HDTenEightyP/NetNews huggingface dataset:
From: tonyb@juliet.ll.mit.edu ( Tony Berke )
Newsgroups: rec.audio.high-end
Subject: MDF is NOT particle board!
Date: 15 Sep 92 13:58:02 GMT
Organization: University of Wisconsin - Milwaukee
Originator: tjk@csd4.csd.uwm.edu
Cc: tonyb@juliet.ll.mit.edu

Perhaps I'm being a nitpicker, and perhaps I'm remembering this
incorrectly, but I'm pretty sure that it is incorrect to refer to
MDF as "just particle board".

Particle board is made of chips of wood bonded together with glue.

MDF is made of wood *fibers* that have been abused in some manner
that I can't recall, then fused together with heat and a huge amount
of pressure.  I believe that the heat, pressure, and abuse result in
the natural sticky-stuff in the wood (pretty technical, huh?) reactivating
and fusing the wood fibers together -- no glue is used.

A few people have mentioned that MDF macines well, and related that to
its density.  It does indeed machine well, but I must point out that
you can get particle board in 80Lb/cu-ft density, and it still doesn't
machine as nicely as MDF.  The difference, as far as I can tell, is
because the re-arranged wood fibers in MDF are of a much more fine-
grained than the glue-encapsulated wood chips in particle board.

I'll go try to look this up in my handy home copy of "Wood Technology"
if people seriously doubt the sanity of this explanation.  Of course,
one might point out that the mere possession of a text by that name
casts even more serious doubts on the sanity of the explainer, but
that's another topic.

Tony
Newsgroups: rec.audio.high-end
From: rogn@telematikk.idt.unit.no (Egil Rognvik)
Subject: Re: CD drive question
Originator: tjk@csd4.csd.uwm.edu
Organization: IDT
Date: Wed, 9 Sep 1992 12:39:35 GMT

In article <1992Sep8.141220.16211@eua.ericsson.se> Jesper.Ullerstam@eua.ericsson.se (Jesper Ullerstam) writes:
>From: Jesper.Ullerstam@eua.ericsson.se (Jesper Ullerstam)
>Subject: CD drive question
>Date: Tue, 8 Sep 1992 21:28:09 GMT

>I have no problems with the fact that different DA-converters
>produce different sound quality. My question concerns the CD
>drive part. I frequently use a CD-ROM player with my computer
>and I know as much about computers that I realise that my
>CD-ROM always must deliver the exact data stored on the disc.
>A CD-ROM is quite cheap if you compare to a high end hifi
>CD-drive. If the CD-ROM delivers the exact information,
>why can't you build a hifi drive that does the same thing, at
>the same price? Do they use different methods for reading the
>data? I'm interested in any information related to this subject.

There's more error correction recorded on the CD-ROM, and the CD-ROM can re-
read the data to if it isn't correct the first time. This makes it easier for
the CD-ROM to present perfect data to the computer.

But:
I've been experimenting with my NAD 5420 (low priced CD). I've connected a 
computer to the Digital Signal Processor. This DSP has got outputs which 
tells how many errors are corrected and how many interpolations are done.
I've counted the errors for different CDs, and found that different CDs 
give from 0 to about 4000 interpolations in 15 minutes (80.000.000 samples).
The results are the same with the famous green pen (which started my 
experimenting). One thing I noticed, though, is that the CD player performs 
better when it has gotten time to warm up (15 to 30 minutes). The error rate
is about 10 to 20 % higher when the player is cold. This may be because the 
lubricants perform better when the player is getting warm.
I also tested (for a friend) a free CD that comes with a classical magazine.
This CD gave about 800.000 interpolations in 74 minutes! This is real bad, 
but I really can't tell if it sounded bad...

So I would say that a reasonable CD drive will give you a near perfect 
reading of a normal, unscratched, center-hole-within-spec CD.

Given a little buffering (and there always is) the drive should be able to 
feed the DAC with almost perfect samples.

