Tube amp cracking noise - AVS Forum
Receivers, Amps, and Processors > Tube amp cracking noise
FlosD 06:36 AM 07-18-2014
Hello everyone,

I'm new here, and don't have a lot of experience with tube amplifiers.
I own a Yarland FV34C tube amp and have a problem with this one.

From time to time it makes an annoying cracking sound, this noise also happens when the volume is completely zero.
It also doesn't matter whether I select the aux, CD or line input.

http://picosong.com/PMJz/

Does anyone have an idea what this can be? If more information is needed, please let me know.

Regards

DonH50's Avatar DonH50 07:14 AM 07-18-2014
Could be any number of things. Bad tube, bad coupling capacitor, noisy rail, etc. Have you contacted Yarland?

Does it appear on both channels? If so, for starters I would swap driver and output tubes between channels since it is independent of the volume and input selector controls (indicating the problem is after those controls). See if it switches channels when you swap tubes around. The catch is that pre-driver and driver stages probably use the same tube for both channels. If you have spare tubes, swap then in and see if the problem goes away. Most tube amp problems are caused by the tubes...
FlosD 07:27 AM 07-18-2014
Quote:
Originally Posted by DonH50 View Post
Could be any number of things. Bad tube, bad coupling capacitor, noisy rail, etc. Have you contacted Yarland?

Does it appear on both channels? If so, for starters I would swap driver and output tubes between channels since it is independent of the volume and input selector controls (indicating the problem is after those controls). See if it switches channels when you swap tubes around. The catch is that pre-driver and driver stages probably use the same tube for both channels. If you have spare tubes, swap then in and see if the problem goes away. Most tube amp problems are caused by the tubes...
I mailed them today, will have to wait a while for them to responce (no dealer around here, not anymore...).
It appears on one channel, I'll try to swap them and see if that's the problem.

Thanks for your reply
DonH50's Avatar DonH50 07:41 AM 07-18-2014
NP. I meant to say "If not, for starters..." -- if it is on only one channel, swap the driver tubes and see if the problems follows the tube. Or just replace them. Same with output tubes, but they may be matched pairs (swap them as a set) and you may have to re-bias the amp when you swap the outputs. Chances are it is just a bad tube.
FlosD 08:08 AM 07-18-2014
Quote:
Originally Posted by DonH50 View Post
NP. I meant to say "If not, for starters..." -- if it is on only one channel, swap the driver tubes and see if the problems follows the tube. Or just replace them. Same with output tubes, but they may be matched pairs (swap them as a set) and you may have to re-bias the amp when you swap the outputs. Chances are it is just a bad tube.
It seems like the problem follows the (output) tubes .
Thanks for your help!
DonH50's Avatar DonH50 08:10 AM 07-18-2014
Good, now you know what to replace! Replace them as a set; they may (probably do) need to be matched (check your manual). Lots of places sell tubes.
FlosD 01:59 PM 07-18-2014
Quote:
Originally Posted by DonH50 View Post
Good, now you know what to replace! Replace them as a set; they may (probably do) need to be matched (check your manual). Lots of places sell tubes.
The manual doesn't say they need to be matched but it do say "bias Voltage State: Self-bias".
Does this mean they don't need to be matched?

Regards
DonH50's Avatar DonH50 03:46 PM 07-18-2014
Probably not.
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