Amp design.

[mtrycrafts]

I
By the way, do you really think Bryston's (4BSST) slightly higher distortion for 500W into 4 ohms matters that much?

< 0.005% 20Hz to 20kHz at 300 watts into 8 W
< 0.007% 20Hz to 20kHz at 500 watts into 4 W

Matters zippo, zilch, nada. Those are so small that it is meaningless LOL
It only matters to a beancounter

 

[zumbo]

Let me put it another way.

200W is needed.

There is an option to obtain a 200W amp that remains 200W, no matter the impedance dip.

You can get your money back, no matter how long you own it.

It maintains it's distortion spec, no matter what you throw at it.

This just seems like a pointless discussion to me.

I have yet to be swayed.

 

[zumbo]

Matters zippo, zilch, nada. Those are so small that it is meaningless LOL
It only matters to a beancounter

Small. Yes. But what about the spec below 4ohm? What happens then? Doubles. Then doubles. Then doubles. Like a 401K?

 

[mtrycrafts]

Let me put it another way.

200W is needed.

There is an option to obtain a 200W amp that remains 200W, no matter the impedance dip.
.

Your premise is flawed. 200 watts is needed at what impedance?

 

[MDS]

What happens then? Doubles. Then doubles. Then doubles. Like a 401K?

If my 401K doubled every year, I'd be retiring next year instead of the more likely 15 years or so from now.

 

[PENG]

Let me put it another way.

200W is needed.

There is an option to obtain a 200W amp that remains 200W, no matter the impedance dip.

You can get your money back, no matter how long you own it.

It maintains it's distortion spec, no matter what you throw at it.

This just seems like a pointless discussion to me.

I have yet to be swayed.

Why would anyone try to sway you from getting a McIntosh? We all have our favourites, but no one would dispute the fact that Mc amps are among the very best.

 

[zumbo]

Your premise is flawed. 200 watts is needed at what impedance?

That is the point entirely. Doesn't matter, if the amp doesn't see the drop. This is why I think other designs are flawed. We all know the speaker doesn't maintain it's ohm spec. Any speaker.

 

[mtrycrafts]

Small. Yes. But what about the spec below 4ohm? What happens then? Doubles. Then doubles. Then doubles. Like a 401K?

Need to spec it, cannot assume anything.
But, even at doubling to .014% is meaningless, so is .028% or .056% And, don't forget, volume matters to audibility of distortion. So does frequency:

http://www.axiomaudio.com/distortion.html#

http://www.mastersonaudio.com/features/20040401.htm

And, there are Journal articles someplace

I think you are number mining here, not audible issues.

 

[zumbo]

Why would anyone try to sway you from getting a McIntosh? We all have our favourites, but no one would dispute the fact that Mc amps are among the very best.

Not about that. It's about the original question. Double, or maintain.

 

[zumbo]

Need to spec it, cannot assume anything.
But, even at doubling to .014% is meaningless, so is .028% or .056% And, don't forget, volume matters to audibility of distortion. So does frequency:

http://www.axiomaudio.com/distortion.html#

http://www.mastersonaudio.com/features/20040401.htm

And, there are Journal articles someplace

I think you are number mining here, not audible issues.

Not audible to human hearing? Yes. But, it has to play a part in SQ. Reliability. Heat. Speaker health. And, many other variables not being considered.

 

[mtrycrafts]

An amp can only deliver a certain voltage and no more (the 'rail voltage') so unless it limits the voltage (and by implication, the current) I don't see how any amp could deliver the same power regardless of load unless it purposely limits the voltage/current for lower impedance loads to make the lower ohm rating equal to the higher impedance rating.

Yes, the amp must be limiting rail voltage but why would you want that? It limits an amp capability. If a speaker dips in impedance and the signal demands high power at that dip point, that amp may not be able to meet that demand, period. That simple. A constant power output no matter of load is useless.

 

[zumbo]

A speaker, such as mine, is rated at 180W max. 4ohm(nominal).

