Thats simply not true!!
2 example's...
The 400PS!
View attachment 782608 435 watts of crushing bass amp, by all accounts it has clean headroom for days!! Only downside(besides being 80 lbs), you needed to run it through *3* cabs to get that full power!!
Which spawned the much more practical 300PS!
View attachment 782611 I have one of these in storage on the mainland!! This was Fenders attempt at competing with the SVT, but it sounds nothing like it except both being 300 watts/all tube!! Clean headroom for days, warm yet uncompressed, sweet highs, tight lows and LOUD, crushingly LOUD!! They made this more club player friendly with it having an output for only one cab(either 4 or 8 ohm)...you can level small buildings with this, the only head that comes even *close* IMO is the SVTII non pro!! They only made the 300PS from 75'-80', I bought mine from one of my bass instructors for $600, it does weigh 76 lbs. though
I think they were just left in the dust by Ampeg's reputation, as to why they didn't sell that many...