spinnet organs...

[jamiewoody]

as i understand, home spinnet organs, such as lowery were basically synths which were stripped down.  an oscillator and the "tremolo" was a type of vcf. this is what i have read. 

has anybody messed with one? it seems that there would be a lot of good stuff to harvest, at least. the drum machine, the bass pedals (which i am working with!), perhaps the keysets.

any insight, photos, etc is appreciated!

[Gordonjcp]

No, that's totally wrong.  Don't know where you read that.

Most of the old "electronic" organs (ie. that generated sounds without mechanical means such as reeds or tonewheels) have an oscillator running somewhere in the 1-2MHz region, from which the top octave is derived by a chain of dividers.  Each note is then produced by further octave dividers - so you start with high C, divide by two to get the octave below, divide again to get the octave below *that* and so on.

This gives you a bunch of squarewaves which can be filtered and mixed in various proportions to give the different organ stops.  Vibrato is achieved by modulating the master oscillator clock.

[Circuitbenders]

isn't that how the weird oscillator in the JEN SX1000 works?

[Gordonjcp]

It is, kind of.  Divider organs (and indeed string ensembles like the famous Solina) are fully-polyphonic, in that you can press every key and they will all sound.  The SX1000 used a custom chip to divide down the notes based on the current keypress, but was resolutely monophonic.  Similar idea though.

You used to be able to get top octave generators and octave divider chips in Maplin, back around the time of the adverts I posted a while back.  Now they don't even have TL07x opamps.

[jamiewoody]

http://www.cgs.synth.net/organ/tgs.html

this isn't my lowery, but the site give some insight...

[SearchAndRescue]

If nothing else, it would be cool to get an effects in/out after the pre-amp circuits and before the higher gain amp. I've got an old Hammond transistor organ that I can't find on the internets, but it's basically a re-badged yamaha (since Hammond carried a kind of cache that Yamaha lacked in the 70's), and I think it'd be cool to route it thru a bunch of effects.

For my paper zine SEARCH&RESCUE, I recently interviewed a guy named Dave who started a website called Free Organs USA, which is basically just a blog consisting of him going on Craigslist looking at the 'free' section and posting the console organs he finds across the country. I don't know if transistor organs were as widespread in the UK as they were in the US, but I think you could find them for the price of '"you carry it out our front door and get it the fuck out of our house and it's yours'".

[Gordonjcp]

That's basically the situation with organs in the UK, too ;-)

I have a nice old Wurlitzer up at my mum's house, and a Yamaha A55 that I got from a guy I worked with.  The Wurlitzer required a small van, the A55 *just* fitted into the back of a Citroën AX if I pulled my seat forward...

[jamiewoody]

there are a lot of valuable parts on a spinnet organ. the bass pedals, the keysets are very nice! the keys are weighted, as opposed to a lot of cheap keyboards. there is the volume pedal. when i get my pedal synth built, i might try to harvest the rhythm section out of it and build that into a box.  i need tp look at it, which i haven't. it might not have it's OWN circuit board. there are about 3 circuit boards in all i think. one of course is the amplifier.

[jamiewoody]

i removed the keysets yesterday. it was not easy, as all the screws were on the INSIDE of the cab, originally for cosmetic puroses.

the keysets are still attached to a piece of wood, and it looks like i will have to remove the actual keys in order to get that  loose. the keys are held in tact by a wire clip. i was hoping maybe i could separate the keys some, as i only wanted one octave from c to c, but  it looks like i will have more notes than that, which i can live with.

so, let the fun begin!