HDTenEightyP/NetNews huggingface dataset:
From: till@acid-rain.lucid.com (Don Tillman)
Subject: Re: class D power amp
Reply-To: till@lucid.com
Organization: Lucid, Inc.
	te.edu><1992Aug10.045231.1144@ccu1.aukuni.ac.nz><1992Aug10.105528.26359@nntp.nta.no>
	<TILL.92Aug11102831@acid-rain.lucid.com>
	<1992Aug11.230042.394@ccu1.aukuni.ac.nz>
Date: 14 Aug 92 09:56:24

   From: stuartw@ccu1.aukuni.ac.nz (Stuart Woolford)
   Date: 11 Aug 1992 23:00:42 GMT
   Organization: University of Auckland, New Zealand.

   till@acid-rain.lucid.com (Don Tillman) writes:

   >Other problems with Class D are that there is zero power supply noise
   >rejection (before applying feedback) and that the output filter makes
   >feedback more difficult to apply.  

   I intent to use a switchmode power supply, followed by linear regulation, and
   MUCH filtering, probably switching at about 100KHz, would this seem like a
   sensible setup.

Well if you're gonna have a linear regulated power supply, you loose a
chunk of the efficiency feature of Class D.

Howzabout a different hybrid approach?  A switching power supply and a Class
D switching amp used to cascode a linear amp running in Class A or AB.
This gets you either the performance of Class A with the power dissipation
of Class B or the performance of Class AB with a lot less power
dissipation.  Anybody know if this has been done before?

  -- Don
Newsgroups: rec.audio
From: dszpiro@student.business.uwo.ca (Daniel A. Szpiro)
Subject: Re: What does "gray-market" mean? (Was J&R Music World)
Organization: University of Western Ontario
Date: Thu, 13 Aug 1992 21:59:20 GMT

hong@diamond.ssc.gov (Rithea Hong) writes:

> In article <1992Aug13.142641.21222@athena.mit.edu>, ascheng@athena.mit.edu (A
> |> Excuse my ignorance, but what does this term "gray-market" mean?  From wha
> |> I can gather from the context of a couple of recent posts, gray-market
> |> products seem to be perceived as inferior to "non gray-market" products.
> 
> Essentially, it refers to products not sold by "Authorized Dealers".  This ca
> be bad because manufactures' warranties and such often do not apply.  The
> warranty you get (if any, you can't be sure unless you check) is only from
> the seller, which may be much more difficult to deal with.
> -- 

Aside from warranties, gray-market products may also offer a technical
problem. The products may have been originally manufactured to the
specifications of one market, and then trans-shipped into a second
where the specifications are incompatible or inadequate.

An example of this is electronics built with CSA certification for the
Canadian market. Gray-market goods imported into Canada may not have
CSA approval. This may not sound like a big deal, but technically any
retailer demonstrating non-CSA electronics can have the goods
confiscated by the local utility (e.g.: Ontario Hydro) and be fined.
Individuals using non-CSA elctronics in their home may be in violation
of their fire insurance policy.

Between the technical probelms and the difficulty of getting warranty
service, you really have to question the "deal" of buying gray-market
products.

----------------------------------------------------------------------------
 Daniel A. Szpiro              | Internet:  dszpiro@student.business.uwo.ca
 Doctoral Candidate            | Telephone: (519) 661-3206, Ext. 5138      
 Western Business School       | FAX:       (519) 661-3292                 
 University of Western Ontario |--------------------------------------------
 London, Ontario, Canada       |                                           
 N6A 3K7                       |                                           
----------------------------------------------------------------------------



dszpiro@student.business.uwo.ca (Daniel A. Szpiro)
Western Business School  --  London, Ontario
Newsgroups: rec.audio
From: jeberger@novell.com (John Berger)
Subject: Adding magnetic shielding to speakers
Summary: How to add to small speakers? Source for materials?
Keywords: speakers shielding video magnetic
Organization: Novell, Inc.
Distribution: us
Date: Fri, 14 Aug 1992 00:36:26 GMT

Is anyone familiar with what materials are available for adding magnetic 
shielding to an existing set of small speakers?  Obviously, these would be 
for video use.  Is it feasable to do this after the fact, or are the 
tolerances so tight that a hobbyist can't do this successfully?

