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New TO-3 Output Transistors

EchoWars

EchoWars

Hiding in Honduras
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Screwed up and blew those uber-rare super-fast impossible-to-find output transistors in your DC-to-Light SS power amplifier? Never fear... Bucking the trend to eliminate the TO-3 device altogether is ST Microelectronics. God Bless 'em.:smlove:

All Hail the new 2ST5949 (NPN) and 2ST2121 (PNP).:ntwrthy::ntwrthy::ntwrthy:

These TO-3 devices are--- 250V, 250W 17A, and...25MHz!

But what good are these super-fast devices if no one sells them where the average Joe like you & me can get them? Well, sit down and pour yourself a tall one...Digikey carries them. :yes::yes:

Ah! But they must be damned expensive, right? After all, those super-expensive transistors for those fast Sansui and Kenwood amps are selling for stupid money, right? I mean, they gotta go for 20-30 dollars each, right? RIGHT?? Nope. The 2ST5949 is $3.04, and the 2ST2121 is the same. A little over $6 for a pair of devices that can restore your AU-919 or L-07MII to near factory specs. :beerchug::beerchug:

I'm impressed.

Read more here, and go buy 'em!

hallelujahgen.jpg
 
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EchoWars said:
Screwed up and blew those uber-rare super-fast impossible-to-find output transistors in your DC-to-Light SS power amplifier? Never fear... Bucking the trend to eliminate the TO-3 device altogether is ST Microelectronics. God Bless 'em.:smlove:

All Hail the new 2ST5949 (NPN) and 2ST2121 (PNP).:ntwrthy::ntwrthy::ntwrthy:

These TO-3 devices are--- 250V, 250W 17A, and...25MHz!

But what good are these super-fast devices if no one sells them where the average Joe like you & me can get them? Well, sit down and pour yourself a tall one...Digikey carries them. :yes::yes:

Ah! But they must be damned expensive, right? After all, those super-expensive transistors for those fast Sansui and Kenwood amps are selling for stupid money, right? I mean, they gotta go for 20-30 dollars each, right? RIGHT?? Nope. The 2ST5949 is $3.04, and the 2ST2121 is the same. A little over $6 for a pair of devices that can restore your AU-919 or L-07MII to near factory specs. :beerchug::beerchug:

I'm impressed.

Read more here, and go buy 'em!

hallelujahgen.jpg
Click to expand...

God bless Digikey also! :yes:

That's good news!

az
 
That's awesome, I don't have to overlook L-07M MKII's anymore. ST Micro is one of our big customers where I work...
 
I already have 12 of each on the way. Not sure where I'll try them, but with the number of blown L-07MII's and AU-919's that have come through here, it shouldn't be long.
 
Great news Glenn, but for this novice and others my question is, will this be THE substitute for the 2SA1116, A1116A/ 2sc2607 pair (G9700/ 9090)and the 2SB681/ 2SD551 pair (G8700). I do not know what outputs are used in the units EchoWars mentioned. I have compared the ratings and most are surpassed by these new TO3's. The Ft 20MHz & 15MHz on said pairs is surpassed with 25MHz. When is to much, to much? Maybe one of the experts can put a Sticky to alert all of the 'fast gun' in town and, moreover what it can substitute for. Bravo Glenn, but loose that Dog.
 
These would be fine to replace the 2SA1116 and 2SC2607. I do not have a manual for the G-8700, so I don't know if it was touted as a high-speed amp. 2SBxxx and 2SDxxx transistors are supposed to be the slower ones, if that's what it used.

In essence, most amps & receivers out there cannot use these transistors. Offhand, I can think of only:

Sansui BA-F1
Sansui AU-919
Sansui G-9700
Kenwood L-07MII
Kenwood L-05M
Kenwood KR-9050

Here they would replace the 2SC2337(A), 2SA1007(A), 2SA1116(A), 2SC2607(A), NMC1012, NMA1012, NMA1216, and NMC1216.

I have absolutely no doubt that there are more transistors these can sub for, and more amps & receivers can that use them, but these are the ones I am sure of.
 
avionic or EW, what's the difference between the 2SA1116/2SC2607 and the 2SA1117/2SC2608? the latter are used in the Yamaha PC5002M. not terribly important for me anyway since i was able to source original spares for mine, but i'm still curious if these new ones would work.
 
The A1116 is a 200V, 15A, 150W device with a unity gain freq. of 20MHz. The A1117 is a 200V, 17A, 200W device with the same freq. Same deal with the C2607/C2608. These higher-power, higher-current devices sacrifice a bit of gain compared to the lower-power devices. The new ST Micro devices look like they'd work well in the Yamaha. I'm sure they are 10x cheaper than what you had to pay for the C2608/A1117 devices.
 
EchoWars said:
The new ST Micro devices look like they'd work well in the Yamaha. I'm sure they are 10x cheaper than what you had to pay for the C2608/A1117 devices.
Click to expand...

Cool. Actually, I got a pretty sweet deal from a US distributor that specializes in obsolete parts. Cost just about the same as these new ones. I cleaned them out of their 2608s, but they still have 1117s left in stock.
 
Good news about the substitution possibilities. The Sansui G8700/G871DB use the 2SB681/2SD551 pair that are rated at: 150V, 12A, 100W, 40-140hFE, 15MHz. Does this alone classify it as a "high speed amp". The G9700 & G8700 are in the same Service Manual, if anyone needs it PM me.

A second consideration for this sub list could be the Sansui 9090 which uses eight (8) 2SA1116A. Cannot find rating for the 'A', but 2SA1116 is; 200V, 15A, 15W, 30~hFE, 20MHz. AK community, your thoughts please.
 
What makes these "not" good for most amps? Is it the high speed? due to potential for ringing and/or oscillation?

Enjoy,
Rich P
 
hatman said:
Good news about the substitution possibilities. The Sansui G8700/G871DB use the 2SB681/2SD551 pair that are rated at: 150V, 12A, 100W, 40-140hFE, 15MHz. Does this alone classify it as a "high speed amp". The G9700 & G8700 are in the same Service Manual, if anyone needs it PM me.
Click to expand...
I'm skeptical about using them in the 8700.
A second consideration for this sub list could be the Sansui 9090 which uses eight (8) 2SA1116A. Cannot find rating for the 'A', but 2SA1116 is; 200V, 15A, 15W, 30~hFE, 20MHz. AK community, your thoughts please.
Click to expand...
The 2SA1116 is a PNP. The 9090 uses eight 2SC1116 transistors, which are NPN.
pustelniakr said:
What makes these "not" good for most amps? Is it the high speed? due to potential for ringing and/or oscillation?
Click to expand...
Yessir. :yes:
 
Since this a new offering, and TO3s are becoming rare as hen's teeth, one could use these, in a pinch, for non-high speed amps with a slight change in topology, adding just smidge of negative hf feedback to the loop. No?

Enjoy,
Rich P
 
I'd not recommend using these in anything except those amps that are designed to use ultra-fast output devices. For these more common amps, On-Semi is likely to carry good substitutions for the foreseeable future...such as the MJ21193/94/95/96, the 140V 20A MJ15003/04, and the MJ15024/25. Much safer.
 
eagerly waiting

now all we need is for someone to come out with good, reasonable priced,
replacements for the Hitachi lateral mosfets!!!!!
 
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