The Secret Society of Lathe Trolls

important · Joined: 19 Apr 2007 Posts: 1 Location: massachusetts

Before I start begging for advice I'll introduce myself.
My name is John Brien & I run a small, though extremely busy, record label called Important Records. Important releases a broad range of music from Japanese psychedelic & noise to Italian instrumental groups & American underground folk-rock etc. We release a lot of vinyl and it is, naturally, my preferred format. So, eventually I became really interested in cutting vinyl and bought a Rek-O-Kut TR 43H, a rebuilt Presto I-D (lathe came w/ an RCA MI-4896), some needles and laquers from Transco & I was ready to go.
The only thing I was lacking was time to work on it. Using a Realistic PA that someone recommended I use I cut some poor sounding tests and that was about it. It was in my basement for a couple of years and now it's in my barn. However, I'm dying to use it and eager to get it to a point where I can cut some laquers that sound good enough to release as limited editions.
I'm wondering if anyone can give me some advice as to what I should put in between my cd player and my Rek-O-Kut and how I should adjust said device in order to get the best sounding record I can. Obviously, I'm not the next Stan Ricker, but I'd like to do a good job with what I have.
Any help & dialogue would be tremendously appreciated.

Best,
John
_________________
www.importantrecords.com

JayDC · Posted: Fri Apr 20, 2007 12:18 am Post subject:

First off.. make sure the impedence of the recording head, and the amp are correct. Both heads you have are stock 500ohm. Most solid state amps will not work well with this. Have your amp/ recording head checked out by gib at westtech services. He will make sure your head is operating at spec, and will tweak it out so you can get a better sound.

After all that, check your turntable, and make sure it's spinning true using a strobo disc.

Mount your head, and set the cutting angle.

Get a nice 10 to 20 band EQ, and set the riaa encoding curve.

Cd player -> EQ -> Amp-> Recording head.

I recommend using a good multimeter, to monitor the incoming AC voltage at the head.

cd player -> EQ -> Amp -> multimeter -> Recording head.

monitor the voltage while test cutting. start low around 1.5vac, and progressively bump it up, with each test cut. Becareful. Too much and you'll blow the head. Note the voltages, so when you hear the good cut, you know about where the volume of the amp should be.

My presto 1-C likes to be about 3.0-3.9vac on a 112LPI screw, this cuts a groove at about +6db/0 reading from my pioneer dj mixer.

Use a microscope to monitor the cuts, becareful of over modulating the groove, this will damage the stylus, and will distort your sound.

My presto head is bass heavy, so I much always adjust the upper end of the riaa curve to suit the source recording, you may have to do this too..

There are many books on mastering the art of cutting records. I have yet to read any of them, although I get a great sounding cut from my equipment.

Use your ears, watch the volts, and keep on tweaking..

cuttercollector · Joined: 11 Jun 2006 Posts: 254 Location: San Jose, CA

One "trick" if you do have a higher impedance head like 500-600 ohm rather than 4-8, is to use one of the higher impedance output taps on your PA amp to better match it to the cutter's impedance. Most PA type amps have a so called "25 volt" and "70 volt" output. These attain the stated voltages when the amp is delivering it's full rated power (25 watts, 100 watts whatever) across a certain rated impedance, which is dependant upon the actual power of the amp. They were there to properly match large numbers of speakers with transformers on them like those typical round white 8" ones you see in ceilings all over the place. Anyway, one of these higher impedance outputs will give you more power and a better match to your head if it is a 500-600 ohm one. This is because as was stated in the previous reply most standard amps with an 8 ohm output impedance will not deliver anything like their rated output into a 600 ohm load. One other thing to add is that the voltages you will measure with your (hopefully analog) meter across the cutter will be higher with a high impedance cutter than with an 8 ohm one. That is OK because there is less current flowing and the same power. It's all a matter of ohms law. You probably want to see no more than about 20-30 undistorted watts peak across that type of cutter.

JayDC · Posted: Fri Apr 20, 2007 2:56 pm Post subject:

Whats wrong with a digital multimeter?.. Question

cuttercollector · Joined: 11 Jun 2006 Posts: 254 Location: San Jose, CA

Nothing is wrong for steady state AC voltages like test tones, but if you are trying to use it like a VU meter for noting peaks in program audio all you will get is a continuous jumble of ever changing numbers that are behind the actual signal by some number of miliseconds update time.

JayDC · Posted: Fri Apr 27, 2007 2:04 am Post subject:

ah.. nice.. just ordered and analog one.. Very Happy