Disk Cutter

[jtwrace]

Does anyone own one of these? It's a different concept. Wonder if it really works....

http://www.audiodesksysteme.de/index.php?kat=10_17_6

 

[SugarMedia]

Does anyone own one of these? It's a different concept. Wonder if it really works....

http://www.audiodesksysteme.de/index.php?kat=10_17_6

Here's a thread that covers some of that.

http://www.martinloganowners.com/~tdacquis/forum/showthread.php?t=1365&highlight=shine+ola

 

[Beat_Dominator]

Depending on the transport that you have in your CD player, the AudioDesk has some interesting upsides. If you rub your finger around almost any cd you will feel lumps created by the machine that pressed the CD. These lumps of course would cause the CD to not be perfectly round and imbalanced when spinning at several hundred RPM in the transport. I can hear the vibrations caused by these imbalanced disks, so the idea of using a lathe to make the disks more perfectly round to improve performance of a digital player seems scientifically sound to me

I have never used the Auto Desk though so I cannot say how well it works.

 

[HsvToolFool]

A lathe, eh? I have a mini-lathe used for pen turning,
and a big lathe for everything else. Might have to bring
that mini-lathe indoors and spin a few CDs.

On the other hand, I've never had a factory CD that
wouldn't play in a DiskMan. I've never felt vibration from
a disk spinning inside such a light-weight player either.
Unless the disk's center hole was punched grossly off-
center, I suspect a small mass of extra plastic on the rim
makes no difference. It's digital; and in this instance,
either the disk plays or it doesn't.

Which reminds me, are tweakers still painting the edges
of their CDs to prevent red laser-light "leaking" from the
edges?

 

[Beat_Dominator]

A lathe, eh? I have a mini-lathe used for pen turning,
and a big lathe for everything else. Might have to bring
that mini-lathe indoors and spin a few CDs.

On the other hand, I've never had a factory CD that
wouldn't play in a DiskMan. I've never felt vibration from
a disk spinning inside such a light-weight player either.
Unless the disk's center hole was punched grossly off-
center, I suspect a small mass of extra plastic on the rim
makes no difference. It's digital; and in this instance,
either the disk plays or it doesn't.

Which reminds me, are tweakers still painting the edges
of their CDs to prevent red laser-light "leaking" from the
edges?

Interesting points! I have some VERY poorly balanced CDs, maybe they melt in the Arizona heat

The only thing I would point out is that you say "It's digital; and in this instance, either the disk plays or it doesn't." That's true to a point, but with error correction and the algorithms used when re-reading the disk doesn't produce a readable bit the player may use a "guess" as to what the bit would have been. I've read some things that say a CD will not audibly skip or pause with an unreadable string of bits that's almost 2mm long!

So in the quest to maximize the accuracy of the pickup and thus gather all of the information on a CD, I still think a lathe poses some possible benefits. Test out your pen lathe and tell us what happens!

 

[HsvToolFool]

That's true to a point, but with error correction and the algorithms used when re-reading the disk doesn't produce a readable bit the player may use a "guess" as to what the bit would have been.

I was assuming that the center hole is off by at least one
spiral so that the disk skips-track each rotation. Otherwise,
I just don't see the lop-sided mass being large enough to
affect balance. Latheing such a disk would correct the
balance, but would not correct the spiral alignment. So the
disk still wouldn't play.

Test out your pen lathe and tell us what happens!

I've got some scrap chunks of acrylic which should make a
good DIY chuck for CD balancing. I'll bring my mini-lathe
inside where it's warm and see if I can't make a mess.

The main benefit I expect is extending the life of the CD
transport. Now that I've finally invested in a quality player,
this is more important to me than before.

 

[Tj Bassi]

Interesting thread.....but I wonder if your mini lathe will be as good as, or *better* in concentricity than the machine that originally pressed the CD. Just for kicks, I arbored up a few blank CD's on an expanding mandrel held in a good Hardinge collet, and found no CD that was worse than .0002 (thats two ten-thousandths, folks). The Hardinge collet iself is typical .0001 runout itself. Assuming there would be .0001 of offset material, I tried to take a cut but didnt find any material coming off of the bit.
Truth be told, my SB10 isnt usually called on to hold tolerances better than .0004~5, and thats only for turning shafts with specific fits. I have access to a Hardinge second-op lathe thats much tighter....I'll have to see if it does better with the discs.
T-

 

[Tj Bassi]

I just re-read the link to the CD sound improver and they talk more about bevelling the edge of the disk as opposed to actually truing up the outer circumference. I dont follow the logic to the bevelling trick.......

T-

 

[HsvToolFool]

Interesting thread.....but I wonder if your mini lathe will be as good as, or *better* in concentricity than the machine that originally pressed the CD.

Good point. Your metal lathe is much more accurate than
any woodworking lathe; generally an order of magnitude
worse than the 0.0002 spec you posted.

When I get a disk that makes out-of-balance noises in the
transport, I've always suspect it's because of a misfeed.
The mechanism didn't quite clamp the disk properly.
Ejecting and closing again usually solves the issue.

I dont follow the logic to the bevelling trick...

I agree. A beveled edge is nonsense... unless you enjoy
paper cuts.

 

[Tj Bassi]

I'm sure there are some 'lumpy' CD's out there that would benefit from some truing, I just dont see how a little $700 machine has the ability to get it done. It might bevel the edges just fine, but to what concentricity?

T-

 

[Rich]

I give this tweak about as much credence as I give any other $600 audio tweak that is designed to "fix" a problem that 99.9% of people never new existed. I'm sorry, but I just don't buy the idea that you can hear variations in the digital bit stream caused by miniscule differences in the edge condition of the CD. I own almost 2000 CDs, listen to them on a regular basis on a high end system, and have never had a problem with this. I think your listening pleasure would be much better served by spending that money on more CDs than on this audio tweak. Just my opinion, of course. YMMV.