If it can be done, what are the sources for the shielding materials?
From: apn@Apple.COM (Alex Novickis)
Newsgroups: rec.audio
Subject: Re: Group purchase: Burr-Brown OPA604, OPA2604 op-amps
Date: 22 Aug 92 02:48:22 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <66478@hydra.gatech.EDU> gt8021a@prism.gatech.EDU (EASON) writes:
>In article <2A93E957.13046@orion.oac.uci.edu> gkwan@balboa.eng.uci.edu (Greg Kwan) writes:
>>I called up Burr-Brown and got the following pricing:
>> 1-24:$14.36
>>25-49: 12.64
>>50-99: 11.13
>> 100+:  5.30
>>
>>I'm personally not in a big rush to get these parts and will probably
>>order two (meets the $25 min order) myself unless there is enough in-
>>terest to get the 100+ pricing (or I may wait until I'm employed and
>>go the sample route :-).
>
>I just did a little calculation on these numbers... 100 chips at $5.30 is
>$530.  Simple enough.  How many at $11.13 would it take to break even and
>go ahead and buy 100 at $5.30?  Only 47.6 chips!  So forget the 50-99
>price scale... if you need 48 or more, just buy 100, and you'll spend
>less money and have lots of free chips.  At the 25-49 price scale, you can
>get 41.9 chips for $530, or 36.9 for $530 at the 1-24 price scale.
>
>So, my point is this:  I'd be willing to buy two of these at any price
>lower than $14.36 each.  At $5.30, I'd buy four.  Do we have 22 more people
>who would buy a pair of these at $5.30 each?  Sounds like a neat toy to 
>have in your junk box for a "one of these days" project, esp. at this price!
>
>Anyone else?
>
>-wte
>-- 
>Bill Eason              w-404/894-2381             h-404/352-6914
>BE-EE/CS Vanderbilt U. May 1987      MS-EE Georgia Tech June 1992
>wte@cdrom.gtri.gatech.edu (pref.)  -or-  gt8021a@prism.gatech.edu

If all you need is FOUR, then call BB and get samples!!



-- 
Alex P. Novickis, Real Time systems demi-guru.  (W)   408-862-4541
ALINK:alex.n                                    (H)   415-691-0657
UUCP:{amdahl,claris,pyramid,sun,decwrl,well,ubvax,ames}!apn@apple.com,apn@nonvon
"I think... I think it's in my basement. Let me go upstairs and check"-Escher.
From: checksix@flyboy.EBay.Sun.COM (Al Conte)
Newsgroups: rec.audio
Subject: Re: The future is now!
Date: 18 Aug 1992 16:05:19 GMT
Organization: Sun Microsystems, Inc.
Distribution: na
Reply-To: checksix@flyboy.EBay.Sun.COM (Al Conte)
NNTP-Posting-Host: flyboy.ebay.sun.com

In article <1992Aug18.000955.1684@udel.edu>, bower@pecan.cns.udel.edu (Tyson Bower) writes:
>Spectral DMA-80 100-W/ch Amplifier
>
>Features DC-coupled circuitry; 300 VA power
>transformers; hand built Vishay precision resistors;
>matched FET output devices. 100 W x 2 cont
>avg into 8 ohms, 250 x 2 cont avg into 4 ohms,
>180 x 1 cont bridged into 8 ohms, or 250 x 1 
>bridged into 4 ohms; S/N 90 dB; distortion 1%;
>slew rate 1,000 V/us; input imp 10,000 ohms.
>19 x 2.5 x 14 in .................................$2,795
>
>(For those who care about specs.  8-)  )

Yeah, except one thing, this is the wrong model.
There is a total difference between the DMA 80 spec'ed here by you,
and the DMA 180 that has just been released.
For one, the power is stated to be 250 watts @ 8 ohms.
The topology is totaly new, having being developed for 2 years.
Spectral makes 3 amps, the DMA 80, DMA 200, and the NEW DMA 180,
which is a night and day audible diference from the latter.
The 80 and 200 are very nice products but, Spectral out did themselves
with the 180, Go listen !!!!!



