HDTenEightyP/NetNews huggingface dataset:
From: rblander@watdragon.uwaterloo.ca (Robyn Landers)
Subject: Re: Tube amp transformers
Summary:  swapping 6L6 for 6V6 etc
Keywords:  tubes transformers
Organization: University of Waterloo
Date: Sat, 12 Dec 1992 00:48:09 GMT

In article <Bz0GpF.Fyn@hfglobe.intel.com> dcovell@hfglobe.intel.com (David Covell) writes:
>
>I recently bought an old tube hi-fi amp that I'd like to cannabilize for
>parts with which to build a project guitar amp. Several people have told
>me that hi-fi output transformers aren't suitable for instrument amps.
>I'd like more data on this; if the problem is that hi-fi output transformers
>can't handle the saturation that guitar amps put out, can I avoid this by
>using output tubes of lower power? 

    From what I understand the problem is the other way around.
Guitar amp xformers are crappy by hi-fi audio standards.  Harry Kolbe
of Kolbe Soundsmith in NYC told me Marshall xformers in particular
are really awful from an audio standpoint.  (This in relation to
discussion of why Power Soaks are so evil.)

>The amp uses a pair of 6L6's in each
>channel. Is there some reason I couldn't use EL84's or 6V6's, which would
>cut the power by at least 40%? This would avoid output wattage in excess of
>the transformer's rating, which is the only potential problem I can see with
>using these transformers. Am I missing something obvious here?

    Check that the smaller tubes can handle the plate voltage the xformer
was providing to the larger tubes.  RCA Receiving Tube Manual says
6L6 can take 360 volts (design centre), or 500 volts (design maximum)
at the plate.   6BQ5 (EL84) says 300V design centre; it doesn't
list design max.  You'll want to check plate (and grid etc.) voltages 
that the circuit you're using is providing.

    I've been thinking of building/converting an amp to EL84 too...
...dare I hack on my nice old Marshall?  :-)


-----
Robyn  Landers
rblanders@math.uwaterloo.ca
	"I'm just doing my rock'n'roll duty." -- Dubois

Newsgroups: sci.electronics
From: mustafa@seas.smu.edu (Mustafa Kocaturk)
Subject: Re: Transmission line question
Summary: current loops may cause power line interference
Keywords: ethernet interference
Organization: SMU - School of Engineering & Applied Science - Dallas
Date: Tue, 15 Dec 1992 21:52:54 GMT

In article <1992Dec15.202004.15878@ucsu.Colorado.EDU> barr@tramp.Colorado.EDU (BARR DOUG) writes:
>Some specs I have call for ethernet coax to be grounded in one location
>and one location only! I am wondering why this is. Antenna effects,
>current loops or something else. Does anyone know why this is the case?

Current loops can cause I*R drops resulting in severe interference from
the AC power network.  The interference level may exceed that of the signal
by several Bels (=orders of magnitude).

I remember dealing with a shielded RS-232 cable that was forming a current
current loop between two otherwise disjoint power networks.  The cable
had become so hot that its plastic insulation would have melted had I not
noticed in time.  I noticed it because the data was corrupted beyond
any recognition, and the terminal would not work even at 50 bits/second !
Ethernet signals would be much more sensitive to such interference
with their smaller amplitude and higher speeds.
-- 
Mustafa Kocaturk   mustafa@seas.smu.edu  EE Dept., Room 305A, Caruth Bldg.
Home: 214-706-5954  Office: 214-768-1475  SMU Box 753190, Dallas, TX 75275
From: s3176997@techst02.technion.ac.il (Daphne Rosenhouse)
Newsgroups: sci.electronics
Subject: Poor man's SERVANT
Date: 21 Dec 92 00:24:35 GMT
Organization: Technion, Israel Institute of Technology

hi all
a friend of mine gave me hundreds of old 'pupular electronics' and 'radio electronics' etc...
in one of them, from 78 i think, i saw a simple project:
a device (gadget) that toggles a RELAY whenever you CLAP YOUR HANDS.
they called it POOR MAN'S SERVANT.

I liked the idea and wanted to construct it... but they used some VOX-chip that is not produced anymore...

