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Author Topic: vinyl cutting  (Read 4573 times)

AndreasN

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vinyl cutting
« on: April 12, 2005, 09:54:23 AM »

Hello!


There's been some interesting information on vinyl records here lately. Was hoping it was possible to get some tips or hints to further reading on the cutting process. Hope this is the right forum, please move if not.


The situation is that the electronic music interest organisation in my little city of Bergen in Norway got hold of a prosumer vinyl cutting machine through government funding. It's a Vestax VRX2000 http://www.vestax.com/products/vrx2000.htm - cutting directly to vinyl from the source. Beautiful little machine! No variable groove distance or other finesses, but it does what it's supposed to do, cutting grooves into vinyl which is much better than regular dub plates. The first totally amateur tries at cutting when it was brand new turned out to be far too noisy. It ended up collecting dust in the office of this organisation after the first dismal results more than two years ago. A shame! So it's been moved to my meager studio. Aiming to improve the results and make a workable routine for the task to hand over to future operators. The machine is wrapped in a dust cover now and will stay there until more or less total confidence in the theories arrives. Got a brand new needle good for 2-300 minutes and 15 blank discs, which is the budget for testing. The machine will be operated entirely on a nonprofit basis and I do this for the love of it.

Some pictures from the first cut: http://info.bergenteknomafia.com/tech/vrx2000T/

Problem is to find information on the subject. Vestax do give some information. Very little actually. They do state that it takes a lot of time and effort to get it right. Doh! This lot of time translates into a lot of money for the blanks and needles. Haven't found much info on the net at all. Haven't heard of anyone else actually owning or operating this machine either. Understood that the AES papers where the bible, am currently waiting for those to arrive in the snail-mail. Also gathered that it needs a microscope fitted, will try to make a contraption to fit one. Only measurements are level VU's and heater current draw, hope it's internally protected against burning the head!


Got some questions I hope some of you experts may answer.

The heater wire action is measured on a VU-style/needle amp meter. The manual states that the proper way to adjust the heater is to look at the vinyl scrap that the needle leaves behind, if they're too thick it's too cold and if they curl up and break it's too warm. This seems too vague to me(like most of the other parts of the manual) so I've been thinking about hooking up a temperature sensor to the heater wire and check the real temperature with the multimeter to find the sweet spot. Will this be a better approach? Microscope? Other method?

The sound level going to the head is also measured on a VU, not peak level. This may overlook some transients the cutter head might not like..? Have no idea what sort of crest ratio a vinyl cutter head likes to get. Should I aim for a high or low crest ratio on the tracks before cutting? Does it matter? The machine will probably spend 99% of the time cutting loud dance floor and scratch-dj tracks.

The machine have a built in RIAA EQ compensation but the curve of the cutter head itself is not compensated in the machine. The manual gives a hopelessly vague chart of it's frequency response which is only a hint to further experimentation. Are most cutting heads almost the same or do they vary wildly between different brands? In other words, can anyone help with the real frequency response of the head? Or any suggestions as to how to compensate for the head?

Locked grooves. It's not made for it. Figure I'll have to stop the cutter head arm motor and lift the needle at precisely 1.8 seconds to make a locked groove. Not likely in reality. It's a much requested feature and if anyone have any suggestions to achieve this it would be plain brilliant!



On the subject of pre-mastering; am looking for spesific time figures for non-skippable sections for playback on a technics S-shaped arm. By looping a sound at 1.8 seconds the needle can skip as much as it wants, it'll always land in identical groove. Almost. Problem is that the spot where needle hits the vinyl on a S-shaped arm, maybe straight arms does this as well, moves away from the tonearm base as the arm travels towards the center of the record. This means that the loop have to be slightly more than 1.8 seconds to a perfect fit. It doesn't matter much for the non-skippable records but if the user wants the attack of the first sound in the loop to appear on the same physical place all over the record it needs more precision. An example is a scratch artist that wants different but similar sounds running along a vertical axis on the record, to be able to drop the needle anywhere on the record to change sounds without cueing to find the attack.


