Is rectifier tube arcing a problem?

I did some research and couldn’t find a definite answer.  I have an amp that I tried 6 different pairs of 5U4G and 5U4GB. 3 pairs has arcing (RCA 5U4G, TungSol, Svetlana 5C3S) and 3 pairs don’t (RCA 5U4G with hanging filament, EH 5U4GB, Sylvania 5931).  I took the amp to a technician and he checked everything, he can’t find anything wrong.  The problem is, I like the sound of the TungSol and Svetlana which both have arcing.  The technician said it is ok to keep using them, but honestly I am not too comfortable.  But I like their sound.  Is it really ok to keep using the arcing tubes?  Will it damage the amp?





One thing that can cause rectifier tubes to arc is too much capacitance at the input of the power supply. What amp are you using?

I've seen a lot more arcing failure with Russian made rectifier tubes. Depending on the amp you may have to stick with NOS tubes to get reliable service.

In some cases its possible to run solid state rectifiers. A bit of attention has to be paid to the amp circuit since doing so will raise the B+ voltage which may not be a good thing. But if you have good rectifiers (like HEXFREDs) they can be nice and quiet. Amps that use solid state rectifiers usually sound more neutral on account of less power supply sag when more power is required. Tube rectifiers are certainly romantic but other than noise they really don't have a place in a hifi power amp; they are great for blues guitar though.

It is a Audio Note Kit Interstage 300B monoblock.   Here is the assembling instructions menu.  I have it built by someone and have another technician to go through it, so, I believe it is not a built issue.  It is design for 5U4G.  However, the company sells the kit, and doesn’t have much detail about the design.  Also, they make their own C-Core transformer.  I read that one possible reason is the transformer is “too good” and has a much lower resistance than others?  Anyway, I think this is more a compatibility issue.  
Any suggestion is appreciated, like adding resistor or capacitor somewhere.

Instruction manual

A 5U4 should handle that load just fine. I think you've had bad luck with tubes... Is this happening in both channels? Do both channels sound the same?

If this is "only" happening when you power down one of the amps and then restart it within a very short period of time, just wait longer (5-10 minutes).

If it happening @ other times, then it needs to be looked into.

I would not reuse a rectifier that I observed arcing, but I've always had plenty of spares.

I found a schematic of the power supply section @ the Steve Hoffman Forums, but could not link it.

I Googled your amp + rectifier and it came up on the first page of hits.