I still want to build such circuit.   Can anyone send me a schem of such circuit which can be built with not-so-hard-to-get components ?

thx in advance
bye
Newsgroups: sci.electronics
From: till@acid-rain.lucid.com (Don Tillman)
Subject: Re: purpose built distortion producing circuits
Reply-To: till@lucid.com
Organization: Lucid, Inc.
Date: 17 Dec 92 11:16:24

   From: ah335@cleveland.Freenet.Edu (Richard Banks)
   Date: 17 Dec 1992 00:14:05 GMT
   Organization: Case Western Reserve University, Cleveland, OH (USA)

   I'm constructing a purpose built distortion producing circuit to
   be used to add gain to audio signal of an electric guitar.

   The circuit uses 4 stage op amp noninverting configuration to
   produce a gain of 1855 running off a 9V power supply.

   My problem is the unit is acting like a noise gate, when the signal
   attenuates the circuit "cuts off."  Therefore it is very quiet,
   but does not produce long sustain, which is what I want.

Without a complete description of the circuit nobody will be able to give
you much in the way of useful advice.  That said, I'll go out on a limb and
predict that from your description of the effects, it sure sounds like at
least one of the op-amps is running with DC gain, and some offset voltage
is throwing it into clipping with no signal present (causing the quiet),
and when your guitar signal is large enough to overcome this, you hear the
distorted sound.

   The value of the feedback resistors are 100k and the value of the
   power resistors is 220 ohm.  

What is a "power resistor" in this context?

   Also on a side note, what is the best op amp config to use
   for distortion, inverting or noninverting?

The non-answer is to not use op-amps at all.  ("Op-amps are for weenies.")

If you insist on using op-amps, and are using diodes in the feedback loop
to generate distortion, an inverting configuration is best because it
doesn't have the minimum gain deal that a non-inverting stage does.

If you insist on using op-amps, and use the op-amps themselves for
distortion (yechhhh!), or using diodes outside the feedback loop for
distortion, then a non-inverting stage is better due to input impedance,
noise, and gain issues.

   I would think noninverting, because inverting amps cause
   a lot more bias current at high gain.

Why do you think inverting amps configurations cause a lot more bias at
high gain?

  -- Don

Xref: sparky sci.electronics:21121 sci.energy:6258 rec.autos.tech:16894
From: fredl@strobe.ATC.Olivetti.Com (Fred Leffingwell)
Newsgroups: sci.electronics,sci.energy,rec.autos.tech
Subject: Flywheel Failure
Date: 18 Dec 92 18:41:56 GMT
Followup-To: sci.electronics
Organization: Olivetti ATC; Cupertino CA, USA


	There is a lot of speculation on this subject and not much
	aggreement.

	I have read (in Scientific American many years ago and in
	more recent Popular Science I think) that there is not 
	the same danger level from modern flywheel designs as would
	be the case from a steel plate for example.

	My thought is - haven't any of the tests been run to the 
	failure point?  Have any actual working prototypes been 
	built?  It would seem not.  This was easy to understand 
	15 or more years ago when I read the first article, but
	now it really seems ludicrous.

	So Is the real reason for not storing energy in a flywheel
	the danger?  If so why the comments that the things simply
	fail in a cotton candy like fluff?

	Fred Leffingwell (fredl@olivetti.com)
From: mpaul@unlinfo.unl.edu (marxhausen paul)
Newsgroups: sci.electronics
Subject: Panasonic Printers with PADS?
Date: 14 Dec 1992 18:22:30 GMT
Organization: University of Nebraska--Lincoln	
Distribution: global
NNTP-Posting-Host: unlinfo.unl.edu

Does anybody know what the optimal printer setting is when using PADS
software with the popular Panasonic KXP-1124/1124i?  It works when
PINSTALL is told to use the IBM Proprinter setting, but I can't help
thinking that one of the EPSON settings might be able to give better output
quality.  Anybody got ideas?

--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .
From: baden@inqmind.bison.mb.ca (Baden de Bari)
Newsgroups: sci.electronics
Subject: Re: /* Directional Gyros *\
Date: Mon, 14 Dec 92 20:32:52 CST
Organization: The Inquiring Mind BBS  1 204 488-1607

miked@syscon.rn.com (Mike DeMetz) writes:

> R/C gyros are rate gyros. They output a 1.5-2.0 mS pulse which
> is a mix of the gyros signal and the r/c channel it is plugged
> into. I don't think they output anything if there is no incoming
> signal to mix with. Two companies are coming out with solid stae
> (piezo) r/c gyros.
> 

 
        I see, but are they conditional to the control pulse widths given 
by the receiver?  In other words, will they act the same no matter what 
kind of frequency they are receiving?
 
