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.
Would this Topology work?Any suggestions are welcome.
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.
An externally hosted image should be here but it was not working when we last tested it.
Would this Topology work?Any suggestions are welcome.
Last edited:
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.
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.
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?
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.
The minimum bias voltage with the 200r is ~3.2*Vbe.
This may turn on the output devices when not intended.
Take a look at the Elektor Q-watt article, as a guide. It is free so why not.
Q-Watt Audio Power Amplifier - ELEKTOR.com | Electronics: Microcontrollers Embedded Audio Digital Analogue Test Measurement
LME49811 seems to be slightly better performer than LME49810 but does not contain the clip flag and baker clamp.
My recommendation is to make the design able to use both of these parts and evaluate
I was wondering what would the best way to make 2 pairs of outputs bjt's using LME49811
Funny how the 49810 has twice the amount of distortion and more slew rate than 49810, any ideas as to why?
Q-Watt Audio Power Amplifier - ELEKTOR.com | Electronics: Microcontrollers Embedded Audio Digital Analogue Test Measurement
LME49811 seems to be slightly better performer than LME49810 but does not contain the clip flag and baker clamp.
My recommendation is to make the design able to use both of these parts and evaluate
I was wondering what would the best way to make 2 pairs of outputs bjt's using LME49811
Funny how the 49810 has twice the amount of distortion and more slew rate than 49810, any ideas as to why?
LME49811 slewrate was measured in its data sheet with a 30pf compensation cap.
In the -810 data sheet it was not...
Thats why.
In the -810 data sheet it was not...
Thats why.
That I can not say as I never evaluated, that is why I ask to see if anyone else has done so.
Thx palstanturhin
You have read better than I. Have you evaluated the difference in operation?
It is impossible to hear a difference between 810,811 and 830. If one can hear a difference, it is because of something else in the circuitry, not because of the chip.
With identical output stages, they will sound identical.
IMHO.
Choose the chip according to your needs, for example:
Very High Power ClassAB BJT output stage; -810
"Low"Power/ClassA; definitely -811
Mosfets; -830
The best of the best of the best is however, -811
With identical output stages, they will sound identical.
IMHO.
Choose the chip according to your needs, for example:
Very High Power ClassAB BJT output stage; -810
"Low"Power/ClassA; definitely -811
Mosfets; -830
The best of the best of the best is however, -811
Even with different output stages unless someone does something mental with them the distortions too low - you can't hear amplifiers over speakers.
Hi Andrew!!
I been searching last night for drivers transistor and i found these on my local supplier.
MJE15030,MJE15031
BD240C,BD239C ---2A
BD241C,BD242C---3A
BD243C,BD244c---6A
Wich pair of these will be ok for my circuit?
The MJE and the 243/4 are both greater than 4A continuous Id. Suitable for very high output current into low impedance loads.
The MJE is also very high Vceo.
Have a look at 2sb649/d669 which would make very good drivers if they were not obsolete.
Try to find other drivers that approach those 649/669 parameters. Particularly fT and SOAR.
Check that Vceo is >=110% of rail to rail voltage.
Check SOAR @ Vce = rail voltage. This is (roughly) the region where the current limit is first exceeded when driving a reactive speaker.
The MJE is also very high Vceo.
Have a look at 2sb649/d669 which would make very good drivers if they were not obsolete.
Try to find other drivers that approach those 649/669 parameters. Particularly fT and SOAR.
Check that Vceo is >=110% of rail to rail voltage.
Check SOAR @ Vce = rail voltage. This is (roughly) the region where the current limit is first exceeded when driving a reactive speaker.
Last edited:
Take a look at Profusions website listing of driver transistors. They have been selling good Taiwanese clones of 2SD6649/B649 and other good parts for some time now. This covers any real need for obsolete parts, provided you can place a total order for economical quantities. Ivanlukic has bought there recently and seemed happy with his Unisonic drivers, give them a try.
- Status
- Not open for further replies.