RCA Victor cutter distortion problems

[hawkweed]

I just bought a RCA victor record cutter that I am restoring. It has a presto cutter head with Brilliantone cutting needle. I have only had it for 2 weeks and just started experimenting with cutting music to plastic plates. I have set the machine so the cutter heads own weight holds the needle to the disc. The tension can be adjusted with a spring but I have gotten the best results leaving the spring relaxed. The needle seems to loosely fit in the cutter head and I can't seem to find away to tighten anything down to hold the needle in. Is this normal? I asked because I have mastered the music for vinyl but in playback of the records the songs sound distorted. The music input has no compression, all tracks are centered and Filtered out sub bass below 30hz and higher frequencies above 4000 hz. Could the loose fitting needle be causing the distortion or is the needle supposed to fit that loose? Any suggestions?
Here is a video of my machine

http://www.youtube.com/watch?v=N3EiOXPNU2k&list=UUVAonqjUS2Ko6G3dbWxwpYw&index=1

[dubcutter89]

welcome to the secret society!

nice lathe you have!
well, a loose needle is not good - is there no stylus set screw on your head (little screw on the bottom of the front?)
is the needle inserted in the right way?
otherwise distortion/noise could also be caused by cutting with the wrong needle into the wrong material,
or by 1000 other reasons...
don't know brilliantone needles (steel or saphire?), but it is not an easy task to cut good sounding records into plastic,
especially for beginners...

there is a little wiki which has some info for beginning:
http://lathetrolls.pbworks.com/w/page/22959575/The%20Secret%20Society%20of%20Lathe%20Trolls

maybe there's somebody else here with a similair setup that can help you...

[hawkweed]

Thanks for the info! The needle is steel and there is a little hole on the front that I tried to use to tighten it down but It didn't do anything. May be it is stripped? I will investigate this a little more.

[vmspoland]

You are welcome , very heartily you are welcome in this beautiful world VINYL MASTERING END RECORD TROLE !
The beautiful recorder , I [ saw your films very good !

[tragwag]

do you use I-RIAA encoding?
if not, that could certainly cause distortion.

judging by your video, you should adjust the depth, and angle of your cut to try reduce the surface noise.
also, that specific brand of plate may not be the best.
give some others a try!
if you have a chance to grab a sapphire cutting stylus, that will work best.

[Steve E.]

Well, yeah, if you are starting cutting with an ancient needle and some random plastic, you can expect distortion no matter what.

From a scientific perspective, it is best to start with the optimal materials (sapphire and lacquers, which you can buy from Apollo) and then work towards rougher materials. There are just too many things that could be giving you problems.

It will be an investment. You can expect to chip a couple needles until you know what you are doing. It can be an expensive learning curve.

[hawkweed]

Thanks everyone for your comments. I will keep you informed on my progress

[Angus McCarthy]

I took a listen to your test video. It sounds similar to my first plastic cuts on a 6N. The weight is probably far too high if you're not using the tension spring at all - that will cut down on the constant hiss. The distortion may point to over-driven audio into a sticky/fried head. If you have to push it that high to get a response from the head, it may need to be re-wound or at the very least, have the shock rubber in the head replaced.

Steve is right, though. To properly adjust everything, your best bet is to bite the bullet and get a fresh sapphire and some new dub blanks to experiment with.

In good news, the playback cartridge sounds great!

[hawkweed]

Thanks again for the info. I opened up the cover of the cutter and the shock rubber has a ripe in it. Does anyone know where I could buy some rubber to replace it? Also how much tension should I have on the cutter head? Should it feel weight less like the needle on a record player?

[Angus McCarthy]

It should have some weight to it, but not the entire weight of the head.

You know, I've never actually measured how many grams I'm cutting under. I just slowly release the tension spring until I get a smooth cut.