VAS transistors update

[altec9440]

A lot of transistors for VAS/driver from Greg list are now obsolete. As a great quantity of fake products are flooding market, finding up to date products with regular distribution can be a good idea

What do you think of KSC2690AYS/KSA1220 or TTA011B/TTA006B ?

 

[duncan2]

Those two complimentary audio BJT,s are high voltage (120V types ).
Renesas (Germany ) has them which is a Japanese manufacturing company of long standing.


I would trust them first before something off eBay.

 

[indianajo]

On semi KSA1220/KSC2690 are stocked at digikey US at $.56 each. They have actual Cob & Fte specs, which the competition MJE340/350 and BD139/140 do not. Yes the mythical Phillips/telefunken/mullard bd139/140 had those specs. The fairchild versions bd139/140 actually for sale now do not.
Hundreds of schematics on solid state thread recommend the installation of the unicorn bd139/140. What you can buy is a goat.

 

[duncan2]

"What you can buy is a goat " - thanks Indianajo my first laugh of the day !



Your right about the BD139/140 its in my Mullard spec book --old version was BD137/138.


Epitaxial silicon transistors for driver pairs in high quality audio amplifiers I have some originals I didn't know they were that wanted .

 

[Mark Tillotson]

KSC3503D / KSA1381E are currently available, 300V rated.

 

[nfsgame]

BF722/BF723 could be okay if you can do smd and if they fit into your circuit. Only 60MHz ft, but 1.6pF/2.5pF Cob.

 

[altec9440]

Better then KSC2690AYS/KSA1220 or TTA011B/TTA006B with more then 19pF but smd

seems to be hard to find actuals VAS references from regulars sellers (mouser, digikey...)

 

[nfsgame]

Well, not the biggest problem at all... For most of the pcb houses you might have to order more than one and cut them by yourself because of the minimal area they can process.... But maybe there are more people interessted in.

 

[capslock]

So what is recommended these days for cascode VAS, specifically for the low voltage cascoded VAS transistor. For the cascode any of the aforementioned 20 -40 pF types will do...

 

[alain98]

I have some Philips BF422 and BF423 recovered from old tv and monitors. Can they be used for VAS transistors?

 

[Mark Johnson]

Bob Cordell's textbook (1st edition) was super enthusiastic about the 2SC3601 / 2SA1407 . 400 MHz , 200V , 3.0 pF. Since the Sanyo datasheet said "Ultrahigh Definition CRT Display" I imagined they would be discontinued pretty soon, and I bought quite a number of them from Mouser at $2.00 per piece. I'm glad I made that investment; they were indeed made obsolete, discontinued, and are now hard to find.