Toshiba 2SC3281/2SA1302 - Are these fakes? - Page 4 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 5th June 2009, 10:07 PM   #31
diyAudio Member
 
CrazzyAbtTubes's Avatar
 
Join Date: May 2009
Thumbs up Other not fakes

For reference here are the 2SD845/2SB755 Toshiba outputs, these are not fakes, but the real thing, from a really good sounding LXI amplifier.
Attached Images
File Type: jpg toshiba output pair(small).jpg (95.7 KB, 715 views)
  Reply With Quote
Old 5th June 2009, 10:48 PM   #32
wg_ski is offline wg_ski  United States
diyAudio Member
 
Join Date: Oct 2007
Default Re: Fakes!!! or not?

Quote:
Originally posted by CrazzyAbtTubes
I have a bunch of Toshiba 2SC3280's and 2SA1301's that I Plan on paralleling in an amplifier, I just have no idea if they will all agree with each other when I do so...

Nextly.... are these Toshiba 2SC3281's and 2SA1302 Fakes? They look genuine, will they work with the others in parallel?

Don't parallel unless they're from the same batch - even if genuine.

That 1302 is suspect. Not only did they discontinue the green cases when they discontinued that script "Toshiba-san" logo, the mounting hole is too small.
  Reply With Quote
Old 5th June 2009, 10:52 PM   #33
wg_ski is offline wg_ski  United States
diyAudio Member
 
Join Date: Oct 2007
Default Re: Other not fakes

Quote:
Originally posted by CrazzyAbtTubes
For reference here are the 2SD845/2SB755 Toshiba outputs, these are not fakes, but the real thing, from a really good sounding LXI amplifier.

I really liked those old transistors. It's a shame you can't get them anymore. I still have a few pair of C2565/A1095 in the same case. Highest freaking fT's I've ever seen in an audio power transistor - which is very good when using them above the audio range.
  Reply With Quote
Old 6th June 2009, 12:39 AM   #34
Banned
 
Join Date: Apr 2005
Location: Stockholm
wg_ski,
Quote:
That 1302 is suspect.
It is, 2SC3281 as well.
  Reply With Quote
Old 6th June 2009, 04:45 AM   #35
diyAudio Member
 
unclejed613's Avatar
 
Join Date: Dec 2006
Default Re: Re: Fakes!!! or not?

Quote:
Originally posted by wg_ski



Don't parallel unless they're from the same batch - even if genuine.

That 1302 is suspect. Not only did they discontinue the green cases when they discontinued that script "Toshiba-san" logo, the mounting hole is too small.
the digits rather than the "JAPAN" under the date code is suspect too. for some reason, it's more common to find PNP fakes than NPN.

there's a document you can download from the Toshiba web site. the subject is their semiconductor reliability tracking program. in there is detailed drawings of exactly what and where every inked or laser etched marking on the case belongs and what the date codes mean. unfortunately, just as with the sanken devices, it takes careful comparison to figure out the mold marks (raised letters or digits inside the dimples in the plastic) and which ones belong where. i am beginning to see a pattern with some mold marks where at least the last digit for the year is usually in one of them, and should be the same as the year mark in the printed date code.
__________________
Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net
spammer trap: spammers must die
  Reply With Quote
Old 6th June 2009, 06:52 PM   #36
diyAudio Member
 
CrazzyAbtTubes's Avatar
 
Join Date: May 2009
Thanks for the reply, I am more used to working with tube equipment (as the name describes ) but I have decided to rebuild one of my SS amps using the Toshiba 2SA1301 and 2SC3280.

I think that I can parallel the output using the ones that have matching numbers, so the "R" going in one channel ( these were in parallel formation in another amplifier along with the fakes) And the "O" will go in the other channel ( from a cheap but working Fisher amp)

If there is anything wrong with this idea let me know, or make a seggestion...

As for the suspected fakes, they can go rott on a shelf for a while.... Maybe later I will split one open since I don't have a full set.
  Reply With Quote
Old 6th June 2009, 07:34 PM   #37
diyAudio Member
 
CrazzyAbtTubes's Avatar
 
Join Date: May 2009
Oooooooo, this is interesting, one chip is smaller than the other, and there is some white stuff on the small one! That ain't a 100 Watt BJT!!!!!

The other one appears to have some copper pad, and has a much larger piece of silicon on it, I killed it!

Well that solves that mistery, I think when I need to find new Toshiba outputs.... I will just go to Ebay and buy some cheap SS amp such as the Fisher CA860 that the really good "O" types were found in.
Attached Images
File Type: jpg fake not fake(small).jpg (83.1 KB, 697 views)
  Reply With Quote
Old 7th June 2009, 02:22 AM   #38
diyAudio Member
 
Join Date: Nov 2004
Location: Florida
I cracked open some ON-Semi 4281/4302 samples I had, after I blew two up in a test.

The chips inside both look similar in size to the Genuine Toshiba in your picture.

I notice the older Toshiba are rated 150W
The newer On-Semi are 230W

I wonder why they use the same size piece of silicon? Is the Toshiba underrated, or the OnSemi overrated, or does the die size matter that much with power dissipation? I couldn't help but notice how big that Toshiba transistor silicon die was.
__________________
You can call me Mad Professor, building crazy experiments in my Electronics Workshop
  Reply With Quote
Old 7th June 2009, 03:51 AM   #39
diyAudio Member
 
unclejed613's Avatar
 
Join Date: Dec 2006
the die size matters mostly for current density. the thermal tab (material, mass, and shape) and bonding method of the silicon die matters for heat dissipation ratings. also some dissipation ratings are calculated for a specific test heat sink, others are calculated for an "infinite" heat sink, to make it easier to calculate heat dissipation with a known finite one.

that was a nice picture. how did you accomplish separating the epoxy from the tab and die so cleanly? i made some pics where i work showing the die size of some MN2488 transistors, but i ended up with just the bottom layer of the die on the heat tab, and chunks of epoxy.
__________________
Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net
spammer trap: spammers must die
  Reply With Quote
Old 7th June 2009, 08:55 AM   #40
Banned
 
Join Date: Apr 2005
Location: Stockholm
unclejed613,
nice explanation, as usual.
Quote:
that was a nice picture. how did you accomplish separating the epoxy from the tab and die so cleanly?
Skilfully done for demonstration purposes. Well, those fellows have obviously not much in common, it`s not just about power handling.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Original Toshiba 2SC3281 and 2SA1302 jean-paul Swap Meet 1 26th February 2006 06:42 PM
2SC3281 2SA1302 Schematic jleaman Solid State 18 16th June 2004 06:47 PM
Help with possible counterfeit 2SC3281/2SA1302 trwh Parts 6 22nd December 2003 05:41 PM
2SA1302 and 2SC3281 Diode Solid State 32 15th October 2003 04:05 AM


New To Site? Need Help?

All times are GMT. The time now is 09:31 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2