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

Showing 5 responses by bigtee

bigtee
803 posts
 
A couple of people hit on it above. The input sensitivity is different with the new amp. It requires more voltage for a given output. No problem as long as your preamp doesn't clip at higher volume settings(or compress dynamics.)
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.
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.
bigtee
803 posts
 
On my Ayre V5x, it has a switch but it doesn't change the levels any really. The sound quality suffers some if it's in the wrong mode. Of course the Ayre doesn't ground the interconnects to the chassis at all anyway.
I think it could just be, considering the drive levels are double for the bigger amp that the perceived volume just ramps up slower. I mean, there is not going to be much of a volume difference with these amps in absolute terms. Your other amps would hit clipping at a much lower volume setting looking at the drive mv required. It would also depend on your displays calibration(as in, is it a true db indicator.)
Also, it still could have something to do with driving 2 amps instead of one. It doesn't appear input impedance is an issue between them.
I don't think you would notice any real difference in volume level between 115/ch and say 85/ch.
Does the bigger amp go on up to full power with more level? If it does, I wouldn't be too concerned about it.
Check the Dbw scale for exact figures.
bigtee
803 posts
 
Yea, I know a lot of manufacturers have different ways of implementing this feature. It sounds like the fellow has solved his problem, so that's good.
It is really hard to say anything on these forums outside of generic information. I used the example of Ayre because I use it and understand how it is implemented.
I also know some equipment is not truly balanced in its circuitry. I think this is why some don't notice any difference from XLR to single ended. It is actually converted back to single ended internally.
Makes it hard not knowing some of this equipments internal workings.
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