HDTenEightyP/NetNews huggingface dataset:
From: jasa@dalton.inesc.pt (Jose Antonio Soares Augusto)
Subject: Tubes+transformers= AMPS !!
Organization: INESC, Lisboa Portugal
Distribution: sci.electronics
Date: Wed, 16 Dec 1992 20:14:28 GMT


Hi folks!

I'm glad to see a growing number of posts related with the above
subject.

So, I would like to make a few questions since I intend to project and
build a tube amp (only the last power stage).    To those who post (please...) you can talk in the
manner you want (very technical, very mathematical etc...) without
problem. Here they are:

1. What are the good materials to use in the output transformer core?
2. Is there any good supplier of these transformers (preferably in
Europe, if someone knows) ?
3. Where can I find suppliers of "good brand" tubes (I think I'll use
EL34 pentodes) again in Europe, preferably, (a good discussion on tubes quality
is going on the subject "Sovtek tubes")?
4. Is there any GOOD book,( the most "techcnical" you can find...) about
amplifiers with tubes, topologies, etc... around? I've some general
references in books on electronics from 50s and 60s (many years before
Horowitz and Hill "Art of Electronics" cookbook appeared *:-) ...) but
I couldn't find one "dedicated" to amplifiers?
5. Where can I find information about specialized topics related with
output transformers, such as, shielding, copper quality, winding
process, etc.


Thanks to all! Please reply. 

J. Augusto 
INESC, Lisboa, Portugal
Newsgroups: sci.electronics
From: pchris@dcc.uchile.cl (Chris Perleberg)
Subject: Analog Circuit Design with Graphic Interface?
Originator: pchris@pehuen
Date: Fri, 18 Dec 1992 15:33:16 GMT
Reply-To: pchris@dcc.uchile.cl
Organization: Universidad de Chile, Depto. de Ciencias de la Computacion


Hi,
	We are looking for software (accesable by anonymous ftp) that can be
used for analog circuit design (discrete components, op-amps, etc.) that uses
a graphic interface for defining the circuit.  The best interface for us 
would be X-Windows (Suns) or something for the PC.  Anybody know where to 
find such a software?

Thanks,
	Chris Perleberg
	pchris@dcc.uchile.cl
	Luis Godoy
	lgodoy@dcc.uchile.cl
Newsgroups: sci.electronics,alt.cyberpunk
From: jeffj@krfiny.uucp (J. Jonas)
Subject: Re: Caller ID block?
Organization: Jeff's house of computer pieces
Date: Wed, 16 Dec 1992 16:19:01 GMT

>>Can't you instead of blocking have the number be reported as something other
>>than the number you are calling from, like the old blue/black box trick

No, the source of the information is the switch generating the
SS7 commands.  As a subscriber, you cannot directly control the messages.
The days of in band signalling are over.


In article <1992Dec15.152116.26829@newstand.syr.edu>
	lruppert@rodan.acs.syr.edu (Dahr--The Beastmaster) writes:

> I was thinking of something just along those lines the other day.
> All you'd have to do is send a short signal to block/jam the legit one
> sent by the phone company, and then send yours afterwards,
> if the the whole transaction only takes a few tenths of a second

Mr. Louis Ruppert:
have you been reading too many Popular Science magazines?
The caller-id signal is sent between the first and second rings.
The recipient's phone is still on-hook.
How do you propose to send a signal to the recipient when
a) they haven't answered the call yet
b) you don't have an audio path to the recipient until the call is answered.

Depending on the recipient's premesis equipment, it may be possible to
transmit messages to their caller-id box during a conversation
(as long as the caller-id box is still enabled when off-hook).
You cannot delete previously received messages, but you may be able to
add new ones.  The problem is in generating the proper tones:
caller-id uses a 1200 baud FSK encoding that's not made by normal
modems (I think it's Bell 202 instead of Bell 212).

> Since your phone can transmit to the other line before the phone is
> picked up, it should be quite easy to implement this.

