HDTenEightyP/NetNews huggingface dataset:
From: henrylin@phoenix.princeton.edu (Henry Hung-i Lin)
Newsgroups: rec.audio.high-end
Subject: FOR SALE: Sumo Ulysses amp
Date: Fri, 18 Dec 1992 05:52:15 GMT
Organization: Princeton University
Distribution: usa
NNTP-Posting-Host: 129.89.7.4
Originator: news@nimaster
Originator: tjk@csd4.csd.uwm.edu


For Sale: Sumo Ulysses 60wpc power amplifier (excellent+ condition)

specs:	
		power : 60wpc into 8ohms from 20-20kHz. THD<.05%
		hum and noise: 105dB below rated power. 90dB below 1watt
		input sensitivity: 1.8v RMS (at rated output)
				   130mv RMS (at 1watt)
		input impedence: 47k Ohms
		damping factor: >500
		interchannel separation: >80dB

comments: it's a beautiful sounding, solidly built amp which has served me well.
	  sonically, it's rather transparent and neutral sounding (as opposed t	  the warm-ish sounding B&K ST140). current handling is rated at 50amps.
	  i'm selling to finance the purchase of a used cary tube amp (i'm a
	  strong advocate of buying used audio components).

asking $340obo+1/2 ship. please contact me at (201)822-3585 or
henrylin@phoenix.princeton.edu. thanks...

					henri
From: henry@monod.biol.mcgill.ca (Henry Pasternack)
Newsgroups: rec.audio.high-end
Subject: Toroidal transformers available for tube amps.
Date: Wed, 16 Dec 92 22:29:44 EST
Organization: University of Wisconsin - Milwaukee
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

   I have just received a FAX from Toroid Corporation of Maryland
describing two new transformers in their standard line designed for
tube equipment.  The information is excerpted below:

   "In response to a growing trend of building vacuum tube
    amplifiers, Toroid Corporation of Maryland has introduced
    two standard designs.

    Part Number		Description		Price (1-4 pcs)

    636.001		Power Transformer	$96.85 ea.
    605.001		Preamp Transformer	$75.35 ea.

    Our prices of these two designs include mounting hardware
    (one metal washer and two rubber pads).  Other types of
    hardware for horizontal or vertical mounting are available
    as shown in our brochure.

    The above two designs will be available for delivery in
    the second half of January on a first come, first serve
    basis.

    Thanks for your interest.  We hope to hear from you soon.

    Lennart Elmlund
    Sales and Marketing Manager"

   Here are the specs on the two transformers:

   1) Power amplifier transformer.

      720VCT @ 750mA
      6.3VAC @ 5A
      6.3VAC @ 5A
      5.0VAC @ 6A

      B+ winding has dual 50V bias taps.

      Physical: OD = 5.0", H = 2.6", Weight = 6.7 lb.

   2) Preamp transformer.

      260VAC  @ 100mA
      13.5VAC @ 1.2A
      7.5VAC  @ 1.6A

      Physical: OD = 3.2", H = 1.4", Weight = 1.3 lb.

   The people at Toroid Corporation are very helpful.  They will sell
to hobbyists in small quantities and they accept credit cards.  I am
using a pair of their transformers in my Chater 40W MOSFET amplifier
and have found them to be reliable, quiet, and cool-running.

-Henry
From: david.suess@medtronic.com (David Suess)
Newsgroups: rec.audio.high-end
Subject: Glass Audio Projects
Date: Thu, 17 Dec 1992 21:11:01 GMT
Organization: Medtronic, Inc.
	(queueing-rmail) id 161047.16690; Thu, 17 Dec 1992 16:10:47 EST
  (5.65c/IDA-1.4.4 for uunet!rec-audio-high-end); Thu, 17 Dec 1992 15:11:10 -0600
Reply-To: david.suess@medtronic.com
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

Has anyone out there built any of the projects in Glass Audio?  I have
recently received a couple of years worth of back issues and am
interested in several of the projects.

