I have no doubt you are very good at what you do . I have been a repair
tech of old and new electronics for 30 years and lived through the heavy
stereo years of the 70`s and lots of record players , speakers and sound
quality but that certainly does not make me an expert .
I only got started in jukeboxes the last 10 or so years and have
restored several and helped restore some and repaired a few on request
from random owners .

I received a Seeburg G and restored it with its original red cartridge
which sounded crappy .
I then went to a juke guy near here who has a Seeburg C and borrowed one
of his brand new O3D cartridges at the same time picked up my used gold
Pickering cartridge and new needles at a local vending outfit .
I came home and tried both in my G . The O3D sounded very clear and all
but lacked in volume and bass so i tried the gold one and the machine
never sounded better , super crisp hi`s and deep bass with tons of
volume .
I heard his Seeburg C while i was there with his O3D in it and it
sounded real nice but not as good of bass as my G .
The G has a tweeter The C does not so we wont compare hi`s .. not fare .

The construction of this gold cartridge explains it all . Before i put
it to perminent use i took it apart to clean and restore it . The needle
on this is set up directly on the armature inside the cartridges coils .
The O3D and red head use magnetic transfer between the needle structure
and the coils inside , this creates a loss .

He told me the input resistors had to be changed in his C to compensate
for that O3D cartridge . The main purpose for the O3D is its very gentle
on records because of its fine needle arm and light tracking force
otherwise its just another cartridge that gained a ridiculous price for
reasons unknown other than over rated word of mouth and the fact they
are getting hard to find .
There were also vintage standard double sided phono cartridges that were
being adapted to a Seeburg tone arm plug that had a rating very close to
the O3D but not as `pretty` .
One of his G mechs had one of those on it that he had me work on so
while it was here i tried that adapted cartrige in my G out of curiosity
and it sounded just like an O3D .
I know the only way to show some people would be to stand them in front
of a jukebox and try each cartridge in it so they could hear for
themselves .

The moral of the story is .. The O3D sounds clear and with a resistor
change it will sound louder . Is it worth 300$ .. NO