TRANSISTORS NEEDED - Page 9 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 12th July 2013, 08:19 PM   #81
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
The B&D J74s i bought were unfortunately fakes too.

There's no telling what is real and what is not these days.
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 12th July 2013, 08:36 PM   #82
labjr is offline labjr  United States
diyAudio Member
 
Join Date: Apr 2003
Location: MA
Quote:
Originally Posted by bear View Post
The B&D J74s i bought were unfortunately fakes too.
Really? That sucks. I guess you need to be absolutely certain the product you buy came from an authorized distributor or directly from Toshiba. Companies like MCM may not be aware of the siutation with a specific part. So their buyers may just be looking for stock and get it ouside the normal distribution chain.

Years ago, a woman that works for a Boston area electronic distributor told me of the problem with counterfeit parts. I had no idea what she was talking about back then. I do now.
  Reply With Quote
Old 13th July 2013, 01:48 AM   #83
diyAudio Member
 
Join Date: Nov 2005
Location: Sarasota FL
Quote:
Originally Posted by zoe View Post
I received my order from B&D yesterday that was fast.
Now I need to build a test circuit to match them. I read on one of
EUVL post how they are not true complementary devices so I think a little miss match
would be ok maybe better I need to go back and read that post.
Received mine also. Same Lot #, and yes, EUVL post was in the back of my head also. If you come up with a circuit to match let me know. Rod has one one his site, ESP article listing. He has some great info.
Paul
  Reply With Quote
Old 13th July 2013, 03:13 AM   #84
diyAudio Member
 
Join Date: Nov 2005
Location: Sarasota FL
Quote:
Originally Posted by 6L6 View Post
That's a great idea!!

Teamwork, not a Group Buy. I like it!
I'll get the adult beverages.

I just read where the J74s from B&D were fake. Makes you wonder what our goverments are doing about all the crap comming in, or out of China. I'm I wrong?
Sorry, I feel better though!

I guess I need to devise a test circuit myself. It seems like this would be a good service to provide
  Reply With Quote
Old 13th July 2013, 03:17 AM   #85
The Dastardly Dad of Three
diyAudio Member
 
Join Date: Sep 2009
Quote:
Originally Posted by 6L6 View Post
I've got some really good news concerning the B&D Toshibas - They appear to be genuine.



I sent my batch to Wayne Colburn (The preamp guru of Pass Labs) who graciously applied all his expertise to measuring them. He is pleased to report back that the Idss and Noise is all within spec, but most importantly, the curve trace is genuine. These are certainly not re-branded switches.

Also of note, they have the Toshiba 2SK2013 / 2SJ313 in stock. These are use in the BA-3 Front End. They are not cheap, but they are still cheaper than tubes... I ordered a few.

So have at it, get while the getting is good, who knows how many they have.

Oh, one other thing, I'm not sure if they are actually "matching" when you order the SKU that is the pair... Perhaps it's just a 'matched set' of the N and P channel. Regardless, I strongly suggest ordering at least 10pr. Toshiba is never going to make these again.
Fabulous news
  Reply With Quote
Old 13th July 2013, 03:20 AM   #86
6L6 is offline 6L6  United States
diyAudio Member
 
6L6's Avatar
 
Join Date: Oct 2010
Location: Denver, Colorado
To test them properly, assuming they are a jfet close to the real thing, you would need a curve tracer. There are some circuits you can build that will plug into an o-scope.

Hopefully Linear can get the yields they need to bring their J74 to market.
  Reply With Quote
Old 17th July 2013, 10:53 AM   #87
WalterW is offline WalterW  Netherlands
diyAudio Member
 
Join Date: Oct 2012
Location: Utrecht
Quote:
Originally Posted by bear View Post
The B&D J74s i bought were unfortunately fakes too.

There's no telling what is real and what is not these days.
How do you know they are fakes? I saw a message from 6L6 that they were real...he had them tested with a Pass Lab guru???
__________________
Pass F5, F5Tv3, ACA, Aleph J, DDDAC1794, DCB1, BA3-preamp, VFET CSX1.
  Reply With Quote
Old 31st July 2013, 03:19 AM   #88
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
I bought some from B&D last year.
I ran them on my curve tracer.
NG.

The IDSS is fine.
The Yfs is way off, and the shape of the curves was NG.

That doesn't mean that they did not buy another batch that happens to be good. Hard to know without testing them.

PM me, within reason I am ok with running some on my curve tracer and posting (or not) the curves.
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 31st July 2013, 03:37 AM   #89
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Amplifier wise, if you have Jfets that operate between 6 and 20 mA Idss
and have a transconductance between 20 and 40 MS, you are in good shape.

MC preamp wise, you want genuine Toshiba or Linear Systems.

  Reply With Quote
Old 31st July 2013, 09:57 PM   #90
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
NP, any comment on the statement in post #64?
The ones I got from Bdent were clearly the same as the bogus asian devices that I got from various sources and countries in asia. Of course my purchase happened about a year earlier, iirc.

The ones I got are not compliments at all to genuine 2SK170s.
Not even close, although their IDSS was spot on. Remarkably so.

_-_-
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  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
Help needed on new output transistors reddish75 Solid State 6 13th January 2012 11:27 AM
Transistors needed NYCOne Swap Meet 0 17th May 2011 04:53 AM
Vfet Transistors needed tubee Solid State 2 28th August 2008 02:50 PM
Help needed Output Transistors blown Rossy Parts 21 14th February 2007 04:14 PM
complementary transistors needed sss Solid State 2 25th October 2003 02:20 PM


New To Site? Need Help?

All times are GMT. The time now is 01:10 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