Al
Newsgroups: rec.audio
From: chinh@sequent.com (Chi'nh Duc Dang)
Subject: I need tele # of Audio Source
Organization: Sequent Computer Systems Inc.
Date: Thu, 20 Aug 92 20:07:45 GMT

  Somebody please send me the telephone number of Audio Source if you've known of???

  Thanks
-- 

      Chi'nh Duc Dang
      Sequent Computer Systems, Inc.
        Internet: chinh@sequent.com
From: rghoff@bb1t.monsanto.com
Newsgroups: rec.audio
Subject: Re: What is DSP anyway?
Date: 21 Aug 92 15:36:31 CST
Organization: Monsanto Company, St. Louis, MO

In article <1992Aug18.191934.2113@merrimack.edu>, desmondw@merrimack.edu writes:
> 
>      Sorry for my naiveness, but it is a question to which I get a lot of
> different answers. My Technics reciever(SA-GA710) has it but doesn't 
> mention how to use this function once in the whole manual(or what its
> good for). A dealer said it just provides three extra listening
> environments(concert hall,stadium,etc) and there should be keys on the
> reciever itself to utilize these environments. But my reciever has no
> button whatsoever saying DSP or Stadium,Concert Hall, etc. Does my 
> reciever have it or not?
>                                           Bill

Hi Bill,

	I've got the same receiver. I don't think it has the DSP (Digital
	Sound Processing - or whatever). The next model up has it (the 910
	is the top of the line I think).

	All we have is digital delay for surround. :-(

	Rick Hoffman.
From: aok@rice.berkeley.edu (Alan Kamas)
Newsgroups: rec.audio
Subject: DAK's BSR equalizer (EQ)
Keywords: EQ DAK BSR Equalizer
Date: 14 Aug 92 23:29:56 GMT
Distribution: world
Organization: University of California, Berkeley
NNTP-Posting-Host: rice.berkeley.edu

I am thinking about buying a BSR EQ 14/14R equalizer from the current
DAK catalog.  But before I make the mail order plunge, I have a few
questions:

Does anyone have an opinion on the BSR equalizer and on BSR in general?
(Also, suggestions on other equalizers would also be appreciated)

Has anyone had any trouble with DAK or DAK stereo equipment?

Thanks in advance,

Alan Kamas
aok@ohm.berkeley.edu
Newsgroups: rec.audio
From: ywlai@skunk.cns.syr.EDU (Yi Wu Lai)
Subject: Test
Organization: Syracuse University, Syracuse, NY
Distribution: usa
Date: Thu, 13 Aug 92 13:53:10 EDT

 This is a test.
From: bsmith@stake.DaytonOH.NCR.COM (ROBERT SMITH)
Newsgroups: rec.audio
Subject: Re: 6th Ave. Electronics--OPINIONS?
Date: 14 Aug 92 17:30:47 GMT
Organization: Stakeholder Relations, NCR Corp in Dayton,OH

<16ec8sINN6um@agate.berkeley.edu>
Reply-To: bsmith@stake.DaytonOH.NCR.COM (ROBERT SMITH)
Followup-To: 
Distribution: world
Organization: Stakeholder Relations, NCR Corp in Dayton,OH

In article <16ec8sINN6um@agate.berkeley.edu> henken@ocf.berkeley.edu (Matthew
J. Henken) writes:
>n my original article, I forgot to ask a question that I had in mind while
>writing it.  I mentioned that I would prefer to buy from the local stereo
>boutique (for reasons of warranty/support), but would prefer not to pay their
>prices.  Sounds pretty typical, no?  I'm eager to hear opinions on how
>appropriate it would be, and how much success I would likely have if I
>explained that to my salesman at the local high-end shop.  Do these shops
>ever have any "give" in their prices when confronted with this sort of
>situation?  I understand that stores vary, but I guess I'm looking for the
>most likely/common result.  Again, any help you can provide would be
>most appreciated.
>
>Thanks again,
>Matthew J. Henken
>henken@ocf.berkeley.edu

