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Atma-Sphere MA2 Mk2.3 / Krell KSA 250 / Passlabs?

Good Evening Fellow Audio Heads!

I'm upgrading my amps (will be a big step up from my NAD S200) which I still love dearly.

The amps that I have the choice to purchase second hand are:

Atma-Sphere MA2 Mk2.3 - AUD $9000
Pass Labs X250.5 = AUD $6995
Krell KSA 250 = AUD $3000

Now the Krell and Atma-Sphere are class A. The Pass labs A/B. Front End will be a Atma-Sphere MP1 Mk3. Speakers are the unfriendly Dynaudio Confidence 5 (no intention of changing these lovely speakers)

Can you please advise your thoughts on what amp would sound best in this situation. Music Reggae / soul / female vocals. What amp listed is the best value? I would say either the Atma-Sphere or the Krell. I have only heard the Pass-Labs in person and that sounded nice and smooth. I like detail in my music.

Many thanks for all your help as it's impossible to do A/B comparisons.

Cheers
Che
che13
mapman's avatar
mapman
22,504 posts
 
"One still needs to be cautious about the speaker's MINIMUM impedance (e.g., probably not less than the mid-3 ohms range) and still to seek speakers that have reasonably smooth impedance curves (no steep drops or spikes) without a lot of crazy phase shifts going on. "

The Dyn Confidence 5's meet this criteria?

I suppose the only way to know for sure how it will sound would be to try it and compare if possible without taking a loss if things did not pan out.

I understand how a lower output impedance opens up more possibilities regarding speaker matches, but I still wonder how to determine anything reliably up front in lieu of more detailed impedance curve info for a particular pair of speaks.
pubul57
3,712 posts
 
If the Atma's can drive them fine - an awful lot of tubes though. I think you should take a look at the Pass XA-160s up for sale for less than $6,000 - I would choose the XA over X if and when money is not a consideration. 160 Class A watts should be enough, just not sure what problems the XA versus XA.5 (more current into lower impedances) might have with that impedance swing - seems like a good deal me though. I imagine Audiofeil would have some insight here.
che13 OP
19 posts
 
Thanks everyone for the input.

This tech stuff has gone way above my head, but the phase shifts according to Dynaudio are as follows:

Impedance, Phase Shift (20-200 Hz):
-19.6º - +18.7º
Impedance, Phase Shift (200-20 kHz):
-5.1º - +15.1º
Impedance, HF (200 kHz):
5.4 ohms

This means nothing to me but I would like your thoughts on the MA2-Mk2.3 driving these lovely speakers.

Thanks again.

rushton's avatar
rushton
2,445 posts
 
Che13, your best source of advice will be to call Ralph and talk to him about this match. Now that RMAF is over, you should be able to catch him via email or phone. His contact information is on the A-S web site.
mapman's avatar
mapman
22,504 posts
 
I'm rooting that the Atmas amp works out.

Good luck!
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