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New TO-3 Output Transistors

last time i checked, they were marked as discontinued on ST's website. looks like Digikey just got a shipment in recently (maybe the last one?), while Mouser has already dropped them.
 
Digikey shows something like over 300 of the PNP's left, but shows (and has shown for some time) zero stock on the NPN's.
 
EchoWars said:
Digikey shows something like over 300 of the PNP's left, but shows (and has shown for some time) zero stock on the NPN's.
Click to expand...

ah, i must have seen the NPN's and assumed the PNP's were out too. you can still find them on Arrow though, which you probably already knew.
 
Arrow (arrownac.com) has 28 2ST5949 left and 200+ 2ST2121 for about $2.20 each. They take Paypal as well as CC. As a bit of advice, don't get an account, or the shipping ends up more.

They show 400 2ST5949 in the pipeline on order for November. Everyone else (Mouser, Avnet, Digikey) is out with none on order. Those might be the last unless someone wanted to put together a group buy and order another batch. 400-500 seems to be the minimum. The 2ST2121s seem abundant still - people buying these for quasi-complementary amps out there or something?
 
If I knew of one, I'd have posted about it. Sadly, the chances of another mfgr coming out with anything like a replacement is pretty slim.
 
Mouser and Digikey show just under 500 total of the PNP 2ST2121. Are there circuits that only use the PNP or NPN? Just curious how the inventories end up like this.

FWIW, when Glen first posted about these new devices, I bought two complete sets, one each for my G971 and KR-9050. I just didn't think these would last...sadly I was correct. :worried:
 
EchoWars said:
If I knew of one, I'd have posted about it. Sadly, the chances of another mfgr coming out with anything like a replacement is pretty slim.
Click to expand...

So, will there be any plastic buds be available with the same rating as those TO-3's?
 
glen65 said:
There are plastic case devices which already exist that could replace them.
You would have to deal with any mounting issues.
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I figure that they already exist but I'm asking "will" they exist? I know that the TO-3 case is nice to have. If TO-3's are being completely phased out, I'm more concerned if there will continue to be such device to replace in the amplifier.
 
ccheath said:
I figure that they already exist but I'm asking "will" they exist? I know that the TO-3 case is nice to have. If TO-3's are being completely phased out, I'm more concerned if there will continue to be such device to replace in the amplifier.
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From reading his post, I dont think he was talking about TO-3 devices
across the board. He was referring to one specific high speed device number.
While it might be inconvenient, there will be plenty of devices to keep the older amps running.
In the event they were to completely phase out TO-3s, there are other devices that can be used, I'll adapt.
Ive already been looking at different ways to use plastic case devices in their place and make it look good.
 
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Not so sure of that...I can name the mfgr's of metal TO-3 devices on one hand with fingers left over.
 
EchoWars said:
Not so sure of that...I can name the mfgr's of metal TO-3 devices on one hand with fingers left over.
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When I said there will be plenty of devices to keep the older amps running,
I wasn't specifically referring to TO-3s. I simply meant that there
will be alternatives that can be used in their place. Would of elimination of TO-3s suck? yep. But I think we would both manage.
 
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glen65 said:
When I said there will be plenty of devices to keep the older amps running,
I wasn't specifically referring to TO-3s. I simply meant that there
will be alternatives that can be used in their place. Would of elimination of TO-3s suck? yep. But I think we would both manage.
Click to expand...

I think converting a T0-3 designed amp/receiver to use a plastic T0-3P's or MT-200 would require lots of work to adapt the mounting to use the T0-3 heatsink with good contact and heat transfer. Sounds like a machine shop project well beyond the skill level of many of the hobbyist that frequent this forum.

Sure, some of the pros here will step up to the challenge to re-engineer T0-3 components when equivalent T0-3 configuration outputs are no longer available, but the majority of units without T0-3 equivalents will turn into e waste. :tears:
 
Bigears said:
I think converting a T0-3 designed amp/receiver to use a plastic T0-3P's or MT-200 would require lots of work to adapt the mounting to use the T0-3 heatsink with good contact and heat transfer.
Click to expand...
As long as there is room for the device, it would make just as good physical
contact as the TO-3. Heat transfer wouldn't be an issue.

Sounds like a machine shop project well beyond the skill level of many of the hobbyist that frequent this forum.
Click to expand...

Not necessarily, at most you might need to drill one hole for each device.
No need to be a machinist for that.

Sure, some of the pros here will step up to the challenge to re-engineer T0-3 components when equivalent T0-3 configuration outputs are no longer available, but the majority of units without T0-3 equivalents will turn into e waste. :tears:
Click to expand...

Nah, Once the procedure would get established, it would quicken the pace
of a conversion. It would no doubt be an inconvenience, but not the end of your equipment.
Think of this way, there would be more equipment that could be had for a lot less money, because
some people simply wouldn't want to fuss with the repair.
 
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