Naw, I'm talkin the one (and only on the quasi side) with 0R33 collector
resistor for current sensing. Definately driven, not a driver... All other
collectors are at equal potential. Why else need there be an insulator?
I would call the outmost pair class C. As they conduct much less than
50%. The driver co-located on the big sink is class AB, maybe B. And
the driver on the card is 6mA class AB, maybe A... Big chain of current
dumpers (in Darlington), each next requiring one mo drop to activate...
For the outmost to activate, I guess the opposing inmost (on the card)
would be shut off, so those can't be A.... Only the VAS on the corner of
the card then, would be the last Class A.
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hello to everyone here , this is my first post .could someone help me out with something,I noticed by reading around the forums that Bear has been playing around with some altec 1590E amps .i just bought a couple of them and i took them apart and seems they have 12 bad 5878 motorola output transistors .my question what do you think my best bet for a replacement should be psssst hey Bear what did you use............thanks for the help as my local knowledge source is very limited .....i live in cancun mexico!
Check out this thread and read the statement from Mr. Nelson Pass:
http://www.diyaudio.com/forums/pass...els-mospec-2n5876-2n5878-mj21193-mj21194.html
have a look also there:
http://www.diyaudio.com/forums/soli...ps-1590b-1590e-771b-771bx-system-cabinet.html
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facts and internal pics arround different 2N3055
Motorola 2N3055 info and counterfeit watch
I am looking for the very first RCA papers/manuals/application notes from that time, where reportet about the 2N3055. Perhaps you know the exactly title and the date of release. About
http://www.diyaudio.com/forums/parts/167680-vintage-transistors-4.html
(go to post #33 and #34) I have posted some cover pics from old RCA books - perhaps one of this book is that, what I need.
Additional I want to have pics or URLs about the very first advertisement of the 2N3055 (about wikipedia I read, the date of release was in the early 60's, but I don't find the exactly date).
Perhaps you know this - thanks for advices.
Motorola 2N3055 info and counterfeit watch
I am looking for the very first RCA papers/manuals/application notes from that time, where reportet about the 2N3055. Perhaps you know the exactly title and the date of release. About
http://www.diyaudio.com/forums/parts/167680-vintage-transistors-4.html
(go to post #33 and #34) I have posted some cover pics from old RCA books - perhaps one of this book is that, what I need.
Additional I want to have pics or URLs about the very first advertisement of the 2N3055 (about wikipedia I read, the date of release was in the early 60's, but I don't find the exactly date).
Perhaps you know this - thanks for advices.
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A long time ago I worked for Lambda, the power supply manufacturer, and a manager claimed that the 2N3055 was designed at their request. I don't if the story is true though.
Another ex boss thought that the 2N3055 data sheet was actionable under the trade descriptions act because it claims to be a 15 A transistor but the current gain is down to 2 (depending on the data sheet) so not really usable at 15 A.
I think that the Maplin Power Amplifier used the 2N3055 beyond it's voltage rating but it was pointed out to me that it just meant that they sold more power transistors!
Another ex boss thought that the 2N3055 data sheet was actionable under the trade descriptions act because it claims to be a 15 A transistor but the current gain is down to 2 (depending on the data sheet) so not really usable at 15 A.
I think that the Maplin Power Amplifier used the 2N3055 beyond it's voltage rating but it was pointed out to me that it just meant that they sold more power transistors!
in this case also this thread could be of interest:
http://www.diyaudio.com/forums/everything-else/205960-checking-geniue-old-2n3055.html#post3101285
http://www.diyaudio.com/forums/everything-else/205960-checking-geniue-old-2n3055.html#post3101285
i found this article by Herb Meisel: RCA Transistor Oral History Meisel Page3 saying that the 3055 grew out of a military contract
the first page is here: http://www.ck722museum.com/history/rca/OralHistory/Meisel/Meisel_Index.htm
the first page is here: http://www.ck722museum.com/history/rca/OralHistory/Meisel/Meisel_Index.htm
the magazines from post #5, 7 and 15 about
http://www.diyaudio.com/forums/soli...rrently-available-electr-audio-magazines.html
there must actually be such advertisements between 1961 and 1964.
Hi all
Yes, I was once shown an advert for a 2N3055 by RCA in the mid-1960's. I would like to track that down too. It showed the three devices introduced by RCA together - the 2N3053, the 2N3054 and 2N3055 in their packages (TO-5, TO-66, TO-3).
I have not come across any patents by RCA for the 2N3055 specifically.
ON Semi transistors can do the same SOAR (more or less at least for D.C.) - for example, MJ15003 (1A/100V (close to the 2N3773)) or better, the MJ21194 (1.5A/100V=match).
