Gain evaluation of a preampli stage

[andreaemme]

Please, can somebody help me to evaluate the gain of the preamplifier stage figured in the attached image?
If yes, how?
Thank you very much.

[lineup]

Looks like some RIAA Phono.
Which means that the gain is different at different freq.
What the gain is at 1 kHz, nominal, I can not say.

Shuold be possible to run in spice simulator, to find out.
And get the AC Analysis frequency/gain curve.

[andreaemme]

Oh, this is certainly a line preamplifier stage, in fact this stage follows the volume control in a Marantz PM78 integrated amplifier. This means that is a strictly flat preamplifier.
Thanks however.

[Andypairo]

At a quick glance the AC gain seems to depend mostly on the ratio between the 2k2 resistor and the series of 270Ohm+1K trimmer, so it can be adjusted in from slightly less than 2 to slightly less than 10.

Ciao

Andrea

[lineup]

Ok.
Gain between 2 an 10 for line amplifier makes sense.
Adjustable with the pot.

[analog_sa]

Originally posted by lineup
What the gain is at 1 kHz, nominal, I can not say.

Shuold be possible to run in spice simulator, to find out.

Goodness gracious. Another spice junkie?

[lineup]

Don't you have Spice, analog_sa
Where have you been last 10 years

[mjf]

hello.
quick estimated: (2.2div0.27)+1=8 high gain
and (2.2:1.27)+1=1.7 x lowest gain...
greetings...........

[andreaemme]

That's all, thank you very much!