HDTenEightyP/NetNews huggingface dataset:
From: peterca@ento.csiro.au
Subject: Component matching
Originator: tjk@csd4.csd.uwm.edu
Organization: University of Wisconsin - Milwaukee
Date: Thu, 27 Aug 1992 13:04:18 GMT

Over the last few isssues their have been various comments about the sound
of this preamp (active or passive) with that power amp, often with the
observation that the bass or high frequencies are better or worse.  I
suspect that in some cases the explanation is simple and one that should be
pointed out to novices.  As an example: My preamp has an output impedance
of 2.4 Kohms which is higher than usual.  My power amp has on its input an
RC filter (1Kohm in series with the input and then 1nF to ground).  This
power amp was designed on the assumption that it would be driven by a
preamp with an output impedance less than 1Kohm.  The input filter would
remove signal above about 150KHz to prevent slew induced distortion but
would be safely away from the audio range.  However with the extra 2K4 in
series with this filter it filters from 50KHz.  With a passive preamp the
output impedance may be higher still leading to a loss of the high
frequencies.  Perhaps this accounts for the observation that some systems
prefer the "hotter" signal from an active preamp whereas other systems
benefit from the removal of extra components in the signal path using a
passive preamp.  I reduced the capacitor in the filter to 330pF to
accomadate the approxamately 3fold higher resistance component of the
filter due to my preamp. 
At the other end of the spectrum, preamps and other components often have a
coupling capacitor on their output (My preamp has 0.47uF).  The load
resitor on the input of my power amp is 100Kohms. The forms a CR high pass
filter which is a few db down at 20Hz -not a big problem but I will
parallel the capacitor with another the same and the combination will be
sloping off an octave lower.  With my other power amp this would not have
been a problem because its input impedance is 1megohm.
Manufacturers of commercial equipment will often save the hassel by using
electrolytic coupling capacitors with large values to avoid the loss of
bass in unusual combinations but this is a compromise in sound quality
compared to using smaller, good quality film-type capacitors.  You can use
better components but you need to do the sums for the combinations you plan
to use.  Also remember this may provide a rational answer to some of the
apparent paradoxes of component matching.

----------------------------------------
Peter Campbell
C/O Div. Entomology, C.S.I.R.O.
Box 1700 Canberra A.C.T. 2601
Australia  (peterca@ento.csiro.au)
Ph.61-6-2464158 (w), 61-6-2516213 (h)
----------------------------------------


Newsgroups: rec.audio.high-end
From: chrisc@gold.gvg.tek.com (Chris Christensen)
Subject: Re: Component matching
Originator: tjk@csd4.csd.uwm.edu
Organization: Grass Valley Group, Grass Valley, CA
Date: Fri, 28 Aug 1992 13:03:23 GMT


The topic discussed, in depth:  measures one person did to better
"match" components of a Hi-Fi system.

It never ceases to amaze me that manufacturers continue to design
output and input circuits in the manner described.

In the rest of the world of audio it is simple. The output stage is
low impedance and the input impedance is high.

Equipment designed with those simple guidelines will interface with minimun 
interaction and maximum transmission of sound.

The low output impedances would be great for the purist who wanted to
use a truely passive preamp.

Low output impedance= 100 ohms

High input impedance= 10k ohms or better.

Can anyone explain, in technical terms,  why it would be necessary or
desirable to use a scheme different from what I have and do use?
-- 
Chris Christensen                  The opinions I express are my own,
chrisc@gold.gvg.tek.com            and sometimes they are wrong!
916-478-3419 FAX 916-478-3887      After all, I *AM* only human.

Newsgroups: rec.audio.high-end
From: martin frederic melhus <mfm0@midway.uchicago.edu>
Subject: Re: AVA Fet-Valve CD Player
Originator: tjk@csd4.csd.uwm.edu
Organization: University of Wisconsin - Milwaukee
Distribution: wi
Date: Tue, 1 Sep 1992 12:55:16 GMT


I am interested in comparing the AVA Fet-Valve CD Player with
the Creek CD-60.  I own the Creek unit, and would like to
avoid the 10% restocking fee if the AVA unit isn't up to 
snuff.  Is there anyone in the Chicago area with their own
(or someone else's) AVA Fet-Valve CD player?  I would be
happy to go to you, or have you come to me; whatever is easiest
for you.  Please contact me via e-mail at
mfm0@midway.uchicago.edu if you are interested.

