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 ?
What do you think of KSC2690AYS/KSA1220 or TTA011B/TTA006B ?
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.
Renesas (Germany ) has them which is a Japanese manufacturing company of long standing.
I would trust them first before something off eBay.
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.
Hundreds of schematics on solid state thread recommend the installation of the unicorn bd139/140. What you can buy is a goat.
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"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 .
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 .
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.
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...) 😕
seems to be hard to find actuals VAS references from regulars sellers (mouser, digikey...) 😕
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...
I have some Philips BF422 and BF423 recovered from old tv and monitors. Can they be used for VAS transistors?
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.