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Buzz problem with Linn AV5105 power amp

I have been using a Linn AV5105 power amp for almost 2 years now without issue. Up until about a few months ago, a loud buzz introduced its ugly self in the right speaker channel when the amp awakens from standby mode (it has an input sensitivity function to power down when no signal is detected). This buzz sound seems to dissipate after about 10-15 secs or so...

I didn't change any components, cables, etc. in my system before this problem occurred. I've tried the following to troubleshoot the issue:
- switched L and R speaker cables
- swapped out speaker cables for another set
- switched L and R speakers
- swapped out interconnects
- disconnected interconnects
Buzz still persists in the right channel on startup. I could live with this issue if it weren't for the fact that there is slight distortion that is very apparent when I'm playing music.

My initial guess is a dying or faulty capacitor????

Any help/guidance greatly appreciated!
ijarrio
7 responses Add your response
ijarrio OP
16 posts
 
All done! There's definitely a lot more punch to the sound now! ;)

The hardest part was getting the PCBs out and back in, not a lot of room maneuver inside the case. Some cleanup of the thermal paste was required as well but other than that, everything went smoothly for my first recap job.
ijarrio OP
16 posts
 
Did my research and chose a set of Linn's recommended 6800uF 80V caps. These are Cornell Dubilier 30mm x 50mm and came highly recommended for filter cap replacement.

The Nichicons were too big and pricey. Besides, I've read that audio grade caps for the PSU is unnecessary. The higher the ripple current, the better. Thoughts?
ijarrio OP
16 posts
 
I have my eye on the Nichicon KG series 10000uF 80V (Gold Tune) caps. I haven't checked the dimensions but I'm fairly confident they'll fit.

Saw a post here: http://forums.linn.co.uk/bb/showthread.php?tid=24200&page=2 where Linn recommended replacing the Elna 10000uF 63V with 6800uF 85V caps, so I guess it's "OK" to lower the capacitance and up the voltage? What are the advantages/disadvantages of doing this? I've also read that you can up the capacitance/voltage slightly as well.
czarivey
5,946 posts
 
Joseph Tawadros "Chameleons of the White Shadow" with
Richard Bona
Roy Ayers
Ludovic Beier
czarivey
5,946 posts
 
Piece of cake.
Just make sure that you connect terminals correctly. Take a picture first before taking things apart.
ijarrio OP
16 posts
 
I think you're right Czarivey. Took the amp apart and all 4 of the Elna LP5 10000uF caps are bulging. :(
I have no experience recapping, but I guess this is as good an opportunity as any to learn. Much thanks!
czarivey
5,946 posts
 
More likely internally filter caps on the R channel take charge slower that in the Left channel.
Most likely all filter caps need replacement.
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