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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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myles_b_astor's avatar
myles_b_astor
134 posts
 
BDP24 writes: Wouldn’t it be great to have the same recording available on all three formats---analog reel-to-reel, LP, and CD/SACD, produced with the care necessary to insure they sound as much alike as possible? One could then compare, for instance, the sound of a recording from it’s master tape to the sound of that recording as reproduced by a given phono cartridge/phono amp/digital player under review.

That already exists. You have RR’s Arnold Overtures, Bill Evans Waltz for Debby, Oscar Peterson on MPS, Garcia-Grisman, Lee Morgan Sidewinder, etc. currently available in all three formats. I’ve done the comparisons and hands down winner is still 15 ips tape.

The real problem however is finding out about the chain of custody. Do they use the same tape, equipment, etc. to make each release? One also needs to do the comparison with the best playback gear too so as to make the comparisons relevant.
bdp24's avatar
bdp24
9,815 posts
 
Right Myles, the comparison would be of not only the formats themselves, but of the playback gear as well. It was in the latter sense I was suggesting a recording be made available in the three formats. I believe it possible to produce them all in such a way as to insure equivalency amongst them. One could then compare the sound of a recording on, say, two different CD players, and the one producing sound most like that of the tape the CD was sourced from would then be judged the more accurate, at least in one way or another. Of course, if neither player is perfect, each might be better than the other in different ways.
myles_b_astor's avatar
myles_b_astor
134 posts
 
bdp24 writes:

Right Myles, the comparison would be of not only the formats themselves, but of the playback gear as well. It was in the latter sense I was suggesting a recording be made available in the three formats. I believe it possible to produce them all in such a way as to insure equivalency amongst them. One could then compare the sound of a recording on, say, two different CD players, and the one producing sound most like that of the tape the CD was sourced from would then be judged the more accurate, at least in one way or another. Of course, if neither player is perfect, each might be better than the other in different ways.
Probably the best "test" available would be from Yarlung records where Bob records in parallel 15-ips tape on Arian Jansen's modded deck and also Quad DSD. The DSD is available as a file and you can either buy the 15 ips tape or in 33 or 45 rpm LP. 
atmasphere's avatar
atmasphere OP
11,834 posts
 
To really get that right though the LP should be recorded Direct to Disc so that the limitations of the other formats aren't built into the recording.

We did our Canto General recording on both LP and CD, both made from the master tapes. Which means that at best, they sound pretty close to the master tapes, which sound great. But take away the tape hiss and bandwidth limitations and it could have been better. But the magic of tape is that you can re-record if you don't like it the first time through...
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rauliruegas
13,084 posts
 
Dear friends: IMHO D2D must be the only way to make LP recordings but this is more easy to tell than to do it for any LP manufacturer.

I own several/many D2D recordings coming from diferent LP labels, including " modern " ones by Acoustic Sounds. ) and till today no one of those labels are near of almost all the Sheffield Labs D2D quality level " performance ".

The D2D recording process is really a continuous " over stress " for all the people involved with because the recording is live with out the facilities that gives the tape to edit the recording in any way and I suppose that not all  recording engineers have not only the knowledge level but skills like SL.

Tape decks ( any ) is always a limitation in the recording process. I own all the D2D SL and own too the samples made it from the tape deck/master tapes and even that are very good can't compare in any way to its " brother " D2D sample.

As I posted in the thread there are many limitations in the overall recording process, the tape deck is one of those limitations.

Regards and enjoy the music,
R.
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