Naturally, I will post a review if I get to do the comparison,
so if you are interested in this and know somebody with the
AVA player, please contact them with this offer.
----------

                          | You have all the time from when you remove the |
     Martin F. Melhus     | card(s) from your hand until you put it (them) |
 mfm0@midway.uchicago.edu | on the pile to say "Last Card".  If you don't, |
                          | take your two. - Hidden texts, Book of MauMau. |

Newsgroups: rec.audio.high-end
From: zaphod@ctrg.rri.uwo.ca (Lance R. Bailey)
Subject: looking for old tube tuner
Originator: tjk@csd4.csd.uwm.edu
Reply-To: zaphod@ctrg.rri.uwo.ca
Organization: University of Western Ontario
Distribution: na
Date: Thu, 3 Sep 1992 12:58:47 GMT


I have a stereo comprised of pieces which i consider to have affected, or
greatly influenced the path of audio (cf. LP12, ESL, B77...) but I am 
missing a tuner. 

I would like to get my hands on a heathkit tube tuner. The 60's and 70's DIY 
scene would not have been as it was if not for those old heath kits.

I found one, but the noise from it was so bad, that stations could not be
heard. It was pretty rusty (yes RUSTY), but i was unwilling to completly 
disassemble and rebuild just in case bad tube connexions were the problem.

If anyone has one with which they are willing to part, then we should chat.
thank you.
--
Lance R. Bailey  System/Network Manager         Robarts Research Institute
     NeXT/email: zaphod@ctrg.rri.uwo.ca    box: Clinical Trials Resources Group
            fax: +1 519 663 3789                P.O. Box 5015, 100 Perth Dr.
            vox: +1 519 663 3787 x4108          London, Canada N6A 5K8
This package contains one (1) electronic message. Do not eat.

Newsgroups: rec.audio.high-end
From: biesel@javelin.sim.es.com (Heiner Biesel)
Subject: Re: Leaking Cap and Dirty Pot
Originator: tjk@csd4.csd.uwm.edu
Organization: Evans & Sutherland Computer Corporation
Date: Fri, 28 Aug 1992 13:00:55 GMT

redfreak@ecn.purdue.edu (Thomas Lobonc) writes:
>Last night I was looking inside my Counterpoint SA-1 (old!) preamp,
>and I discovered a whiteish crystalline lump growing out of the end
>of one of my capacitors. The capacitor said: Sprague Atom TVA-1716
>80uF-450VDC 85(deg)C 7904L USA 5205. The cap is bypassed by two 
>Rel-Caps (3 in parallel), of .10uF and .001uF. There are two of these
>cap units in the preamp, located near the power supply regulation and
>caps on the PCB.

>If anyone could answer my questions, I would appreciate it.

>1. What is leaking?

The electrolyte.

>2. Where can I find a replacement cap?

Most any electronics store, including Radio Shack. Since this 
component is almost certainly part of the power supply, most any
equivalent component (i.e. same or higher capacitance, same or
somewhat higher voltage rating) will do OK.

>3. Could this have caused any damage to other parts?

Unlikely, unless the electrolyte spilled on them, or if the capacitor
shorted out.

>4. Should the bypass caps still be OK?

In all likelihood.

>5. Would it be worth it to replace with a higher grade cap?

If it makes you feel better to know that you have the greatest
dielectric in the world right there in your power supply filter
capacitors, do. It won't affect the sound, though.

>6. Is anyone familiar with this circuit (what do these caps do)?

I don't have a schematic for your circuit, so I'm guessing. Capacitors
of the rating you specify (80 mfd @ 450VDC) are usually used as part
of the filtering of the rectified AC coming from the bridge. They
store charge, smoothing out the pulsating DC. Their capacity affects
both the hum level of the system, and the headroom of the amp. Going with
a bigger unit won't hurt.

>My volume pot is noisy and loose. I was thinking about cleaning or
>replacing it. The pot says: A.B Nod Pot A-100k 70P1N0485104A.

Try cleaning it first. If you replace it, get a high-quality unit.
Allen Bradley (the A.B. on the pot) apparently no longer makes pots.
Clarostat has taken over some of their lines. Just make sure the resistance 
is the same, as is the taper. Mechanical fit is essential, of course.

>7. Is this a good pot?

I don't know.

>8. How can I clean it?

Spray cans of cleaners for pots and such are available from most electronics
supply houses.

>9. Where can I get a replacement?

If you have to find a replacement, try calling Allen Bradley first; they
may still stock some, or be able to suggest a direct replacement. If not,
remove the pot, measure its taper, and select a suitable replacement from
an electronics supplier like Newark, or Allied.

