Volume level mystery - can you solve it?


I recently replaced a pair of Linn LK power amps (85 and 140, in passive biamp mode) with the much more powerful Linn 2250 amp (just one). My preamp is a Linn Kairn. I have noticed that in order to achieve the same volume levels with the 2250 as I was getting with the 85/140 combo, I need to crank the Kairn volume setting much higher. By way of example: on a scale of 1-100, 50 used to be my normal listening level, but to achieve that level I now need to turn the Kairn up to 70 or higher. The Kairn only goes up to 100, but with the new amp, everything below 60 or so is very, very quiet. After 70, the volume ramps up pretty quickly, whereas with the 85/140, the distribution seemed more of an even straight line graph. Does anyone have any idea what this is all about? Are amps just calibrated differently? If anything, I would have expected the 2250 -- a more powerful amp -- to produce higher volume at lower settings, but the reverse seems to be true. Any thoughts about this would be much appreciated. I am a little worried that something is wrong with the amp, but aside from the volume issue the sound seems good. Thanks.
kdl6769

Showing 3 responses by eldartford

Gain of the more powerful amp (volts out per volt in) can be lower than the less powerful amp. It's just that the more powerful amp will continue increasing it's output beyond the voltage where the less powerful amp quits. Like the story of the rabbit and the tortoise. The tortoise wins.
Kdl6769..The little button is your problem for sure. When an amp with balanced inputs is operated single ended the
(-) pin of the input connector must be grounded. That's what the switch does.

Gunbei...When the two amps are both driven by the preamp, the combined input impedance goes down, not up. For example: two amps with 20K would be 10K. Actually, cutting the impedance in half like this might not make much difference if the pream[ is low impedance, and can hold the voltage up dispite the increased current needed.
Bigtee...On some balanced equipment (I have some) the use of unbalanced connection is sensed, and the gain adjusted accordingly. I have one piece that is unbalanced in, and balanced out, but unity gain through the piece is assured by this feature.