Perhaps I'm naive or gullible, but IMHO a _good_ local store is worth paying
more for.  In addition to warranty considerations, I would tend to buy from
the local store if I spent a lot of time there listening to components.  When
I recently bought some speakers, for example, I made 3 or 4 trips to each of
two stores to listen to various speakers.  The local retailers added value by
making their time and facilities available to me.  However, I think one should
always try to bargain on price, and look at the mail order places as a
reference point.  Also, where I live (Dayton OH) I only know of 2 acceptable
dealers within 50 miles.  If there was a piece of equipment I really wanted
that was not carried by these dealers, then I might buy mail order.  But I
would still like to listen to it first, somehow.
-- 
E-mail => Robert.D.Smith@daytonoh.ncr.com (Bob Smith)
          NCR Investor Relations/Stakeholder Relations
Newsgroups: rec.audio
From: sethb@fid.morgan.com (Seth Breidbart)
Subject: Re: Who dat say dey gonna buy dat DAT?
Organization: my opinions only
Date: Fri, 21 Aug 1992 01:00:21 GMT

In article <25019@castle.ed.ac.uk> sss@castle.ed.ac.uk (S S Sturrock)
writes: 

>A cheapo $600 DAT deck outperforming $2000 analogue decks?  har har har!
>Leave those scopes alone and listen to the damn thing!  The *APPALLING* ADC
>set ups in consumer DAT decks with their magnificent pre-sampling filters
>are just a joy to behold.  Har har har!!!!  Not to mention the things being
>full to the brim with poxy op-amps giving cheaps**t Japanese sound.
>
>Sheesh, do you people only listen to bass?  Are your ears so damaged by
>years of excessive volume listening that you cannot hear the detail you are
>missing?  The life?

No, some of us also listen to the high frequencies and *don't* like
hiss.

Seth		sethb@fid.morgan.com
From: smee@bristol.ac.uk (Paul Smee)
Newsgroups: rec.audio
Subject: UK news snippets...
Date: 17 Aug 92 11:22:57 GMT
Reply-To: P.Smee@bristol.ac.uk (Paul Smee)
Organization: University of Bristol

Two items picked up from the mags:

Ariston has gone into receivership.  (Not sure how this translates into
US-speak.  Basically, the company is in hot water, and it is the job of
the receivers to try to dispose of it in a way which is least harmful
to its creditors -- ideally by finding someone who will buy it as a
possible going concern or by reorganising it into profitability, but if
necessary by breaking it up and disposing of its assets.)

Celestion has just signed up to distribute Adcom equipment in the UK.
(Now, at long last, maybe we'll get to find out what all you guys keep
going on about.)

-- 
Paul Smee, Computing Service, University of Bristol, Bristol BS8 1UD, UK
 P.Smee@bristol.ac.uk - ..!uunet!uknet!bsmail!p.smee - Tel +44 272 303132
Newsgroups: rec.audio
From: finton@lactic.cs.wisc.edu (David J. Finton)
Newsgroups: rec.audio
Subject: Sticky CD player
Summary: gummy rails??
Keywords: NAD 5255, CD, problem
Date: 14 Aug 92 18:31:09 GMT
Organization: University of Wisconsin, Madison -- Computer Sciences Dept.

I'm seeking advice about my CD player, which is starting to act up on some
discs.  The player is 7 years old, and our local repair shop was sure that
the problem is either the laser or the motor wearing out.  

My opinion was that the player probably just needed to be cleaned, 
especially the rails that the laser assembly slides on.  The repair person
said that CD players didn't really suffer from that problem.

Here are the symptoms:
  (1) On some discs, the player can't find the beginning of some tracks.
      Usually the problem is with the first tracks on the disc. 

