TDA1308 - changing gain resistors


2007-06-14 1:42 pm
Is anyone able to ascertain how the gain stage of this chip functions?

The circuit appears in the datasheet (page 6, entitled Typical Application) and is geared for 32 ohm headphones, however mine are 600 ohm beyerdynamic DT880 and the circuit as I've implemented it gets to listening levels around 90% on the pot.

R3/R4 and R5/R6 control the gain (via some kind of phase inversion). Can anyone suggest what a suitable change to these resistors would be, to drive the DT880 more efficiently?