An amp is rated 100W @ 8ohm/ 200W @ 4ohm. As the impedance drops, the amp doubles it's power and distortion. So, what happens as a 4ohm speaker dips to 2ohm, or even 1ohm. Certainly this happens. The amp continues to distort, and increase it's output above what is desired or needed.

This has to certainly play a part in SQ, amp life, and speaker health.

 

[mtrycrafts]

So, how is it that Mcintosh retains their value, while others lose value?

An issue of preference for an old and stable name in audio
Collectors care for it. Nice amp. A classic. Why do older cars, collectible ones, demand 6 and 7 figures? Are they better? Rarity for one.
And, I bet other reasons, like nostalgia but that would go with old and stable company, and a good product for what it can do.

 

[zumbo]

An issue of preference for an old and stable name in audio
Collectors care for it. Nice amp. A classic. Why do older cars, collectible ones, demand 6 and 7 figures? Are they better? Rarity for one.
And, I bet other reasons, like nostalgia but that would go with old and stable company, and a good product for what it can do.

But, even current used models sell at retail. Some, even above the original purchase price.

I have seen current Krell models for sell at a fraction of their retail price.
I don't mean to get this into a brand war, but I had to throw some names out there. So, lets try to keep this to the point of double, or maintain. Myself included!

 

[mtrycrafts]

The point here is being cool under pressure, that means delive high current with a huge transformer and caps, and be distortion less at the same time, thats the attribute of a good amp.

You are resurrected? Haven't seen you post in so long, I though you were a distant memory

 

[PENG]

Not about that. It's about the original question. Double, or maintain.

Well then, read the poll results, you set up the poll.

 

[mtrycrafts]

Actually, 8ohm speakers require more voltage. 4ohm speakers allow more current to flow through.

From Mcintosh website:
The Dynamic Power Manager automatically controls and optimizes the power supply’s voltage and current balance delivering higher voltage that 8 ohm speakers require, and automatically adjusting for current-hungry 4 ohm speakers.

This is not a new debate for me. Back in my car audio days, Xtant and Phoenix Gold were all the rage because of this type of design. I had brought this up here about three or four years ago, and it turned out the same. I lost. Didn't change my thinking though.

Now that I am looking for a new amp, I ran across this fact about many McIntosh amps. I have decided on the MC205 for sure.

Play with Ohm's Law: E=I*R

You drop R to 4 Ohms and you drop V as well, guess what, I may not change much. There goes the current needed. No, V needs to be high to get the power to that low impedance speaker.

 

[zumbo]

Well then, read the poll results, you set up the poll.

Yep. I lost three or four years ago as well.

Funny thing though. My Linear Power amps are worth as much as they were then. That's more than I paid for them over ten years ago.

Seems to be the same for MacIntosh.

 

[zumbo]

Play with Ohm's Law: E=I*R

You drop R to 4 Ohms and you drop V as well, guess what, I may not change much. There goes the current needed. No, V needs to be high to get the power to that low impedance speaker.

But again, if the amp resists this behavior? What then? It maintains it's composure? Delivers the power needed? At a well respected, and acurate distortion spec?

 

[PENG]

A speaker, such as mine, is rated at 180W max. 4ohm(nominal).

An amp is rated 100W @ 8ohm/ 200W @ 4ohm. As the impedance drops, the amp doubles it's power and distortion. So, what happens as a 4ohm speaker dips to 2ohm, or even 1ohm. Certainly this happens. The amp continues to distort, and increase it's output above what is desired or needed.

If your speaker impedance drops to 1 ohm and the source(music/movie) you play requires 500W at that point but your amp adjust the rail voltage so as not to deliver more than 200W then you end up starving your speakers for that short duration for the sake of limiting the distortion to that 0.005% from the otherwise much higher distortion of say 0.08%. That's why for peace of mind some people prefer the 300/500W amp because they know they cannot hear the 0.08% distortion but they sure can detect a 4 dB increase in volume.

Now you can always get the MC-602 and keep all those high dynamic transients even with the autoformer output interface. For the best of both worlds, MC-602 is the answer.