I can't imagine not having a spare 5U4 if you are dealing with boat anchors.  
Also, not knowing what application you are talking about limits the amount of 
useful advice one might acquire.  However, if I were substituting a 5U4 and 
only had a 5Y3, I would opt for using a couple 1N4007 diodes.  Yes, the voltage 
will be higher but you have no worry of filament current or tube current or 
voltage rating.  At 5 cents each or less, that is what I would use with no 
spare 5U4 and not knowing other parameters or limitations.
Lee, w0vt
 
_______________________________________________
Boatanchors mailing list
[email protected]
https://puck.nether.net/mailman/listinfo/boatanchors

Reply via email to