LTP degeneration

[Bigun]

I'd forgotten about the Blameless.
I think it has a current mirror, which changes everything really.
There are also 2nd order effects, especially when you aren't using a current mirror, which probably go beyond this thread, in the way that the LTP is set up, including it's interaction with the power supply rails which can and affect the sound signature.

 

[EdGr]

In addition to improving linearity, emitter degeneration makes the LTP less sensitive to device variations. This can be important in a fully-complementary amplifier that uses two LTPs.
Ed

 

[lineup]

I have not got any satisfactory answer.
How can we get the value of a transistor inner resistance?
Can we set up a circuit and do measure it?

 

[EdGr]

gm is not measured but rather computed from the collector current (gm=ic/vt where vt=0.02585 volts at room temperature).
Ed

 

[PMA]

I have not got any satisfactory answer.
How can we get the value of a transistor inner resistance?
Can we set up a circuit and do measure it?

Measure and plot transistor characteristics and then calculate it. Or look into Spice models. You will have to learn something yourself, not only to ask for precise answers.

 

[ctrlx]

How can we get the value of a transistor inner resistance?

R = 26 / mA

if the ltp is 5mA, each bjt has 2.5mA hence 26/2.5 = 10.4 ohms

 

[PMA]

Yes but there are parasitic junction resistances as well.