When a 511B is a 511A

[bowtie427ss]

Those are the brackets that make a 511 an "A" version, they are very much Altec.

or Altec made? I don't recall seeing any mounts like these before.

[Cal Weldon]

Are those not the same brackets as available with the 511B also?

http://alteclansingunofficial.nlenet...&811B-Data.pdf

[bowtie427ss]

Are those not the same brackets as available with the 511B also?

http://alteclansingunofficial.nlenet...&811B-Data.pdf

Cal, my WAG is that it really depends on the time period.

EDIT: In answer to your question, those are exactly the ones. They might have always been available as an accessory, perhaps by special order in the early days.

AFAIK, there was a point in time where if you asked for/ordered a 511A you got a 511 with an undrilled mounting flange and that fancy bracket assembly included.

http://altecpro.com/pdfs/vintage/Spe...HF%20Horns.pdf

If you asked for/ordered a 511B you got a 511 with 6 holes drilled in the mounting flange and no bracket.

My further WAG is that eventually there was only the 511B, and the fancy bracket assembly became an optional accessory for it as the factory sheet shows.

[Cal Weldon]

That all makes sense, thanks.

[Altec Best]

Those diaphragms have been used and have been hot.. Yeah I would say some serious cleaning went into those before the Pics. I also agree about showing stuff with the objects listed, that are not included is just going to cause confusion.

[A7fan]

Thanks for posting the links to the literature. Might get the project off the back burner.