Your Test for "Dynamic Headroom"

[gregz]

Thanks, Richard. I was playing some of my classical CDs today, and Wagner backed up what you said. On some of those pieces the peaks can be measured in seconds, not miliseconds so steady state does seem more relevant when you're not just trying to squeeze out a techno drumbeat.

Those NADs are nice, but way more expensive than my pea brained plot of bi-amping using a pro/dj amp for the subs.

I've opened the cases on some pro/dj amps and found that the Crown XLS series has vertical heatsinks that might work by convection with the fans disabled under easy load conditions. Most of the other brands have heatsink tunnels that mandate fan operation. 300W x 2 for $300? Wahooo!!!

 

[WmAx]

Alternative cheap and silent power...

Adcom 555 can be had for about $300 USD on ebay. It has no fans and outputs 225-250 watts x2 into 8 ohms according to 3rd party measurement publications. Power level increases approx. 1.6x into 4 ohms.
It is stabile under demanding use into as low as 2.8 ohms(the lowest nominal impedance I have used this amplifier under constant abuse(uhm, i mean use ). Amp is mono bridgable.

-Chris

Thanks, Richard. I was playing some of my classical CDs today, and Wagner backed up what you said. On some of those pieces the peaks can be measured in seconds, not miliseconds so steady state does seem more relevant when you're not just trying to squeeze out a techno drumbeat.

Those NADs are nice, but way more expensive than my pea brained plot of bi-amping using a pro/dj amp for the subs.

I've opened the cases on some pro/dj amps and found that the Crown XLS series has vertical heatsinks that might work by convection with the fans disabled under easy load conditions. Most of the other brands have heatsink tunnels that mandate fan operation. 300W x 2 for $300? Wahooo!!!

 

[gregz]

Thanks WmAx, that Adcom does look like it was quite the champ. There seem to be quite a few product changes along the way, with some of the later ones carying more fuses for the different output stages...

Well, since this thread has morphed into an amplifier choice discussion, I'm going to split this part of the discussion over into the Amps and Receivers section where it probably belongs at this point.

Thanks for all the advice, folks, and if you have other amplifier advice to add, feel free to take the walk over with me:

http://forums.audioholics.com/forums/showthread.php?t=6812

Of course, I'm still open to discussing any further dynamic range and relevant testing here in this thread.

Cheers,
-Greg

 

[WmAx]

Thanks WmAx, that Adcom does look like it was quite the champ. There seem to be quite a few product changes along the way, with some of the later ones carying more fuses for the different output stages...

The first version was designed by Nelson Pass. The later revisions were not by or authorized by him, but were Adcom's own revisions. There was a thread about it a couple of years ago at diyaudio.com with Nelson Pass providing some information on that matter. An archive search should turn up the thread.

-Chris

 

[gregz]

Interesting info; thanks, Chris.

 

[WmAx]

Interesting info; thanks, Chris.

BTW; the thread:

http://www.diyaudio.com/forums/showthread.php?threadid=5280&perpage=10&highlight=&pagenumber=1

-Chris