2. amps-preamps
  3. 1102018440

Rectifier tubes?

I have an Air Tight HTM-300 amp which has tube rectification. I've rolled a number of NOS types over the last three years and am wondering two things: 1) How long a life do these tubes have, in general, and 2) Any suggestions for good rec. tubes (5U4GB) in this amp or in general? I'd especially be interested in new tubes as NOS are hard to get and are iffy.
tomryan
s23chang
619 posts
 
You can look at many options like the GZ37 or 5R4GYB. GZ34 might work in some applications too
tomryan OP
796 posts
 
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?
jake42
3 posts
 
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
jphii
485 posts
 
Albert,

Thanks for the BWS link. He does have some good prices. Has anyone heard their preamp? Also, will the 5931 interchange with 5ar4?

Joe
john_tracy
341 posts
 
Jake 42 - 5U4G is rated for 225ma; 5U4GB for 275ma. I don't have my Tube manual here; but I think the GB may be rated for a higher voltage also. Voltage sag under load may be slightly different too. A GB can be subbed for a G, but you need to check circuit demands before subbing a G for a GB.
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