I have a nice hard to find old stock GE Tall 5U4G rectifier that just started making a slight buzz sound coming only from the tube itself. It is a really nice sounding tube but should this be a warning of a failure coming.  Anyone have this come up?  Is it a concern and should the tube be retired. I have never experienced this before.  Thanks

I have older Decware before the internal fuses on the rectifiers were added, so I have only the fuse at the IEC. Whenever I was trying or using suspect rectifiers, I would replace my more costly IEC fuse with a glass slow blow with heavy internal wire structure, fuses I had taped sound cleaning stickers on, the tape also damping the fuse some. And they sounded pretty good. Then when the rectifier went, I only had to move the taped setup to a new low cost fuse.

I have no experience with interior fuse setups though... So my first question about continuing with a suspect rectifier is, are there costly fuses in the amp, internal or at the IEC. The other question for me... if using a good fuse at the IEC and plain glass on the rectifier... Do the internal fuses fully protect the IEC fuse when a rectifier shorts?

This is one reason I have been trying to dial in Swiss Digital Fuse Boxes in my system, especially for my stuff with rectifiers...Not often for me, but over years, they will fail, sometimes without warning. Not having to worry about losing costly fuses along with a rectifier, though I have not used any tubes that are clearly compromised for quite a few years, I like some 4 Volt, old Euro tubes with different electronic parameters... quite reliable for the most part, but some have blown over years.

Mike, I had a pretty long affair with older, straight 5U4Gs with my Torii III. As I remember them, they tended to sound like they had more power than 5U4G-STs, generally making everything a little stronger, the nicer ones especially, all parts of the signal strengthened in pretty well balanced ways from bass, through the mids and the highs. The ones I really liked had a full rich sound with spaciousness and fine detail across the spectrum, so textured and good with harmonics, and keeping them from being too warm or thick. Even so, in my system they did tend toward bass in the overall balances ... and other tube choices opening and speeding up the sound some helped the 5U4Gs to be sweet and lively.

A few years ago, I tested some old favs in my tuned up Torii MKIV, and really liked them, full, rich and textured. But finally they were too strong in it, lacking some space and speed I have come to love... The more transparent and easy flow the MKIV became with modifications, the less powerful the rectifier needed to be to pull the deep beauty.

But if a system/room is a little on the lean side, the benefits from a more beefed up sound of a well balanced, and often inexpensive 5U4G can be really nice!