[ForSale-Swap] Question

[Phil (VA3UX)]

At 10:10 AM 10/16/2001 -0400, Leisman wrote:


>I need a 5AR4 vacuum tube and have 4 or 5  5U4 tubes sitting around.  I
>have checked my RCA tube manual and the pin alignment is very similar
>and with nominal re-wiring I think I could use the 5U4 rather search for
>the 5AR4.  Anyone know of any reason why I can't use the 5U4 in place of
>the 5AR4?

There are some differences. Examine the specs in the tube manual carefully.
One big difference is that the filament current for the 5U4 is 3 amps
compared to 1.9 amps for the 5AR4. Will the existing filament
winding/transformer handle the extra current?  Other differences : the 5U4
has slightly lower max peak inverse voltage rating but higher current
rating than the 5AR4; you should be OK there. The 5U4 has lower plate
impedance than the 5AR4 so the final B+ voltage may be higher with the
5U4.  Check the operating curve of the 5U4 to make sure your application
will fall inside the appropriate operating region.

Phil


>Thanks in advance.
>
>Dave, W8QW
>
>
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