On what equipment is this allowed?  Certainly no ESS or crossbar that's
commonly used around here.

-- Jeffrey Jonas
jeffj@panix.com
-- 
Jeffrey Jonas

jeffj@panix.com
Newsgroups: sci.electronics
From: billmcd@netcom.com (William B. McDonald)
Subject: Re: Static electricty problem
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Fri, 18 Dec 1992 02:51:06 GMT

 had a simmilar problem to this a few years ago with 
a printer. When there is a static discharge, you have a 
spark gap transmitter very close to the electronics
you wish to protect. What I found worked was grounding 
the metal plate ( drawer in your case ) through about a
100 to 470 ohm half watt carbon comp resistor. This tend to dampen
the transmission and bleed of the charge. A commercial
anti static pad may work as well, and they are cheap to
try.  Grounding the metal plate just made a nice 1/4 wave antenna
and did not fix the problem.  The next step beyond adding the 
resistor is to add a metallic shield between the object
being touched and the electronics being protected.
This can start to cost money.

The failures I had were some what random, so I used a
static gun and would try about ten zaps. On unprotected
units I would get 8-9 failures, and on protected units
abut one failure out of twenty. It might be usefull
to try to keep good data as you try an empiracal solution.
Best of Luck.
billmcd@well.sf.ca.us
Bill McDonald
:wq
:W
:Q
:WQ
ZZ
:ZZ
zz
:zz
From: 2575brooksr@vms.csd.mu.edu (Ryan K. Brooks)
Newsgroups: sci.electronics
Subject: TMS320C40 info wanted
Date: 19 Dec 1992 06:16:08 GMT
Organization: Marquette University - Computer Services
Reply-To: 2575brooksr@vms.csd.mu.edu
NNTP-Posting-Host: vmsa.csd.mu.edu

Hi all!
	I'm beginning a project utilizing the C40, and I'd like
to talk to anyone else who's had some experience with device,
especially with PCB layout.  Thanks!
 ----------------------------
 Ryan K. Brooks                        "You're never dead till you're        
 2575BrooksR@vms.csd.mu.edu                  out of quarters."     
 Marquette University EECE              
 NemeSys Corporation
 "Curtains for Windows" 
Newsgroups: sci.electronics,sci.energy,rec.autos.tech
From: cmwolf@mtu.edu (christopher m. wolf)
Subject: Re: Flywheel batteries as EV power source
Organization: Michigan Technological University
Date: Wed, 16 Dec 1992 23:25:21 GMT

andyh@chaos.cs.brandeis.edu (Andrew J. Huang) writes:
>In article <1992Dec15.194558.2556@adobe.com> pngai@adobe.com (Phil Ngai) writes:
>2. There are several places for the energy to go during an explosion.
>Since the energy is kinetic, a lot of it will end up as particle
>velocity.  Some will dissipate into the air as air friction (some hot
>air as a side effect).  A quantity of energy will go into the
>mechanical breaking of the flywheel disk itself.  Some more will go
>into the penetration of the flywheel housing.  What residual energy
>escapes these will have to be determined by testing.

They are supposedly designed within a box held at a vacuum (sp?), with
the box string enough to contain them, I thought.

>3. You don't need to destroy cars to test the safety/danger of
>exploding flywheels.  You just take a flywheel, spin it to 10 times
>its rated capacity, and give it both barrels of a 10ga shotgun loaded
>for elephant.  If it explodes, you measure the explosion.  If not,
>send it to Ralph Nader for further tests.

There is a different between shooting it and having it break up though.
From: jscherer@db (John Scherer)
Newsgroups: sci.electronics
Subject: shaft encoder question.
Date: 17 Dec 92 00:02:42 GMT
Organization: Novell, Inc.
X-Newsreader: Tin 1.1 PL4

I have a shaft encoder that I want to interface to an 80c31 mpu for use in
digital setting circles for my telescope.  What I would like to be able to do 
is to connect one phase if the encoder to int1 and the other phase to T1 on 
the mpu.. That way when the mpu interrupts on int1 I can test T1 to determine
the direction.  My problem is that the outputs on the encoder are triangular,
 do I need to convert this to square wave?

