Why don't Mcintosh amps double down? - AVS Forum
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post #1 of 27 Old 04-14-2007, 07:11 AM - Thread Starter
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Why don't Mcintosh amps double down? What benefits does this provide?
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post #2 of 27 Old 04-14-2007, 07:23 AM
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They have a transformer with 3 sets of output taps. 4,6,8 or 4,8,12?

They seem to think it's beneficial but I don't know the logic.
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post #3 of 27 Old 04-14-2007, 09:40 AM
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Quote:
Originally Posted by Will d s View Post

Why don't Mcintosh amps double down? What benefits does this provide?

Will,

Usually an amp fails to "double down" when it flat runs out of current.

If you have a very high current, well regulated power supply; then it is going to be able to
produce the required voltage, "come what may", so to speak.

For a given output voltage, when you halve the load impedance; the current has to double
in order to sustain the given output voltage with half the impedance. That's also why the
power doubles, because the output voltage is fixed and you double the current; and the
power is the product of the two.

If the power supply, and/or the rest of the audio circuitry can't double the current when the
load impedance is halved; then it can't "double down". The amp runs out of current at that
particular load impedance.

Unless the designer specifically designs the amp to be able to "double down"; it probably won't.
The ability to "double down" is more the exception than the rule.

The ability to "double down" means that you can run speakers that have low impedances like
some ribbons.

It also means that the system will be less susceptible to the variations of the load impedance
with frequency. That is, no matter how the speaker varies its load impedance as a funtion of
frequency; the amp has the current reserves to be able to put the correct voltage on the
speaker terminals, as opposed to being taxed by a low load impedance.
abatsky likes this.

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Physicist
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post #4 of 27 Old 04-14-2007, 10:25 AM
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It's not that big of a deal because they are so conservative with the specs. The MC501 is rated at 500 watts a channel. However Stereophile got 720 watts from the 8 ohm tap and 1000 watts from the 4 ohm tap. Mcintosh does not advertise that about the MC501 but it will double down as you say.

Never become so involved with something that it blinds you.
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post #5 of 27 Old 04-14-2007, 10:45 AM
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Quote:
Originally Posted by Bulldogger View Post

It's not that big of a deal because they are so conservative with the specs. The MC501 is rated at 500 watts a channel. However Stereophile got 720 watts from the 8 ohm tap and 1000 watts from the 4 ohm tap. Mcintosh does not advertise that about the MC501 but it will double down as you say.

A lot of amps that quote 2x the power of 8 ohms at 4 ohms are simply understating the 8 ohm power in order to appear they are capable of 'doubling down'. My guess is that the number of amps that can truly perform in this manner is pretty small.

"Nature Abhors a Vacuum Tube" -  J. R. Pierce
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post #6 of 27 Old 04-14-2007, 11:04 AM
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Quote:
Originally Posted by ehlarson View Post

A lot of amps that quote 2x the power of 8 ohms at 4 ohms are simply understating the 8 ohm power in order to appear they are capable of 'doubling down'. My guess is that the number of amps that can truly perform in this manner is pretty small.

ehlarson,

Yes - and if Bulldogger is correct in his figures; then that's what McIntosh is doing.

From Bulldogger's post:

The MC501 is rated at 500 W at 8 ohms.
The MC501 actually does 720 W at 8 ohms, as per Stereophile's measurement.
The MC501 actually does 1000 W at 4 ohms, as per Stereophile's measurement.

So the MC501 is actually an amp that could be rated at 720 W (8 ohms), that does 1000 W (4 ohms)
and hence doesn't really "double down".

However, McIntosh "artificially" rates the MC501 at 500 W ( 8 ohms); so that it will "double down"
when one considers that it actually can drive 1000 W into 4 ohms.

So one can make an amplifier that really doesn't "double down" APPEAR to "double down"
merely by rating its 8 ohm output conservatively.

What this means is that one shouldn't get too "hung up" on whether the amp "doubles down".

One should be mindful of what type of load one's chosen speakers will present to the amp;
and then be sure that the amp can actually provide sufficient drive at the sound levels one
wishes to play.

Otherwise, you're just getting involved in an ill-defined "marketing" game.

Dr. Gregory Greenman
Physicist
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post #7 of 27 Old 04-14-2007, 05:57 PM
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from what mcintosh engineers say, that no amp can double down, no matter what brand or make.
they have the different taps so as it wont matter what speaker you buy, the amp will work with any reasonable load.
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post #8 of 27 Old 04-14-2007, 07:45 PM
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Quote:
Originally Posted by ehlarson View Post

A lot of amps that quote 2x the power of 8 ohms at 4 ohms are simply understating the 8 ohm power in order to appear they are capable of 'doubling down'. My guess is that the number of amps that can truly perform in this manner is pretty small.

agreed... Very small indeed, I know the old Krell Reference the KRS-200 would double down but several (most?) subsequent Krell would not truly do it. The actual measurements of their output would show that the 8 Ohms rating was understated...