>10. Does anybody know of any mods other than the 2 factory updates that
>    can be done to this preamp?

No info.

Regards, 
       H. Biesel

Newsgroups: rec.audio.high-end
From: Jon.Fairbairn@cl.cam.ac.uk (Jon Fairbairn)
Subject: Re: Driving ELS Directly
Originator: tjk@csd4.csd.uwm.edu
Reply-To: Jon.Fairbairn@cl.cam.ac.uk (Jon Fairbairn)
Organization: U of Cambridge Comp Lab, UK
Date: Mon, 31 Aug 1992 13:13:39 GMT
          id <sg.13078-0@ben.uknet.ac.uk>; Sat, 29 Aug 1992 14: 57:52 +0100
          id <10534-0@eros.uknet.ac.uk>; Sat, 29 Aug 1992 14: 57:49 +0100
          with SMTP (PP-6.2) to cl; Sat, 29 Aug 1992 14: 57:34 +0100
          Sat, 29 Aug 92 14: 57:28 BST

I didn't see the original posting in this series, so apologies if I'm repeating
something already said.

The idea of driving ESL*s directly raises the interesting possibility of
driving the individual rings of a QUAD ESL63 from separate amplifiers. This 
would eliminate the analogue delay line and its associated phase shifts.
Instead one could take the digital signal direct from the source, put it into
a digital delay line tapped at the appropriate places, feed each of the 
taps into a DAC followed by a 5.25kV amplifier and drive each ring
individually.

I've been amused by this idea for a while.  The ESL63s are already pretty
good for detail -- what could this monster do?

Mind you, since there are five rings and an inner (I think) that means
six DACs and six high voltage amplifiers (all doubled up for stereo, of
course).  So somewhat outside my price range!


________________

* QUAD uses the initials in that order: Electro-Static Loudspeaker.
From: denio@scubed.scubed.com (Dennis O'Neill)
Newsgroups: rec.audio.high-end
Subject: article on audiophiles
Date: 4 Sep 92 14:06:07 GMT
Organization: University of Wisconsin - Milwaukee
Originator: tjk@csd4.csd.uwm.edu

The New Yorker of August 31, 1992 contains an article called "Audio
Husbands".  It gives a bit of a view of how some of the rest of the
world sees rec.audio.high-end types.  An amusing article.

Dennis O'Neill
Newsgroups: rec.audio.high-end
From: AXLEROD@ubvm.cc.buffalo.edu (Harvey Axlerod)
Subject: Dynaco controversy
Originator: tjk@csd4.csd.uwm.edu
Organization: University at Buffalo
Date: Thu, 27 Aug 1992 13:00:25 GMT

    The lastest edition of Stereophile has a semi-negative review of the new
Dynaco 70 amp by Panor. The is  a real war of words between Corey Greenberg
and the Panor folks. Other mags, including TAS, praise the Dynaco. Anyone have
any first hand experiences w/ this amp that they to share and illuminate with.
Thanks.
 
 
 
-----------------------------------------------------------------------
Harvey Axlerod                   Voice:    716-645-3570
University at Buffalo            FAX:      716-645-3734
University Computing Services    BITNET :  axLErod@ubvm
224 Computing Center             Internet: axLErod@ubvm.cc.buffalo.edu
Buffalo, New York 14260
-----------------------------------------------------------------------

Newsgroups: rec.audio.high-end
From: kester@mat.mte.ncsu.edu (Dan Kester)
Subject: Tube sources
Posted-Date: Mon, 31 Aug 1992 13: 50:44 GMT
Originator: tjk@csd4.csd.uwm.edu
Organization: Mat. Sci. & Eng., NCSU
Distribution: usa
Date: Tue, 1 Sep 1992 12:54:04 GMT
	for info-high-audio@csd4.csd.uwm.edu
	for rec-audio-high-end@speedy.mcnc.org

Having recently bought a hybrid-tube preamp (Counterpoint SA-1000 with 3 tubes)
I have started to pay attention to ads for tubes.  What I'm wondering is how
different are the different tubes?  What is a good source of tubes that netters
have been satisfied with?  The tubes in the preamps are 6DJ8 and 12AX7.  

Is there a difference between 12AX7 and 12AX7A?

Is it worthwhile to try different tubes in a hybrid preamp?

Are there specific versions (manufacturers/sources) of these two tubes that
anyone would recommend? 

Any advice on how to tell if a tube is running as well as possible?

Is it desirable to mechanically isolate a tube preamp (as compared to other
components)?