 Thanks for any help

John Scherer
Newsgroups: sci.electronics
From: L.Chisholm@massey.ac.nz (Len Chisholm)
Subject: Re: What are the threshold levels for RS-232?
Summary: IBM and Toshiba equipment requiring negative-going RS232 signals
Keywords: RS232 voltage
Organization: Massey University, Palmerston North, New Zealand
X-Reader: NETNEWS/PC Version 2c
Date: Mon, 14 Dec 92 02:59:12 GMT

My computer ( a Toshiba T5200 portable ) and a number of our REAL IBM PC
and AT serial cards have the bias pins on their RS232 inputs connected
in such a fashion that they require a negative-going input to operate
i.e. the lower hysteresis threshold is below zero.

The clone/Taiwanese/etc. multi-function cards we have used seem to work
on positive-going signals only.

If you are building general purpose equipment you should emit negative-
going signals to be sure - you may get the same problem from other
BIG-NAME suppliers.

-- 
-------------------------------------------------------------------------
|  LEN CHISHOLM , Systems programmer  | EMail: L.Chisholm@massey.ac.nz  |
| Department of Production Technology | Phone: +64 6 3505262            |
|         Massey University           | FAX:   +64 6 3505604            |
|   Palmerston North, New Zealand     |                                 |
-------------------------------------------------------------------------
Xref: sparky sci.electronics:21231 rec.autos.tech:16970 sci.energy:6289
From: mwilson@ncratl.AtlantaGA.NCR.COM (Mark Wilson)
Newsgroups: sci.electronics,rec.autos.tech,sci.energy
Subject: Re: Flywheel batteries as EV power source
Date: 20 Dec 92 19:24:15 GMT
Organization: NCR Engineering and Manufacturing Atlanta -- Atlanta, GA

In <gfATnhq00iUzI1mV0H@andrew.cmu.edu> cd1i+@andrew.cmu.edu (Christopher Bradley Devlin) writes:

|into a light cotton like fiber.  Heat, yeah, but how much kinetic energy
|does a flying piece of cotton have?

As much kinetic energy as the original flywheel obviously.
-- 
Mob rule doesn't become any prettier, just because the mob start to call itself
a government.
It ain't charity if you are using someone else's money.
Mark.Wilson@AtlantaGA.NCR.com
Xref: sparky sci.electronics:20743 rec.audio:16702 alt.guitar:10862 rec.music.makers.guitar:930
From: dam@dcs.glasgow.ac.uk (David Morning)
Newsgroups: sci.electronics,rec.audio,alt.guitar,rec.music.makers.guitar
Subject: Re: Tube amp transformers
Keywords: tubes transformers
Date: 15 Dec 92 10:23:03 GMT
Organization: Glasgow University Computing Science Dept.

npstewar@eos.ncsu.edu (NATHAN PHILLIP STEWART) writes:


>1) What exactly is the relation between plate voltage and the level where output
>   distortion begins. As far as I understand it now, the higher the plate 
>   voltage, the higher output level before distortion sets in. Is this the
>   relationship? Is it more complex than this? (of course it is)

Roughly speaking, yes you're right. However for a more accurate answer you
have to look at the characteristic curves and the load line which will give
you the points where the amp will start to clip, however, unlike a preamp
stage, a power amp has a dynamic load line which makes rather more complex
to work out accurately but, broadly speaking, the higher the HT voltage (is
this B+ in the US?) the higher the output level before overload distortion
sets in.


>3) About measuring plate voltage, it occured to me that if the impedance of 
>   my voltmeter is not high enough I could fry my voltmeter and quite possibly
>   more (me for instance.)  Is this a real concern, or do Multimeters generally
>   have a high enough impedance that I don't need to worry.