If anyone wants to see the exact figures from the testing I'm willing to 
post it.


egil

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Egil Rognvik                                * egilro@idt.unit.no
The Norwegian Institute of Technology       * rogn@telematikk.idt.unit.no
Division of Computer Systems and Telematics *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

Newsgroups: rec.audio.high-end
From: matthews@eecs.ucdavis.edu (Thomas W. Matthews)
Subject: Re: Celestion SL6S Port recommended
Originator: tjk@csd4.csd.uwm.edu
Organization: Division of Electrical Engineering and Computer Science, UC Davis
Distribution: rec.audio.high-end
Date: Fri, 11 Sep 1992 17:39:11 GMT


I agree that a tuned port (also called "bass reflex") can often be 
the best compromise for a given driver and enclosure volume.

Bear in mind, however, that a ported enclosure adds a low-Q
resonance to the system's response.  The effect of this resonance 
is that the energy radiated by the port is approximately
in phase with the energy radiated by the driver for
a particular range of frequencies.  If that range is
carefully chosen, the port can extend the low-frequency response
of the system.  However, below a certain frequency range, the 
energy radiated by the port is more out of phase with the energy
radiated by the driver; at very low frequencies the port does 
not help, it hurts.  If the port is helpful at all frequencies
of interest (above the designed low cut-off frequency), then
its use involves no compromise.

The subsonic motion you observe is possible because 
the stiffness of the air in the enclosure is no longer
restricting the cone's motion, but the system is probably
not an effective radiator at those frequencies.

An analogy can be made to high-pass filters, where a sealed
enclosure might be well modeled by as first-order response
with some -3db frequency and a ported enclosure might be 
modeled by a second order filter with a lower -3db frequency
but with a steeper slope.  

It may well be that the right port helps a particular speaker,
but in general the choice to port or not depends on many
of the design parameters.

Happy listening!

Tom Matthews

Newsgroups: rec.audio.high-end
From: europe@europe.corp.sgi.com (Patrick Renvoise)
Subject: DIY Power conditioners, Tips?
Originator: tjk@csd4.csd.uwm.edu
Organization: Silicon Graphics, Inc.
Date: Tue, 8 Sep 1992 21:22:26 GMT

As every body knows power line conditioners sell for $300 to $500 and a lot of people have mentioned here that they are easy and cheap to build, so I am asking the following:
* Where I can by the isolation transformers? Which ones are recommended? Price?
* I have a transport, D/A, pre-amp and amp  do I need to buy 4 transformers?
* How do I measure the VA required for (each, the) transformer(s)? The power comsumption is not available in the doc, and inserting a voltmeter serially on the power cord is not easy.
* Do we need any kind of filters? EMI filters, RFI filters? Where to get them, at which price?
* Are fuses recommended?
* Is there any schematics available somewhere?

Your inputs would be greatly appreciated. I will be posting a summary of what I received?

-- 
Patrick Renvoise  Tel (415)390-3525 Fax (415)961-0573
Silicon Graphics International Marketing
/----------------------------------------------------------------------\
| "Il faut cultiver notre jardin." Voltaire (last phrase of Candide)   |
| "It is necessary to cultivate our garden." (1st level translation)   |
\----------------------------------------------------------------------/




Newsgroups: rec.audio.high-end
From: jreiser@skidmore.EDU (jason reiser)
Subject: Re: What is MDF?
Originator: tjk@csd4.csd.uwm.edu
Organization: Skidmore College, Saratoga Springs NY
Date: Fri, 11 Sep 1992 17:40:29 GMT

piscine@rs1.tcs.tulane.edu (henry bart) writes:
> I've seen many references to MDF for stereo racks, etc.  I would like to build
> my own rack but don't know what MDF board is or what MDF stands for.  Is MDF
> available through regular lumber supply houses?
> 
> Thanks....
> 
> 
> 		Mike
> 
> 

Mike, 
	MDF stands for Medium Density Fiberboard.  It is a fiberboard
(by definition) with a density of approx. 49 pounds per cubic foot.  A
lot of lumber places might look at you funny when you say MDF, but if
you let them know what density you need... it shouldn't be a problem.


