Ampeg GVT-5H - Should I replace this capacitor?

[Strebs]

I have an Ampeg GVT-5h that I occasionally use as a pedal platform. It has a half power mode that I usually don't use, but when I switched it on the other day it gave a nasty hiss sound. The full power setting is not affected. I figured that it probably needed a new tube. The 12ax7 was in there really tight and hard to get to, so I decided to remove the chassis rather than break something or bust my knuckles. Anyway, when I looked in the chassis, one of the capacitors seemed to be slightly bulging on the top and had some discoloration. I was planning to replace this cap before I plugged it back in, but wanted to make sure I'm not overreacting from people that know more about this than me. Is this something that you would replace? The amp is only around 10 years old.

 

[BigDaddy23]

That looks to be one of the main filter capacitors. The bulging isn’t good sign, nor is what appears to be the electrolytic starting to make its way out.

If it were my amp, I’d change all of the filter capacitors at the same time and do a full inspection of the solder joints everywhere, touch up as required.

 

[Blrfl]

If the other 'lytics are the same brand, replace them all while you have the board out because they're likely headed the same way.

There was a thing called capacitor plague in the early 2000s where some widely-sold brands of electrolytics had mis-formulated electrolyte or were overfilled and didn't have room for expansion. Both conditions caused swelling and bursting. Nichicon and LTE were the most common. Your amp may be old enough to have been built with those if they got hold of parts from that era.

 

[Strebs]

Thanks to both of you! That sounds reasonable and like good advice to avert future problems.

 

[Jon Snell]

They look like 85°C capacitors, I would fit 105°C versions. Not much more expensive and well worth the effort for the added reliability.