In general there's no real need no worry about your multimeter loading down
the reading. If it's a digital one it'll have an input impedance of about 
10 megohms!! If it's an old fashioned moving coil type meter, you *may* have
to be a bit more careful. If it's rated at 20kohms/volt or better, it'll be
ok.
What you *will* have to watch, particularly if your hanging it off the HT
voltage or the anodes of the power stage is that the probes or the meter
can actually handle the *voltage*. It's usually stamped on the case it's
max dc input level but that's only for the meter circuitry *not* the probes
so make sure the probes are well insulated.

>4) If I want to leave my 6L6's, but drop their plate voltage (This depends on
>   the answer to the first question), without changing my transformer, can this
>   be done.  (Since my carvin uses some FET EQ circuits and reverb buffering,
>   I can't just sub a lower power transformer.)

In short, no unless you fit some sort of additional transformer inside the
amp to drop the HT while maintaining the filament voltages etc.

Dave
-- 
Newsgroups: sci.electronics
From: brownt@seq.uncwil.edu (brown todd francis)
Subject: MIND-L
Keywords: Mind/Brain Machines
Organization: Univ. of North Carolina @ Wilmington
Date: Fri, 18 Dec 1992 15:30:11 GMT

Does the MIND-L group still exist?  If so, how can I subscribe?



Also, I am interested in building a light&sound brain machine
which uses a simple circuit for intensity/frequency control of
embedded leds in light goggles.  The trick I am having trouble
with is to include a dc  timer delay into the circuit.

Any ideas?
From: rla@netcom.com (Robert Armstrong)
Newsgroups: sci.electronics
Subject: U.S. Cyberlab (was Ranking the Electronics...)
Date: 17 Dec 92 20:57:05 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest)

ardai@zax.eda.teradyne.com (Michael Ardai) writes:

>Unfortunately, most of the interesting projects are from Nick Goss aka
>US Cyberlab.  I have tried (many times) to get a catalog from them, and 
>it has never shown up.  If they can't send out a catalog to a prospective
>customer (and I was planning to by about 30 kits for a kit-building
>workshop with the Boston Amateur Radio Club), I won't send them any
>money...

  I ordered a copy of "Extreme High Technology" (Nick's book) from
them.   After about a month they sent me a letter saying that "the
book was so successful we need a second press run", and "it will be
shipped in a few weeks."  After two more months I finally gave up
waiting on it.

  The thing that annoyed me the most was that they continued to advertise
the book in "Computer Craft", soliciting even more orders even though they
obviously could not deliver.

  Did _ANYONE_ get a copy of this book ??

  One thing that I will say in Nick's favor is that he did refund my
money promptly and without hassle when I asked for it.  That did make
me feel a little better about U.S. Cyberlab.

  I guess I'd order stuff from them, but I'd do it COD :-)  And I wouldn't
depend on receiving it!

Bob Armstrong
rla@netcom.com
From: cyberman@toz.buffalo.ny.us (Cyberman)
Newsgroups: sci.electronics
Subject: Re: D O E S   A M E R I C
Date: 14 Dec 92 06:19:59 GMT
X-Maildoor: WaflineMail 1.00r


  Sir Maier spoke forth saying:
"Re: D O E S   A M E R I C" toward
 on 12-12-92  06:58

 JM> I know that it is not a reasonable comparison since English is my
 JM> first language and I have only been trying to learn Japanese for one
 JM> year, but 2000 kanji seems like a hell of alot of literacy to me!

    Ehhmm well try learning written english in that time if it's
    not native.  The only thing more difficult to learn than
    written and spoken english is NAVAHO!

