This is the bass in question, a 1991 Thumb that I've owned since about 1992.
The barrel jack socket is accessible and I do have the ability to replace it; I'm just reluctant to, although it would be an opportunity to replace it with a black one.
It's shown in this table from the Ampeg quick start document. It doesn't mean it will be as good at producing bass as a 610 cab of similar sensitivity. Don't fixate on sensitivity; it's only part of a cabinet's performance.
Yes, some others have used this combo like that. The only issue may be that the short speaker cable won't reach an amp placed on top of the combo. You can either open the combo up and replace it with a longer one (may require soldering skills) or buy/make a female to male jack speaker extension cable (may require soldering skills).
I may get shot by the luther mafia but when my maple Sterling neck got grubby I cleaned it up and gave it a single thin application of tru oil. I prefer the feel of it over the original and it stays lovely and clean now.
Normally I'd agree with you completely. In this instance however this is a 30 year old bass in totally original condition and this lead has never been used with it previously so it's not the cause. It works perfectly with the bass but is 20 feet long which is longer than I need for most gigs.
Does anyone still produce instrument cables with this type of connector? I need the extra springy contact at the base to maintain a good connection on one of my basses. (I'm looking for a 10 foot cable; ideally right angled to straight connectors).
Many thanks for any guidance.