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Old 25th March 2008, 03:15 PM   #101
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I can't see any reason for which these shouldn't work, but i can't find any beta-ic plots so maybe the driver will have some trouble driving them loud. LME49810 and LME49811 are better right now.

The transistors can give > 10A peak which should give more than 100Wpk with 45 loudspeakers, which is probably loud enough for you. Paralleling a pair would help preventing beta droop and make a more rugged amplifier.

Remember to use nice thermal compensation.

Good luck!
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Old 25th March 2008, 04:02 PM   #102
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Quote:
Originally posted by bobekucor
hi, just wanna ask is it possible to use 2SD2488 and 2SB1620 darligtons in building amp with Lm4702, i have 5 pairs tooked from Sony HT receiver, and wanna build something that would sound good but also have enough power (maybe using a multiple darlingtons at output?)
so I would appreciate if someone`d be kind to tell me how to do that in schematic, I am a quite newbie with this stuf
I think these parts are from the old Sanken product list -- they are probably sufficiently beefy for the task. I have used MN2488, MP1620; TIP142, 147 etc.
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Old 25th March 2008, 04:10 PM   #103
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thanks for answers, could you explain me or draw in short how to connect multiple darlingtons, I am planing to use this Schematic

btw sorry for so many questions
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Old 25th March 2008, 04:28 PM   #104
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Quote:
Originally posted by bobekucor
thanks for answers, could you explain me or draw in short how to connect multiple darlingtons, I am planing to use this Schematic

btw sorry for so many questions
Multiple Darlingtons (i.e. Darlingtons in parallel) are NOT a good idea.
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Old 25th March 2008, 04:50 PM   #105
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ok, thanks again, now I`m gonna do some job
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Old 26th March 2008, 12:13 AM   #106
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When we worked on Darlingtons in parallel with the LM4702 we could never get it stable. Agree with above post, don't bother.

-SL
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Old 25th August 2008, 11:58 PM   #107
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Default I need one of these

where to get this LM4702 i can't find it anywhere pls help i know its an old post
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Old 26th August 2008, 02:14 AM   #108
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I have them on my webstore -- as I bought a bunch a year ago.

http://www.tech-diy.com/Store/Drivers.htm
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Old 27th August 2008, 09:55 AM   #109
glennb is offline glennb  Australia
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Quote:
Originally posted by jackinnj
Multiple Darlingtons (i.e. Darlingtons in parallel) are NOT a good idea.
I can be done with good results, but the Emitter resistors required to get decent current sharing are quite high in value. My tests many years ago revealed that 0.5 Ohm was required to get below 10% mismatch in current. I've used up to 4 in parallel without stability problems (TIP142/147).

I also used 47 Ohm stopper resistors on all the Bases. This probably helps more with stability than current sharing.
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Old 31st August 2008, 02:30 AM   #110
Shaun is offline Shaun  South Africa
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Quote:
Originally posted by JustBuildLspkAS
hi everyone.(sorry for my poor english)

Need help for the BJT O/P stage for newbie ss amp. design as me.

I would like to use this output stage for my amp . How I chosen the correct bias for this circuit ,(for the out put transistor I need run idling 50-100mA / piece)
Hi JustBuild

That circuit looks interesting, and is presently my preferred configuration for tagging onto an LME49811, of which I have a few samples. Any idea why it has dual (60V/55V) rails?
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