6BX7 Amplifier:  Has anyone successfully built this?  I would like to
possibly do a monoblock version.  What about substituting 6AS7 tubes
for the 6BX7?  Can I really use output transformers from old stereo
integrated units and still get good sound?  Speaking of sound - how
does this thing sound when built?  With the low watts (10) that this
things puts out, what currently available speakers would make sense?

FM-3 Improvement:  Is this worthwhile?  I like this unit and would like
to keep it around.  I like being "all tubes". Does the replacement of the
PEC's make a big difference?

-David
From: rup%pdib39@uunet.UU.NET (Ruppert Georg (IMPRO))
Newsgroups: rec.audio.high-end
Subject: Re: Dynakit 70 Tube Amp
Date: Wed, 16 Dec 92 12:48:13 GMT
Organization: Technical University of Graz, Austria
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

CHARLES ACTOR X2922 P7091 (ep502ca@pts.mot.com) wrote:
: I can't get the bias voltage quite right.  A friend of mine said the
: caps in the bias circuit were probably dried out.  If it's worth
: keeping, should I change anything with it?  I don't want to spend alot
: on it.  A friend suggested replacing all the caps (with what kind?) and
: changing the voltage to the preamp tube (plates?) to DC.  How can you
: tell when you need new tubes?

I have an old Radford STA 25 Renaissance power amp with user adjustable
bias voltage. If I can't adjust that voltage correctly (->indicator led),
I will habe to replace the power valves (sorry, tubes). Once I ignored
that, resulting in a broken valve and some damage to the feedback
resistors. To be on the secure side change the valves first.

--
Georg RUPPERT                         | e-mail: rup@piis10.joanneum.ac.at
Institute for Digital Image           |         
Processing                            | phone:  (++43/316) 8020-755
JOANNEUM RESEARCH GRAZ /  AUSTRIA     | fax:    (++43/316) 8020-720
From: tjk@csd4.csd.uwm.edu (Thomas Krueger)
Newsgroups: rec.audio.high-end
Subject: Re: Laser Illusions Spacial Filter
Date: 14 DEC 92 16:35
Organization: University of Wisconsin - Milwaukee
NNTP-Posting-Host: 129.89.7.4
Comments: Automatic Return Receipt Requested

I purchased one of these guys for my EAD Ultra Rotel about 3 months ago, based
on the glowing review in Stereophile and upon the high recommendation of my
dealer and personal friend (Ken Gould of Audio Nexus in New Jersey).  I was a
bit peeved by the high price of the item, which had to cost pennies to
manufacture, but who said life as an Audiophile was inexpensive?

The conclusion: I didn't notice a damned thing.  Neither did my good audiophile
friend (the A3 M5 owner I'd recently written about).  However, for what it's
worth, the sound didn't degrade!  Oh yeah- one favorite CD, an Ivan Moravec
recital, no longer tracks at one point.  I'd never failed to track anything
before, but obviously the diminished diameter of the CD player's lens aperture
would accentuate any misalignment problems.  Anyway, I've left the thing on.

As I trust Ken Gould's audio opinions, perhaps there's something about the EAD
modifications to the Rotel that negates the effects of this glorified washer.
I had previously put Ed Strnad's ferrite product, "Blockers", on the power cord
and on the interconnects of the EAD, and also could not reproducibly confirm an
effect.  Maybe the player is "untweakable"!  Or maybe my ears are a disgrace.

  Arthur L. Shapiro        ARTHUR%MPA15C@TRENGA.TREDYDEV.UNISYS.COM
  Software Engineering
  Unisys Corporation       Speaking as a civilian, rather than for
  Mission Viejo, CA        Unisys, unless this box is checked: [ ]
From: rup%pdib39@uunet.UU.NET (Ruppert Georg (IMPRO))
Newsgroups: rec.audio.high-end
Subject: WANTED: tube manual
Date: Thu, 17 Dec 92 09:08:18 GMT
Organization: Technical University of Graz, Austria
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu


Hi all,

is anybody out there who could sell me a tube manual or even a copy
of one? I have no change to get one here in Austria.

