The drivers have also been replaced. AFAIK, Sunn never used Altec drivers. But the Altec 418B is a superb driver, every bit as good as the JBLs of the era.
As far as I'm aware, while JBLs were the standard premium standard drivers in the early period, a customer could spec just about anything into a cabinet. I've read a few times before that Noel Redding had Altecs mounted in his cabinets from the factory, and have seen a handful of examples.
Did Ampeg ever use Altec drivers for their larger cabinets? Reason I ask is a friend had an Ampeg cabinet and amp that were stolen maybe 7 years ago locally and they were both re-covered with white tolex of some sort. It isn't a common color to see on amps or speakers since it gets dirty so easily. I wonder if that might be an Ampeg cabinet and someone put a Sunn logo on it to hide the identity and sell it?
Greg
Yes they did, I used to own a B-25 cabinet with 418s in it stock. Can't say it held much of a candle to any of my Sunn cabs, but I put that up to a shallow cabinet design more than the 418s.
To Newtosunn, yes, that appears to be an original cab, likely '67, as Conrad said, either a Spectrum or I believe the PA systems (studio PA) also used the offset cabinets like these.