Quote:
Originally Posted by meltemi
IMHO the problem with the McIntoshs is their use of output transformers. Depending on the taps used, the output power remains "constant" for the given load impedance. However a speaker's load impedance is almost never constant at all.
So if one uses the 8Ω output taps, how much current can the amp then deliver at say 3Ω (a B&W's minimum impedance) ? McIntosh does not specify.
In addition, using output transformers leads to a relatively low damping factor; hence the amp can not truly control the speakers.
There are amps which can deliver the current required by the speakers regardless of the actual load impedance.
Example: Accuphase A-250 nominal Class A 100W@8Ω / 200W@4Ω / 400W@2Ω / 800W@1Ω
And their damping factor is >1000 @8Ω (i.e. their output impedance < 8mΩ !)
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The current specs provided by McIntosh are derived
with a load equivalent to 20% of the tap's rating.. IE - a 1.6 Ohm load driven from the 8 Ohm tap.