Audio Research LS-25 MK1 Owners

I had a LS-25 MK.I and found the bass response to be exceptional. Is it a new unit? Have the tubes settled in as of yet? Might get a bit fuller response after a couple of hundred hours on the tubes? Also you might try the Sovtek NOS 6H23 as a tube substitute, as I found that they improved performance of the pre-amp in all areas and are not too expensive.

Also a fuller/rounder (Shunyata?) A/C cord might improve things as well. Good Luck.

Yeah and I had to chase it down at Audio Clasics.
Now it has found a home in merry Old England.

Remember doggie?

The most overlooked reason has to do with the fact that you set up the speakers for the bass balance of the other pre amp. Did you adjust the placement of your speakers after instaling the new one? Every time you change something in the system that effects the tonal balance it's time to adjust the position of the speakers. It may only take a 1/2" adjustment. It's free. It's the single biggest reason most of these guys never get anywhere with their systems. They plop in some new thing. "Oh gee", "it's this", or "it's that", up for sale it goes. Did they ever move the speakers? I doubt it.

Save the great tweaks for after you get the basics right. Then those things will just put a smile on your face. You may need to move them again after the new tubes or the new power cord. Give it a try,very small adjustments can make a huge difference.