Melo Glide

[Anthony]

In case you haven't seen these before, here is how it was done. I assume it is the treble pulley which has more difference between the diameters, being driven by a larger pulley.

Glide.jpg (34.2 KiB) Viewed 82405 times

[Lucien Nunes]

Hi Anthony
I am intrigued by those two pulleys having different tapers. I had understood that only the bass generator had the glide mechanism, the treble running at fixed speed. That is the arrangement on the chassis I have looked at and also the one shown in the Compton factory documentary, where you can even see the belt scoot across the pulley in-shot. Admittedly that unit is described as belonging to an Electrone but there's nothing to distinguish it from an ordinary Melotone and little likelihood that factory shots would have shown the as-yet unreleased Electrone. At first I wondered why they didn't make both generators glide, then reasoned that as there was no way of keeping the glide progression in-sync between the two, it might do more harm than good to have the treble glide as well. Do you know the origin of those pulleys?

Lucien

[Anthony]

Hi Lucien,
That is interesting! While I was assuming things I had not twigged that the ratio change would be the same if fitted to either disc anyway.
I think the wider taper should give a 60 cent reduction; the other only 30 (doesn't seem much?) Running diameter is the same. On Al Bollington's recordings where the glide is used, the sliding notes sound like they are outside the bottom two octaves, in which case the full bass disc was wired. That could explain why the vibrato on my unit won't set quite right for that sound. I had thought these pulleys were saved from the junked Paramount TCR unit, at least one of them anyway!
Anthony

[Lucien Nunes]

It just struck me that unless a layshaft and double belt was used on the treble generator, it would have been impossible to fit that size of tapered pulley as there would not have been room for the corresponding size of motor pulley. My hunch is that if both those pulleys came from the Paramount they were two alternatives for the bass. When you mention 30c and 60c tuning shift, is this from the generator pulley alone or including the effect of the taper on the motor pulley? I don't have any measurements handy, but recall doing a top-of-head calculation in the absence of the motor pulley (making assumptions about the effective belt length) that the glide should be about a semitone, much as it sounds on Mood Indigo at the Paramount and as glides are on many electric organs.

Referring again to the slide-equipped Melo in the factory film, which I just looked at to refresh my memory, the bass generator is definitely wired for 48 notes and the treble for 24 as evidenced by the thickness of the two wiring looms. So at least this matches Al Bollington's recordings, which I also now need to listen to again!

Lucien

[Anthony]

That is from these tapers only- if the motor pulley was tapered to match belt length, that estimates 106ct variation on the steeper pulley. I had a stretchy belt in mind!

[Anthony]

Thanks for confirming the wiring arrangements Lucien; those two octaves have made all the difference. If you fancy a listen, please see http://www.youtube.com/watch?v=6qt1S5NGjtg
Anthony

[Lucien Nunes]

I won't try listening to it here on my phone, will give it a whirl later. I asked on the EOH forum for nominations as to the first use of glide on electric organ and the concensus was that this was post-war by Lowrey. So, it seems to have been a Compton first!

Lucien