    Stephen - Cyberman@toz.buffalo.ny.us/Cyberman@exucom.com

... On a clear day, you can see......45 nautical miles.
---
 * Blue Wave/QWK v2.11 *
                   
Newsgroups: sci.electronics
From: rfc@allegra.att.com (Robert F. Casey)
Subject: Re: Various national colour code of wires (e.g. earth) for elec. plug
Organization: AT&T Bell Laboratories, Murray Hill, NJ
Date: Tue, 15 Dec 1992 19:13:56 GMT

Someone mentioned, in this thread, that, in USA, white is only used for the
neutral power return.  But there is one exception that I've seen:  Imagine
you have a ceiling light controlled by a wall switch.  And that the powerline
source comes into the ceiling box, and you have a two wire (excluding the 
safety ground) cable running to the switch.  The two wires connected to
the switch.  Two wire cable ("BX", "Romex") only comes with a white wire
and a black wire, in addition to the ground.  So, how to wire the switch,
what color for what?  Usually, what gets done is to make the white wire
to the switch the hot supply, and the black the switched hot.  So, the
light fixture will be supplied with a black (switched hot) and white (neutral)
from the source.  and the hot white going to the switch connected to the
hot black source.  

                 box in ceiling          box on wall
hot black============--------------------- hot white
source                                  switch
neutral white-------   =================== switched black
                   |   |
                 light bulb
                 in ceiling

safety grounds connect all boxes too.

Go to the library and they should have a book on housewiring.  It's just
as easy to do it correctly as to do it wrong.  And if you do it right,
and you neglect to have your work inspected, it's doubtful that they will
ever know you did anything.  

Disclaimer: Don't blame me.
Newsgroups: sci.electronics,sci.energy,rec.autos.tech
From: morrison@cs.uiuc.edu (Vance Morrison)
Subject: Re: Flywheel batteries as EV power source
Organization: University of Illinois, Dept. of Comp. Sci., Urbana, IL
Date: Thu, 17 Dec 1992 15:12:06 GMT

I would just like to chime in that while I beleive that the problems
of catastrophic failure is a real problem with flywheels, I also feel
that the problem might be solvable.

As was discussed, all the energy of the flywheel will be dumped in
a accident and methods must be developed to insure a explosion does 
not result.   Here are some possibilities

1) Slow down the rate of energy dumping.  Good design should allow that
  even under conditions of a crash the flywheel will remain intact and
  contained.  Thus instead of blowing apart what we want is for the
  wheel to bang around inside a housing, loosing energy as it colides
  with the housing.  Thus instead of dumping all its energy in under
  a second, it will release it over the period of many seconds (the
  longer the better)  This reduces the problem tremendously.

2) Avoid or control the explosion.  If the materials in the housing 
  vaporize only a VERY high temperatures, then even in the flywheel
  dumps its energy, no GASES will be generated, and thus no explosion.
  Alternately, you can use gas creation to absorb the enery and design
  methods of savely venting it.

3) Absorb the energy.  There is no reason why some of the energy could
  be converted to something besides heat.  If the housing was lined with
  some chemical that underwent fast, a heavily endothermic reaction, much
  of the energy could be absorbed as chemical potential energy.  (High
  heat of melting or vaporization?) If such chemicals can't be found, as 
  a worst case, the housing could be made out of something with a high heat 
  capacity and high melting point.  

Finally, if all of these fail, a flywheel will still be possible simply
by scaling it down.    As was mentioned, the large POWER density of
a flywheel make it ideal for regenerative breaking.  It may be desirable
to have a small flywheel for this purpose.  Since it holds far less 
energy, make int safe should be easy.

I believe a road worthy flywheel can be made.  The only question is 
is it worth it.  It might be too heavy or too expensive, or there simply
might be better ways of storing energy for vehicular applications.

Vance
From: rp@llex.ll.mit.edu ( Richard Pavelle)
Newsgroups: sci.electronics
Subject: Using 500W halogen instead of 300W in a fixture
Date: 18 Dec 92 12:55:29 GMT
Organization: MIT Lincoln Laboratory
Originator: rp@llex


I purchased a ceiling fixture that uses a 300W halogen. 
I would like to use a 500W halogen instead. The fixture
is glass and brass and is about a foot from the ceiling
with lots of air flow. Is there any reason for not testing
the 500W and monitoring the resulting heat or am I foolish
to not follow the manufacturers guidlines?