				- Jason
From: jas@proteon.com (John A. Shriver)
Newsgroups: rec.audio.high-end
Subject: CD drive question
Date: 15 Sep 92 13:53:56 GMT
Organization: University of Wisconsin - Milwaukee
Originator: tjk@csd4.csd.uwm.edu
Cc: daver!cypress.com!ssr@decwrl.dec.com

I think I agree and disagree with Bapcha.

Agreements and reinforcements first:

First, CD-ROM drives are different from audio CD drives in ways that
don't really matter for audio.  First, the best ones can run at higher
data rates than the audio ones.  This is not easy, the three servos
(focus, radial, and rotational) have to remain accurate while tracking
much faster.  This is not easy (the surface roughness of a CD is 10
times greater than the depth of focus of the laser), and drives up the
cost at no benefit to audio.  Indeed, the faster servos may not be as
stable at the slower audio rate, and may modulate the power supply
more.  This is turn can muddy the SPDIF clock, if that chip runs off
the same supply.

Second, error rates are not the reason for "CD sound".  Even at
300,000 errors per disk, that's well under 0.1% errors.

Now the disagreements:

People who are concerned with clock jitter in digital audio are not
idiots.  It's a real problem.  Your semiconductor neighbors over at
Crystal Seminconductor make real products that solve real problems,
like the CS8412 input chips for D/A converters.

Crystal's first jitter eating chip was for the 802.5 token ring, which
uses almost exactly the same encoding as SPDIF and AES/EBU.  This chip
solved very real jitter problems, which can be caused by unequal rise
and fall times in the digital data transmission.  After 100 clock
regenerations by the nodes in the ring, the jitter can be 15 bits,
that is a bit is 15 BITS early or late!  Now, head to tail clocks are
not a problem in CD, but the underlying causes are still there.
(Although digital tape copies can accumulate clock jitter in exactly
the same way as the 802.5 ring.)

Here, the CD-ROM is very different from audio.  Most current D/A boxes
really really care when the next clock transition is in the SPDIF data
stream.  Any change in this timing has a measureable affect on the
output waveform.  The 1's and 0's are correct, but their timing is far
more critical than in computers.

Hopefully, chips like the Crystal chip will make this a thing of the
past.  I hope so, the industry needs to invest the design smarts to
make $5000 CD transports an anacrhonism.  Crystal is doing their part,
D/A designers not using it (or something similar) aren't.

When D/A boxes are designed right, a $100 transport will be good
enough.  $5000 transports are a miguided band-aid.
Newsgroups: rec.audio.high-end
From: sliberm@nyx.cs.du.edu (Sergio Liberman)
Subject: stands for Celestion SL6si
Summary: what's the difference between heavy and ligh stands?
Originator: tjk@csd4.csd.uwm.edu
Keywords: speaker, stands, Celestion
Organization: University of Denver, Dept. of Math & Comp. Sci.
Date: Tue, 15 Sep 1992 13:59:45 GMT


I have a question regarding the kind of speaker stands which
are appropiate for the Celestion SL6si speakers.

I have a pair of the above mentioned speakers, seating in a pair
of Celestion 24" Si stands, the manufacturer recommended stands
for the SL6si. The booklet says to fill the stands with heavy
shot and sand. I also read a review in the British Hi-Fi Choice
magazine stating the importance of using heavy stands (15kg or more)
for these speakers.

Before going to all this trouble of getting the materials, I would like
to hear from somebody that have tried it, and get some pointers regarding
the proportion of sand to shot, how many kg, is it worth changing the
stands for heavier ones, etc. And of course, has the sound improved? 8-)

For the record, the rest of th system is as follows: Audiolab 8000
integrated amp, Rotel 965BX CD player, Monste Interlink 550 interconnects,
Denon DRM800 cassete deck, Monitor PC 6 sq. mm speaker cable, Stax
Lambda Pro with battery operated amp. The system is in a fairly small room,
about 4m x 3.5m.

