Problem with gain change after replacing TL084

[kiranswaps]

hi frnzs
m designing a circuit analog part in which i have made a particular gain to boost the voltage level.i am using tl084 .when i change the ic .... i mean replace one tl084 with another one the gain changes. same thing happens with lm347,lm324...i have tried with atleast 25 brand new tl 084 but same problem iwth every one... please help me sort this problem.

 

[timo67]

gain change

Hi kitanswaps

I need more explanations
How many gain stage have you?
what is the value of the gain ?
at which frequency are you working?
How are you measuring the gain?
may be your measure is diturbed by:
the offset
the slew rate
the cut off frequensy ?

 

[Verba]

gain change

may be it's just output impedance of the gain stage ?
Can you post the schematic, please ?