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Please help. Why would higher power amp require gain? Marantz/Adcom

Hi,

This is my first post.

I recently connected my Adcom GFA-555 to the front preouts of my Marantz SR5015. I recently had the Adcom evaluated at a reputable repair business as I’ve owned it for 30 plus years. The Adcom had a clean bill of health.
I prefer to setup my speaker gains manually with a sound meter manually with slow C weighting at 75db. I set the Front Left speaker at 0db then turn the volume up to obtain 75db.
The Marantz receiver volume required was 84 where as with the Adcom it was 88. As a result the remaining 5 speakers required a reduction in db to balance out.
Hope this makes sense.....I was expecting a lower volume number on the Marantz to obtain the same 75db, as the Adcom is rated MUCH higher wattage.

Please explain.

Newbie
volfan72

Showing 1 response by auxinput

auxinput
2,920 posts
 
I don't know about the Marantz, but most receivers have one main shared power supply (for both the amp section and the preamp section).  The preamp power is just regulated from the main power supply section. 

Putting an amp on the rear channels doesn't reduce the demand on the preamp/preout.  The Marantz preamp section will still have to drive an amplifier (whether it's built into the receiver or external).

I would use the receiver speaker connections for surround channels because the volume/energy on the surrounds are actually very small.  The fronit left/right speaker along with the center require an enormous amount of power.  It's still best to use an external amp for these.
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