Thanks,
Sergio Liberman
sliberm@nyx.cs.du.edu
sergio@msil.sps.mot.com


Newsgroups: rec.audio.high-end
From: rsd@sei.cmu.edu (Richard S D'Ippolito)
Subject: Re: Tube sources
Originator: tjk@csd4.csd.uwm.edu
Organization: The Software Engineering Institute
Date: Tue, 8 Sep 1992 21:28:17 GMT


In article <9209030534.AA02737@spider.ento.csiro.au>, Peter Campbell writes:
|> 
|> Dan Kester asks various questions about tubes.  I am fairly new to this too
|> but will pass on what I have gathered.
|> >
|> >Is there a difference between 12AX7 and 12AX7A?

|> I'm told it is a small internal mechanical improvement- not something to
|> worry about.


It depends on your point of view -- the "A" version has "controlled" noise
and hum characteristics, having an average of 1.8uVRMS (10KHz bandwidth)
refered to the grid.  Note that this is narrow by an octave and only 60dB
below a typical phono source in the millivolt range.  Furthermore, the number
is essentially meaningless as the spectrum is not given.  I wouldn't suggest
either device for low noise applications.


Rich


   "Please keep in mind that the ultimate goal [of hi-fi] is the
   reproduction of art, and that the invocation of science, while a neat
   parlour trick, is often unnecessary, flawed, and unreasonable."
   --  name mercifully withheld...                            rsd@sei.cmu.edu

Newsgroups: rec.audio.high-end
From: wyatt@othello.fnbc.com (Wyatt Sutherland)
Subject: Re: Newbie Needs Help....
Originator: tjk@csd4.csd.uwm.edu
Organization: First National Bank Of Chicago, Chicago IL, USA
Date: Thu, 10 Sep 1992 12:56:25 GMT

In article <Bu9xCL.5rs@news.cso.uiuc.edu> wem53067@uxa.cso.uiuc.edu (The  
Bard ) writes:
> Ok, here is the problem. I've owned various junk Sony stuff in the past,
> but I believe it's time for me to move up in the audio world.
> The Problem is, that although I've gone and aditioned a bunch of
> equipment, my newbie ears are overwelmed with what they hear. 

Well $5K is a lot to spend.  Here is my suggestion.  You live in a state  
that has one of the world's greatest orchestra.  The Chicago Symphony  
Orchestra.  Let's say you attend a concert every 2 weeks.  You will be  
able to hear app. 15 concerts ( the CSO also has vacation time, and  
Ravinia isn't the greatest place to hear a concert ).  Let's assume that  
you would pay $25 a ticket - you can pay less and get a better sound up in  
the crows nest.  If you go by yourself you could hear the CSO in Orchestra  
Hall for 13+ years, or you could take a friend and enjoy almost 7 years of  
live, punchy brass in a rich hall.  Taking in account that you probably  
are young and likely to climb into a more comfortable income bracket, you  
will then be able to afford a better system, and you will have educated  
your ears.

By the way Champaign-Urbana has a very good hall, and the CSO records  
someplace in or near your stomping grounds.  I know that great artists  
travel through your area.  Also if you want great opera at an affordable  
price, go to Indiana University in Bloomington, Indiana.  Members from the  
Met in N.Y. attend opera rehearsals and concerts in Bloomington, IN.

You'll also be supporting the arts, which need more of our support  
especially in these financially turbulent times.

Just some suggestions.

Good Luck.
Wyatt

wyatt@jupiter.fnbc.com

Newsgroups: rec.audio.high-end
From: tivoli!lendy@cs.utexas.edu (Lendy Dunaway)
Subject: FOR SALE: Various Equipment
Originator: tjk@csd4.csd.uwm.edu
Reply-To: tivoli!lendy@cs.utexas.edu (Lendy Dunaway)
Organization: Tivoli Systems Inc., Austin, TX
Distribution: na
Date: Mon, 14 Sep 1992 12:58:23 GMT



Audio Equipment for sale:

	Audio Research:
		1 pr. M-300 mk II hybrid mono amps.
		1 SP-11 mk II hybrid preamp.
		1 pr. 3 meter speaker cables.

	Duntech:
		1 pr Crown Prince speakers.

	Denon:
		CDC-3300 CD player.

