2. amps-preamps
  3. 1109824073

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
lugnut
1,190 posts
 
Kdl6769,

Unlike the posters above I share your concern. All Linn amps have the same gain, or at least they did the last time I inquired. I realize you aren't running these Aktiv. Remember though that when one goes Aktiv the cards are available in mono or stereo and you can mix and match amps without any concern. If the situation were as you described then they couldn't do that. I'd fire off an email to Linn customer support asking about this phenomenon. Better yet, if you have a Linn dealer that you purchased this amp from I'd have them inquire on your behalf.
bigtee
803 posts
 
When you use 2 amps instead of one (as you did,) your TOTAL input impedance has been changed being a factor of the two input impedances in parallel. This presents half the load to the preamp as that of one amp assuming that lugnut is right about the impedances. Some preamps like more load, some less but there is your difference.
gregm
3,021 posts
 
Bigtee wrote:
Some preamps like more load, some less...
No, not really. Lowering the load's impedance always makes things more difficult for the source. The higher the destination impedance and the lower the source impedance, the better.

If all Linn amps have identical input impedance across the FR spectrum, the single 2250 should be a MUCH easier load (twice as high in fact).

Maybe you should follow Lugnut's advice, pronto!
bigtee
803 posts
 
Maybe so, but I haven't always found this to be the case in real life as for actual levels(few other factors envolved.) I don't know about Linn equipment and the type of input configuration it has ( Jfets or whatever) I do know a lot of preamps like a certain load and I based my statement on that ( a generic one at best) and I agree, most preamps like a higher impedance load (especially tubes without a buffer)
I also concur, call the factory.
lugnut
1,190 posts
 
Bigtee might be right. I have no experience with passive bi-amping. The tech people might be able to shed some light on this. In my experience they are slow to respond. Expect up to a week to get an answer.
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