  (2) The player will set the laser several minutes into such a track,
      and in the pause mode.  Sometimes the player seems to have its
      laser stuck; going into play mode refuses to play, or advance the
      time on the display, until I skip the player to another track.
      Also, attempting to scan forward or backward from such a point
      affects the laser position (as evidenced by the time displayed) 
      unpredictably;  it skips back and forth.

  (3) Sometimes skipping tracks to the end of the disc and then 
      skipping back to the beginning several times removes the problem.

  (4) Some discs show no problem.

Point (3) makes me think that the problem is gunk on the rails
that the laser assembly slides on, and driving the laser sled through
it several times clears the path somewhat.  (2) makes me think that
the rails are actually sticky and the laser head assembly is just
getting stuck.  Or could this be caused by an aging (7 years) laser
and motor?

Our local repair shop contact said that she didn't think that they 
cleaned the rails when someone asked for a "cleaning/adjustment."
Is this something I can do myself?  If not, and I find another
repair center, what's a reasonable price for this service?
My player is an NAD 5255, which has the laser and spindle integrated
into the drawer assembly, and I'm not really sure how I'd go 
about getting at it.

Thanks in advance for any suggestions.

--David Finton
Newsgroups: rec.audio
From: dplatt@ntg.com (Dave Platt)
Subject: Re: Passive preamps revisited
Organization: New Technologies Group, Inc.  Palo Alto CA
Date: Thu, 20 Aug 1992 18:31:59 GMT

In article <1992Aug19.000850.23817@verdix.com> bill@verdix.com (William Spencer) writes:

>>IMHO, the major problem with the passive control is the dynamic range.  The
>>dynamic transients sound compressed and lifeless.
>
>Anyone care to speculate why this (reputably) is?

I can offer an additional speculation:

-  The source component (CD player, RIAA phono gain stage, tuner, etc.)
   wasn't designed to work into a low-impedance load.  The amplifier's
   input impedance, in parallel with the relatively low impedance of the
   passive control's attenuator, is low enough that the source component
   is having difficulty driving it.  At low signal levels, things work
   OK... but when the source component tries to emit a high-level
   transient, its output driver isn't capable of pushing enough current
   into the load it "sees", and it goes into some form of hard or soft
   clipping... in effect, compressing the signal.

   Stiffening up the output-driver power supply in the source component
   might improve matters, as might the addition of a high-current driver
   device.
-- 
Dave Platt                                                VOICE: (415) 813-8917
              Domain: dplatt@ntg.com      UUCP: ...netcomsv!ntg!dplatt
 USNAIL: New Technologies Group Inc. 2468 Embarcardero Way, Palo Alto CA 94303
Newsgroups: rec.audio
From: winalski@adserv.enet.dec.com (Paul S. Winalski)
Subject: Re: Who dat say dey gonna buy dat DAT?
Reply-To: winalski@adserv.enet.dec.com (Paul S. Winalski)
Organization: Digital Equipment Corporation, Nashua NH
Date: Wed, 19 Aug 1992 17:57:45 GMT


In article <1992Aug19.164701.11755@wdl.loral.com>,
trw@spl1.spl.loral.com (Tim R Witort) writes:

|>   One of the reasons that DAT prices are not plummeting like other
|>audio developments is the complexity of the mechanism. The DAT
|>technology requires very tight tolerances to squeeze 6 gigabytes of
|>data onto a 2" by 3" cassette. The technology is modeled on the
|>rotating drum head technology used in VCRs but the rest of the
|>technology took a lot of R&D that the consumers will have to pay for.

The main reason that DAT prices are not plummeting is lack of sales volume.
The producers are having to amortize their R&D costs over many fewer units,
hence, each unit is more expensive.  When/If DAT catches on, the prices will
drop.  They're already $200 lower now than they were a year ago.

|>There are also some hits incurred by the copy management system and
|>additional charges on blank tapes to "offset the inevitable loss of 
|>income to the music industry as a result of copying."

There are no such additional charges on blank tape.  There is legislation
pending before Congress to apply such charges, but the law has not yet passed
and no such royalties are being collected.

|>  The thing still makes better recordings than any analog deck in the
|>world. And those babys can go for $2000+!

