[Mariusz]

I am not familiar with the preamp's circuit but it uses 5V4 rectifier tube.
Can anyone enlighten me on good tube choices or other alternatives????

Thanks

Mariusz

[JohnR]

Here's some useful information:

http://www.fourwater.com/files/fullrect.txt

[Mariusz]

Useful indeed.
Wasn't aware of this link.
Worthy bookmark.

Thanks John

[jamesdb]

The 5V4 has a filament voltage of 5.0 volts, and its filament current rating is 2 amps. If you look at substitutes, you need other tubes that are 5V and 2 amps on the filaments. Using a tube that requires current greater than 2 amps may cause problems (those that need 2.5 A or 3.0 A). If a tube only requires less, like 1.7 amps or 1.9 amps, that is okay. The 5V4 is an indirectly heated rectifier, you probably want to replace it with other indirectly heated rectifiers. The usual close ones are 5AR4, GZ34, GZ32. Other tubes like GZ37 may have a voltage drop that changes the B+ too much. The greater the voltage drop, the lower your B+ voltage will be.