[JMS] Recently acquired a James Millen Preamplifier Model 92101 with plug-in coils

[Don Buska]

I can handle this too Sherrill,

The preamp was based on the design from the Nov/Dec 1946 Issue of the GE 
Ham News magazine. Called the R9'er and later variations were also built 
under the Q5er name.  The schematic is on the JMS website.  I will scan 
the manual and email it to you.

Millen didn't make a power supply unit for it.  My guess is they figure 
you will steal the DC and AC from the receiver.  Since it only uses one 
tube.  I built a little standalone power supply for mine.  Yes I have 
actually used it with my HRO-5 on ten meters.  Finding the plug-ins is a 
hit or miss deal.  Keep watching eBay or at swapfests.  They do turn 
up.  The preamp was delivered with the 10M plug-in and that is the one 
you will find in 99% of the preamps you find. It was also the weak point 
on early ham superhets. They are not rare.  Next to the dip meters it 
was one of the highest produced equipment products from Millen.

The RF connectors on the preamp are a bit unusual.  They use Amp(henol) 
connectors that have the same body as the common two pin jobs used for 
mic connections on many old BA radios (like Heathkit and the Collins 
KWS1).  The difference being the insert only has the one male pin right 
in the center (cable side).  Often you find these removed from the 92101 
and replaced with SO-239's or BNC's.  That's to bad as I have also found 
the correct connectors to plug into the 92101 on swapfest junk tables.

I took my 92101 to the 1996 Central States VHF Conference in Bloomington 
MN to enter into the Preamp GAIN/NOISE FIGURE contest.  As expected it 
didn't win against the newer GASFET jobs on six meters.  It did turn a 
few heads though, hi.

73

Don N9OO

Sherrill Watkins wrote:
> Hi Don: Thank's for the great information and pictures explaining the vfo.
> Now I know what a swing arm vfo is. 
>
> Also, during December, I acquired a Millen Preamplifier, Model 92101 with
> three plug-in coils.  I will be registering it on the equipment list in the
> near future. I now need an owners manual and schematic and additional coil(s)
> to cover 15 to 27 MC! Also, was a separate power supply made for this unit? 
>
> Also, has anyone actually used the Millen Preamplifier Model 92101? If so,
> please give me you thoughts and comments. Many thank's!  - Sherrill k4own
>
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