need darlington amplifier schematics

mbates14 · 29th November 2004, 03:25 PM

I have a bunch of mn2488, and mp1620 transistors, working pulls from a sony that had a bad 5.1 decoder board.

I found out they are darlington transistors, and i was wondering if there was a schematic that is reletivly simple to build using darlington outputs?

i have 5 pairs of these, or 10 transistors in total.

Can a parallel them?

i need some ideas! Thanks!

jaycee · 30th November 2004, 04:01 AM

Any amplifier that has an EF topology output stage would be suitable. Your darlington transistors simply become the driver and output transistor in one package.

For example, with reference to http://www.ampslab.com/c70.htm, your darlington transistors would replace Q7/Q9 (ignore Q11), and Q8/Q10 (ignore Q12)

The transistors you mention are custom 2SB1620 and 2SD2488, made originally for Sony by Sanken. I haven't had any luck tracking down any data sheets, unfortunately. Someone else here might know better. Most japanese semiconductor manufacturers are a pain once they've discontinued a product, they like to pretend it never existed.

mbates14 · 30th November 2004, 05:06 AM

but, thats japanese for you.

they make streight junk anyway.

jaycee · 30th November 2004, 06:16 AM

I dunno, from what I hear Sanken make pretty bloody good transistors. If you'd rather not risk messing with them, you could easily sell them on here for a pretty penny, I'm quite willing to bet plenty of people would offer to buy them.

mbates14 · 30th November 2004, 05:59 PM

like the dude mentioned above, these are strickly sony amplifier transistors, but I have these exctras I would like to build an amp with them.

cunningham · 30th November 2004, 11:42 PM

As mentioned, darlingtons have the driver inside. One big drawback is the driver is the same temperature as the output. This makes a temperature compensation circuit (servo) an absolute must, well with class AB applications. But they work basically the same.

Less soldering

mbates14 · 1st December 2004, 02:53 AM

i come across a free service manual floating around the web for a sony, that has the exact same transistors.

after looking at the schematic, they done things very very cheap.

first, they used a driver IC from NEC, and then two vas transistors, and then the two outputs. cheap cheap cheap.

cunningham · 2nd December 2004, 12:54 AM

That's Sony for you...

29th November 2004, 03:25 PM	#1
mbates14 diyAudio Member Join Date: Jun 2002 Location: non	need darlington amplifier schematics I have a bunch of mn2488, and mp1620 transistors, working pulls from a sony that had a bad 5.1 decoder board. I found out they are darlington transistors, and i was wondering if there was a schematic that is reletivly simple to build using darlington outputs? i have 5 pairs of these, or 10 transistors in total. Can a parallel them? i need some ideas! Thanks!

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30th November 2004, 04:01 AM	#2
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Any amplifier that has an EF topology output stage would be suitable. Your darlington transistors simply become the driver and output transistor in one package. For example, with reference to http://www.ampslab.com/c70.htm, your darlington transistors would replace Q7/Q9 (ignore Q11), and Q8/Q10 (ignore Q12) The transistors you mention are custom 2SB1620 and 2SD2488, made originally for Sony by Sanken. I haven't had any luck tracking down any data sheets, unfortunately. Someone else here might know better. Most japanese semiconductor manufacturers are a pain once they've discontinued a product, they like to pretend it never existed.

30th November 2004, 05:06 AM	#3
mbates14 diyAudio Member Join Date: Jun 2002 Location: non	but, thats japanese for you. they make streight junk anyway.

30th November 2004, 06:16 AM	#4
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	I dunno, from what I hear Sanken make pretty bloody good transistors. If you'd rather not risk messing with them, you could easily sell them on here for a pretty penny, I'm quite willing to bet plenty of people would offer to buy them.

30th November 2004, 05:59 PM	#5
mbates14 diyAudio Member Join Date: Jun 2002 Location: non	like the dude mentioned above, these are strickly sony amplifier transistors, but I have these exctras I would like to build an amp with them.

30th November 2004, 11:42 PM	#6
cunningham diyAudio Member Join Date: Jun 2004 Location: Knoxville	As mentioned, darlingtons have the driver inside. One big drawback is the driver is the same temperature as the output. This makes a temperature compensation circuit (servo) an absolute must, well with class AB applications. But they work basically the same. Less soldering

1st December 2004, 02:53 AM	#7
mbates14 diyAudio Member Join Date: Jun 2002 Location: non	i come across a free service manual floating around the web for a sony, that has the exact same transistors. after looking at the schematic, they done things very very cheap. first, they used a driver IC from NEC, and then two vas transistors, and then the two outputs. cheap cheap cheap.

2nd December 2004, 12:54 AM	#8
cunningham diyAudio Member Join Date: Jun 2004 Location: Knoxville	That's Sony for you...