John
Yes, I was once shown an advert for a 2N3055 by RCA in the mid-1960's. I would like to track that down too. It showed the three devices introduced by RCA together - the 2N3053, the 2N3054 and 2N3055 in their packages (TO-5, TO-66, TO-3).
I have not come across any patents by RCA for the 2N3055 specifically.
ON Semi transistors can do the same SOAR (more or less at least for D.C.) - for example, MJ15003 (1A/100V (close to the 2N3773)) or better, the MJ21194 (1.5A/100V=match).
John
Tiefbass here some pictures from my modest vintage SS stash :
Picture 1 ) Motorola 2n3055 , 5pcs , they all come to me from discarded very old EI NIS B10 color CRT TV which date from early or mid of 70 ` , they serve there as output power Tranz. in Vertical deflection unit driving deflection Yoke .
First from left is very old Toshiba 2N3055 , from same source , very massive one , with twice of Motorola weight , and with very thick pure CU bottom plate .
And top one is example of very old SE3055 from Hong Kong , they work as charm .
Picture 2 , is vintage Motorola 2N3773 , several very old but OK pcs.
And picture 3 , two very old Tesla KD503 in comparison with Motorola 2N3773 where is obvious that Tesla have perfect copied Motorola , 100% same shape ,100% same case material , but more powerful than 3773 , second difference is that Tesla used much thicker device pins plated with gold .
Best Regards !
Picture 1 ) Motorola 2n3055 , 5pcs , they all come to me from discarded very old EI NIS B10 color CRT TV which date from early or mid of 70 ` , they serve there as output power Tranz. in Vertical deflection unit driving deflection Yoke .
First from left is very old Toshiba 2N3055 , from same source , very massive one , with twice of Motorola weight , and with very thick pure CU bottom plate .
And top one is example of very old SE3055 from Hong Kong , they work as charm .
Picture 2 , is vintage Motorola 2N3773 , several very old but OK pcs.
And picture 3 , two very old Tesla KD503 in comparison with Motorola 2N3773 where is obvious that Tesla have perfect copied Motorola , 100% same shape ,100% same case material , but more powerful than 3773 , second difference is that Tesla used much thicker device pins plated with gold .
Best Regards !
Attachments
The H means Hometaxial, a much more robust construction than standard (cheaper) Epitaxial, which "regular" 2N3055 use.
That, coupled to the fake transistor pandemia is the real cause of repair problems.
They should be replaced by MJ1502x transistors or MJ1500x ones or MJ2119x types.
Way beyond what's needed, but that is never bad
And parts cost is still reasonable.
2N3055H were not "higher voltage" per factory spec, but "higher SOAR", the safe area.
Of course, among them, some higher voltage ones could be hand picked.
I suggest using the MJ15015 to replace any of the 2N3055 versions.
They are hand selected to meet 120V and 60V/3A SOA and are shown with the same curve graphs as the 2N3055.
http://www.datasheetcatalog.org/datasheet/motorola/MJ15016.pdf
They are hand selected to meet 120V and 60V/3A SOA and are shown with the same curve graphs as the 2N3055.
http://www.datasheetcatalog.org/datasheet/motorola/MJ15016.pdf
Thank you for this pictures. Are there genuine data sheets or data books from TESLA's power devices in TO-3 outline ?
an other question: Which historical (vintage) and currently available electronic magazines in your country there was exist and is currently available ?
Please let me know any examples by this topic:
http://www.diyaudio.com/forums/soli...rrently-available-electr-audio-magazines.html
thank you very much in advance.
perhaps by this history report in danish language are additional details to find - go to
Aktuel Elektronik Nr. 10 (2008) Page 24
An other interest URL is here:
http://n4trb.com/AmateurRadio/RCA_Ham_Tips/issues/rcahamtips2701.pdf
http://www.ebay.com/itm/GE-Ham-News...8-and-Western-Radio-Amateur-N-R-/110954943697
http://n4trb.com/AmateurRadio/RCA_Ham_Tips/rca_ham_tips.htm
Here must actually be an advertisement concerning the 2N3055.
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Tiefbass
Here is document with that vintage Tesla SS parameters for you :
Must check for that old electronics magazines , they exist here for sure , but I need some time to recheck all that !
BTW , I support all your efforts & work here on this BIG DIY Audio site !!!
Best Regards !
Here is document with that vintage Tesla SS parameters for you :
Must check for that old electronics magazines , they exist here for sure , but I need some time to recheck all that !
BTW , I support all your efforts & work here on this BIG DIY Audio site !!!
Best Regards !
