Rudi was clever. He had the socket centre pin modified to take
the Eimac tubes and put a 6V tap on the transformer in the DX-2SP
amplifier. I have tried both the 4CX1500B and the 4CX1000A in a
friend's amp and the 4CX1000A is the much better choice. The
output with the 4CX1500B installed was quite a bit lower.
73, Alek VK6APK
On 26/11/2023 8:00 pm, Louis
Parascondola via groups.io wrote:
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If an amp uses FU728 by design and has an actual 728 socket stem,
a 4cx1000 will not just fit in. The center shaft is too wide in
diameter. ?It may be possible to enlarge the center hole on the
4cx1000 with the right size drill bit to make it fit. ?The FU728
with a larger hole will fit a real 4cx1000 socket without an
issue. ?Change filament voltage of course either way..
On
Sunday, November 26, 2023, 6:49 AM, Adrian Fewster
<vk4tux@...> wrote:
Alek, see?
Can dropin for a FU-728 with filament voltage changed to 6v ..
73
vk4tux