        >>Baden<<


baden@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607
From: dnwangus@flash.LakeheadU.Ca (Dave Angus)
Newsgroups: sci.electronics
Subject: Re: Testing solar cell performance w/computer assistance?
Keywords: Solar cell
Date: 15 Dec 1992 22:33:11 GMT
Organization: Lakehead University, Thunder Bay, Ont., Canada

In article <1992Dec14.223424.21680@unlv.edu> bill@pauli.lv-physics.nevada.edu (Bill ODonnell) writes:
>
>     If extreme accuracy isn't a major concern you may
>want to consider using the game port on the Apple.  The
>Apple II series and the Apple IIGS both use a 4 channel
>A/D converter to read the voltage (via a variable resistor)
>at the game port.
>
(stuff deleted)

Sorry; that ain't correct.  The Apple ][ game ports work almost exactly
like the IBM game ports:  they use a 558 quad timer chip to generate 
time delays proportional to RC time constants.  The C is built into
the game port, the R is provided by the joystick or paddles' 
potentiometers.  The game ports can measure resistance, but not 
voltage.

I think that CoCo's have actual A/D converters on their game ports;
I don't know this for a fact, however. 

It is incredibly easy to interface some A/D converters to the
Apple ][ bus; some of the data sheets for Analog Devices converters
include complete details.  Offhand I think the AD7578 might be one
of those; maybe someone else who has the data sheets can confirm
this. 

regards,
--
Dave Angus                                   "Kundalini wants his hand back"
From: pauls@trsvax.tandy.com
Date: 11 Dec 92 10:40 CST
Newsgroups: sci.electronics
Subject: Re: Query: What are pseudo-static RAMS?
Message-ID: <288200048@trsvax>
Nf-ID: #R:cc.gatech.edu:5022:trsvax:288200048:000:307
Nf-From: trsvax.tandy.com!pauls    Dec 11 10:40:00 1992


They are made by Hitachi. I have lots of data on them.

Internally, they are self-refreashing DRAM cells. They are used when you
DONT want to battery-back them up. That's why they are cheap. There is some
minor timing constraints, but generally they are just like a SRAM, except
they suck power like DRAMS.
From: tell@rukbat.cs.unc.edu (Stephen Tell)
Newsgroups: sci.electronics
Subject: Re: Various national colour code of wires (e.g. earth) for elec. plug
Date: 16 Dec 92 21:31:20 GMT
Organization: The University of North Carolina at Chapel Hill

In article <1992Dec15.191356.22205@allegra.att.com> rfc@allegra.att.com (Robert F. Casey) writes:
|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.

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


|Go to the library and they should have a book on housewiring.

If the book is any good, in this case it should tell you to "re-code" that
hot white wire to blue, red, or black using plastic electrical tape or some
kind of marker.  This should be done at both ends of the cable, of course.


-- 
Steve Tell       tell@cs.unc.edu H: 919 968 1792  | #5L Estes Park apts
UNC Chapel Hill Computer Science W: 919 962 1845  | Carrboro NC 27510
Engineering is a _lot_ like art:  Some circuits are like lyric poems, some
are like army manuals, and some are like The Hitchhiker's Guide to the Galaxy..
Newsgroups: sci.electronics
From: miguel@ldgo.columbia.edu (miguel maccio)
Subject: Intelligent (serial) LCD/LED display module
Keywords: Display,LCD,LED.
Organization: Lamont-Doherty Geological Observatory
Date: Fri, 18 Dec 1992 19:45:11 GMT


Hi there!
        I'm trying to find something like an intelligent LCD/LED display
module.
        By intelligent I mean that I could send characters (maybe one or
two lines of 20 charcters each) via RS232 and the display module will take care
of all circuitry, e.g.:LCD drivers and controller,RAM, serial interface etc.

        Does anybody have heard of them?
        Who sells them?

Thank you in advance.

Miguel Maccio
e-mail: miguel@lamont.ldgo.columbia.edu

P.S.: Please respond to my e-mail address.
From: mpaul@unlinfo.unl.edu (marxhausen paul)
Newsgroups: sci.electronics
Subject: Tough tape recorders?
Date: 20 Dec 1992 21:49:05 GMT
Organization: University of Nebraska--Lincoln	
Distribution: global
NNTP-Posting-Host: unlinfo.unl.edu

Like most schools, our church school uses a lot of your low-end general
purpose cassette recorders - the non-stereo, piano-keyboard control, 3"
speaker jobbies that cost about $35.  Of course, they get used to death,
and kids really hammer those keys, and my wife always brings them home for
me to fix.

