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Amplifier Bakeoff: Purifi Eval1, McIntosh MA252 & Benchmark AHB2

peng

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Not mono but bridged. Just saying...

From their website:
"In bridged mono, the AHB2 can deliver over 518 watts into each of 4-Ohm speakers."

Yep, that's why I wouldn't buy the AHB2 because I can't afford $6,000 for two, and one would be rated 100 W 8 ohms, that doesn't seem enough headroom for comfort in my application.
 

peng

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No. I couldn't. But I probably couldn't say why there shouldn't be a difference.

That sounds fair.. thank you. I suspect some of the highly competent amp designers would be able to, or should be able to.
 

Ataraxia

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Not mono but bridged. Just saying...

From their website:
"In bridged mono, the AHB2 can deliver over 518 watts into each of 4-Ohm speakers."
Got it. I'm not up to speed on that. I just typed mono because when there's two amps I think "mono-blocks."

I need to get that straight in case I decide if it's worth it when I upgrade my amplification. I've heard bridged amps could have worse performance, not sure what that's about.
 

Ataraxia

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Yep, that's why I wouldn't buy the AHB2 because I can't afford $6,000 for two, and one would be rated 100 W 8 ohms, that doesn't seem enough headroom for comfort in my application.
That's what happened to the guy in the video. He added one because he was clipping a single AHB2.
 

DHT 845

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Its not placebo when the music sounds so much different from one amp to another, even you would tell the difference. One sounds fast the other slow. Anyway this is a cult, good luck with your purifi.
I agree with you, but I am minority here. At the begining I was quite shocked that people here do not hear many phenomenons (like cables etc.) but now I got used to it :) Actually I respect their view, there are differences that are not so important anyway.
 

pogo

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Oh With DF are you only talking about Damping factor, oh yeah the purifi have a lot of damping factor and the ahb2 too, there is no problem.

With only about 100 is more than enough, both amplifier doesn't have any problem in this apartment.
Where is this value specified and is it valid under all operating conditions? The values that I can read in reviews or specs are always determined under idealized conditions at one operating point on a non complex load. The matter is probably much more complex and also depends, as already linked, on the speakers used.
With your statement, you have indirectly disqualified the AHB2, since it only reaches a DF of 65 and even only half in bridge mode, see also here:
Link
 
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BrokenEnglishGuy

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Where is this value specified and is it valid under all operating conditions? The values that I can read in reviews or specs are always determined under idealized conditions at one operating point on a non complex load. The matter is probably much more complex and also depends, as already linked, on the speakers used.
With your statement, you have indirectly disqualified the AHB2, since it only reaches a DF of 65 and even only half in bridge mode, see also here:
Link
Well, 50 is perfectly too.
As I said, the purifi and the ahb2 doesnt have any problem of df.
 

Blumlein 88

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Damping factor is there, but I am interested in the slew rate.
Gain bandwidth is 110 mhz. While gain bandwidth and slew rate are not exactly directly related, given the relatively low gain of these amp modules I would expect slew rate to be rather high. At the very least it isn't likely to be a bottleneck to performance in or near the audible band of frequencies.
 

pma

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Do you have the slew rate spec for the Purifi? I couldn't find it on the data sheet.

This question comes again and again, obviously without much understanding on the subject. Let me quote from Hypex literature:

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ahofer

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I just want to applaud the OP for running a blind test and reporting the results. Obviously, there are technical qualifications, but more people should attempt it, whether they can nail down perfect test conditions or not (I could not, but I did arrive at a 'no difference' conclusion, so I took less guff here).

Just fantasizing here, but it would be fun to set up a "test day" in a city where there are a lot of ASR members. Everyone could bring in their equipment, and technical users could help set up comparisons for different equipment throughout the day. Essentially crowdsource the equipment and expertise for a day of reasonably well-designed listening tests. Maybe a null tester and even an analyzer to look for measurable differences.

And drinks afterward, while our ears ring.
 

peng

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Blumlein 88

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What on earth is "slow" sound?
Rounded off in a way that it lacks transients and lacks inner detail. Think if you put a slight, but significant downward slope in EQ and added a little low level barely perceptible noise to cover up the lower level details. Done right, you won't think it rolled off or noisy, but it sounds slow and unresolving.

In the old days the difference in a Shure MM cartridge and a good MC cartridge.
 
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