Digitising Vinyls (OT for uk.tech.digital-tv)

Rob wrote:

Well, that's not such a good example because God is a human construct.

WHAT??!! Zillions of Christians, Jews and Muslims around the world
would disagree - they say that humans are a God construct!

Anyway, I'm an atheist, so I think they're all talking ********.

--
SteveT

Strange noise from Dual turntable (but I think I've heard it on the
Project as well).

On certain albums, towards the end of a side, a rumble builds up. The
strange thing about it is that I can make it go away by picking it the
arm and then dropping it back down again, whereupon it slowly builds
back up again.

In this sample, you hear the stylus being dropped into the playout
groove of an LP (quite loud, sorry, but I thought it would be easiest
to have a clear beginning to the process), there's some crackling as
the stylus makes it's way to the innermost groove, then go round and
round the innermost groove many times. As it does so, a low hum, like
a distant didgerido or bittern, gradually builds up.

As it can't actually be recorded in the groove (because then it would
be audible immediately), I presume it is some sort of resonance
building up, but I have no idea whether it is mechanical or
electrical, or what can be done to eliminate it

http://www.macfh.co.uk/PrivTest/Didgerido.wav

Any bright ideas?
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On Sat, 12 Nov 2011 20:34:35 +0000, Java Jive
wrote:

Strange noise from Dual turntable (but I think I've heard it on the
Project as well).

On certain albums, towards the end of a side, a rumble builds up. The
strange thing about it is that I can make it go away by picking it the
arm and then dropping it back down again, whereupon it slowly builds
back up again.

In this sample, you hear the stylus being dropped into the playout
groove of an LP (quite loud, sorry, but I thought it would be easiest
to have a clear beginning to the process), there's some crackling as
the stylus makes it's way to the innermost groove, then go round and
round the innermost groove many times. As it does so, a low hum, like
a distant didgerido or bittern, gradually builds up.

As it can't actually be recorded in the groove (because then it would
be audible immediately), I presume it is some sort of resonance
building up, but I have no idea whether it is mechanical or
electrical, or what can be done to eliminate it

http://www.macfh.co.uk/PrivTest/Didgerido.wav

Any bright ideas?

Sounds like a turntable with a bearing problem. There is a large
constant LF peak just under 13Hz, which I would say is probably due to
a cartridge resonance. Then there is broadband low frequency noise
that pumps in and out at the rotation rate of the record. You can
check this by doing the same test on another disc.

I'm not getting any low hum building up though, it is there all the
time.

d

On Sat, 12 Nov 2011 20:51:11 GMT, (Don Pearce) wrote:

Sounds like a turntable with a bearing problem. There is a large
constant LF peak just under 13Hz, which I would say is probably due to
a cartridge resonance. Then there is broadband low frequency noise
that pumps in and out at the rotation rate of the record. You can
check this by doing the same test on another disc.

Thanks. I'll check the bearings anyway. I'm not too worried by 13Hz,
I can filter that out if need be.

I'm not getting any low hum building up though, it is there all the
time.

Weellll ... all I can say is something is definitely building up as
the stylus goes round and round the innermost groove. The first five
or so times around it's either not there or inaudible, but from about
the sixth it gradually becomes more and more apparent, building up to
a constant level within about five or six more circuits. I've found
it in the trace, and it has about 16 or 32 (depending on which
component you count) wavelengths in about 0.319s, which is about
50/100Hz for the two components - mains hum. But why should mains
hum build up as the innermost groove goes round, and go away when the
arm is lifted off the record?

I've never heard of this one before!

Bl*dy analogue.
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I think it must have been some sort of crosstalk leading to feedback,
hence the gradually rising level.

The deck is right next to, and the USB soundcard is sitting on top of,
the Denon amp. Therefore there is quite a lot of cable slack in the
three cables involved, Deck to Phono In, Tape 2 In and Out to the
soundcard. This slack was laid out between the deck and the amp, so
all three were close together. I put the deck cable slack behind the
deck, and one of the other two behind the amp, and left the third one
where it was, so all three are now separated, and it seems to have
fixed it.

