Rectifier tubes?

NOS 5U4GBs are dirt cheap. $5-$10 each. Cheaper than the new ones. Shop around on ebay and try several different flavors for little investment. RCA, Sylvania, Tung Sol etc. Just look at the ones offered for carefully. Do they appear to be NOS. Original boxes; JAN military boxes; etc. Don't mess with the used crap at these prices. Have fun. If your amp can use 5U4Gs (225ma vs. 275ma) you might want to look into these. More expensive, but in my Cary SLI-80 much better sonically. Also, if your amp can use the 5U4Gs, look into some NOS 5AS4s. A pair of Mullard 5AS4s worked magic in my amp. Good luck!

You shoulc contact Sophia Electric. They make a 274B solid plate or mesh plate that could be magic in that amp.
www.sophiaelectric.com

They are very nice folks too!

You can look at many options like the GZ37 or 5R4GYB. GZ34 might work in some applications too

Man, maybe I've been overpaying for the Jan, Ken-Rad, and RCA used tubes! Anywhere from $65.00 to $85.00 and two of them looked well used. I also bought a tube that was advertised as NOS but came pretty well worn. This was from a private individual. Think I'll give BWS a try.

Chris,
Is the 274B a drop in replacement for 5U4GB?

I'm kinda new at this so if what I say isn't true, somebody jump in and say so.

I have an Audio Note Kit 1. The biggest change I have noticed so far was going from a Raytheon 5U4gb to a 2/59 US Army Coke bottle RCA 5U4G

I think the 5U4G and 5U4GB are interchangeable

I also like the JAN Sylvania 5931. This is also one of the coolest looking tubes I have. This sucker has 3 micas and a "girder" in it. Huge base also.

jp