[Delta77]

I have a DECWARE ZP3 phono preamp that says it takes a 5u4g or 5y3gt, for the rectifier.

I'm also getting advise to use a 274b instead.

I'm a bit confused. Can some explain the difference between a 274b and a 5u4g.

I'm also hearing that a 5u4gt 5u4gb is not the same as a 5u4g, is this true.

Burt..

[FullRangeMan]

The 5U4GB valve is a full-wave direct-heating(no indirect filament Soft Start) diode, designed to operate as rectifier in power supply for CRT TVs, amplifiers and other equipments with high direct current consumption. The 5U4GB valve has a standard T-12 bottle with straight sides, which allows it to be used in place of the 5U4G and 5U4GA types.

Currently 5U4GB is used in guitar amplifiers as the Mesa-Boogie Dual Rectifier and Mesa Boogie Triple Rectifier or Fender EC Twinolux.

Amplifiers that use the 5U4GB tube or another vacuum rectifier tend to have fewer problems due to over-voltage and power spikes. Because it has considerable thermal inertia, the 5U4GB takes a while to come into operation, giving the equipment a "soft-start" whenever the power is turned on.

The 5U4GB valve can supply currents of up to 300mA with peaks of up to 1A and starting transients of up to 4.6A. However its possible use 5U4GB with filter capacitors with much higher values than other rectifier valves.

I have seen 5U4G and GB, but not GT.
5U4GB are suited to currents up to 275mA at 450V.
Usually the G refers to the Glass Bottle.
GB has a bit more max current capability.
Said it I would prefer NOS 5U4G 1940/50, but no Sylvanias 1970s.

[Rusty Jefferson]

Why don't you reach out to the builder?  The 274b/5r4 type may not be appropriate as they have a much faster in-rush than the types listed in the manual for the preamp. There are plenty of great sounding rectifier tubes from the options listed as recommended.

[Rusty Jefferson]

Why don't you reach out to the builder? ....

I was going to suggest checking to see if Decware has an active forum but I see they do and you did post there asking what people use. Try using the contact page and talking with them directly about what rectifier to use. Just following the lead of others may not be the best path.

[JakeJ]

Responding directly to the OP's thread title.  The 274B is Western Electric's equivalent for the 5U4G/5AR4.

Here is a bit of info on the 274B:
Emission Labs
Radio Museum

Data on the 5U4G:
Duncan Amps

[Delta77]

After reading the responses that were given, I feel a lot more comfortable with putting a 274b in place of the 5u4g.
I actually had a 274b (Sophia Electric Aqua) in house.
So here we go..
Currently listening to the turntable through my headphones.

DP59L (TT)- ZP3 (phono)- CSP3 (headphone amp)- Auteur (headphone)…

[FullRangeMan]

All about tubes, impressive system 

[JakeJ]

I do believe that's called "SET La La Land".