Any help much appreciated!


Cheers,

Andreas Nordenstam (young and learning)




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Gold

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Re: vinyl cutting
« Reply #1 on: April 14, 2005, 04:40:23 PM »

AndreasN wrote on Tue, 12 April 2005 09:54


Problem is to find information on the subject. Vestax do give some information. Very little actually.  hope it's internally protected against burning the head!



I took a look over the specs a while back. They couldn't even make the machine look good that way. The specs are terrible.
I don't think there are high frequency limiters and I don't think there is a circuit breaker to disconnect the head in case of overload. So, no the head isn't protected.


Quote:


The heater wire action is measured on a VU-style/needle amp meter. The manual states that the proper way to adjust the heater is to look at the vinyl scrap that the needle leaves behind, if they're too thick it's too cold and if they curl up and break it's too warm. This seems too vague to me(like most of the other parts of the manual) so I've been thinking about hooking up a temperature sensor to the heater wire and check the real temperature with the multimeter to find the sweet spot. Will this be a better approach? Microscope? Other method?



The reason you heat the stylus is to reduce noise in the cut. So the best way to adjust stylus heat is to turn it up until the cut is as quiet as possible. On lacquer you have to take into account horning which comes from too much heat and can cause noise in the plating process. You won't hear it on the lacquer though. You don't have to worry about that.

Quote:


The sound level going to the head is also measured on a VU, not peak level. This may overlook some transients the cutter head might not like..? Have no idea what sort of crest ratio a vinyl cutter head likes to get. Should I aim for a high or low crest ratio on the tracks before cutting? Does it matter? The machine will probably spend 99% of the time cutting loud dance floor and scratch-dj tracks.



IIRC the system is only spec'ed to 12k. If there is a steep low pass filter built in than you are safer than if there is none. Of course it doesn't help the sound much if it's there. I guess a PPM would help. There is a PPM on my cutting console. Get yourself a good deesser. BSS402 would be my choice. Don't expect to cut loud records with that machine. It doesn't do it.

Quote:


The machine have a built in RIAA EQ compensation but the curve of the cutter head itself is not compensated in the machine. The manual gives a hopelessly vague chart of it's frequency response which is only a hint to further experimentation.



You have a toy. An expensive toy. They couldn't quite hide how bad it was on the website.

Quote:


Are most cutting heads almost the same or do they vary wildly between different brands? In other words, can anyone help with the real frequency response of the head? Or any suggestions as to how to compensate for the head?



A good head sound great, a bad head doesn't. Not much you can do about it. If I had $10,000 I sure wouldn't buy that thing. For free it isn't bad but don't expect too much.

Quote:


Locked grooves. It's not made for it. Figure I'll have to stop the cutter head arm motor and lift the needle at precisely 1.8 seconds to make a locked groove. Not likely in reality. It's a much requested feature and if anyone have any suggestions to achieve this it would be plain brilliant!



Locked grooves in tempo are hard to do on any system. It takes lot's of practice and some luck.



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AndreasN

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Re: vinyl cutting
« Reply #2 on: April 15, 2005, 12:32:28 PM »

Hi!

Thanks a lot for taking your time to reply!

Expectations are now turned down to the point where any sound at least resembling the original will be fine. Did a few test cuts today to get a feeling for it. Frustratingly poor results, yet definitely rewarding! Watching the RTA and oscilloscope have been a nice learning experience. May be a stupid machine but it's still a magic thing to be able to cut grooves. Lovely job you have! =)

Found a few numbers in the manual. 2x80w amps.. General limiter too, not specified, kicks in way early. The end product is about 10dB down compared to the general modern vinyl level. SNR with 1kHz sine is about 30dB now. Distortion poked out like combs on the RTA! Can only get better from here.

