Hello Vic,  Devtronics stopped using the Hartley oscillators due to
the oscillator coils becoming unavailable.  As far as I know there
are no modern organs using the Hartley oscillators.  However, if you
are only looking to build one or two band organs using the Hartley
oscillators, look for used organ parts on eBay.

Oscillator coils for Conn and Rodgers organs will work.  Conn coils
are Hartley, Rodgers coils are for Armstrong [oscillator circuits]
or series-connect the feedback coil and make it a Hartley.

For production, I would go MIDI and use a EDIROL Sound Canvas synth.
I have very good band organ simulations using the Sound Canvas.  In
addition, live instruments may also be controlled via MIDI.  I have
several situations where a customer had live band organ elements but
not enough to complete the band organ.  So MIDI controls the live band
organ elements and they're supplemented with the Sound Canvas synth.
I hope to have some recordings soon of one of these instruments.

I can provide assistance to you if you would like to look into MIDI
control.  I also have two complete sets of Conn Hartleys and one set
of Rodgers oscillators.  I have two sets of the Octave 7 and one set
of octave 0 Devtronics oscillators as well.

One of my favorite demo pieces is "Painting the Town Red, White and
Blue".  By re-arranging the tracks I can make the MIDI file play just
about any band organ instrument arrangement.  Great piece, Robbie,
do you have more?

 [ The song was composed and arranged for concert band by MMDer Stephen
 [ Kent Goodman.  I adapted it for band organ (still awaiting perforation
 [ as a Wurlitzer 165 music roll) and George Bogatko created the MIDI
 [ file version for a large synthesizer, available to download at the MMD
 [ Sounds site and http://mmd.foxtail.com/Sounds/index.html  -- Robbie

Vern Jones, Sound Research
http://www.sound-research.net/