I've just purchased a Marantz PM6005 and CD6005 to go with my new B&W 685 S2's for the lounge hifi system. However, as soon as I wired up the amp and CD player I noticed the left/right output levels seem subtly but noticably different to each other (in this instance the left ouput is quieter). This was more noticable at lower volumes and in fact you could fade the volume down and the music would appear to track across to the right hand side.
I set about testing the system thoroughly in order to identify the problem. This involved placing a matched pair of microphones directly in front of each speaker and playing a test oscillator (sine wave) through the amp and recording the result back (photo in link below). What this showed up was a difference of around 6db between the two outputs - a significant amount.
I made a video of these tests (links at bottom) where I ruled out any other components by swapping speakers, cables, outputs A & B, and even speaker placement (to eliminate any room resonance). The problem was consistent and the culprit definitely seemed to by the PM6005 amp. Consequently I contacted the vendor and arranged to take the unit in to look at. They informed me that "this is a common problem in various amps, particularly at low volumes". Sure enough we tested it in store with other speakers and against another PM6005 and the problem seems to be inherent in the amp.
This is not a problem I've encountered before and I'm now unsure what to do as this undermines its very basic function in my opinion and is hugely disappointing. Equally I'm surpised this is apparently a 'common problem' and that people just live with it. I fully expect a £279 amp to be able to output on the left and right side equally! So what are peoples experience of this? What do you advise?
I would greatly appreciate any advice on the matter whilst I decide how to resolve it. Thanks in advance, Sidx
Photo:
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test.JPG
Videos:
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test%201.mov
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test%202.mov
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test%203.mov
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test%204.mov
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test%205.mov
I set about testing the system thoroughly in order to identify the problem. This involved placing a matched pair of microphones directly in front of each speaker and playing a test oscillator (sine wave) through the amp and recording the result back (photo in link below). What this showed up was a difference of around 6db between the two outputs - a significant amount.
I made a video of these tests (links at bottom) where I ruled out any other components by swapping speakers, cables, outputs A & B, and even speaker placement (to eliminate any room resonance). The problem was consistent and the culprit definitely seemed to by the PM6005 amp. Consequently I contacted the vendor and arranged to take the unit in to look at. They informed me that "this is a common problem in various amps, particularly at low volumes". Sure enough we tested it in store with other speakers and against another PM6005 and the problem seems to be inherent in the amp.
This is not a problem I've encountered before and I'm now unsure what to do as this undermines its very basic function in my opinion and is hugely disappointing. Equally I'm surpised this is apparently a 'common problem' and that people just live with it. I fully expect a £279 amp to be able to output on the left and right side equally! So what are peoples experience of this? What do you advise?
I would greatly appreciate any advice on the matter whilst I decide how to resolve it. Thanks in advance, Sidx
Photo:
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test.JPG
Videos:
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test%201.mov
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test%202.mov
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test%203.mov
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test%204.mov
https://dl.dropboxusercontent.com/u/74474385/Temporary/Hifi%20Test%205.mov