How do I reduce the overall gain in my preamp ?

I would not try to modify your preamp.

I would look at getting a different preamp or look at getting a source that outputs less. Or look at getting speakers that are less sensative.

Just my 2c.

KF

KF, I believe you meant poweramp and not speakers.

If poweramp is sencitive and source component(s) with high output why not going for passive preamp and sell the line-stage?

Hi Albert
Dweller's suggestion is definitely the best of the above. If you aren't able to follow the mod instructions for lack of technical know-how, a local repair shop should do this for you fairly inexpensively. Retain the mod instructions for future reversal in case you decide to sell it later on.
Or insert a quality passive attenuator into the tape loop, as an aside on Newbee's suggestion.

Marakanetz, you can do it as you state with a less sensitive amp OR speakers. Going from 95db sensitive speakers to say 92db speakers will give your system less overall gain/volume.

KF

I have LS-2 that had gain reduced by dealer. There is a
jumper on the board that is replaced with a resistor. Gain
is reduced by 12 db I believe. Do not know where in circuit
they do this, contact dealer or ARC.