Looking at Mc gear without autoformers?

[LostArk]

I've got my eye on the MA5300. The only thing keeping me from pulling the trigger is its direct coupling. I keep hearing the refrain "only buy Mc gear with autoformers." I've also heard the reverse is true, given that most speakers are engineered with direct coupled amps in mind. Unfortunately my dealer only has the MAC7200 on the floor for demo, so I can't do a comparison. Will I get the "house sound" with the 5300, lack of autoformers notwithstanding? Thank you!

 

[Archguy]

The MA5300 is a really great-sounding amp. I heard one at my local dealer's. People whose gear has autoformers say that's the way to go, and then there are people like me who prefer the direct-coupled amps. I've owned several and have two now. Like many questions in audio this one can start fights and I don't think it's worth fighting over. Frankly I've never heard a bad-sounding Mac amp of either variety.

 

[jayvis]

I've had both and I prefer the autoformer amps. There just seems to be some magic stuffed inside those autoformers that takes the amp to another level for me. The only way to know for sure is to listen to both at the same dB level on the same speakers, preferably your own. You could order a MA5300 from any of a number of on-line dealers who have a satisfaction guarantee. You'd only be out the return shipping if you decide against the MA5300. Your dealer should let you take his MAC7200 home for a trial run and you can compare the two in your system. If you don't have access to a dB meter, you could play both at approximately 1 watt on their output meters to get a decent comparison. This might sound like a lot of trouble to some, but I think it's the best way to make sure that you made the right choice.

 

[Porthos]

Between my now sold MC2155 with autoformers and new MHA150 (direct coupled speaker amp & autoformer headphone amp) I can say you would would be happy with either.

Autoformers would have a slightly smoother sound and I think that's more how it interacts with the speaker crossover than the iron, which should be better than even the most expensive output transformer. Autoformers are easier to wind than output transformers and have less compromises. I have heard a MC302 and it was just as capable of disappearing, tricking me into thinking that instruments were in the room with me.

Both have PowerGuard and Sentry Monitor protecting the amplifier and speakers, any differences in sound are subtle. Autoformers can supply the same power into higher impedance loads. While autoformers don't double their power at lower 4 or 2 ohm loads the transistors see a constant load, lowering distortion and stress upon the transistors. Also, should the amplifier fail (unlikely but never impossible) the autoformers are incapable of passing DC to your speakers (a good thing).

If the price is the same or close always go for autoformers but both are capable of great sound and protecting your speakers.

 

[audiobliss]

If you are young and strong get the autoformers.

 

[damacman]

I've owned a lot of both. I tend to migrate toward the big power amps, of which most have autoformers. However, the MC2002s that I've owned were all quite pleasant. Also, the MA6200 remains king on my list of integrated amps - no autoformers.

I don't think you can say with any great certainty that one is better than the other. At least I can't . . .

 

[MRL_Audio]

If you are young and strong get the autoformers.

Dang if that ain't true. Bought my first Mac setup over the course of this year. The amp, a MC2205, made me double over the first time I picked it up. First time in 30 years I decided I better start working out again if I want to be a Mac owner.

 

[Mike Gibson]

I've owned both over the years and comparing them I have stayed with the autoformer amps only because the higher power amp I wanted has autoformers. At one time I had a MC-275, Mc-2505 and a MC-502. So I had autoformers on the 2505, direct coupled on the 502 and tubes in the 275. The 2505 was warmer sounding to me than the 502. The 275 has a sparkle in the highs but the bass isn't as pronounced as the SS amps IMHO. They are all about the same wattage give or take a bit.

I have efficient speakers so 5 watts was a one or two song burst and then back to 1 1/2 watts and 80-90Db. Either way you go you're not looking at a major loss if you decide to sell whichever you chose and go another way. The best of luck to you however you decide.

