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-   -   Lme49810 with 2SC3263 & 2SA1294 output HELP!!! (http://www.diyaudio.com/forums/solid-state/245269-lme49810-2sc3263-2sa1294-output-help.html)

basi 4th November 2013 12:26 PM

Lme49810 with 2SC3263 & 2SA1294 output HELP!!!
 
Hi to All!!!

I have: lme49810
Pre drivers 2sc2705,2sa1145
Drivers 2sc3423,2sa1360
Output trans are 2SC3263 & 2SA1294

Bias tran is 2sc3419.

Here is my test schematic.Power Deoucupling inputs and other elements i will add later.

http://i248.photobucket.com/albums/g...ps1b8a0757.jpg

Would this Topology work?Any suggestions are welcome.

palstanturhin 4th November 2013 02:40 PM

Quote:

Originally Posted by basi (Post 3690823)
Hi to All!!!


Would this Topology work?Any suggestions are welcome.


No.

Turn PNPs around...

basi 4th November 2013 03:24 PM

Quote:

Originally Posted by palstanturhin (Post 3690980)
No.

Turn PNPs around...

Got it.


http://i248.photobucket.com/albums/g...psc3084947.jpg

dadod 4th November 2013 03:26 PM

Aside the wrong PNP connection, why do you use predrivers here, there predrivers are inside the LME 49810 already? In your case yuou will get oscilation, probably.

AndrewT 4th November 2013 03:30 PM

a1360/c3423 make good pre-drivers and good VAS.
They are not rated for driver duty.

basi 4th November 2013 03:46 PM

Ok here i remove predrivers.

http://i248.photobucket.com/albums/g...ps6a8c4c65.jpg

Ian Finch 4th November 2013 03:58 PM

10R base stoppers for the output transistors are probably excessive. 3.3-5.6R range values should be adequate even with these LAPTs, assuming no other sources of instability. I'm not sure the 0R1 emitter resistors were wise for a triple if that is what you intended. This will probably depend on a few factors like heatsink and thermal comp. performance too.

basi 4th November 2013 03:59 PM

Quote:

Originally Posted by AndrewT (Post 3691034)
a1360/c3423 make good pre-drivers and good VAS.
They are not rated for driver duty.

Ok Andrew i understand but i only have these transistors.
What is the alternative for driver trans or that i remove them also and leave only Lme with outputs?

AndrewT 4th November 2013 03:59 PM

I think you should increase the bias voltage setting VR to 500r.
The minimum bias voltage with the 200r is ~3.2*Vbe.
This may turn on the output devices when not intended.

AndrewT 4th November 2013 04:00 PM

Buy driver transistors. These should be rated around 1A to 2A. Even going to 4A is OK


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