Any other good advice for a new tube user? 

Thanks for all comments!

Dan Kester
kester@mte.ncsu.edu

Newsgroups: rec.audio.high-end
From: bit!grego@ogicse.UUCP (Greg Sanguinetti)
Subject: Re: house grounding (another warning)
Originator: tjk@csd4.csd.uwm.edu
Organization: University of Wisconsin - Milwaukee
Date: Tue, 1 Sep 1992 12:54:41 GMT
	id <m0mPHz5-0004ouC@ogicse.cse.ogi.edu>; Mon, 31 Aug 92 13: 04 PDT

In article 3413 Gary Bronner (actually Bob Blase) writes:

>Outdoor ground rods help quite a bit. The power line ground is
>too noisy. I use a separate ground rod to the ground post of
>each EMI filter (I know, that's a lot of them, but it sounds
>better than connecting them together). And another one (two in
>parallel, actually) that's connected only to the equipment
>chassis (not to any power filters or the power ground).
>
>I also disconnect any grounding plugs on the equipment so the
>gear isn't connected to the power line ground (the filters
>aren't either). The power line ground is noisy, and with all
>the external grounding it isn't needed.
>
>   Bob Blase

Be careful here. This is actually illegal unless all the ground
rods are also connected to the grounding bus at the circuit breaker
pannel. The reason given by the building department is that there
can be a difference in potential between the grounds and if you
should find yourself in contact to your 'local' ground and something
grounded to the regular panel ground, you will conduct current (not good).

For instance, I have several 'outbuildings' on my property. I have
installed service subpannels in a few. Even though the buildings that
house the main pannels have ground rods and the buildings with the
subpannels have grounding rods the inspectors insisted that I tie
the subpannel ground system to the ground of the main pannel that
supplied it (with a separate ground wire). This was required even with
the fact that the neutrals were already connected together. The inspectors
are usually willing to work with me on grey areas but were quite firm on this.

-grego
---------------------------------------------------------------------------
Grego Sanguinetti, Bipolar Integrated Technology | Water, water everywhere,
grego@bit.uucp or grego%bit%ogi.cse.edu          | but I'd rather drink
or bit!grego@ogi.cse.edu or ...!ogicse!bit!grego | beer.

Newsgroups: rec.audio.high-end
From: mzk20@pecan.spa.amdahl.com (Makoto Kobayashi)
Subject: Any listening experiences with WADIA 6?
Originator: tjk@csd4.csd.uwm.edu
Organization: Amdahl Corporation  Sunnyvale, CA
Date: Wed, 26 Aug 1992 13:07:20 GMT
  (5.65c/IDA-1.4.4 for <rec-audio-high-end@ames.arc.nasa.gov>); Tue, 25 Aug 1992 14: 19:56 -0700
	id <m0mN8Iv-0001vBC@amdahl.uts.amdahl.com>; Tue, 25 Aug 92 14: 19 PDT
	id <m0mN8Ej-0000dtC@juts.ccc.amdahl.com>; Tue, 25 Aug 92 14: 15 PDT


The WADIA 6 was introduced this past Spring or earlier.  My dealer claims
that it got 1,000 orders even before it was on the market.  A one-page
preview in the latest issue of Stereo Sound (published in Japan,  
probably the best audiophile magazine in the world) is quite favorable
for the WADIA 6.  Has anybody already listened to it for an extended
period of time so that he/she can make some comments on the 6?  Is it worth
US $3,700?  Any comments will be welcome. 



Newsgroups: rec.audio.high-end
From: p0p4018@zeus.tamu.edu (PREMTHAMKORN, PRAKIT)
Subject: FOR SALE: ARAGON 4004 II 
Originator: tjk@csd4.csd.uwm.edu
Organization: Texas A&M University, Academic Computing Services
Date: Mon, 31 Aug 1992 13:17:59 GMT

For Sale:  Aragon 4004 Mark II power amplifier 200 watt/ch
	   Twenty month old, perfection conditions sonically and cosmetically
	   with orginal boxes and manual (a single sheet in Mondial's style)

Asking:  $1200 (retail $1850)

Reasoning for selling: Buying a Krell amp.  Actually I am not sure how much 
			improvement I will get but I buy the Krell amp to
			match my recently acquired Krell KSL preamp.

This amp should be very well known by this news group subscribers.  So I don't
have to say much about it.  There is a rave review in September issue of 
Stereophile.  

You may email me your inquiries or call me at 409-845-1949 (office) or
409-846-6851.