My question is, does anybody have a recommendation for a more-durable tape
player for school use?  I know the ones we use are cheap enough we should
just pitch them, but if I can get a little better quality without buying
a zillion-dollar Nakamichi, it would be nice.
 
--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .     
Xref: sparky sci.electronics:21152 sci.energy:6267 rec.autos.tech:16914
From: stead@skadi.CSS.GOV (Richard Stead)
Newsgroups: sci.electronics,sci.energy,rec.autos.tech
Subject: Re: Flywheel batteries as EV power source
Date: 18 Dec 92 23:15:25 GMT
Followup-To: sci.energy

In article <1992Dec18.032310.12293@ast.saic.com>, gregor@kafka.saic.com (gregg hanna) writes:
> At least some energy would be absorbed heating up the Halon as it
> expands from the tank, and then the mixture would hit air.
> What would this look like?  I know the heat has to go somewhere,
> but since the Halon interferes with combustion would it mitigate
> the damage?

Halon "interferes with combustion" by removing oxygen.  The flyweel doesn't
care.  It's energy is released without the need for oxygen.  This has nothing
to do with heat.  Sure, the Halon would heat up, too, but an explosion
capable of melting more than 100 kg of iron will not be significantly
affected by heating up some halon.


--
Richard Stead
Center for Seismic Studies
Arlington, VA
stead@seismo.css.gov
Newsgroups: sci.electronics
From: cwatters@magnus.acs.ohio-state.edu (Coyt D Watters)
Subject: CC decoding TVs
Organization: The Ohio State University
Distribution: usa
Date: Mon, 14 Dec 1992 17:47:30 GMT

Sears is selling a Zenith 25" (maybe 27") television with built in Closed 
Caption Decoding now.

They're obviously using the character set used by the on-screen adjustment 
software, but I noticed one thing I had not seen with the outboard "BOX"
decoder...

The captioning was in different colors.  In _Return of the Jedi_, offscreen
voices' text would have a different background from the normal captioning.

The captioner must've had fun with this one...  

[Speaking Huttonese]     - Jabba the Hutt 
[bleep][beep][whistle]   - R2D2
[roar]			 - Chewbacca

I also saw the color change during commercials.

BTW:  I believe this set ran about $449.99, right in the middle of sets in
the same size range.  I'll try to get a Zenith/Sears model number.

-Coyt
Newsgroups: sci.electronics
From: jeffj@cbnewsm.cb.att.com (jeffrey.n.jones)
Subject: Looking for MC3363
Organization: AT&T
Distribution: usa
Date: Tue, 15 Dec 1992 16:31:54 GMT

I am looking for who sells the MC3363 chip from Motorola. Could someone
please steer me to a known place that sells this and other chips from
Motorola. I need only a few chips for some homebrew projects. I have called
the obivious places and so far no luck. Thanks for any help here!

Jeff
-- 
 Jeff Jones  AB6MB         |      
 jeffj@seeker.mystic.com   |     
 Infolinc BBS 415-778-5929 |
From: bb099@cleveland.Freenet.Edu (Adam Trent Phillips)
Newsgroups: sci.electronics
Subject: Re: "The Glob" Atari 2600 processors ???
Date: 17 Dec 1992 05:43:11 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
NNTP-Posting-Host: slc10.ins.cwru.edu


	Might be a different version of the board than you expected.
I would have to see this "golb" to know what it was.  I have seen some 
WEIRD parts. I would NOT remove it .... just in case...


-- 
A. TRENT PHILLIPS |" A mirror is a negative space with a frame and a place for
  also known as   | your face, it reveals what the rest of us see. It conceals
   WHITE  ROOK    | what you'd like you to be."--Blue Oyster Cult
-------bb099@cleveland.freenet.edu-----aa1439@freenet.lorain.oberlin.edu-------
Newsgroups: sci.electronics
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Canabalism of old electronics
Organization: Motorola Computer Group, Tempe, Az.
Date: Sat, 19 Dec 1992 12:30:47 GMT

In article <1992Dec18.203808.25583@kong.gsfc.nasa.gov> mark stephens <stephens@kong.gsfc.nasa.gov> writes:
> do yall routinely canabalise old radios, TVs, etc. for spare parts?  