And that is the second reason why DAT prices are high.  It is competing in the
high-end audio niche right now against analog open-reel decks.  In that market,
the competition (analog open-reel decks) runs about $2000, whereas you can get
a DAT deck of equal or better quality for $600, and even pro DATs cost under
$1300.  Likewise, the media are cheaper:  $20 and up for a 10" open reel blank
tape vs. $7 for a DAT cartridge with equal recording time (120 min).  Compared
to what this market is used to paying, DAT is a bargain.

--PSW
From: trw@spl1.spl.loral.com (Tim R Witort)
Newsgroups: rec.audio
Subject: Re: ISO Headphones
Date: 21 Aug 92 21:47:49 GMT
Organization: Loral Software Productivity Laboratory

In article <1992Aug21.191743.5714@leland.Stanford.EDU>, mrbill@leland.Stanford.EDU (William Bowen) writes:
|> In article <16n4ilINNrjn@stanley.cis.Brown.EDU> Guy_Seebohm@brown.edu writes:
|> >
|> >If you have any recommendations for a pair of mid to low end headphones please
|> >either post or send me mail.
|> 
|> Check out the Sony MDR-V6, available for around $70. They are unequivocally the
|> best headphones available at that price, and are among the best I've ever
|> listened to at any price. Those I've listened to include models from Stax,
|> Beyer, Sennheiser and AKG. For under $200, I can't recommend any of them over
|> the MDR-V6.

  I concur. They are extremely efficient and have a very good freq.
response (5 - 30,000 Hz I think). They can also dish out very high
volume distortion-free sound (not recommended on a regular basis due
to hearing damage of course).

     //=====\\
    ||       ||
    ||       ||
   //|       |\\
  || |))Tim((| ||
  \\ |       | //
   --/       \--
              |
              |
              \_____________===
Newsgroups: rec.audio
From: shiv@bnr.ca (Shiv Naimpally)
Subject: Re: Who dat say dey gonna buy dat DAT?
Reply-To: shiv@bnr.ca (Shiv Naimpally)
Organization: Bell-Northern Research Ltd.
Date: Wed, 19 Aug 92 17:51:53 GMT

You can buy a DAT deck for not much more than a top quality 3 head
cassette. The tapes are more expensive though $6-8 for a DAT120
vs $2-$3 for a good Metal 100 or 100 min tape. There isn't much
pre-recorded stuff yet, but since Sony (inventors of DAT) own CBS ...

Phillips is bringing out DCC (a consumer oriented digital tape format)
so Sony will feel pressure to bring prices of DAT decks & tapes, and
to make prerecorded stuff available. I'm sure they want to avoid
having another Betamax fiasco (ie. their format loses in the marketplace),
but then again they are introducing MiniDisks !
From: The Amp Droid
Newsgroups: rec.audio
Subject: The future is now!
Date: 14 Aug 1992 22:38:24 GMT
Organization: Sun Microsystems, Inc.
Reply-To: checksix@flyboy.EBay.Sun.COM (Al Conte)
NNTP-Posting-Host: flyboy.ebay.sun.com
Keywords: Spectral DMA 180


In my constant trek for power amp perfection, I have found great differences
in tonal qualities from amp to amp, even though the price difference from
amp to amp has ben pennies.
Well, today I spent lunch hour down at a local shop that carries the
Spectral line.  Spectral ? you say!.
Who is Spectral?
A small firm over here in Sunnyvale Ca.
The Spectral DMA 180 is IMHO, the finest solidstate amp regardless of
cost, ever made.
It's detailing rivals the best tube product.
It's control of the lower freqs is better than anything from Krell or
Mark Levinson, believe me I know I A B'ed them together on a pair of
Martin Logan Monoliths.
You must make an effort to hear this new topolgy design from Spectral.
BTW, it's size is roughly 1/2 that of the Krell / ML designs.
4 in. x 19 in. x 20 in.
I've made my descision, the amp for me is the new DMA 180 from Spectral.


Al

Newsgroups: rec.audio