[Boatanchors] RE: [Heathkit] DX-100 whata good amp for my DX-100, i have a SB-220 now

[Glen Zook]

The Thunderbolt is a grid driven linear and requires
only a very few watts of drive.  Remember, Johnson
used a 6 dB attenuator when the Ranger was used to
drive the Thunderbolt.  The DX-100 will require more
like a 10 dB attenuator.

The SB-220 is a grounded-grid linear and requires
substantially more drive.  However, to keep the linear
down to the 300 to 375 watt output range that would be
required for proper AM operation this means that the
drive from the DX-100 is going to be have to be
reduced by between 3 dB and 6 dB.

In either case, you are going to have to dissipate a
lot of the power provided by the DX-100.

The real question is whether or not the additional
power output is really worth the effort.  

If you really want to use the DX-100 as a driver for
either the SB-220 or the Thunderbolt then I do make
equivalent attenuators of the Johnson design.  Go to

http://k9sth.com/uploads/attenuatorad1.JPG

for details.

Glen, K9STH


--- Ross Stenberg <k9cox at charter.net> wrote:

The SB-220 is great for AM. Just keep in mind that 375
watts of modulated carrier is 1500 watts PEP which is
the legal limit (I believe the SB-220 is officially
rated at 1200 watts PEP output so 300 watts of carrier
is appropriate for the purist). I have heard many
SB-200's on AM as well at lower power levels. The
Thunderbolt would require a significant amount of
attenuation on the input since it does not need much
drive. Either case would require throttling back the
output from the DX-100.







Glen, K9STH

Website:  http://k9sth.com


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