#11
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Stereo, I am happy for you that you are achieving a better sound. Mac has increased the ability of its amps to deliver current so that with a modern Mac amp you can get away with an impedance mismatch. I think the key for you is that you amp is only warm. Rules are made to be broken. But if you used a larger Mac amp at the correct impedance you would achieve a similar or better result. The impedance mismatch mainly affects the bass and this affects the perception of the overall sound. I don't recommend it.
Best Charles p.s. When you ask Mac, that's their stock answer. Last edited by Charles; 05-16-2021 at 09:55 AM. |
#12
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You went from an Alexia V2 to a Blade. That's a big step down in price but apparently to you not in sound quality. Did you run your Alexia off the 8 ohm tap? Best Charles Last edited by Charles; 05-16-2021 at 09:56 AM. |
#13
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I run Blades on 2 MC611 using the 4 Ohm tap.
The manual is quite clear on that "If the Loudspeaker’s impedance is in-between the available connections, use the nearest lower impedance connection." and "For the best performance and safety it is important to always match the impedance of the Loudspeaker to the Power Amplifier connections.". |
#14
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Quote:
Best Charles |
#15
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I was under the impression that the output transformer protected the output device (SS or tube) by providing a constant load regardless of the output tap used.
Mike S. |
#16
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Quote:
Best Charles |
#17
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As much as I respect Charles and his opinion, I still believe that McIntosh gave me the correct answer that to use whatever tap sounds best and to not overthink it. Shouldn’t the people that build the amps know best?
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#18
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McIntosh amp taps vs current
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It does. Every active amplifying device, tube or transistor, has a safe operating area, or SOA. The McIntosh autoformers allow the output transistors to always run inside their safe operating area by matching the speaker load to the amplifier. Also, every amplifying device has an optimum linear operation point, allowing for the lowest distortion with the least amount of negative feedback and generating the least amount of heat. Autoformers allow the output devices to run in their most linear range.
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Main System: Amati Futura Mains Amati Homage VOX Center, Proac Response 1sc Rears, Three MC2301's for L,C,R MC 602 for the rears C 1100, MX 151, MCD 1100, MR 80 Nottingham Dais with Wave Mechanic Sumiko Palo Santos Presentation SurfacePro 3, RPi 4, ROON, WW Starlight Platinum USB, Schiit Yggdrasil, Benchmark DAC3 HGC MX 151, OppO BDP-95, JVC RS-500 DILA projector, 106" diagonal Stewart Luxus Screenwall Deluxe with Studiotek 130 G3 material. Lake House: Ohm F, MC 275V, C2300, MR 77, Rega P3 OnDeck: McIntosh MAC 4300v Last edited by W9TR; 05-25-2021 at 09:39 AM. |
#19
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It's interesting to read some on the technical side of this issue, but I have had similar situations with Klipsch speakers (impedance varies with frequency, from just below 4 ohm on the lows to 12ish on the highs). I wondered and asked this question years ago, and got an answer one a Mac related forum that either 4 or 8 was OK, whatever sounded best, but it was the 8 ohm taps that sounded "proper". "Balanced". The 4 ohm was bloated in comparison - this on properly operating MC30 and MC250. It seemed pretty obvious that the 4 ohm was definitely "off". in terms of sonics.
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#20
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Look at a MC 7300 owners manual. In the back they show how a 7300 can drive a 2 ohm load from the 8 ohm tap putting out more than 800 watts a channel. If you will look at a Stereo phile review of a MC 501 you will see how well a MC 501 drives a 4 ohm load from the 8 ohm tap putting out close to 800 watts still meeting specs. So I would not worry about you driving a low impedance from the 8 ohm tap of your 600 watt Mac amp. One of the British magazines tested a 611 and put out close to 960 watt peaks across 8 ohms. So there is plenty of current there so you don't have to worry. Now crossovers can compromise woofer capabilities and this may be why you are wanting more from your Mac amps. All I can say make the speaker lines large and short as possible and make sure you have 20 amp 120 volt AC circuit feeding each amp separately.
All speakers have dynamic limits and after reaching that level the speakers compress the sound not matter how much power you have available. Last edited by TWInsall; 06-28-2021 at 04:19 PM. |
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