 

[twiiii]

For me its all about the speakers you buy. The sophistication of the crossover, and they whether the box is sealed or not depends on the impedance of the speaker at any frequency. The more complex everything is you have to depend on the speaker designer to get the damping of the speaker correct. The more complex the speaker also the more the chance the speaker loading will efect the over all response of the amplifier. Take a 275 for instance. A crossover can make the response of the amp almost vary 5 to 6 db. So thats why it was so important to match amps to speakers in the old days. Where if you look at a Direct coupled Crown or Accuphase with the same speaker the vaiance would be less tan a half of a DB by the amplifier due to speaker loading. Well the Autoformer amps with damping over 40 the issue is almost not an issue anymore. Especially when using speakers with passive crossovers. Now if you were bi-amping with out the use of passive crossovers and using electronic crossovers with separate amps for LF and HF yes there would be a big difference between a 275 with a rating of 16 and say a a MC 7200, 6200 or modern direct coupled amps. The woofer is connected directly to the amp so there is more control on the woofer and because the HP section is also removed from the HF speaker there is more control there, too. But is to much control a good thing. Well, if a speaker is all ready critically damped like a ML-1 or XR-5 then it doesn't make any difference in most cases as far as woofer control goes, but you can have still have frequency response issues with low damping amps. Mac speakers have very consistent impedances. It doesn't make amps with autoformers always better, though the design can relieve strain on out put transistors. But if the amp is over designed like the 7100 and 7200 were to specifically drive certin speakers there is no issue either. The autoformer does introduce a penality. Lets say your speaker is a paneled speaker and the impedance is 85% over most of the range . But in the bass and top octave it drops down to or below two ohms. Well if your current Mac amp doesn't have the current reserves or necessary heatsink cooling your amp will shut down. Making you choose two ohm tap. But that penalizes you 6 db in power to the 85% of the spectrum that is near or above 8 ohms. Well if you have enough power at 2 ohm tap you are OK, but what if you need the extra 6 db you have lost. TILT. You need a direct coupled amp that has the necessary current capability. Well in the age of the 2000 series amps, 2105 2125 2205 2255 etc. They didn't have the current capability the newer amps have. A MC 501 will put out over 700 watts driving a 4 ohm load from the 8 ohm tap. So you are not penalized today like you were in the past. N0t that capability comes with a penality. The old amps would run all day and all night at full power. When the new amps driving a mis matched load will over heat and the sentry monitor will kick in shutting the amp down. But there is an easy solution. But an unit with more power than you need for 90% of your applications and let the power guard take care of the rest. This is where experience comes in. If you are running Mac speaker designed by Roger Russell his power ratings could be straight forward. Now days they give peak ratings most of the time. So in Rogers case he said 1000 watts for an XR 290, you bought a MC 2500 or a MC 1000. Today you know a Mac amp will typically put out 30 % more power than rated when the power guard clicks on and thats is the power you buy for your speaker less 3 db. The peak capability of the amps gives you that back before the power guard starts triming thing back. So today you would buy a 611 power amp for 290's to be safe as it puts out close to 900 watt peaks. . If you want to live on the wild side you buy a 1.2 K and hope the 1600 watt capability doesn't damage the speakers. For replacement drivers might not be available any more. But then no one listens at 120 db levels! 104 peaks is about all I can take any more. But if you like to feel your bones rattle at 43 hz go for it.

So the question is a 5300 enough. I would want speakers with at least 94 db efficiency. If you are less than that then you have to decide whether your music choices and room size will allow you to be happy. Remember most people seldom go over 90 db. Throw in 10 db for distance and 6 db for peaks thats 107 db. One system I have I can reach that with 40 watts. The other takes 120 watts. I have 240 watts per channel so I am fine. But I still want to MC 830's = 480 watts 4 ohms or almost 600 watts peaks for sure.

 

[LostArk]

Thank you all for the thoughtful and detailed replies, it's been of great assistance my decision making. My main takeaway: I better hit the gym if I wanna be able to deadlift the MAC7200