2. amps-preamps
  3. 1227946250

Tube amplifier bad caps

Hey,

My integrated tube amp has been experiencing the symptoms of bad filter capacitors. Crackling in my amp is so bad on both channels that I'm afraid ALL of the filter caps will have to be replaced. Tube swapping and tightening the socket pins has had no effect so I'm lead to believe bad caps are the problem.
A pic similiar to the inside of my amp can be found here. Are the can caps or the axial caps what I should be looking at replacing? I'm confident I can do the repairs myself (purchasing caps, discharging old caps, soldering, etc.) since I'm afraid of what the price tag might be for such a repair by a professional repair shop.
hitman_hifi
bradf's avatar
bradf
324 posts
 
hitman_hifi

Wanted to know what you (or Tech) found to be the problem that was causing the above referenced  failure generating crackling sound.

Thnx
Brad
bradf's avatar
bradf
324 posts
 
If any other member may know what was the fault to the above referenced fault and corrective action, would appreciate you posting it here


thnx
Brad
bradf's avatar
bradf
324 posts
 
@hitman_hifi 

Refer to your description of fault symptoms:

Hmm...now I'm second guessing. A lot of uncertainty as I've been told it's definitely the filter caps. However, the amp is not even 10 years old and I've been suspicious of this assessment. I've seen what cap leakage looks like and they definitely look fine.

I'll try and explain the problem in more detail. Upon startup, the "bacon frying" sound gradually builds and becomes constant once the tubes are lit. The power tubes flicker with every pop and crack. This symptom used to be only in the right channel and now it's in both. As indicated, I've swapped all of the tubes with new ones. I'm afraid I've probably ruined the new tubes because of this.

I purchased this amp used from a local hifi company that is out of business now. I live in a small city so finding a tech that specializes in tube amps will be difficult. Are there any fellow Canucks out there that know of a tech near Regina? As a last resort, I may end up contacting the UK manufacturer and seeing what can be done.

Explanation to similar fault referenced above from bradf:
I had very similar experience with my integrated amp.  Trouble shooting revealed resistor in circuit to -B rail voltage had failed. The failure was gradual and was a result of one of the leads becoming loose in the resistor to the point that the body of the resistor could be rotated while the lead remained stationary.  There are two rail voltage fuses close to failed resistor. I suspect while removing the fuse cover(s) the resistor may have been contacted and damaged mechanically.  I am the 2nd owner of this amp so not sure what else may have taken place to cause this resistor to fail; the resistor was found bent over to one side, not perpendicular to the board.
If your having or ever experience similar problem, I would start by checking the rail voltage.  After complete failure of said resistor, there were 0 volts at the rail supply.
Hope the above info may help someone else down the line that may experience the same problem 


Brad
More to discover