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Amps for Maggies

Some use these due to the high current and I’ve heard mostly good thing.Some also use Crown amplification as a vfm alternative.
 
AndrewR said:
Resistance and reactance does not change with frequency, but it will influence the frequency response and power losses.

Andrew
Click to expand...

Depends what is creating the "resistance and reactance". A cable connecting to a load *will* produce an impedance to the amp that varies with frequency *unless* you can match them. i.e. Use a cable whose characteristic impedance is the same as the impedance of the load ( at all relevant frequencies).

That's the problem. Most speakers aren't a 8 Ohm resistor at all frequencies, and most cables don't have a uniform 8 Ohm characteristic impedance at all frequencies.

What the results may be then depends on the circumstances of the case.

Comms 101.
 
Which is all very well except that Maggies have a very uniform low impedance and aren't very reactive at all, as 'speakers go:

719MLRSfig1

The mild dip corresponds to the crossover point and if you look very closely there is a tiny ripple around 50Hz which likely corresponds to the tensioned Mylar tuned resonance.

The load uniformity means that Maggies will retain their character within tight limits across a wide range of solid state amplifiers However in the interests of efficient power transfer you want to keep series resistance low given the very low impedance.

Interestingly, larger Maggies appear easier to drive than small ones, possibly because the larger diaphragm and correspondingly longer foil trace has higher series resistance.
 
An Armstrong 700 would do the job nicely. 3 Ohm loads wouldn't be a problem.

FWIW I used to use pairs of 200W test resistors as loads. 2, 4, 8 Ohm ones. Each on a modest heatsink. During one test I noticed that the bench surface under the loads was melting and the loads were sinking into it! 8-]

I'd been using the 2 Ohm loads thinking they were the 8 Ohm ones.

Your problem, of course, would be finding a 700 nowdays as only about 40 sets were made. I know where 5 or 6 are, and still working. Alas, a design killed by a reviewer who couldn't change a fuse. :-/
 
On a slightly different track, has anyone had experience of the Crown amps? They appear reasonably priced and have garnered something of a reputation on various sites.
 
Del monaco said:
On a slightly different track, has anyone had experience of the Crown amps? They appear reasonably priced and have garnered something of a reputation on various sites.
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Which ones? They have hundreds of SKUs.

I haven't, but I'd be curious to hear a MacroTech, MicroTech, or PowerBase amp in the context of a hifi system. These amps all use a balanced bridge output stage and will happily work into a near short circuit. There are probably thousands of them sitting in warehouses that could be unloaded for cheap, since no one wants to carry them to gigs anymore.
 
I was thinking about the dual core power amps. Lot of current for a reasonable cost. Thought of trying one with my Maggies. I’d need a pre of course.
 
Del monaco said:
On a slightly different
track, has anyone had experience of the Crown amps? They appear reasonably priced and have garnered something of a reputation on various sites.
Click to expand...

I have an older Crown PSA2 which I used with my IMFs. Immensely powerful and never ran out of steam. I only took it out of the system because I built some NCC300s.
 
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