Rogue Audio Atlas Magnum III Power Amplifier

Your speakers have 3-ohm impedance in the midbass region.  

While they may sound god with the Atlas at moderate volume, the 3-ohm midbass region will tax the amp such that above moderate levels midbass will run out of steam.  

Can you stretch to the Stereo 100?  

I probably can. Will it be a match though? Both are 100 watts. Parasound is many more watts than the two. It makes me wonder if I am going to lose something going from solid state to tubes at a lower wattage. 

The Rogue amps perform really well from their 4 ohm taps into 8 ohm nominal speakers, so a 3 ohm dip shouldn’t be any problem when running from those taps. But the Stereo 100 should perform better overall, if you can go there.

100 Watts, even sacrificing a little of that for running 4 ohm taps into 8 ohms (this mismatch will generally sacrifice some power in exchange for lower distortion and better bass), should be enough for you 93dB speakers.

I like the A21 (owned one in the past) but I think the Rogue amps will be more enjoyable. They also bring a lot of flexibility for tube rolling, etc.

@couger4u 

I owned the Rogue Cronus Magnum II for several years (Atlas amp section).  Then I upgraded to a Rogue pre and Stereo 100 amp.  

The Stereo 100 felt and sounded like twice the amp of the Atlas regardless of wattage spec.  

Sounded on par with my Parasound a21+ but better overall refinement, transparency and sound stage.  The ST100 is a world beater for the money.  

Answer- the S

@avanti1960, + 1

I had an original Atlas and compared it to a Stereo 90 in my system, long ago. Yeah, the ST90 was definitely better (I later upgraded to Apollos). So I agree with @avanti1960 - you should probably just stretch to the Stereo 100. 

I was reading Stereophile review, and it says that Output power is 100Wpc in Ultralinear mode and about 60Wpc in Triode. Will my Focal 936 handle 60WPC?  Sorry am a newbie when it comes to amplifiers. Also, can the amp take KT150 tubes? 

@couger4u,

If you go with Rogue, get the Rogue ST-100 DARK version it’s better in the bass. Talk to Nick or Mark at Rogue Audio.

http://www.rogueaudio.com/New.htm

@couger4u 

I've tried the Apollos in triode, they still have plenty of power that way (150 Watts into my 96dB speakers) but the sonics just don't do it for me. I prefer ultralinear every time. The triode mode gains you like 1% worth of a sweeter midrange, at the expense of significant bass power, slam, and dynamics. IMO the Rogue amps sound like they're supposed to in ultralinear. If you want a super sweet lush tube amp, these aren't that.

And no, you definitely should NOT use KT150 in any Rogue amps. Even in amps that can use them (like my VACs) I think they will not sound good unless the amp was designed specifically for that tube. They sounded bad in my VACs.

I noticed minimal to no difference running the ST 100 in triode with my Harbeth speakers.  seems to be mirrored by other Stereo 100 users.  

Stick to ultralinear.