	ADS:
		2 PB-1500 dual 10" self powered 100 watt
		stereo sub-woofers with electonic cross-overs.

	Luxman:
		PD-1000	vacuum stablized turn table with
		vacuum pump and signet #35 tone arm.

	Yamaha:
		DSP-3000 Digital sound processor.

	Adcom:
		2 GFA-535 55 watt stereo amplifiers.

	DBX:
		3-BX dynamic range extender.
		21 dbx noise reduction decoder.

All equipment was purchased new by me. Original packing and
owners manuals available. Details available on request. Serious
inquires only. Please contact me by email or telephone.

Lendy Dunaway
lendy@tivoli.com

hm. (512)335-1565
wk. (512)794-9070

Newsgroups: rec.audio.high-end
From: daver!cypress.com!ssr@decwrl.dec.com (Bapcha/FPGA)
Subject: Re: CD drive question
Originator: tjk@csd4.csd.uwm.edu
Organization: Cypress Semiconductor, San Jose, CA
Date: Fri, 11 Sep 1992 17:39:56 GMT

In article <1992Sep9.090412.4048@bristol.ac.uk> P.Smee@bris.ac.uk (Paul Smee) writes:
[misc stuff deleted]
>reason.  With audio CD, on the other hand, it is the drive which is
>responsible for making sure that everything happens once, in the right
>order, and at the right time.

I am sure that this idea was put in your head by the idiots who write
about clock jitter in the magazine 'Stereophile'.  In digital circuit/
peripheral design (with the exception of magnetic tape drives and EPROM
programmers,  you get 1 ONE chance to read/write the data correctly.
All associated circuits are expected to work - irrespective of marginal
shifts in clock,  etc......  Soo.....  I am sure that CD ROM drives read
the data correctly with an MTBF (mean time between failiure) of 4 years
to 5 years.


>
>(Note that most of this could be dealt with by putting, say, a
>1Megabyte cache RAM between the CD-ROM and the digital output, to
>smooth out any variation in the drive's reading speed.  I note that
>Sony plan to do this in their mini-disk players, and keep wondering why
>no one seems to want to apply this approach to CD.)

Looks like SONY has done that with their latest portable CD player (I 
forget the model number).  Retails at around $450,  and has 3MB of cache.
It is a regular portable CD player and not an MD player.... I saw it in
the J&R Radio catalogue.....



-- 
Bapcha - A very bad boy from Cypress Semiconductor
3901 N.  First Strasse
San Jose,  CA 95134, 408-943-2719
From: Guha@mcc.com (R. V. Guha)
Newsgroups: rec.audio.high-end
Subject: Help with Power-amp hum
Date: 15 Sep 92 13:57:21 GMT
Organization: University of Wisconsin - Milwaukee
Originator: tjk@csd4.csd.uwm.edu



I recently bought a pair of used Krell KMA-100 amps and am experiencing
a problem with one of them. There is an extremely irritating hum (at
around 50-60 Hz) that it produces (through the speakers). The noise
persists even when the preamp is switched off. The problem is not with
the mains (I tried the other amp with that outlet and it works fine) or
the speaker (the problem persists even on changing speakers). The volume
of the hum is independent of the music level.

Interestingly, placing a weight on top of the other amp causes it too to
hum. Otherwise, there is nothing sitting on either of the amps.

Any suggestions/help would be appreciated.

Thanks

Guha
Newsgroups: rec.audio.high-end
From: Eric Meyhofer <em3j+@andrew.cmu.edu>
Subject: FOR SALE: Daniel II Line Stage
Originator: tjk@csd4.csd.uwm.edu
Cc: Eric Meyhofer <em3j+@andrew.cmu.edu>
Organization: University of Wisconsin - Milwaukee
Date: Thu, 10 Sep 1992 12:56:02 GMT
          ID </afs/andrew.cmu.edu/service/mailqs/q003/QF.IefXNDi00YV7M0jGsS>;
          Wed,  9 Sep 1992 13: 37:20 -0400 (EDT)
          ID </afs/andrew.cmu.edu/usr13/em3j/.Outgoing/QF.cefXN6600YV744CYxA>;
          Wed,  9 Sep 1992 13: 37:10 -0400 (EDT)
          via MS.5.6.t-pcs1.acs.cmu.edu.pmax_ul4;
          Wed,  9 Sep 1992 13: 37:10 -0400 (EDT)

Is anyone in the market for some of the best High-End equipment made at
any price?  Daniel II Line-stage with a Daniel II 2-way crossover in a
lexan case (a work of art).  If you are interested in seeing, hearing,
or purchasing do not E-mail this account but call (412) 727-7901 and
ask for Dennis.


