Calling Valve experts

I have a small amount of low level hiss/crackle coming from my Cayin A88T . It's been suggested that there maybe dirty contacts causing the problem. I've checked inside and everything is fresh and bright, no signs of component problems. The valve sockets are showing no sign of corrosion, but I took an old valve to use as a cleaner, popped it in and out a few times with a lick of servisol contact cleaner on the pins (didn't want to be squirting anything into potentially charged sockets). Still have a bit of crackle though - any thoughts?

Cheers people.

 

Try swapping the valve (or swapping tubes between channels) and see if the problem stops or moves with the suspect tube.

Rustling in tube amps can also be caused by failing resistors, particularly if they've been running hot or over spec.

 

Interesting.

The amp originally came with KT88's but has been retro fitted with KT90's and some NOS 2x 6SL7s + 2x 6SN7s . Will give it go swapping them around.

 

KT90s are not automatically drop in subs for KT88s

If was designed for KT88s then use them. The power advantage in KT90s is negligable, and recent KT90s suffer from poor QC