Regards, Georg.

--
Georg RUPPERT                         | e-mail: rup@piis10.joanneum.ac.at
Institute for Digital Image           |         
Processing                            | phone:  (++43/316) 8020-755
JOANNEUM RESEARCH GRAZ /  AUSTRIA     | fax:    (++43/316) 8020-720
From: pod@eksignal.kodak.com (Mike Podhorecki)
Newsgroups: rec.audio.high-end
Subject: New mini-CDs
Date: Mon, 14 Dec 92 20:01:01 GMT
Organization: Eastman Kodak
  (5.65c+/IDA-1.4.4 for <rec-audio-high-end@cis.ohio-state.edu>); Mon, 14 Dec 1992 15:01:09 -0500
  (5.65c/IDA-1.4.4 for rec-audio-high-end@cis.ohio-state.edu); Mon, 14 Dec 1992 15:01:07 -0500
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

Hi,
Is anyone familiar with the new mini CD from Sony.
    - Frequency range? ( same as CD? Same as DCC )
    - Read only, read/write, write once?
    - Disk record/play time?
    - hardware cost, disk cost?
    - etc, etc, etc.....

Anyone heard one yet???

Thanks,
Mike Podhorecki    pod@eksignal.kodak.com
From: pvh@apple.com (Pete Helme)
Newsgroups: rec.audio.high-end
Subject: Re: Linaeum Speakers
Followup-To: rec.audio.high-end
Date: Thu, 17 Dec 1992 21:08:01 GMT
Organization: Apple Computer Inc.
	for 
	for rec-audio-high-end@ucbvax.berkeley.edu
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

In article <1gnciaINNe6h@uwm.edu>, mikero@microsoft.com (Michael Robin)
wrote:
>
> people regard this as a good thing). One thing to remember is,
> by virture of the design, that the vertical swwet spot is very narrow -
> i.e, stand up and the highs disappear. (Kind of like the Stages.)
>

Odd, I thought MF in The Absolute Sound said you could walk around the LFAs
and still here the highs.

name: Pete Helme
work: Apple Computer, Inc.
mail: pvh@apple.com
From: jas@proteon.com (John A. Shriver)
Newsgroups: rec.audio.high-end
Subject: Class AB1 operation
Date: Mon, 14 Dec 92 15:46:40 EST
Organization: University of Wisconsin - Milwaukee
NNTP-Posting-Host: 129.89.7.4
Cc: henry@ginger.sri.com
Originator: tjk@csd4.csd.uwm.edu

Yeah, I just had fun over the weekend (snowed in!) playing with my
freshly restored AC current probe and a stock Stereo 70.  I put it
around the low end of the 15.6 ohm common cathode resistor.  Then I
dual traced it with the output pumping out 1 KHz sine wave near full
power.  Sure enough you get big bumps in the current draw every half
cycle.  Something like 100 mA swings at full power.  (Of course, I
can't see the underlying 100 mA DC bias current since the AC current
probe doesn't go down to DC.)

I tried to see where the Class A power point was using the current
probe (searching for a flat waveform as I reduced the input), but
eventually the 60 Hz hum (from the power supply, maybe electrically,
maybe magnetically) started to swamp things at those low current
levels.  Also, it may have been that the signal was modulating the
power supply back at the driver stage, and I was seeing that at the
output.

This does, however, look like a really handy way to do bias balancing,
AC balancing, and tube matching.  Just get the current pulses from the
positive and negative swings of the output waveform equal.  (However,
you've got to be pretty lucky to get together a working Tektronix AC
current probe and amplifier for $60.  The same setup new is $1390.
There are benefits to the defunct New England economy when shopping
for used and surplus test equipment.)
From: DEASTMAN@vnet.ibm.com (Don Eastman)
Newsgroups: rec.audio.high-end
Subject: Acurus A250 comments requested:
Date: Mon, 14 Dec 92 10:30:42 PST
Organization: ADSTAR - SAN JOSE, CA.
Reply-To: DEASTMAN@vnet.ibm.com (Don Eastman)
NNTP-Posting-Host: 129.89.7.4
Disclaimer: This posting represents the poster's views, not those of IBM
News-Software: Usenet 3.0
Originator: tjk@csd4.csd.uwm.edu

