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New Adcom 👀585 SE. anybody heard this monster

Ladies
I am thinking this could be fun to buy 2 of these place in bridge mode and get
about 900 watts of juice each side.   My Revel ultima 2 Salons are very hungry
Has anyone heard these.   Only 3k each
 
128x128blueskiespbd
auxinput
1,538 posts
 

Al, that’s what I thought originally as well, but I was correct by erik squires. It’s not half impedance, it’s actually quarter impedance.

If you look at Parasound A21 specs:

250 watts x 2 into 8 ohm

400 watts x 2 into 4 ohm

750 watts x 1 into 8 ohm (bridged)


If each channel of the amp only saw half the load in bridged mode, it would want to push 400 watts, not 750 watts.

blueskiespbd's avatar
blueskiespbd OP
161 posts
 
Wow. You guys really understand how all these elements should mesh together.   I almost think I
can understand what you are saying. 
So I will ditch the Adcom idea 
the Aragon Palladium’s I have are the original
preferred model. That was determined by the
fact that they only have a balanced connection, no single ended like later models.   These have
the preferred Toshiba metal film caps that are
harder to find than unicorn nuts
i have a great tech but assume he would have
to replace every cap , total number unknown
so is that a practical upgrade that doesn’t run
the risk of ruining the sound?
almarg's avatar
Ag insider logo xs@2x
almarg
8,673 posts
 
Hi Auxinput,

No, you were right the first time, and if Erik disagreed he was uncharacteristically incorrect.

From the perspective of each amplifier channel a given output voltage will result in twice as much current being drawn from that channel in bridged mode than in stereo mode. That is because in bridged mode a voltage that is equal in magnitude but opposite in polarity will appear on the other side of the load, driven by the other channel, resulting in twice as much voltage across the load than each channel is outputting individually.

Twice as much voltage across a given load means twice as much current, of course, per Ohm’s Law (stated for this purpose as I = E/R; if E is doubled and R remains constant I is doubled). And from the perspective of each channel having to deliver twice as much current for a given output voltage corresponds to each channel "seeing" the load impedance divided by two, again per Ohm’s Law (stated for this purpose as R = E/I; if I is doubled and E remains constant R is halved).

The factor of 4 relates to power, not to impedance, as doubling the current into a given impedance corresponds to a 4x increase in power. As I’m sure you realize, for a resistive load Power = (Current squared) x Resistance.

So for an ideal design a bridged amp can deliver 4x as much power as each channel can deliver by itself, in stereo mode. In practice, though, current capability and thermal limitations usually reduce the factor of 4 significantly.

Best regards,
-- Al
Post removed 
auxinput
1,538 posts
 

@blueskiespbd - The Aragon sound is a very warm sound with slightly rolledoff / smooshed highs. The highs are there, but they definitely rich sounding and slower than other amps.  The Aragon doesn't have a huge amount of attach / resolution / detail.  If you love this sound, then great.  Generally speaker, older amps may need to replace the electrolytic capacitors as they can dry out.

At this point, the only reason to change amps is if you're looking for different sound.  Monoblocks such as Bryston 7B series or Parasound JC1 will have a lot more detail and attack than the Aragon.  It's really a personal preference. The Aragon Palladium will have enough current to run your Revel speakers.

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