I don't go to the trouble of removing the parts from the board. I have
a large box into which I toss the whole circuit board. If I need a part,
I remove it then.

John

PS, if you like parts, forget TVs and head for those surplus/salvage
industrial auctions. Odds are you'll be the only one there who knows
what the parts do!


-- 
+--------------------------------------------------------------------------+
| John R. Schuch  -  Motorola Computer Group  -  Manufacturing Engineering |
| N7XVS - schuch@phx.mcd.mot.com - (602) 438-3008 - CompuServe: 70733.3330 |
+--------------------------------------------------------------------------+
Newsgroups: sci.electronics
From: zklf0b@gs144.hou.amoco.com (Fergason)
Subject: Re: INTEL 8052 w/BASIC - is the code public domain?
Keywords: BASIC INTEL PUBLIC DOMAN
Organization: Amoco Production
Date: Tue, 15 Dec 1992 17:54:51 GMT

In article <533@bit.UUCP> thomas@bit.UUCP (Thomas Walter) writes:
>
>Did INTEL place the BASIC rom code for the 8052 (8031, etc.) in
>PUBLIC DOMAIN?
>
>A friend, who is a High School Teacher, asked if I could make up
>some microcontroller boards for some of the students to use. Rather
>than use assembly, it would be best if BASIC could be used, to allow
>then fundamental idea's be learned. 
>
>Just wanted to check to make sure that the BASIC program is public
>domain, so I can place it into EPROM and run it with a $2 8032 uC.

according to the recent Computer Craft, it is, and the src is
available on an Intel BBS.

>
>Does INTEL still supply the 8052BASIC chip?

dont know.


Kelly

Xref: sparky sci.electronics:20770 rec.audio:16732 alt.guitar:10868 rec.music.makers.guitar:938
From: jhalvers@plains (Jon Halverson)
Newsgroups: sci.electronics,rec.audio,alt.guitar,rec.music.makers.guitar
Subject: Re: Electric Guitar Pickups?
Date: 15 Dec 92 20:22:56 GMT
Article-I.D.: ns1.BzBHy8.G8o
Organization: North Dakota Higher Education Computing Network
X-Newsreader: Tin 1.1 PL4


  Well as far as I know, Most high imp. humbuckers max at about a volt or
so, less for singles. You can check by puting a V/ohm meter set to read AC
votltage across it and strum real hard. I'm not sure on impeadences off
the top of my head though but they can be quite different from one to
another, especially between single and double coils.

 Active pickups are another story. Basically what they are is a very low
imp. pickup with a built in pre-amp. The signal therefore is much cleaner.
The output voltages are usually set up to match reg. pkups.

 You have to remember that there is quite a bit of leway as far as input
voltage and imp. in most amps. It's just that if the input voltage is high
enough it will distort.

Hope I could help,

jh
Newsgroups: sci.electronics
From: dave@imax.imax.com (Dave Martindale)
Subject: Re: Halogen Lights
Keywords: halogen lamp life
Organization: Imax Corporation, Mississauga Canada
Date: Sun, 13 Dec 1992 19:40:18 GMT

acampane@magnus.acs.ohio-state.edu (Angelo Campanella) writes:
>
>4/ "Halogen: is usually iodine or the like which has heavy molecules that will
>   discourage the sputtering of the filament material away (sputtering
>   depletes the filament and otherwise shortens its life).  Deterioration due
>   to sputtering is evident by darkening of bulb interior.

Actually, the tungsten does evaporate and deposit on the bulb.  But the
chemicals in the gas fill and the high temperature of the bulb cause
the tungsten to be cleaned off the bulb and redeposited on the filament.

Thus, the bulb doesn't get dark as the lamp ages.  The filament doesn't
get gradually thinner, but it does change as tungsten evaporates from
one place and is redeposited elsewhere.  The lamp does eventually fail.

>5/ Quartz is usually used for the envelope because it expands very little when
>   hot.  However, quartz is also very brittle hot or cold, so be careful.

The lamp envelope has to run very hot for the necessary chemical reactions
to take place.  So it has to be small and close to the filament, and has
to withstand high temperatures.  Thus quartz is used.
Newsgroups: sci.electronics