I have been auditioning amplifiers for use with my B&W 801's (has to be
low cost at this time) and have found one that sounds very good to me.
It is the Acurus A250.  I purchased the amp this weekend and have 7
days to return for a full refund.  I would appreciate hearing some of
your opinions about this amplifier, especially as compared to its
'brother' the Aragon 4004.  Also, the input impedance is only 20K, is
there any reason for concern over this with respect to cables or
compatability with other brand preamps?

I selected this amp over the following which I also auditioned at home:

Rotel 980 (Pair Bridged)
Rotel 990
Sony N80ES
BK (Model slips my mind right now)

Any comments will be greatly appreciated.

 =======================================================================
|           Don Eastman            |   INTERNET: DEASTMAN@VNET.IBM.COM  |
|     ADSTAR (IBM) Corporation     |     BITNET: DEASTMAN@VNET.BITNET   |
|       San Jose, CA. 95193        |        FAX: (408) 256-7221         |
 =======================================================================
From: gfl@herahera.cc.bellcore.com (lenahan,grant f)
Newsgroups: rec.audio.high-end
Subject: Re: Amplifier specifications
Date: Mon, 14 Dec 92 14:38:36 GMT
Organization: Bellcore, Livingston, NJ
  (5.65c/IDA-1.4.4 for rec-audio-high-end@uunet.uu.net); Mon, 14 Dec 1992 09:38:40 -0500
NNTP-Posting-Host: 129.89.7.4
Summary: more on slew rate
Originator: tjk@csd4.csd.uwm.edu

In (Malte Uhl) writes:
I wrote:
> |> Anything under 20 V/uS for power amps is terrible.
> |> 
> |> 4.4 v/uS is fine for a preamp, since 2.2 V rms is typical
> |> maximum Vout.
> |> 
> |> Grant
> 
> How comes that slew rate < 20 V/sec is terrible ? My NAD 2155, rated at
> 55 W(RMS) is specified to have a slew rate of 5.5 V/sec. It doesn't
> sound terrible at all!
> You''l also rarely find a tube amp with that slew rate.

Malte-

First, understand that a 100W amp (which I referenced, but you
deleted), requires about 30% more voltage swing, and thus
slew rate, than does your 55W amp.  Next, notice that an amplifier,
in ordewr to meerly reproduce a 20 Hz sine wave at 100W rated power,
requires somewhere in excess of 3.1 v/uS _just to keep up_.  This
assumes:
1. Zero headroom
2. Zero design tolerences
3. running design at its limit

This is not good design.  I generally insist on at least 300%-400%
margins for assured excellent performance ( I also stated this, and you
also deleted it).  Since a 20 v/uS slew rate is not hard to acheive, 
shy settle for less?

Now, I'm referring to the circuit's capabilities, not the actual
frequency limitations of any applied filter.  In general, I'll
bandwidth limit a circuit at 2-3x its maximim frequency (20 kHz
for us humans), in order to limit out-of-band noise.  If this
is taken into account, the SR might be calculated at a lower number,
more like that of your NAD.  Such cal;culations are not the 
usual for such a question however.

I don't knwo about tube amp SRs, but since tubes traditionally
have better HF performance than transistors (thus their continued
use in microwave's, radar, etc.), I find this hard to beleive.
Of course, I refer to the best designs, not a middle of the road
design from the  40s.

Hope this clarifies why 5.5 v/uS is shaky at best.  PArticularly
since NAD claims gobs of headroom.  probably not broadband
power with the headroom.

