Arcam P-25. Whats does my system drive?



Dear all,

Please help - I really need to get my head around this but my tiny, peanut shaped brain will just not get it! :)

I have the Arcam P-25 as my front three-channel amplifier and my Denon 3802 as my processor for the channels.

I understand that the Arcam is 100W into 8Ohms and in the manual it states that the centre channel is 170W into 4Ohms. My speakers are M&K S-85's and they are 4Ohm speakers.

Right, what does this all mean? Does this mean that all my front three speakers are driven at 170Watts at 4Ohms or just the centre or what?

Also, and more importantly, does this mean that I would get more oomph out of my P-25 amp if I used 8Ohm speakers?

Sorry to be thick here - sometimes I pick things up very quickly and others times it just doesn't sink in. :rolleyes:

O - and make it simple so the village idiot can understand it! ;)



Um, Brad, you've asked a lot of questions to which there aren't many easy answers.

Firstly you'll get more power out of an amplifier with lower impedance (Ohms) speakers, until you kill it. A perfect amplifier will double it's power output if you halve the impedance - ie 100W/8Ohms -> 200W/4Ohms and so on. Arcams are fairly good, so if it says in the manual it will drive 170W into 4Ohms I'd guess that with all three channels being hooked up to the same speaker, all three channels should get 170W. However this doesn't always happen in reality.

Secondly - if you want more oomph, look for speakers with a higher sensitivity (measured in dB per Watt). This will give you more volume for a given power. Although normally 8Ohm speakers are more sensitive, you are getting a lot more power out of your amp by using 4Ohm speakers.

PS Does this indicate you have caught the dreaded pre-Christmas upgraditis?:D


:D Not upgrade itus - more really trying to learn about my system and how exactly what everything means to the finest detail that my small brain can take.

I have an Arcam power amp and 3 M&K S-85 front speakers (90db sensitivity I believe) in a room no bigger then 12 foot x 12 foot. The sound fills the room nicely actually but wont quite make reference level without losing some quality and become a little harsh. The M&K V-125 sub seems to handle ref level (probabley the decent Headroom maximiser) but not the Amp......which I expected it to do really.....

However, if you listen to my system at around -10db from reference level in my room you'll understand why reference level is a luxoury I can do without!

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