Newsgroups: rec.audio.high-end
From: andrew@alice.att.com (Andrew Hume)
Subject: Re: Corey's Buffered Preamp
Summary: errata & addendum
Originator: tjk@csd4.csd.uwm.edu
Article-I.d.: alice.23647
Organization: AT&T Bell Laboratories, Murray Hill NJ
Date: Thu, 10 Sep 1992 12:56:32 GMT



	let me cover some errata and missing information.

	firstly, my comment about a cheaper BUF-03 should have said
get the BUF-03FJ, not the AJ. (For those who care, the BUF-03s
come in two classes distinguished by slightly different specs
but most noticeably DC offset and bandwidth; class 1 is
the AJ (milspec) and EJ (the one i used), and class 2 is
the BJ (milspec) and FJ (the cheapest).)

	secondly, the lovely enclosure came from graybox
(actually lansing instrument) at 800-847-3535 (usa and canada).
they are friendly to individuals too (ship and invoice).

	thirdly, i run the BUF-03s at 15V supply rails.
greenberg's article says 18V but this was repudiated later
by both Galo and a honcho at PMI (who makes the BUF-03);
thebottom line is that the buf-03 was designed for 15V rails
and the 18V is the absolute maximum and there is thenormal
warning about reduced lifetime/reliability if you run the
device at its maximum ratings for extended periods.


			andrew hume

Newsgroups: rec.audio.high-end
From: yoda@deathstar.stanford.edu (Terry Lee)
Subject: Re: McIntosh Dilemma
Originator: tjk@csd4.csd.uwm.edu
Organization: Residential Computing, Stanford University
Date: Thu, 10 Sep 1992 12:55:46 GMT

In article <18bqtjINNko6@agate.berkeley.edu> ereiss%ocf.Berkeley.EDU@ucbvax.Berkeley.EDU (Edward Reiss) writes:
>I recently acquired a used McIntosh 117 preamp/tuner.  My original intention
>was to purchase a new McIntosh amplifier, and build a system around these two
>components.  The preamp is solid state and so is the amplifier that I am
>considering purchasing (A discontinued model (754) now available for approx
>$700).  Now I'm having second thoughts and wondering if I could get better
>value by selling the preamp and buying different brand components.  This being my
>first excursion into high end audio, I would appreciate any and all opinions
>about the quality of the McIntosh models in question and any alternative 
>routes that I could take.  

Look no further.  I assume you are getting the 754 at House of Music.  It's
an amazing deal.  It is just the most amazing thing I've ever heard in that
price range.  Also I'd buy it just for the name.  At $700, you could sit on
it for a couple of years and still get your money back.  I mean it's amazing
that over 10 year old solid state equipment by McIntosh still sells for
hundreds, even thousands of dollars.  You can't beat McIntosh for reliability
and resale value.  And heck, it sounds better than anything I've ever heard.

Terry Lee


Newsgroups: rec.audio.high-end
From: kaplan@unamas.esd.sgi.com (Larry Kaplan)
Subject: FOR SALE: Martin Logan Speakers
Originator: tjk@csd4.csd.uwm.edu
Organization: Silicon Graphics, Inc.
Date: Fri, 11 Sep 1992 17:40:18 GMT


For Sale - One pair Martin Logan Sequel II Speakers.

Perfect Condition. $1700 firm. Call Mike at (510) 820-8503

-- 
  Larry Kaplan  (415)390-1584 Silicon Graphics, Mtn View, CA 94039 USA



Newsgroups: rec.audio.high-end