Grant
gfl@hera.cc.bellcore.com
From: cal@gsbux1.uchicago.edu (Cal Lott)
Newsgroups: rec.audio.high-end
Subject: Re: MD
Date: Thu, 17 Dec 1992 21:52:07 GMT
Organization: University of Chicago Computing Organizations
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

Scott Dorsey <kludge@grissom.larc.nasa.gov> writes:


>                                     There were a lot of rather interesting
>artifacts, which were even audible on the cheap Sony speakers they were
>using for the demo. 
>--scott

	Well, Scott, you should keep the intended market of the Mini-Disc
format in mind. It is intended for use as a portable medium, not as an
audiophile-quality archival medium. Out in the hustle and bustle of the
real world, ambient noise would likely mask all those artifacts that you
found to be so painfully obvious.

						-Cal
--
----------------------------------------------------------------------
Cal Lott          "Oh, I see-- I thought 'no' meant 'spoon'!" --Dan
Email me, baby!   cal@gsbux1.uchicago.edu   cjl1@midway.uchicago.edu
----------------------------------------------------------------------
From: ahchan@rd.hydro.on.ca (Arthur Chan)
Newsgroups: rec.audio.high-end
Subject: Re: Amplifier recommendations needed
Date: Tue, 15 Dec 92 20:56:40 GMT
Organization: "Ontario Hydro - Research Division"
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

jacek@lakme.East.Sun.COM (Jacek Ambroziak - Sun Microsystems Labs BOS) writes:
: Hi everybody,
: 
: I think I may be splitting hair, but I'd like to hear your opinions
: on Adcom vs. Acurus vs. Hafler amplifiers.
: 
: At the same time I'm trying to decide between Adcom CD changer and Rotel 965BX

I have the Adom 555/500 system and I also have the Hafler HD200 amp.  The Adom
is definitely better than the Hafler except the treble.  The Hafler sounds a
little sweeter.  I am not sure about the newer Hafler though.  But I assume the
MOSFET amps are about the same as the old ones.  As for the Adom CD player vs
the Rotel, again, I like the Adom better.  But I bought the Rotel instead,
because the Adcom costed $200 more in Canada and I did not think the difference
worth more than $200.  One thing though, the Adcom comes with a better inter
connection cable (may not be high-end but better than the one comes with Rotel).
It cost me a bit more to get a better cable.                             

Arthur Chan
-- 
Arthur Chan
Operations Research
KR297 (6173)
From: rmcghee@fnma.COM(Rich McGhee)
Newsgroups: rec.audio.high-end
Subject: FOR SALE:  HK Integrated Amp
Date: Mon, 14 Dec 1992 14:18:16 GMT
Organization: Fannie Mae
	(queueing-rmail) id 101110.7712; Mon, 14 Dec 1992 10:11:10 EST
Reply-To: rmcghee@fnma.COM
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

FOR SALE:  HK Integrated Amp
$450 or best offer

Harmon Kardon PM655Vxi

Average Power:  90 Watts @ < 0.08% THD into 8 ohms   (20-20,000Hz)

Instantaneous Current Capability:  45 Amps

Signal/Noise :
	Phono		80db
	Video/CD	98db
	Main-in		110db

** Preamp and/or main amp can be used separately or integrated

Tone Control Characteristics:
	Bass Turnover Freq:	200Hz/400Hz
	Treble Turnover Freq:	2kHz/6kHz

Filters:
	Subsonic and High cut

Phase Correct Loudness

Dimensions	17.5"x5.25"x15.8"

Weight:		25 lbs.

It has been a great unit.  I have never had a problem with it.  It does  
not run
very hot either.  I have manuals and packing materials.


--
Rich McGhee, Advanced Technology
Federal National Mortgage Association
3900 Wisconsin Avenue, Wash DC 20016
NeXTMail: rmcghee@fnma.COM
From: eric@binoc.bih.harvard.edu (Eric Hansen)
Newsgroups: rec.audio.high-end
Subject: Q: Upgrades for Matsushita MASH D/A and Signetics NE5532 opamp?
Date: Thu, 17 Dec 92 9:34:52 EST
Organization: University of Wisconsin - Milwaukee
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

Hi -

I have an NAD 5000 CD player, and would like to know if anyone has effectively
upgraded the D/A converter and/or op-amp in this unit.  A review of the
player in Stereophile (a while back) lists the stock parts as the following:

D/A converter:  Matsushita MASH chipset (1-bit)
Dual op-amps:  Signetics NE5532

Since I've seen alot of talk in this group (and in rec.audio) about this
subject, I figure there must be someone out there with this player who has
done this.