But, b*gger, will have to rerecord some more stuff now!

Earlier today, I also relaid the pick-up arm cabling in an attempt to
improve the tracking - the slack is just dragging across the floor
of the cabinet now - and it seems to have improved things.

I might take a look at the bearing tomorrow. If it needs new grease,
does any body have any idea what sort it should be? I think I still
have some motor grease somewhere, but I presume that might be a bit
too thick.

On Sat, 12 Nov 2011 22:20:21 +0000, Java Jive
wrote:

Weellll ... all I can say is something is definitely building up as
the stylus goes round and round the innermost groove. The first five
or so times around it's either not there or inaudible, but from about
the sixth it gradually becomes more and more apparent, building up to
a constant level within about five or six more circuits. I've found
it in the trace, and it has about 16 or 32 (depending on which
component you count) wavelengths in about 0.319s, which is about
50/100Hz for the two components - mains hum. But why should mains
hum build up as the innermost groove goes round, and go away when the
arm is lifted off the record?
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header does not exist. Or use a contact address at:
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In article , Java Jive
wrote:

Weellll ... all I can say is something is definitely building up as the
stylus goes round and round the innermost groove. The first five or so
times around it's either not there or inaudible, but from about the
sixth it gradually becomes more and more apparent, building up to a
constant level within about five or six more circuits.

The 'rubber' used to hold and damp the stylus can often be nonlinear in its
behaviour. Deliberately so. Makers like Shure used to make suspension
materials whose elasticity, etc, were strong functions of frequency because
of the conflicting requirements for good tracking and minimising HF
resonances, etc.

So it may be that the behaviour of the stylus suspension is taking a while
to adjust to having the stylus dropped onto the LP and the displacement and
force this applies.

No idea, though. Just a guess. But a possible alternative to the more
obvious feedback effects.

Slainte,

Jim

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Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
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Audio Misc http://www.audiomisc.co.uk/index.html

Jim Lesurf wrote:

I sit corrected. Must admit it is mumble years since I read the Alice
books.

Was it the first edition?

Bill

In article , Bill Wright
wrote:
Jim Lesurf wrote:

I sit corrected. Must admit it is mumble years since I read the Alice
books.

Was it the first edition?

Wish I had a copy. :-)

I do have a copy of "Wasp in a wig", though.

Slainte,

Jim

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Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On Sun, 13 Nov 2011 14:46:34 +0000, Bill Wright
wrote:

Jim Lesurf wrote:

I sit corrected. Must admit it is mumble years since I read the Alice
books.

Was it the first edition?

Bill

Ouch.

d

On 12/11/2011 15:06, Don Pearce wrote:
On Sat, 12 Nov 2011 14:23:05 +0000, wrote:

On 12/11/2011 09:28, Don Pearce wrote:
On Sat, 12 Nov 2011 09:19:32 +0000, wrote:

Ah well then that's where you'd be mistaken. I do of course understand
that quite a few people do think digital sounds better than analogue a
lot of the time. It's mildly annoying that quite a few here can't accept
that I prefer analogue.

Why are you not getting this? Nobody here has the slightest problem
with you preferring analogue to digital. It is when you go on
repeating your baseless assertion that analogue is BETTER than digital
that we get irritated. Have you truly still not understood the
difference? I'm finding this increasingly hard to believe, and am
rapidly coming to the conclusion that you are just trolling.


Er. Find one occasion when I have stated that analogue is better than
digital, other than in my opinion. I have never stated that. The
'better' comment was simply a mixture of lost context ('to me') and poor
writing.

In fact, I'd venture to suggest that a good many people wouldn't know
(or care).

Rob

I'm not going to plough through this entire thread, but here are a
couple of your sentences as an example:

"I find that reality is better reconstructed with analogue systems,"


Yes, it's the 'I find' that you seem to miss.

"I'm afraid I still need to know - how does that get anyone closer to
thinking that the analogue sound is, often, a better rendition of the
original performance?"


And here it's the 'anyone' - you appear to read 'everyone'

That'll have to do.


Cant blame you :-)

Rob