Noisy K8 cuts, what the deal?

This is where record cutters raise questions about cutting, and trade wisdom and experiment results. We love Scully, Neumann, Presto, & Rek-O-Kut lathes and Wilcox-Gay Recordios (among others). We are excited by the various modern pro and semi-pro systems, too, in production and development. We use strange, extinct disc-based dictation machines. And other stuff, too.

Moderators: piaptk, tragwag, Steve E., Aussie0zborn

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Self-lather
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Post: # 13257Unread post Self-lather
Wed Mar 09, 2011 4:02 pm

piaptk wrote:Heating the stylus isn't going to improve major noise.... it only helps with very minor noise... if its a super noisy cut, there is something else the matter, most likely the stylus. Especially if you can hear the music coming out of the head, but it's not translating on the lacquer. But old lacquers 70% of the time sound awful. You should buy a $50 USB microscope to check your styli... it works relatively well.
Is the groove tracking correctly?
Its seems to be groove tracking correctly. My laquers are new so I know that is not the issue. I think I will invest in that $50 microscope. Would the damage be obvious to the untrained eye?

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Self-lather
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Post: # 13258Unread post Self-lather
Wed Mar 09, 2011 4:06 pm

JayDC wrote:
Self-lather wrote:
So is it just nichrome wire that is being heated? Any chance I could get a pic?

-Thomas
yes, I'm using 36 gage wire on all the stylus I self wound.. Looks like 40 gage is what is used on NIB stylii from apollo..

Nichrome is resistance wire, so when coiled, it does not create a magnetic field (like copper) but rather heat from the resistance of the wire..

You can get nichrome on ebay.. I got 100 feet of it for about 5 bucks..
Cool, I'm going to go order some now!

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greybeard
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Post: # 13262Unread post greybeard
Wed Mar 09, 2011 4:48 pm

the magnetic field is still there, it is created by the amp-turns, i.e. the current times the number of turns. Copper wire has been used for heating, the only problem is that you want the heat to be in the coil and not in the wires leading to the coil. If it is all copper, you need heavier gauge to where you clip onto your copper heating wire. The problem with copper is that vibration will harden it, and it will break eventually. But everybody has copper!

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JayDC
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Post: # 13263Unread post JayDC
Wed Mar 09, 2011 5:02 pm

greybeard wrote:the magnetic field is still there, it is created by the amp-turns, i.e. the current times the number of turns. Copper wire has been used for heating, the only problem is that you want the heat to be in the coil and not in the wires leading to the coil. If it is all copper, you need heavier gauge to where you clip onto your copper heating wire. The problem with copper is that vibration will harden it, and it will break eventually. But everybody has copper!
I love learning new stuff.. thanks for the info greybeard!....

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opcode66
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Post: # 13265Unread post opcode66
Wed Mar 09, 2011 5:29 pm

greybeard wrote:the magnetic field is still there, it is created by the amp-turns, i.e. the current times the number of turns.
Yea there is no ducking the basic laws of physics. I remember doing those ele/mag field calculations. Using your thumb and first two fingers on your hand to figure our field orientation based on direction of current flow. Fun stuff.

Any current flow through wire windings produces a field. However if the windings are made from a material with a high resistance the current flow is minimized and so is the resulting magnetic field.

The resistance produces the heat in the nichrome wire.
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JayDC
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Post: # 13266Unread post JayDC
Wed Mar 09, 2011 5:34 pm

opcode66 wrote:
greybeard wrote:the magnetic field is still there, it is created by the amp-turns, i.e. the current times the number of turns.
Yea there is no ducking the basic laws of physics. I remember doing those ele/mag field calculations. Using your thumb and first two fingers on your hand to figure our field orientation based on direction of current flow. Fun stuff.

Any current flow through wire windings produces a field. However if the windings are made from a material with a high resistance the current flow is minimized and so is the resulting magnetic field.

The resistance produces the heat in the nichrome wire.
for as smart as I can be, I sure as hell feel dumb all the time..