Also, if there is an archive file or printed listing somewhere which tells
which chipsets have the same pin layouts as others (and hence can upgrade them)
then please email me with it or post it.

Thanks!

Eric Hansen

*---------------------------------------------------------------------------*
| Eric J. Hansen                            Center for Clinical Computing   |
|  eric@binoc.bih.harvard.edu              350 Longwood Avenue, Boston, MA  |
|  eric@prodigal.psych.rochester.edu                (617) 732-5925          |
*---------------------------------------------------------------------------*
From: bellcore!gizmo.bellcore.com!mo@uunet.UU.NET (Michael O'Dell)
Newsgroups: rec.audio.high-end
Subject: Re: Amplifier Slew rate
Date: Thu, 17 Dec 92 15:22:34 GMT
Organization: Center for Chaotic Repeatabilty
Reply-To: bellcore!mo@uunet.UU.NET
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

When speaking about slew-rate, it is important to
consider that the units usually listed is Volts/microsecond.

The problem is that speakers are current-mode devices.
WAIT - you say, Ohm's Law says we can translate between
the two, and that a large VOLTAGE slew rate will obviously
imply a large CURRENT slew rate.  That would be true for
a constant, pure Ohmic load (signal into a perfect resistor),
but speakers are pretty-far removed from a pure Ohmic load.
In fact, most of them are reactive as hell - especially 
various planar driver types, but good ol' EM cones can be
pretty weird as well.

One must actually be concerned with the AC Current
transfer function if you want to really understand what your
amplifier is managing to assert into your speaker's drivers.

While voltage slew rate is an interesting parameter,
and not without considerable merit as a rough rule-of-thumb,
it does NOT explain why one amplifier will drive some speakers
well and does poorly on others.

Who knows? This might even explain some part of the observable
voodoo-cable effects.

The biggest problem is that the AC current transfer function is
bitchin' hard to measure, present, or interpret with any
real-life signal.  Swept tones, or swept two-tone signals
are about the only thing that I can see how to measure.

Anyone know of any published research in this are?

	-Mike
From: pohsk@ecst.csuchico.edu (Lee Kuan Yew)
Newsgroups: rec.audio.high-end
Subject: Naim Nait & Epos ES11
Date: 16 Dec 1992 13:20:21 GMT
Organization: California State University, Chico
  (5.65c/IDA-1.4.4 for rec-audio-high-end@uunet.uu.net); Wed, 16 Dec 1992 05:20:22 -0800
Distribution: world
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

Hi fellow audiophiles,

Anyone out there driving the Epos ES11 speakers with the Naim Nait 
amplifier?  I am considering buying the Naim Nait to go with my ES11.
However, I am a bit concern about the low output of this amp. (15 watts).
Will the low output Naim Nait amp restrict the dynamic range?  Will the 
"clipping" distortion cause damage to the loudspeakers if the amp is 
driven beyond its capability in an attempt to obtain high volume 
levels.
I will be glad to hear from anyone, especially the advise from those 
Naim Nait and ES11 users.  Thanks in advance.
From: rslugg@med.unc.edu (Robert Slugg)
Newsgroups: rec.audio.high-end
Subject: Re: Toroidal transformers available for tube amps.
Date: Thu, 17 Dec 1992 20:33:44 GMT
Organization: UNC-CH School of Medicine
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

As of last week, Surplus Electronics in Cleveland still had in stock a
great power amp for tube preamps.  It has roughly 600 V @ 100 mA and a 17
volt 2 amp tap for a regulated heater circuit.  The best part, Its still
only $4.50.  Dimensionally, It won't fit in a PAS chassis, but then, who
wants AC in that chassis anyway?

Bob