>IIRC the system is only spec'ed to 12k. If there is a steep low pass filter built in than you are safer than if there is none. Of course it doesn't help the sound much if it's there.

-3dB at 12k, not too steep filter. Response is weird.

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(20-20K sine log sweep, it does fade out at 15k but drowns in the noise)

The two strong peaks are at 1100 and 1700, first jump at 6000 where it suddenly goes up approx 20db, next and last jump at 9000, sine trails off nicely to 15K where it fades sharply. The left side have a few millisec lead in this response, otherwise they're identical. Any idea why the response jumps like that and is asymmetrical in time?

>You have a toy. An expensive toy.

Laugh! So true. Will never grow tired of toys, especially not the expensive ones. Glad it's not mine though! Could have made a dozen small run releases for the price of this machine. Cut loads of regular dub plates. Bought ten sets of vinyl->timecode interfaces with laptops too. Price tag vs. performance have been a total failure so far. There's a upgrade and new compound for the blanks available which haven't been fund-raised yet. Hope it may solve some of the issues!

If they refined the concept and made it a viable option for regular users they'd help prolong the lifetime of vinyl as medium for new music. Only the big names can afford to play their own tracks now, the rest will resort to digital solutions. (Among Dj's)


Wish you all a splendid weekend!


Andreas
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JGreenslade

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Re: vinyl cutting
« Reply #3 on: April 15, 2005, 01:11:00 PM »

Does anyone know if Vestax actually ever got around to demo-ing the lathe at shows?

Part of my job involves attending shows for PA / "DJ" gear, and I first saw the Vestax cutter turn up at a show about 5-6 years ago (friends put deposits on them, none took delivery...). Every show after I heard rumours they were going to cut live with it, but whenever I visited their booth it was unplugged..

At the last couple of shows I've attended Vestax weren't even displaying the lathe; kind of strange for something they've obviously put much R+D budget into wouldn't you say?

Is it cutting in stereo now then? I was under the impression it was downgraded to mono, or did the 12K filter enable stereo operation?

I have still yet to see one of these in action:  http://www.vinylium.ch/dubcut/dubcutter.html I know it's been in development a long time.

Incidentally, if you managed to get anything over about 18K onto a vinyl cut, wouldn't it get wiped out after a handful of plays? Even if you used a decent low tracking force cart?

Justin
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Re: vinyl cutting
« Reply #4 on: April 18, 2005, 12:48:12 PM »

AndreasN wrote on Fri, 15 April 2005 12:32

 The end product is about 10dB down compared to the general modern vinyl level. SNR with 1kHz sine is about 30dB now. Distortion poked out like combs on the RTA! Can only get better from here.


That sounds about right. The vinyl blanks will be about 30dB noisier than an acetate. The level sounds about right from reading the specs.

Quote:


The two strong peaks are at 1100 and 1700, first jump at 6000 where it suddenly goes up approx 20db, next and last jump at 9000, sine trails off nicely to 15K where it fades sharply. The left side have a few millisec lead in this response, otherwise they're identical. Any idea why the response jumps like that and is asymmetrical in time?



If there was only one peak at about 1k i would say the head is under damped. I think that is what it is but it seems strange to have a peak/dip/peak so close together. I guess the feedback could be set for 1k2 with a narrow bandwidth and produce those results. That would be incredibly bad design though.

Quote:


Price tag vs. performance have been a total failure so far.



It sure is.
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AndreasN

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Re: vinyl cutting
« Reply #5 on: April 19, 2005, 06:12:22 AM »

Hi!

Thanks Paul. Seems the only thing they got right was the longevity of the vinyls, they stand up to a lot of abuse(read: scratching).

Thermionic wrote:
>Incidentally, if you managed to get anything over about 18K onto a vinyl cut, wouldn't it get wiped out after a handful of plays? Even if you used a decent low tracking force cart?

Would you be able to tell? Can you hear that high?

Embarrassingly enough I didn't test if it was stereo. Will do!


Andreas
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