Legit Source for ORIGINAL 2SC2565 and 2SA1095???

[megasat16]

I am burnt not once but twice with the Cheap Fake or Chinese Remake of 2SC2565 and 2SA1095. The E-C is shorted in all 5 of 2SA1095 and 2SC2565 at about 50W of output power.

These cheap Fake will have a gain of about 70-80 at very low Ib of 10uA. I measured the Original Japan made ones from my amp and they will have no gain at these very low Ib. This will be a good indication if you have the fake ones or the Original Japan Made ones. All the fakes I bought before have the Hfe of 70-100 at Ib = 10uA. If the ones you have are like this, DO NOT USE THESE in the circuits first and try it in a test board instead (PROPERLY Mounted on a HeatSink). If it's not going to withstand 100W+ heat dissipation, it will not likely work in the amp and you'll likely end up with Huge Frustration like me.

I need to buy at least 5-10 each 2SA1095 and 2SC2565.

[megasat16]

Woola...Wowla...Woo loo loo...Wayyyy....Yayyyy...

Sorry about the rhyme there!

But no one uses These Toshiba in Decades?

[wg_ski]

Originally posted by megasat16
But no one uses These Toshiba in Decades?

Toshiba hasn't made them in decades. I used them in *one* design back in 1987, and when I went to buy more a few months later they were GONE.

I found what I thought were more about 5 years ago - but the PNPs ended up being fakes. The NPN pair is still good and I ended up using them for a 100W RF amplifier. 80 MHz FT (with no PNP) is good for something....

[RocketScientist]

Yeah the inventory I've seen is all in Asia and probably suspect. I think it's great we can all buy inexpensive PCBs and other parts designed for DIY use from China/HK. But I helped a friend with some Asian DIY amp modules that didn't perform very well. Further investigation revealed the "Toshiba" 2SC5200 and 2SA1943 outputs didn't measure anything like the real ones do. He replaced the outputs with real Toshiba parts from Mouser and the problems went away.

I would think your mostly likely options would be a fellow DIYer somewhere who might have some on hand, a repair shop that has some they're willing to sell, or to scavange used parts out of dead/cheap power amps. But, regardless, it will probably be tough to find 5-10 each without using multiple sources. Otherwise, I suppose, you need to find the best substitute for your application and/or tweak the design to use available parts?

[megasat16]

Originally posted by wg_ski



Toshiba hasn't made them in decades. I used them in *one* design back in 1987, and when I went to buy more a few months later they were GONE.

I found what I thought were more about 5 years ago - but the PNPs ended up being fakes. The NPN pair is still good and I ended up using them for a 100W RF amplifier. 80 MHz FT (with no PNP) is good for something....

Thank you for chiming in! I guess there is no legit source for the real ones. The ones I came across are all fakes!

Originally posted by RocketScientist
Yeah the inventory I've seen is all in Asia and probably suspect. I think it's great we can all buy inexpensive PCBs and other parts designed for DIY use from China/HK. But I helped a friend with some Asian DIY amp modules that didn't perform very well. Further investigation revealed the "Toshiba" 2SC5200 and 2SA1943 outputs didn't measure anything like the real ones do. He replaced the outputs with real Toshiba parts from Mouser and the problems went away.

I would think your mostly likely options would be a fellow DIYer somewhere who might have some on hand, a repair shop that has some they're willing to sell, or to scavange used parts out of dead/cheap power amps. But, regardless, it will probably be tough to find 5-10 each without using multiple sources. Otherwise, I suppose, you need to find the best substitute for your application and/or tweak the design to use available parts?

Thanks for the info! I guess you are right! I have little choices left. I have other people suggesting to use newer replacement and it's what I should and I am going to do.

[tiefbassuebertr]

there are some new bjt's available, e. g. "ST" and "ON"
I have listed the most populare types - go to
bipolar (bjt) transistor families for audio power output stages

[wg_ski]

Originally posted by tiefbassuebertr
there are some new bjt's available, e. g. "ST" and "ON"

Of course you can always use a newer device - most of the time. You don't *really* need 80 MHz fT in an audio amp and that's the only spec that really sets these apart from the rest. 20 or 30 MHz is just fine even for high speed wide band. And some of the newer parts have very low Cob.

The real problem is the obsolete TB-34 package. On a new design, I'd say just use a TO-264 and be done with it. But for replacement you may not have that luxury. In some cases, you may not be able to rework it so that a TO-247 or TO-264 will fit. The closest thing still in production is Sanken's MT-200 package, but even those aren't widely available everywhere and still might not fit if they're mounted between the PCB and heat sink.

[325addict]

I once bought some Chinese fakes also, they looked exactly the same as the originals... and guess what? The quality was just great!

I used them in a test amp, which effortlessly exceeded 100kHz bandwidth (no more than 1dB down).
With exaclty 2X 63V power supply(!) and just one output transistor each, I tried a 4 Ohm load. I blasted full power with demanding music and... it survived all tortures!
In fact, it should have blown: Pd=(0.5*Ub)^2 / 4 = 248 Watts!!!

But, some people were less lucky in this indeed.... ß varied quite wildly between 80 and more than 160.

And YES, I am 100% sure they were fake! I could clearly see this due to the shape of the pins, and the metal part that comes from the plastic part of the housing and goes into the pins.

Best thing is to replace it with the SanKen 200W transistors.
2SA1295 and 2SC3264 or the pair 2SA1216 and 2SC2922 are the best here I think.