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Conference napalm::commusic_v1

Title:* * Computer Music, MIDI, and Related Topics * *
Notice:Conference has been write-locked. Use new version.
Moderator:DYPSS1::SCHAFER
Created:Thu Feb 20 1986
Last Modified:Mon Aug 29 1994
Last Successful Update:Fri Jun 06 1997
Number of topics:2852
Total number of notes:33157

484.0. "Need Chips to Fix Sick Chroma" by STAR::MALIK (Karl Malik) Wed Aug 27 1986 15:54

    
    	Ok, hardware buffs - 
    
    	My (still!) ailing Chroma needs some 74SL138 chips.  I can
    order them (free) from Fender, but was wondering if maybe they
    are so common (and cheap?) that I could get them faster by
    just buying them.
    
    	1) Are they just standard chips?
    
    	2) What, roughly, do they cost?
    
    	3) Where, in Southern New Hampshire, can I get them?
    
    						Thanks, Karl
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484.2ANT::JANZENTom LMO2/O23 279-5421 Wed Aug 27 1986 16:271
They probably cost about $1
484.3STAR::MALIKKarl MalikWed Aug 27 1986 17:008
    
    	Thanks, Tom.  I don't think they're bad, just inappropriate.
    
    	The company screwed up on a batch of Chromas (mine included)
    and used L138's instead of LS (or SL, whatever you said).  This
    may or may not account for my MIDI boxes not functioning.  Worth
    a try.
    							- Karl
484.5Analog is not dead, it's just sleeping.JON::ROSSWed Aug 27 1986 17:3917
    
    We now know our resident ecl-maniac hardware type. They love
    speed.
    
    You got it on the L-series: L for sLow. Seems like a mistake
    in general. When I designed 'stuff' at ARP, LS was a prefered
    technology (if you couldnt use cheep CMOS). The CHROMA was
    designed by a fellow Ex-Arpist, Paul Derocco, between the time
    I left and CBS bought ARP, so I dont know alot about the 
    instrument other than Derocco's design style. Ocasionally one
    would use an "L" series part on purpose to s-l-o-w some signals
    down, but I doubt Paul would stoop to that.
    
    Second Active Electronics for a wide variety of parts at GOOD
    prices. Go there just to browse sometime...
    
    
484.6calling Mr. ECLAPOLLO::DEHAHNWed Aug 27 1986 17:567
    
    I don't remember 74Hxxx, but 74HCxxx is High speed CMOS TTL, if
    that's what you mean.
    
    CdH
    
    
484.7Noteriety where it is due...DECEAT::AURENZScot Aurenz, ACO/e45, 232-2277Wed Aug 27 1986 18:2419
	Re: .4

>...74LSnnn is low-power Schottky (remember the elitist (actually, there
>are better -ist words for him) who put his sperm
>in a bank, he's invented more semiconductor devices than anyone else, I guess).

	Tom -
	Good review of logic families, but in this paragraph
	you mean SHOCKLEY, not Shottkey. Shockley was one of 
	the developers of the semiconductor diode and the transistor.
	You are right, though, that he is one of the biggest jerks
	ever to do something significant. (Since this is a music
	notesfile, perhaps we could lump him in with Wagner...)

	I don't know who Mr. Shottkey is, but I hope he has a 
	more reasonable outlook...
							Scot

484.10"H" means HungryCLOVAX::RATASKITom RataskiWed Aug 27 1986 18:339
    The  74Hxxx was another mistake which came out about the same time
    ar the 74Lxxx parts did. The "H" means High speed (which means faster
    than the standard part [74xxx]. It had a few drawbacks - namely
    "H" also stood for Hungry - drew lotsa power and it had a very low
    fanout. In the end it was an interim part like the "L" part and
    has mostly been abandoned for the "LS" type.
    
    Fanout = the number of TTL loads that the output of one of these 
    critters could drive.
484.11Don't You *DARE* Couple to my EmitterERLANG::FEHSKENSWed Aug 27 1986 18:5511
    Sorry Scot, Tom's right, the S in S and LS stands for Schottky.
    He's the guy who figured out that by clamping things you could
    get higher speed.  This has nothing to do with Schockly, one of
    the guys who invented/discovered the transistor.  Also the L in
    LS and L stands for Low power, not sLow, although a usual consequence
    of low power consumption is low speed.
    
    Didn't Francis Schottky write the Star Spangled Bandanna?  ;^)
    
    len.
    
484.12Why Say It Again?ERLANG::FEHSKENSWed Aug 27 1986 19:005
    Oops - already all been said.  I should read all replies before
    replying.
    
    len.
    
484.14APOLLO::DEHAHNThu Aug 28 1986 15:5010
    
    Thanks for the clarification.
    
    One of the reasons 74 and 74L parts aren't around much anymore is
    that they're gold-doped, which is expensive to produce and is fairly
    unreliable compared to Shottky devices.
    
    CdH