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Self-lather
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Post: # 13271Unread post Self-lather
Wed Mar 09, 2011 10:47 pm

Wow, quite a night over here is Presto K8 land. I inspected my new stylus under a microscope. Busted, no doubt. Ouch, a pricey mistake. I must have cut down to the aluminum and not realized it.

So I decided to check out my old stylus. I have been ridiculously abusive to this stylus when I was cutting on my Wilcox-Gay machine. I cut into everything from plates and cardboard to lexan. Turns out its looks pretty good under the microscope.

So I give it a try on the new lacquers under the 100w lamp. Wow, I'm suddenly getting the best results I've ever had! I think before I never really had the angle quite right, and I was cutting too deep.

I also tested on some lexan, which also sounded remarkably great!

Thanks for all the help guys! I'm finally getting some good results.

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JayDC
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Post: # 13272Unread post JayDC
Thu Mar 10, 2011 12:15 am

thats what its all about man, glad ur making headway.. next thing to do is to start tweaking out ur riaa curve to get the most out of your head.

I'd also think about putting a fuse on your head so u dun blow the coil..

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emorritt
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Post: # 13274Unread post emorritt
Thu Mar 10, 2011 9:45 am

...fuse on your head so u dun blow the coil..
"Lucy you got los of splaining to do..." :lol:

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Self-lather
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Post: # 13276Unread post Self-lather
Thu Mar 10, 2011 11:51 am

JayDC wrote:yeah, thats how it is for the first few months, but once u have learned, and setup everything correctly, its golden.. and like riding a bike ;)

another thing.. what cutterhead do you have, and whats its ohm rating.. if its 8 to 15 ohms, it might be better to drive it off a more modern mosfet amp (home theater style) Thats what I'm doing right now, and its super sexy, coz I can utilize the optical input to the amp from my computer..
Hey, I wanted to get back to this for a minute. Now that I seem to be getting some better cuts, I think I might like to try something else.

So.. how does one tell what the ohm rating of their head is? I'm not sure how to tell. Here's a link to what my head looks like:

http://thomasbot.tumblr.com/post/3735583166

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markrob
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Post: # 13277Unread post markrob
Thu Mar 10, 2011 1:00 pm

Hi,

Usually, they are specified at 1Khz. You would need to measure the impedance at this frequency. You can make a good guess by measuring the DC resistance using an ohmmeter. The true impedance will always be more than the DC ohm reading. So you might read something like 4-5 ohms for an 8ohm head and 8-10 ohms for a 16 ohm version. If you read much higher than thses figures, its probably 500 ohms.

Mark

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JayDC
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Post: # 13278Unread post JayDC
Thu Mar 10, 2011 1:14 pm

most presto head are marked on the back with the ohm rating..

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Self-lather
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Post: # 13313Unread post Self-lather
Sun Mar 13, 2011 12:27 am

JayDC wrote:most presto head are marked on the back with the ohm rating..

Unfortunately, there is no indication on the back of this head. Just the cryptic inscription "50 4340". I think I'll ask Gib if he knows.

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Self-lather
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Post: # 13314Unread post Self-lather
Sun Mar 13, 2011 12:31 am

JayDC wrote:thats what its all about man, glad ur making headway.. next thing to do is to start tweaking out ur riaa curve to get the most out of your head.

I'd also think about putting a fuse on your head so u dun blow the coil..
Umm, wow. Proper eq, turtle wax, and a 100 watt lamp. I've been cutting into Lexan and getting unbelievable results. Now we're talking!

The only thing I notice is there is a low hum that I can hear in the silence. Its only audible when there is silence. I'm grounding the k8, but I think the amp may be introducing this. All the more reason to move to using a different amp.


-Thomas

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d
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Post: # 13315Unread post d
Sun Mar 13, 2011 3:18 am

Self-lather wrote:
JayDC wrote:thats what its all about man, glad ur making headway.. next thing to do is to start tweaking out ur riaa curve to get the most out of your head.

