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Perhaps your filament voltage is a bit low. low voltage =3D low =
emission.
Maybe the transformers can't give the 4x(15A/tube) required by the 4 =
tubes?
.....Merit W6NQ
=20
I have started work on a new amplifier (80 - 10 meters) utilising the =
popular grounded grid design but with a slight difference than the norm =
as I use four valves in parallel, of the AMPEREX 4-250 type. I still =
would like to break the 1 KW barrier on output.
=20
I have a similar working one I build in 1999 but although it is =
working it is not very efficient and prone to destroying chokes and =
by-pass capacitors. Power output is also way below what I expected .. =
and not breaking the 1KW barrier.
I run the valves with +/- 3,400 Volts on the plate and the filaments =
have two transformers connected in parallel giving the 5 Volts at +/- 15 =
Amps.
I =20
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<DIV><FONT size=3D2>Perhaps your filament voltage is a bit low. =
low voltage=20
=3D low emission.</FONT></DIV>
<DIV><FONT size=3D2>Maybe the transformers can't give the 4x(15A/tube) =
required by=20
the 4 tubes?</FONT></DIV>
<DIV><FONT size=3D2>.....Merit W6NQ</FONT></DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: =
0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial"> </DIV>
<DIV style=3D"FONT: 10pt arial"> </DIV>
<DIV><FONT face=3DArial size=3D2>I have started work on a new =
amplifier (80 - 10=20
meters) utilising the popular <FONT color=3D#000080><EM>grounded grid=20
</EM></FONT>design but with a slight difference than the norm as I use =
four=20
valves in parallel, of the AMPEREX 4-250 type. I =
still would like=20
to break the 1 KW barrier on output.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I have a similar working one I build =
in 1999 but=20
although it is working it is not very efficient and prone to =
destroying chokes=20
and by-pass capacitors. Power output is also way below what I =
expected=20
.. and not breaking the 1KW barrier.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>I run the valves with +/- 3,400 Volts =
on the=20
plate and the filaments have two transformers connected in parallel =
giving the=20
5 Volts at +/- 15 Amps.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>I =
</FONT></DIV></BLOCKQUOTE></BODY></HTML>
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