X250 Heatsinks and To-3 cans!

Zero Cool · 14th November 2004, 08:31 PM

I found this photo of the heatsinks for the X250, interesting heatsink design. I didnt know the X series used TO-3 style output devices. Anyone know what these are?? N.P.??

Zero

GRollins · 14th November 2004, 09:05 PM

The TO-3 style can is slowly being phased out. Nelson has a large number on hand, so he uses them. Looking forward, the TO-247 (I think the current official nomenclature is TO-3P--why the devil they can't pick a number and stick to it is beyond me), is probably the case of choice. Don't forget that you may have to service a unit at some point in the future--if the original devices are no longer available, you'll have a problem.

Grey

EWorkshop1708 · 14th November 2004, 09:47 PM

IMO the TO-3 devices can take more abuse and are more rugged.

Nelson Pass · 14th November 2004, 09:57 PM

As the TO-3's become more scarce and expensive, we have
gone over to the same chips in TO-3P plastic cases, and
reserve our stock of TO-3's for the XA and X600, X1000.

When we deplete those stocks it will be plastic everywhere,
sometime about 3 or 4 years from now.

I have not seen an alteration in performance or reliability,
but we always preferred the look of the TO-3's.

uli · 14th November 2004, 10:02 PM

Quote:

Originally posted by GRollins
Looking forward, the TO-247 (I think the current official nomenclature is TO-3P--why the devil they can't pick a number and stick to it is beyond me)
Grey

Hi Grey,

there is a difference between TO-247 and TO-3P:

while the TO-247s middle node is isolated from the hole, the TO-3P has a complete metal flange connected to the middle node or
drain if you want.
Surprisingly the TO-247 has better thermal characteristics - even better than the old TO-3.

Uli

GRollins · 15th November 2004, 01:16 AM

I remember the first time I opened a piece of equipment and saw something other than the (then) standard TO-3 (which for that matter used to be called something different, but I can't remember at the moment what that term was). I flipped. Whazzat? Surely those things can't be serious transistors! Hell, the plastic'll melt the first time someone runs the thing hard. Must be cheap equipment if they're using weird lookin' things like that. And on and on.
Time passed.
Now I see a TO-3 and think...oh, how quaint...
It's all a question of what you're accustomed to. For that matter, it's rare to see small signal transistors in metal cans these days. Metal tubes, like the 6SN7? Nary a one to be seen. They're all glass, unless you're talking about high power triodes and such.
In ten years we're likely to be talking about how strange it is to see plastic devices in gear, what with those nifty fused silicon cases they came out with back in '08...

Grey

P.S.: With ten numerals, 26 letters in the alphabet, not to mention dashes, hypens, etc. you're telling me that someone couldn't get creative enough to come up with a case designation more distinct than TO-3P, knowing that there would be a large number of people who would simply think that it was a variation on the TO-3? Harrumph! Grumble. Curmudgeonly noises.
Santa's gonna leave 'em ashes and switches. Wait and see.

EWorkshop1708 · 15th November 2004, 03:03 AM

Anyone know where to get some nice TO-3 heatsinks that can hold 4 pairs of transistors or more?

Zero Cool · 15th November 2004, 03:31 AM

How many do you need???

I have 1 heatsink that will hold 8 TO-3 devices if that would work...

Zero

highbias · 15th November 2004, 03:35 AM

Even the new Levinson amps use TO3P devices now.

Mark

GRollins · 15th November 2004, 03:45 AM

Check www.apexjr.com. The last time I looked, he had some pretty big heatsinks pre-drilled for TO-3s.

Grey

15th November 2004, 03:35 AM	#9
highbias diyAudio Member Join Date: May 2004 Location: Salt Lake City, Ut	Even the new Levinson amps use TO3P devices now. Mark __________________ Now I too Have a Cool Screen Name!

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14th November 2004, 09:05 PM	#2
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	The TO-3 style can is slowly being phased out. Nelson has a large number on hand, so he uses them. Looking forward, the TO-247 (I think the current official nomenclature is TO-3P--why the devil they can't pick a number and stick to it is beyond me), is probably the case of choice. Don't forget that you may have to service a unit at some point in the future--if the original devices are no longer available, you'll have a problem. Grey

14th November 2004, 09:47 PM	#3
EWorkshop1708 diyAudio Member Join Date: Nov 2004 Location: Florida	IMO the TO-3 devices can take more abuse and are more rugged.

14th November 2004, 09:57 PM	#4
Nelson Pass The one and only Join Date: Mar 2001	As the TO-3's become more scarce and expensive, we have gone over to the same chips in TO-3P plastic cases, and reserve our stock of TO-3's for the XA and X600, X1000. When we deplete those stocks it will be plastic everywhere, sometime about 3 or 4 years from now. I have not seen an alteration in performance or reliability, but we always preferred the look of the TO-3's.

15th November 2004, 01:16 AM	#6
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	I remember the first time I opened a piece of equipment and saw something other than the (then) standard TO-3 (which for that matter used to be called something different, but I can't remember at the moment what that term was). I flipped. Whazzat? Surely those things can't be serious transistors! Hell, the plastic'll melt the first time someone runs the thing hard. Must be cheap equipment if they're using weird lookin' things like that. And on and on. Time passed. Now I see a TO-3 and think...oh, how quaint... It's all a question of what you're accustomed to. For that matter, it's rare to see small signal transistors in metal cans these days. Metal tubes, like the 6SN7? Nary a one to be seen. They're all glass, unless you're talking about high power triodes and such. In ten years we're likely to be talking about how strange it is to see plastic devices in gear, what with those nifty fused silicon cases they came out with back in '08... Grey P.S.: With ten numerals, 26 letters in the alphabet, not to mention dashes, hypens, etc. you're telling me that someone couldn't get creative enough to come up with a case designation more distinct than TO-3P, knowing that there would be a large number of people who would simply think that it was a variation on the TO-3? Harrumph! Grumble. Curmudgeonly noises. Santa's gonna leave 'em ashes and switches. Wait and see.

15th November 2004, 03:03 AM	#7
EWorkshop1708 diyAudio Member Join Date: Nov 2004 Location: Florida	Anyone know where to get some nice TO-3 heatsinks that can hold 4 pairs of transistors or more?

15th November 2004, 03:31 AM	#8
Zero Cool Audio Junkie diyAudio Member Join Date: Sep 2004 Location: MN	How many do you need??? I have 1 heatsink that will hold 8 TO-3 devices if that would work... Zero

15th November 2004, 03:45 AM	#10
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	Check www.apexjr.com. The last time I looked, he had some pretty big heatsinks pre-drilled for TO-3s. Grey

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