Frantz
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post #9 of 27 Old 04-14-2007, 11:04 PM - Thread Starter
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Thanks for all the info so far. So would you use your speakers rated, avg., or min. ohm rating to decide which tap to connect it to.
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post #10 of 27 Old 04-15-2007, 12:59 AM
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average or nominal. whichever wording you would like to use.
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post #11 of 27 Old 04-15-2007, 05:07 AM
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Quote:
Originally Posted by Will d s View Post

Thanks for all the info so far. So would you use your speakers rated, avg., or min. ohm rating to decide which tap to connect it to.

My speakers are rated 4 ohm. I use that tap on my amps. You can always experiment which is what some do to see which sounds best with your speakers.

Never become so involved with something that it blinds you.
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post #12 of 27 Old 04-16-2007, 07:21 AM
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Quote:
Originally Posted by ehlarson View Post

A lot of amps that quote 2x the power of 8 ohms at 4 ohms are simply understating the 8 ohm power in order to appear they are capable of 'doubling down'. My guess is that the number of amps that can truly perform in this manner is pretty small.

The Parasound JC-1 does this extremely well.

Parasound's specifications promise 400W@8ohm/800W@4ohm. In Stereophile's lab test they measured 585W@8ohm, 1154W@4ohms, 2250W@2ohms, and 4200W@1ohm. That's the way a great amp should double IMHO!
http://www.stereophile.com/solidpowe...74/index6.html

Peter
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post #13 of 27 Old 04-16-2007, 07:17 PM
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Mac uses an "Autoformer" technology both on the input and output side.

The thought is simple. High current = high demand on components = noise = distortion.

Now don't all you doctors and scientist flame me now but it makes since.

After all say you have 120 V - 20 amp service that can product 2400 watts. The McIntosh, Parasound JC1, Halcro, Levinson, Lamm etc will only be 50 % effecient at best or will ONLY produce 1200 watts. BTW, 5 - 10 RMS watts is very loud! It takes 10x to be twice as loud.

OK, let the flames begin.

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post #14 of 27 Old 04-16-2007, 07:46 PM
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You shouldn't compare tube amps specs to solid state specs. Solid state amps have close to zero output impediance, which has a huge impact on behaviour.
Tube amps have a high ouput impediance, and most use output transformers to match loads. Again, this has a huge impact on behaviour.

The other issue is both how amps are "spec'd", and designed. A solid state amp with 32v rails will only sink 4 amps in 8 ohms. You can design an amp with 32v rails to sink 32 amps in a one ohm load. Yet, the 8 ohm spec will fail to reflect that.
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post #15 of 27 Old 04-16-2007, 08:43 PM
 
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Too bad they did not put the same amount of research and design into their processors/DVD players, wink wink.
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post #16 of 27 Old 04-17-2007, 02:50 PM
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NAD amplifiers also sense a 4 ohm load and drop the voltage in half to make the amplifier happy and stable regardless of speaker being attached.

I would think that, if an amplifier has the ability to double its current *and* has ability to put out twice as much wattage, that it would always do proportionately more at 8 ohms (as in, more than half of what it does at 4 ohms). I mean, the transistors would have to hard clip at some point trying to double the output into 4 ohms. Maybe that's what McIntosh is getting at.

John
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post #17 of 27 Old 04-17-2007, 06:57 PM
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I'll make reference of this thread to the guys at McIntosh and see if they have a formal reply.

As far as their processors and DVD players are concerned they are fantastic.

The MVP-861 is very highly review player with excellent audio performance. (MVP-871 is a 1080p HDMI version of that player)

The MX135 (MX-136 has HDMI 1.1 video switching) and MX-119 (MX-120 has HDMI 1.1 video switching) also get great marks. Though pricey for the features per dollar paid the quality of construction and ease of use are second to none. However if you still listen to two channel (CD or analog/turntable) in the same system they are hard to beat.

As far was what's coming. Lets say the future is very bright at McIntosh and they understand fully that home theater is a market they are and want to stay in.


Regards,
Mike

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post #18 of 27 Old 04-19-2007, 05:24 PM
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Quote:
Originally Posted by mmiles View Post

Mac uses an "Autoformer" technology both on the input and output side.

The thought is simple. High current = high demand on components = noise = distortion.

Now don't all you doctors and scientist flame me now but it makes since.