Prakit


Newsgroups: rec.audio.high-end
From: jas@proteon.com (John A. Shriver)
Subject: Driving ELS Directly
Originator: tjk@csd4.csd.uwm.edu
Organization: University of Wisconsin - Milwaukee
Date: Fri, 28 Aug 1992 13:02:50 GMT

Joe Curcio builds direct drive tube amps for various electrostatic
speakers.  He does not distribute plans on these (unlike his other
modifications), he claims due to the lethal voltages invovled.  (Of
course, from my point of view, selling someone one poses an even
larger liability threat...)


Newsgroups: rec.audio.high-end
From: mrbill@leland.Stanford.EDU (William Bowen)
Subject: Re: Questions on Digital Cable
Originator: tjk@csd4.csd.uwm.edu
Organization: DSG, Stanford University, CA 94305, USA
Date: Thu, 3 Sep 1992 13:03:08 GMT

In article <9209020938.AA15171@sun60.src.bae.co.uk> Andy Sheen <sheen@src.bae.co.uk> Wed, 2 Sep 92 10: 38:32 BST writes:
>
>BTW I think it is impossible to cut the cables to a pre-determined
>length since the signals that are going down the cable will all have
>differing frequencies (Fourier analysis into sine waves only holds for
>continuous, repetitive square waves I believe)
>
Fourier analysis is valid for all waveforms, repetitive or otherwise, and 
regardless of shape.

Regards,

Bill
mrbill@leland.stanford.edu




Newsgroups: rec.audio.high-end
From: weems@cs.umass.edu (CHIP WEEMS)
Subject: Re: Philips DSS speakers
News-Software: VAX/VMS VNEWS 1.41
Originator: tjk@csd4.csd.uwm.edu
Organization: University of Massachusetts CS Department
Date: Wed, 26 Aug 1992 13:06:25 GMT


In article <JANNE.ANTTILA.92Aug24134707@kannel.lut.fi>, Janne.Anttila@lut.fi (Janne Anttila) writes...
> 
>No, it has not been done before. What is really new about Philips DSS 
>speakers is that they have a digital crossover. Meridian only had a
>built-in D/A-converter and a conventional active crossover. Am I right?
> 
That is correct for the Meridian D600. But the Meridian D6000 (their $15K
model) actually does everything in the digital domain, then feeds three
separate differential pairs of D/A converters (in each speaker) which
directly drive the three mono power amps (in each speaker).

The D6000 provides digital volume and "tone" controls (i.e. a few different
equalization settings for different room setups), digital crossover, and
digital bass equalization. Of course it only accepts digital inputs --
you have to buy an outboard A/D to use it with analog sources.

Chip

Newsgroups: rec.audio.high-end
From: aburgh@iastate.edu (Aaron J Burghardt)
Subject: Re: What ever happened with Stereophile?
Originator: tjk@csd4.csd.uwm.edu
Organization: Iowa State University, Ames IA
Date: Thu, 3 Sep 1992 13:04:33 GMT
Return-Path: <news@news.iastate.edu>

In <PHILG.92Sep1185725@zug.ai.mit.edu> philg@zurich.ai.mit.edu (Philip Greenspun) writes:

>In article <zarthac.715206560@camelot> zarthac@camelot.bradley.edu (Matthew Simmons) writes:

>   I keep hearing references to some kind of Armor-All incident.... What happened?
>   (I must have missed that/those issue(s)....

>They told people to Armor-All their records and they in turned out
>that the stuff ate away at the plastic or gummed up the stylus or
>something.  Anyway, it was all kind of disturbing because the
>Armor-All proved nearly impossible to remove.

	<text deleted>

>Philip Greenspun
>MIT Department of EE

Are you sure about this?  I have the May and June, 1990, issues of
Stereophile, and there is much reference to Armor-All on _CDs_.  It seems
that in a previous issue Sam Tellig recommended using AA to polish CDs,
after which they received stories of AA making CDs unplayable with longterm
use.  So in the May issue Sam retracted his advice.  In the June issue he
repeated the warning about AA and apoligized for suggesting it.
Unfortunately, I don't have the next issues, so I'm not sure if this was
the end of it or not.

BTW, for removing the AA, Sam recommends washing the CD with running water
and Dawn (the brand matters, according to Sam) Dishwashing Detergent.
If there is still any left, use isopropyl or grain alcohol (not rubbing
alcohol) and cotton balls, wiping from the inside out.  

Does anyone have a more complete account?

Cheers,

Aaron
aburgh@iastate.edu
 

Newsgroups: rec.audio.high-end