Amati Futura/ARC Reference 75?

[RLF]

I own an Audio Research 75 amp. I am considering the Amati Futura with it. Does anyone here have first hand listening experience with both products in their room and if the Ref 75 has enough juice to drive it at sufficient levels with adequate low frequency impact and dynamics?

I've read that it takes that some serious power to get the Futuras really singing, but have read the opposite too. I will try to get an audition of this combination at my dealer, but was curious what other owners of Futuras have found.

BTW, my current large ProAc D80 speakers, rated at 4 ohms and 91 dB sensitivity are driven by my Ref 75 with amazing power, bass, and slam my 28'x14'x8' room. My listening chair is about 9 feet from my speakers.

Thanks.

Bob

[jdandy]

Bob.......The Sonus faber Amati Futura has a sensitivity of 90 dB /1w /1m with a nominal impedance of 4 ohms. That alone doesn't tell the full story. When looking at John Atkinson's electrical impedance and phase chart from Stereophile magazine's review of the Futura you will notice a dip in the impedance (solid black line) to about 2.5 ohm from 60 Hz to 100 Hz. This means that in order to produce rich solid bass in this critical frequency range your amplifier will need to deliver plenty of current, especially at higher listening volume levels. Your ARC 75 should have no issues at moderate listening levels but you may notice some loss of bass definition at more robust listening levels. Your room is larger than many listening rooms which may add to your power requirements. Remember, too, reserve power is essential for clean dynamics.





I own the Sonus faber Amati Anniversario speakers with a sensitivity of 92 dB /1w /1m with a nominal impedance of 4 ohms. As you can see from John Atkinson's electrical impedance and phase graph below, the Anniversario's impedance (solid black line) dips quite low in the 70 Hz to 100 Hz range. The additional 2 dB sensitivity the Anniversario's have over the Futura's helps offset some power requirements but my speakers still need lots of current in those frequency ranges to develop the type of bass authority and definition I desire.





I have driven my SF Amati Anniversario's with quite a few different power amplifiers including the McIntosh MC275 MkV, two MC275's in mono, MC352, MC452, a pair of MC501's, MC601's, and currently being driven by a pair of MC2301 amplifiers. Although the MC275 MkV amplifier made sweet music with the Anniversario's, moving to a more powerful amplifier definitely improved the definition and dynamic authority of the bass. The MC275 delivered good bass but a bit loose and not quite as quick with dynamics. With all of the other amplifier's used the bass snapped into focus even in the deepest frequency ranges. My current MC2301's drive the Anniversario's without reservation.

My suggestion is be ready to get more performance from your Sonus faber Amati Futura's with more power than the Audio Research 75 is capable of delivering. An ARC Ref 150 would probably be a better amplifier for your Futura's. The ARC Reference 250 would be even better.

[RLF]

Dan. Thank you for the most helpful and informative reply.

I did see the the impedance dip in the 60 Hz to 100Hz range and that was my concern with the Ref 75. I do own a 175 watt Ayre VX-5 amp too which might be a better match as far bass is concerned as well as yield more headroom. In the meantime I'll try to get an audition with the Ref 75 with the Futura at my dealer to get a handle on the capability of the combination together.

[cmalak]

Bob...Dan's response is spot on and your plan to take the Ref 75 to demo it with the Futuras is the right thing to do. If you can swing it, take your VX-5 as well to compare the two amps. My guess is you will find the Ref 75 will do quite nicely in areas of timbre, resolution, imaging and spatial cues but will have a tougher time with bass depth and more importantly articulation as well as macro dynamics. The VX-5 will probably beat the Ref 75 on those two dimensions but may underwhelm on the ARC's strengths. You can also see if your dealer has a more powerful ARC or other tube amp (but again the key here will not be power rating but current throughput - amperage - given the difficult load). You really want an amp that is stable into 2 ohms and probably the auto former on the Mac amps will give them the edge vs. other tube amps. More likely though will be the need for a SS amp that keeps on doubling power as impedance is halved and is stable into a 2 ohm load. Perhaps the dealer will have some other options for you to consider (maybe try out a Class A SS design as an example). Good luck and let us know how you make out.

[metaphacts]

Originally Posted by cmalak

Bob...Dan's response is spot on and your plan to take the Ref 75 to demo it with the Futuras is the right thing to do. If you can swing it, take your VX-5 as well to compare the two amps. My guess is you will find the Ref 75 will do quite nicely in areas of timbre, resolution, imaging and spatial cues but will have a tougher time with bass depth and more importantly articulation as well as macro dynamics. The VX-5 will probably beat the Ref 75 on those two dimensions but may underwhelm on the ARC's strengths. You can also see if your dealer has a more powerful ARC or other tube amp (but again the key here will not be power rating but current throughput - amperage - given the difficult load). You really want an amp that is stable into 2 ohms and probably the auto former on the Mac amps will give them the edge vs. other tube amps. More likely though will be the need for a SS amp that keeps on doubling power as impedance is halved and is stable into a 2 ohm load. Perhaps the dealer will have some other options for you to consider (maybe try out a Class A SS design as an example). Good luck and let us know how you make out.

