• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

HFE question

Mike Sweeney

Mike Sweeney

Well-Known Member
I'm looking at two subs for the 2SD427/2SB557 NPN/PNP transistors for a Marantz 2285B. The specs on the two are the same ( 250 volts, 16amps, 4Mhz, 250 watts) except for the HFE rating. The OEM was >20 at 5 volts. One sub is 25@5 volts.. but the other recommended is 15@4 volts.

So my assumption is that sub#2 is not acceptable due to the low HFE but I'm curious to the 5 volts. vs the 4 volts for the HFE?

Sub #1
MJ21193GOS

Sub #2 -
MJ15023G
 
Register to hide this ad
Transistors may have different gain at different operating points. The different parts were simply tested at different operating points. In any case, it seems like on paper the first sub is the better pick (if the originals were ">20 at 5V" then "25 at 5V" certainly qualifies), but of course you're going to need to order quite a few and match them yourself.
 
You must log in or register to reply here.
Back
Top Bottom