In general what advice do you give about installing higher
power illumination than the manufacturer suggests?

 
Newsgroups: sci.electronics
From: jhwhit01@ulkyvx.louisville.edu
Subject: Re: Where to get 8097/7 microcontrollers
Date: Sun, 13 Dec 1992 05:32:38 GMT
Organization: University of Louisville

In article <1992Dec12.211939.15464@ssc.com>, markz@ssc.com (Mark Zenier) writes:
> jhwhit01@ulkyvx.louisville.edu wrote:
> : In article <Bz5528.4HI@newsserver.technet.sg>, kewta@solomon.technet.sg (Kew Tow Ann) writes:
> : > Would appreciate if anyone knows of a mail order source for Intel 8096/7
> : > micrcontroller? 
> :  
> : Try JDR Microdevices.  They have the 80C96 and 80C97 listed for 95cents each.
> 
> Those are tristate bus buffers made by National, 
> not a 16 bit microcontroller.
> 
> Great choice of part number ;-).
  
Okay.  Arrow Electronics has the Intel N8096-90 (stock # 2936TNE) "ROM less
16-bit Sgl Ch uC PLCC" and N8097BH (stock #2936KE9) "16-bit Sgl Ch uC w/o ROM"
and A8097-90 (stock #2936TNF) "Hi-perf 16-bit Sgl Ch uC w/o ROM, w/10-bit AD,
68 pin grid array" and N8097-90 (stock #2936TNG) "PLCC 8097-90" listed in a
1988 catalog.  Also have P8098 (stock #2936KFA) "16-bit Sgl Ch w/o ROM, 10-bit
AD, 8-bit BUS, 48L DIP".
 
Prices ranged from $7.15 for the P8098 to $10 for the N8096-90 to $20.50 for
the high performance A8097-90.  The other two parts were $10.50 each.  Arrow
Electronics can be reached at 1-800-93-ARROW, or 1-800-932-7769.
 
Jeff White    jhwhit01@ulkyvx.bitnet
Newsgroups: sci.electronics
From: tindle@ms.uky.edu (Ken Tindle)
Subject: Re: XMAS Lights Theft Alarm
    <1992Dec10.182447.16893@vpnet.chi.il.us> <1992Dec17.211226.9348@mav.com>
Date: Fri, 18 Dec 1992 14:41:15 GMT
Organization: University Of Kentucky, Dept. of Math Sciences

Y'know, this is such a common problem, I wonder why nobody has ever made
commercially a socket with a snap-switch built-in, and an extra integrated
wire down the length of the whole string.  Make detecting a physically 
missing bulb a, er, snap.  No pun intended.

--------------------------\ /-----------------------------------------------
INTERNET:tindle@ms.uky.edu | "Could you please continue the petty bickering?
BITNET: tindle@ukma.bitnet |  I find it most intriguing."   ---    Data, 
Ken Tindle - Lexington, KY |  Star Trek, The Next Generation, "Haven"
--------------------------/ \-----------------------------------------------
Newsgroups: sci.electronics
From: doherty@melpar (Kevin Doherty)
Subject: Re: Very sharp RF notch filter sought
Organization: E-Systems, Melpar Division
Date: Tue, 15 Dec 1992 17:14:44 GMT

  A fair technique would be to use a tuned stub - a piece of coax cut so as
to be (I believe) 1/4 wavelength at the frequency you want to notch.

  At 100 MHz, this would be on the order of a few feet of coax; doesen't
seem like a problem.

  It's how we routinely notch out signals from a tower radiating several
megawatts only a mile away (megawatts because at least six stations use
the tower).

  The nice thing about it, is that since you make it yourself, you can tweak
it by trimming it shorter until attenuation is max.  Careful, though-can't
make it longer if you cut too much.

  The response is periodic, but since you're looking at a narrow band I don't
expect you'll see any but the fundamental response.

  
Xref: sparky sci.electronics:21115 rec.autos.tech:16886 sci.energy:6253