Let me preface this with yes, I did a search and kept coming up with answers that were unrelated to what I'm looking for. I own an older Ampeg SVT-410E cabinet that doesn't seem to match up with any of the serial number lookup info I've found. It's from the SLM era and it only has a 6-digit serial number. From what I've seen on various ampeg serial number lookup sites, there was a more common 10-digit serial number used during the SLM era. So when was this thing made? Any ampeg gurus have the knowledge I'm looking for?