[Amps] Re: Palomar

[skipp isaham]

Hi Steve (and amps), 
- 
The Palomar 300a is a 40-10 meter amplifier with 
six sweep tubes in grounded grid. In low power 
mode, the exciter drives the final quartet and it's 
SSB operation with 40 watts drive is similar to 
the many handbook projects published in ARRL 
and W6SAI handbooks. 
-
In high power mode, the two tube driver stage 
is placed in operation (bypassed in the low 
power mode) and the drive requirement is 
reduced to 4 watts.  
-
This amplifier layout works very well, the 
amplifier is/was very popular with the 10 watt 
rated (turned down to 4 watts drive) HF radios 
made in the 70's and 80's.  It would also be 
very nice with the brand new Icom 703 qrp 
rig that is coming out (most of you don't 
know about it yet, a qrp version of the 706). 
-
The power supply is a very well done doubler 
circuit, replacement transformers are sold by 
Peter Dahl.  This amplifier along with many 
other SSB rated units rely upon a measure of 
peak supply voltage for an extra few watts out. 
Swan also employed "peak power" in some 
of their circuits. 
- 
The amplifier has a matched input, a nice pi 
output, is legal for operation in the amateur 
bands. A diagram is available at the 
www.cbtricks.com  web site. 
- 
This is one of the first amplifiers I've seen 
with instructions to the user to rotate the 
Loading cap after tune up to increase Linearity. .
- 
A stock unit with 4 watts CW input would 
output about 325 watts with fresh tubes. 
It is an AB2 amplifier so SSB operation 
works very well.  I have at least 3 of the 
various models made in my collection. 
The black face unit was first, followed by 
one mixed and one white faces version. 
-
Hope that helps
-
skipp
- 
> steve garner <stevegadget at juno.com> writes:
> Hi
> I wrote  last week asking  info on a Palomar that I did not have 
> the model for.  Since then I have found out the model no.
> It is  a 300A.  I would like to know the  specs for the  P.S.
> 
> I did hook up a transformer  and managed to get 200
> watts out of it  then smelled smoke... the transformer is 
> too small... at least I know it works.... I just need a bigger
> transformer.  Any help would be appreciated.
> Steve   KD5EPZ
> 


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