DIY Moog construction comments

Some useful information for the home constructor of the Moog circuit Theremin based on my findings, no guarantee given!
I have recently been constructing a Theremin to the well known Moog circuitry and included the buffer modifications. The idea behind the mod. is to isolate the two oscillators permitting extenson of the bass end of the spectrum.
In practice it is only necessary to place a single emitter follower buffer in either of the oscillator paths, that will provide isolation and does work just as well as two. (save 50c !)
With the two buffers my Theremin produced the dreaded low frequency plop plop problem, this vanished with the one buffer solution.  Has anyone actually determined the cause?
I noticed the power supply rails right at the output of the regulator IC's were bouncing a few mV in sympathy which surprised me as they are not operating anywhere near their maximum capacity and are normally very stable devices, all a bit of a mystery.
On the subject of the "linearizing" coil I initially wound one similar to the Rockmore valve design, close winding about 1650 turns of 36G wire on a 75mm (3 inch) diameter former, it ended up being 285mm long, came in at 39mH and 250 ohms resistance. ( i just kept winding until I reached the length, didn't count the turns.) It worked extremely well beyond all expectaions after many failures with other coils.
The Variable frequency oscillator must be set to resonate with the coil to gain maximum audio range, I achieved 5 octaves easily albeit the last high frequency increment was very small and unuseable. Tuning was done by loose coupling an oscilloscope probe near the coil and tuning the VPO for maximum RF output. The FPO is then tuned to match. About 300kHz in mine.
Not wanting to use the bulky coil I found some Ferrite Choke Inductor coils on EB that are performing satisfactorily but not as good as the air wound coil.
The total inductance of the FCI's is 27.5mH made up from 5 units, don't try a lesser number of higher value, mine didn't work. I guess it is related to self resonance and capacitance. I now have an adequate playable range up to about C3.
A 47pf capacitor is used between the pitch antenna and the coils (in series), without it the physical distance from low to high was poor, it is now about 60cm.
The same type of FCI were used in the volume circuit with excellent results.
So it all works well except for finding the ever elusive original Theremin sound. Hope this is of interest and help.