Spot on Cyril, though bass depth is no problem with a REF 75.

I've heard the combo extensively. I love the REF75 but depending on music and room, it's just not enough for Futuras. Maybe the KT150s help that but I've heard REF250s not being enough in a big room with large scale classical works. With the engaging beauty of the ARC/ Sonus combination, the inability to scale dynamics can be frustrating.

As for stability that is not the issue. The MC-275 coughs up a lung before the REF75 shows strain or compression. The MC275 is really not remotely in the same league once you remove the nostalgia factor. If I could live without ultimate dynamics, I'd do a REF75 (SE ) and never look back

YMMV

[tompj]

I very recently heard the ref 75 on a Guarneri Futura at my dealer. For what it is worth...

I was there to audition (and buy) a pair of Memento (about the last new pair available in Holland). When I walked into another listening room, on a very low level, a pair of GF was playing on ref 75. On walking in, even at this low listening level, I was immediately captured. Sheer bliss. Incredible. A pairing made in heaven. The smooth character of the Sf's together with the powerfull almost tangible midrange that the Audio Research produce just gelled together. A perfect combination of detail and peaceful smoothness. Now I have to start saving up....

[gaboudreaux]

Novice question here. I'm familiar with looking at watts and ohms when judging what amps are capable of, but what do you look for in the technical specs to determine the amps current?

I have the Amati Futura and VX-5 and have no complaints with the bass. I feel it's clean and has adequate slam for my taste, but would prefer the mid to high frequency range to open up a bit more.

[cmalak]

Originally Posted by metaphacts

Spot on Cyril, though bass depth is no problem with a REF 75. I've heard the combo extensively. I love the REF75 but depending on music and room, it's just not enough for Futuras. Maybe the KT150s help that but I've heard REF250s not being enough in a big room with large scale classical works. With the engaging beauty of the ARC/ Sonus combination, the inability to scale dynamics can be frustrating. As for stability that is not the issue. The MC-275 coughs up a lung before the REF75 shows strain or compression. The MC275 is really not remotely in the same league once you remove the nostalgia factor. If I could live without ultimate dynamics, I'd do a REF75 (SE ) and never look back YMMV

Bill...thanks for your comments. How are things at Transparent?

[tompj]

Originally Posted by gaboudreaux

Novice question here. I'm familiar with looking at watts and ohms when judging what amps are capable of, but what do you look for in the technical specs to determine the amps current?

I have the Amati Futura and VX-5 and have no complaints with the bass. I feel it's clean and has adequate slam for my taste, but would prefer the mid to high frequency range to open up a bit more.

I don't think looking at the specs will give you answers here. Your amp has been designed to give good control. Even the power ratings don't tell the whole story there. If it is in control, then it might be the specific character or sound signature of it you are looking for. The Ayre's I have heard where good and gave a lot of insight, but where not the richest in their mid's and highs. Even a lower powered tube amp will bring hou a lot more if that is what you are looking for.

[cmalak]

Originally Posted by gaboudreaux

Novice question here. I'm familiar with looking at watts and ohms when judging what amps are capable of, but what do you look for in the technical specs to determine the amps current?

I have the Amati Futura and VX-5 and have no complaints with the bass. I feel it's clean and has adequate slam for my taste, but would prefer the mid to high frequency range to open up a bit more.

Some but not all amplifier manufacturers report Output Current expressed in Amperes, and they may report either Mean Weighted or Peak current levels but not all do, so that's a harder spec to find out typically but you can call the manufacturer or the dealer and see if they can provide you with that info. More importantly is to ask the manufacturers and the dealers their opinion about whether a particular amplifier matches well with a particular speaker given the specs and most important is to hear for yourself. As Bill mentioned in his answer above, he's heard the Ref 75 with the Amati Futuras many times (Bill Peugh used to be a senior executive with Sumiko Audio and is known as the Sonus Faber speaker whisperer for his skill in setting up SF speakers for SF dealers and clients and is now Managing Director at Transparent Audio so let's just say he knows his stuff ) and it delivers on most fronts but it did give out on ultimate oomph in bass region and in dynamics, and if you have a big room that will put even a bigger demand on the amplifier. Ultimately it all depends on what sonic attributes you prize most highly and how hard you are going to drive the amp (how far away you are going to sit in your largish room and how loudly you will want to play the speakers).

Good luck and let us know how you make out when you audition the speakers with the Ref 75 and other amps.