Comparing LME49810, 49830 and 49811

[jackinnj]

The compensation capacitor will affect the slew rate --

 

[panson_hk]

The only problem I see is the slew which is 15v/us and that is relatively low when compared with 810. Is it possible to get more slew out of 811? like 50v/us.

I am fixing with 811 as its more pure. Like I said If its possible to get more slew then its fine is that internally fixed?

I do agree that we dont require more slew in general but on selling front it makes big different.. and to be precise the slam will be great...

I wonder we can make it higher in a simply way as everything contributing to slew rate (except the comp. cap) is integrated.

 

[panson_hk]

Best TI Audio Regards,

Mark Audioman54

Hi Mark,

We miss you!

Panson

 

[rhythmsandy]

hi can we use a predriver 2sc5171 1930 and a driver the same transisors and output being 2sc5949 2121?

Is there any schematic that I can look at the predriver and the driver stage?

 

[andrewlebon]

Hi rythmsandy
greetings are geniune 2SC5171 2SA1930 available in bombay
warm regards
Andrew

 

[rhythmsandy]

I have 100 each in stock... anyway thank you...

 

[AndrewT]

predriver duty requires parameters that also suit VAS duty.
i.e. low Cob, high speed and adequate hFE in the chosen operating current range.

 

[rhythmsandy]

How about 2sc5171 1930 for both pre driver and driver as Ft 200MHz cob 16pf and hfe between 100 and 320. what do u suggest Andrew..

 

[AndrewT]

Ft is good @ ? Toshiba don't show a plot for Ft, just a typical spec value.
hFE is good @ >=10mA Toshiba don't give figures for <10mA
Cob 26pF @ 10Vce. About 5 to 10 times too high for VAS and pre-driver duty.
SOA 100mApk @ 55Vce for 100ms, one shot pulse, with Tc=25°C. This precludes it from driver duty at medium and high supply rails.

Save them for 50W into 8ohms amplifier drivers.
or as buffers in line drivers
or other low SOA duties

 

[rhythmsandy]

So what do u recommend Andrew..

 

[AndrewT]

Proper VAS and Pre-driver transistors. There are many here that recommend suitable types/models.
Proper driver transistors that suit the duty you require.
look up Greg's database for many examples.

 

[bimbla]

Biasing the STD03P/N

Hello,

I read somewhere in this long thread that the use of STD03P/N paid does not require the use of VBE multiplier. Can anyone kindly elaborate on this?
Does this mean that we can set the bias current using just the fixed resistors instead of a transistor acting as a variable zener and measure the quiscent current value across the emitter resistors?

I also see the quest for lower THD+N. What is the final outcome? Sonically what inferences do we have?

Thanks in advance!

 

[Mihkus]

No, they dont. They have internally built in diodes and act alot faster than Vbe multiplier. All you need is small resistor to increase voltage drop. Or trimmer to adjust..

 

[rhythmsandy]

Proper VAS and Pre-driver transistors. There are many here that recommend suitable types/models.
Proper driver transistors that suit the duty you require.
look up Greg's database for many examples.

Mostly they are sanyo which are decent.

I have a question that adding a pre driver is compulsory for lme49811?
Will there be any sonic benefit adding a pre driver even for lme49810?

 

[bimbla]

Sanken STD03x or ONSemi Thermaltrac

For use with LME49811, which are preferred: Sanken STD03x or ONSemi Thermaltrac NJL3281D/NJL1302D?

 

[AndrewT]

Can you buy NJL3281/1302?

 

[bimbla]

Thanks Andrew!
Just read in another thread that the ONSemi devices are no longer manufactured.

 

[Mihkus]

The performance of onsemi devices is probably the best of its class.

 

[AndrewT]

Some of the many NJL are still stocked.
Worth asking a few retailers.
I think one model of NJL is not yet obsolete.
Again worth asking.

 

[jacques antoine]

Some of the many NJL are still stocked.
Worth asking a few retailers.
I think one model of NJL is not yet obsolete.
Again worth asking.

ThermalTrak 15A, 260V, 150W NJL0281D (NPN) and NJL0302D (PNP) are still available @ Mouser. (I am not affiliated with them)
Cheers,

Jacques