Yamaha RA-100 Rotating Speaker Organ Amp | Hacker News Reader

Yamaha RA-100 Rotating Speaker Organ Amp

lydian.ca

36 pointsgennarro12 comments

See also the Leslie speaker.

https://en.wikipedia.org/wiki/Leslie_speaker

IIRC, Leslie had the better design, but they also patented important parts of it. So Yamaha had to do this crazy thing to get a similar effect.

Yes, if I'm not wrong the fundamental difference is the Leslie rotates the horn where the other companies had to rotate the entire speaker.

I remember decades ago helping Oh My God move a Leslie into a venue for a show. It was huge.

Wow. Oh My God rocked my teenage world while growing up in Michigan. They were probably the most exciting band to consistently come through my town and blow all of the other bands away at the local venue. We went ape for their shows.

Never ever thought I’d hear someone mention them on HN.

Leslie, king of the rotating speaker cabinets.

The RA-100 rotates two tweeters out of phase, with fixed woofers. The Leslie (122 and 147 models) has a rotating horn for the tweeter and a rotating baffle for the woofer.

The Leslie has two speeds, and when switching speeds, the woofer baffle both speeds up and slows down more slowly than the tweeter horn, causing audible phase shifting.

Ironically, while transistors for the later RA-100 are out of production, the power and preamp tubes (6550, 12AU7) for the Leslie are still available new, and the regulator can be found cheaply NOS.

Reading all of this reminded me that I have a bag full of 50's-70's transistors and a box full of 12AU7 Telefunken tubes that I should probably list for sale.

Yes, please

This is a massive part of the Pink Floyd (Dave Gilmour) sound, he use the RA-200's https://www.gilmourish.com/?page_id=83

But what about how it _sounds_ ?!

https://www.youtube.com/watch?v=mB3RkjgRQ9c

I kind of what to hear how OP's modded one sounds, see if there is a difference or how much of their enjoyment of the amp is colored by having Amp of Theseus'd the whole thing.

I saw this “Allen Organ Gyrophonic Projector Rotating Speaker” for sale yesterday on Craigslist. I’d never heard of such a thing before.

https://seattle.craigslist.org/oly/msg/d/olympia-allen-organ...

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