Integrated Amp for Martin Logan Mosaic

I am planning of setting up a 2-channel music stereo system for my room (12'x10'). I decided for my mains would be the new Martin Logan Mosaic. These speakers have an impedance load of 5-ohms, 90db sensitivity level, and power handling requirement of 175W/ch. The CD player would depend on what integrated amplifier I would mate the speakers with. The Classe CAP-101, Electrocompaniet ECI-4 or the Arcam Diva A90 are really nice but out of my reach so scratch them out. Hi-Fi Choice just gave the Rotel RA-1062 the Best Buy but it only has 60w/ch. Although they tested the integrateds with a B&W Nautilus 804 speakers, those speakers are easier to drive in that they only have an impedance load of 8-ohms (see link):

http://www.rotel.com/reviews/pdfs/in...oice-mar04.pdf

Would a 60w/ch (or lower) amp suffice to drive the Mosaics or should I get an amp that would match the load of the speakers? Unfortunately, it's always the case that the more power you need the less affordable the amp would be. But if 60w or lower is enough to drive the MLs then I should be able to afford a high-end integrated.

Hi there,

I'm thinking of getting the ML Mosaic as well.
I heard them together with the entry level NAD and the new Cambridge Audio Azur 640. The sound was great !!!

I think I will go back to the shop to try them together with the Arcam 65 or 75.

ief

Good quality is the key nopt watts. The Sugden A21a is a class A integrated amp - maybe the best under 3k of any design and it's a mere 25 watts. What was a common partner for this amp in the 70s - The Quad Electrostic 63. And the Sugden does not ouble in 4ohms. The amp in the 70s was only 10 watts and has since been upgrade to push 25.

Can it handle the impedence is all that matters. My Sugden is 70 watts but it can't drive Electrostats as well as the A21a. With 2 ohms my amp's fuse would pop.

People think high current means better but it's a meaningless buzz-word.

The NAD C370 will drive anything. Rotel is built well but I htink their preamp section (at elast in the past) was the weakspot.

I would try and buy a good preamp and maybe a used Rotel Power amp. More clean power with stats would be nice. Even a Used Bryston 3B ---You'd get the remaining years of the 20 year warranty - A ten year old Bryston 3B or 4B will probably better than any new $1200.00Power amp and you'd still have 10 years left on the warranty - likely 5 more years than buying new.

Preamps are abound for not huge money...even tubes if you want to try em out.

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Originally Posted by junkeroos

I am planning of setting up a 2-channel music stereo system for my room (12'x10'). I decided for my mains would be the new Martin Logan Mosaic.

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I'm with RGA on the quality vs. quantity issue as well given your chosen speakers. I offer one more avenue of choice if you do not have a vinyl setup: CD directly to power amp using passive attenuators. This answer isn't for everyone and careful component matching (including cables) is a must. Many CD players today put out more than enough current to drive most amps. Although I have heard a number of $10k + preamps on the market, none in my experience are perfect. Kick them out of the circuit altogether.

I stumbled on this realization when I replaced my CDP and moved the older one into the garage system. Originally I used an old Dyna PAS-3x but noticed that the gain control was rarely above 9 o'clock. So I built a passive attenuator using $15 worth of Radio Shack parts and tried that instead. It worked just as well. On a lark, I took my El Cheapo project downstairs and compared it with the $2500 ARC preamp - it was no contest. Bypassing the active stage of the preamp resulted in higher resolution, better dynamics and a more neutral tonal balance. I later built a higher quality passive for that system with marginally better results.

Here are the gotchas:

1. You need to make sure there's enough gain in the mix to avoid dynamic range restriction issues. On my big system, I have the fortuitous combination of high gain CDP (4 volt output) and sensitive amp (1.3 volt). I rarely crank the attenuators past the -10 db level. On my garage system, however, I cannot fully drive the power amp. I don't find that a problem since the Advents will get plenty loud enough with a 100 watt / channel Threshold Stasis.

2. The cable runs must be short and the cable of a low capacitance design to avoid high frequency rolloff. If you're interested, there is a calculator on the DACT site that will plot the response given the variables.

3. Multiple inputs requires playing musical connections. To some, that is either impractical or excessively awkward. I gladly switch the interconnects from either the passive or the preamp (for when I listen to vinyl) to the amps to benefit from the better sound.

So given a particular budget, you may get more bang for your buck with a CDP-passive-amp arrangement. If you've ever done some electronic wiring (I built a couple Dynakits in my teens) , you can try out a passive design for $15. I posted a recipe including part numbers on AA.

rw

The Arcam is a good choice. Maybe you can afford one of the smaller integrated. I have seen the Arcam receiver drive an all ML system. I saw the old Alpha one drive a pair of ML Aries. Arcam has amazing drive ability. It is due to their high current amp design. Those who say "high current" is a buzz word are missing some information on amps. One of the basic fundamentals is, it takes current to run low impedances. In my opinion the Arcam even a low power one, will sound much better than either Rotel or NAD. When you get into better amps all the ones I can think of are all high current. So Krell, Mark Levinson and others who are high current make this to have a buzz word yet they don't supply tone controls or other "buzz word" features of mass market products? These companies don't promote "high current" because it's just a given that it is a good amp design and necessary to drive the higher end inefficient speakers on the market. I believe high current also promotes a better sound but I will concede that this point is up to the one listening. The higher current also allows the amp to deliver the faster transient responses needed for a dynamic sound.

Does Sugden have you on retainer?

I have to tout Sugden since they don't advertise. I always regretted not buying the A21a the first time around. Over the last decade I have heard no integrated that i would rather own - at least not under 3k. (well except one - yup you're groaning - Audio Note.) Interestingly, one of the AN designers now works for Sugden's design team - both companies use the same crown 18 dac and Peter Qvortrup used to sell Sugden along with the original Snell speakers in the 1970s.

I came at both very independantly - coincidencadental bliss.

Dumb luck because you have to listen to stuff sitting on dealers shelves. When neither of them look great and neither of them advertise...they sure don't help themselves...until you turn them on of course. And that point seems to get lost in Audiophile land...we're more concerned with good reviews to help the possible re-sale value. The trick is finding stuff that you won't want to re-sell in the first place.