After all say you have 120 V - 20 amp service that can product 2400 watts. The McIntosh, Parasound JC1, Halcro, Levinson, Lamm etc will only be 50 % effecient at best or will ONLY produce 1200 watts. BTW, 5 - 10 RMS watts is very loud! It takes 10x to be twice as loud.

OK, let the flames begin.

Im just speculating here, but I THINK their entire premise behind using an autoformer is supposedly that transistors have a relatively small window of ideal operating range. By "matching" the amp's output tap to the speaker's impedance, the transistors can operate more efficiently and effectively.

HOWEVER, im not so sure that this is actually true, since there are about the only solid-state amplifier company that does this. I think if it were vastly superior then someone else would "hop on the bandwagon".

The general concensus with Mcintosh is that it is a music-lover's amplifier, meaning it does color the sound somewhat. An audiophile amplifier would be something a little more neutral like Halcro, Simaudio, Krell, Bryston,etc.

Regardless, cool looking stuff!
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post #19 of 27 Old 04-19-2007, 07:33 PM
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i would say that all amplifiers have a somewhat colored sound. keep in mind that there has to be a reference to compare to. i havent heard of a perfect system yet.

mcintosh does indeed use the autoformer technology for various reasons and other companies can indeed use them as well but they would have to pay mcintosh for the use. they have the patents to prove it.

i wouldnt say that all mac amps are colored, some are and some arent. just like other models from other companies.

i would like to guess that there are different amps to match to different speakers and set-ups to get close to a 'reference' sound. meaning that speakers and amps are both colored to a degree.

just as yourself, being a dali dealer, people will say that they arent the cleanest or uncolored speaker around but it doesnt stop people from loving them.

but you are right, they do look cool.
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post #20 of 27 Old 04-19-2007, 10:38 PM - Thread Starter
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Thanks again for all the replies, I'm trying to narrow down my choices for auditioning.
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post #21 of 27 Old 04-20-2007, 03:42 PM
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Here is all you need to know about the McIntosh autotransformer from the horses mouth:

http://www.roger-russell.com/mcintosh1.htm#autoformer

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post #22 of 27 Old 04-20-2007, 04:55 PM
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I've been trying to get my girlfriend to double down for years but she says no way. Maybe I need a newer model, I hear most of them double down. Does tube size matter?
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post #23 of 27 Old 04-20-2007, 04:59 PM
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You always double down on 11 Mikey.


Quote:
Originally Posted by QQQ View Post

I've been trying to get my girlfriend to double down for years but she says no way. Maybe I need a newer model. Does tube size matter?

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post #24 of 27 Old 04-20-2007, 05:22 PM
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Quote:
Originally Posted by AudioArchitect View Post

".

The general concensus with Mcintosh is that it is a music-lover's amplifier, meaning it does color the sound somewhat. An audiophile amplifier would be something a little more neutral like Halcro, Simaudio, Krell, Bryston,etc.

Regardless, cool looking stuff!

I avoided Mcintosh for years because I read so many comments like this. I think this must have been true at some point in the company's history. It is not now. No amps are perfect. The newer Mcintosh amps are very neutral. Read the Stereophile review of the MC501 http://www.stereophile.com/solidpoweramps/804mcintosh/ The major difference is that when you get rid of the electronic grain, you also loses some detail. For me, it is a reasonable compromise. I wondered how could the loss of some detail could ever be good? Then after trying Classe 400 watt monoblocks, fine amps which I could own, and Mcintosh MC501s , I understood. I wish that I could have both ultimate detail and lack of grain. If that exist, it's likely out of my budget. My wife tilted the balance in my decision making process.She absolutely loved the look of the Mcintosh amps. This really surprised me. She called my old multi-channel amp, "The big black thing." She has made several comments on how pretty she thinks the Mcintosh amps are. That is the first and only praise my wife has ever given the appearance of any audio component.

Never become so involved with something that it blinds you.
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post #25 of 27 Old 04-21-2007, 04:04 PM
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If anyone is seriously considering purchasing a McIntosh amp and has doubts or their technical merit I'd suggest contacting McIntosh directly.

Director of technical services is Chuck Hinton. A real professional.


Regards,
Mike

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post #26 of 27 Old 12-08-2013, 04:16 PM
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Quote:
Originally Posted by QQQ View Post

I've been trying to get my girlfriend to double down for years but she says no way. Maybe I need a newer model, I hear most of them double down. Does tube size matter?

I just ran across this old post doing some research.

Too funny.

What you got back home, little sister, to play your fuzzy warbles on? I bet you got little save pitiful, portable picnic players. Come with uncle and hear all proper! Hear angel trumpets and devil trombones. You are invited.
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post #27 of 27 Old 12-18-2013, 08:39 AM
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I always liked Mcintosh gear for the simple fact its pretty much the only hifi setup you can work while completely in the dark

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