Looking to build The DC30 or a variant and have been advised that decent 5V4 valves are becoming difficult to find but the GZ34 is in production. Is there any reason why it shouldn't be a straight swap in The Match circuits?
Here's what a knowledgeable valve supplier said in response to a question about replacing the 5V4 with a 5U4:
GZ34 heater current is 1.9A so no issues there
The 5U4 can supply less current whereas the GZ 34 is the same as the 5V4.
The GZ34 and the 5V4 are both rated for 500 volts rms but the 5U4 is rated at 350 V
The GZ34 can suppy more current than either the 5V4 or 5U4
The GZ34 is extremely popular and is a current production item with multiple makers so good long term availability
From this it looks like the GZ34 is a good choice but I would like to know of any drawbacks.
If the GZ34 can supply more current would a single rectifier work in the DC30 circuit?