Is rectifier tube arcing a problem?

@sns 

it is a Audio Note Kit, not the Audio Note UK.  However, there is a bit of a history.  What I learn is that the circuit of this monoblocks is initially designed by Andy Grove who is a prime engineer at Audio Note UK.  

fiesta:

Not going to happen on my end, so your decision is all on you from here on.

You remind me of a recently new "member" who posted that my abbreviation of Audiogon as A’Gon was "pretentious".

DeKay

@jaytor 

i would say I like them.  I sold my X5 before I bought this amp.  I am using them to drive a pair of JBL 4341 now.  I only have 3 power amps to compare: a custom built 300B by Otomon Lab from Japan using Luxman mq-300 schematics, the ANK, and Coincident 211 Dragon.  I then sold the Otomon Lab.  The ANK sound as good as the Coincident yet different.  The ANK are faster, a bit lighter, better mid range, and a bit more holographic.  The Coincident also sound very good.  It is a 211 push-pull delivering 75W per channel.  It produce a lot more power but also sound very lively and holographic.  I had a McIntosh MC 275 IV before.  It is a KT-77 push-pull, and it sounds boring and flat, which leave me an impression that is the characteristic of a push-pull amp.  It is not the case for the Coincident.  On my Harbeth 40.1, it will be clear it needs the Coincident 211.  But for my JBL, both sounds great.  

Just want to provide an update. I tried adding the diodes but then one of the Sylvania 5931 (which is a rugged 5U4G) dies. I had one of these died died before adding the diodes. And they didn’t arch, but just died with no sound. I think it is not conclusive if the diodes works or not because the tube and symptom are different. But I am concerned and took out the diodes.

then I bought 3 pairs of 5U4GB, 2 pairs of TungSol and 1 pair of Westinghouse. So far so good. I will keep observing. Maybe the amps are just more demanding on the tubes, and some of the old tubes I tried are just bad.