[Central-Electronics] AP adapter question

[George Maier]

Hi there CE fans & aficionados.....

As most of you know, CE made several interface adapters for their Model A
and Model B Slicers.  They were known as AP adapters, and the ones I'm
familiar with include:

AP-1
An outboard IF amplifier for 450 to 500 kHz that adds both gain and
isolation.  It plugs directly into the back of the slicer, and connects to
the IF via coax cable.  

AP Converter - may also have been known as the AP-2, but I don't know this
for certain. 
Similar to the AP-1, but includes a mixer stage to allow using the slicer
with a receiver that does not have a 455 kHz IF stage.  The one I have here
has one tube (6BE6), and includes a crystal marked 27.0 MHz.  The 27.0 MHz
xtal is not really on 27 MHz, its' a WWII era surplus xtal with an actual
frequency of 500 kHz to allow use with 50 kHz IF's (i.e. - Hallicrafters) or
915 kHz IF's, if there were any.  

AP-3 
A cable made for use with the Model B, to allow the Q-Multiplier to be
available when the SSB slicer is not in the circuit.  

OK - here's the question......
The AP-1, and AP Converter both have one tube, and several people I've
contacted on this list are familiar with that configuration.  An
acquaintance of mine on the west coast came up with an AP converter that has
two tubes, and no one seems to know exactly what model it is, and why it was
made.  It uses the same "27.0 MHz" xtal as my AP converter, so presumably it
serves the same purpose, but may be an early model, or one with more gain.

Anybody have any info ??   JPG scans are available for the curious.

Vy 73
George Maier - K1GXT