I'd also think about putting a fuse on your head so u dun blow the coil..
Umm, wow. Proper eq, turtle wax, and a 100 watt lamp. I've been cutting into Lexan and getting unbelievable results. Now we're talking!

The only thing I notice is there is a low hum that I can hear in the silence. Its only audible when there is silence. I'm grounding the k8, but I think the amp may be introducing this. All the more reason to move to using a different amp.


-Thomas
hey,

i have confused a little bit. as i got from the posting you are cutting lexan or embossing? from the previous posts I thought you have sapphire stylus?

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Self-lather
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Post: # 13323Unread post Self-lather
Sun Mar 13, 2011 10:23 am

d wrote:
Self-lather wrote:
JayDC wrote:thats what its all about man, glad ur making headway.. next thing to do is to start tweaking out ur riaa curve to get the most out of your head.

I'd also think about putting a fuse on your head so u dun blow the coil..
Umm, wow. Proper eq, turtle wax, and a 100 watt lamp. I've been cutting into Lexan and getting unbelievable results. Now we're talking!

The only thing I notice is there is a low hum that I can hear in the silence. Its only audible when there is silence. I'm grounding the k8, but I think the amp may be introducing this. All the more reason to move to using a different amp.


-Thomas
hey,

i have confused a little bit. as i got from the posting you are cutting lexan or embossing? from the previous posts I thought you have sapphire stylus?
I do have a sapphire tip. It behaves differently than expected when i use Lexan. Technically I am set up to be cutting, and the same setup is definitely cutting when I use a Transco lacquer. But when I use Lexan, it produces no chip at all, so I guess technically I am embossing.

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d
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Post: # 13324Unread post d
Sun Mar 13, 2011 11:22 am

I do have a sapphire tip. It behaves differently than expected when i use Lexan. Technically I am set up to be cutting, and the same setup is definitely cutting when I use a Transco lacquer. But when I use Lexan, it produces no chip at all, so I guess technically I am embossing.
Hmmm... interesting... if cutting face is directed for cutting there must be chip going... Depends on setup. Can you take a picture or youtube a video of cutting? also interesting angle of a head.[/quote]

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Self-lather
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Post: # 13327Unread post Self-lather
Sun Mar 13, 2011 1:20 pm

d wrote:
I do have a sapphire tip. It behaves differently than expected when i use Lexan. Technically I am set up to be cutting, and the same setup is definitely cutting when I use a Transco lacquer. But when I use Lexan, it produces no chip at all, so I guess technically I am embossing.
Hmmm... interesting... if cutting face is directed for cutting there must be chip going... Depends on setup. Can you take a picture or youtube a video of cutting? also interesting angle of a head.
[/quote]

Yeah, it is strange, but it sounds great. I'll see about getting a video up on it embossing onto Lexan. I just need to go buy some more Lexan first.

-Thomas

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d
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Post: # 13328Unread post d
Sun Mar 13, 2011 2:15 pm

heh. nice. in your way it would be cutbosing. let us know about vid.

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emorritt
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Post: # 13329Unread post emorritt
Sun Mar 13, 2011 3:04 pm

Self-lather wrote:
The only thing I notice is there is a low hum that I can hear in the silence. Its only audible when there is silence. I'm grounding the k8, but I think the amp may be introducing this. All the more reason to move to using a different amp.


-Thomas
If your amp is humming, you need to replace the filter stack. But, it could also be motor noise you're hearing. The Presto K series were rim-drive turntables and the thick tire did help squelch most of the drive noise, but the motor is still attached to the turntable deck and some of the noise of just the motor running is transmitted up through the turntable shaft. Also, I've seen some K series recorders with a thin sort of oil cloth looking mat. If you don't have a good rubber mat (or an old dried out one) you might try making one from this material:

http://www.rubbercal.com/Soft_neoprene.html

I've used them for turntable mat materials for different machines and the quality is great.

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