has nothing to do with the LPs?
So from where came the audio signal that we are listening during LP's playback?

Yes, could be that I'm stupid but I don't get it your answer to my question.

Can you help me?, appreciated and than's in advance.

Regards and enjoy the music,
R
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