Loss of bass

I've changed my hi fi gear quite a lot recently, from an Arcam AV50, to an Arcam AVR250 and now an Arcam FMJ A22.

The latter is what many would call serious Hi Fi even now a few years after it's discontinuation from the Arcam line.

I've partnered all of these with my Longball speakers based on the Tidy design.

The sound from the AV50 was warm but lacking a bit of detail, then sound from the AVR250 had bags of bass but shrill treble, so I stuffed the lines with double what I had before, about 600g each of polyester fibre. It did nothing to tame the treble but the overall the sound was still good including bass.

Now with the A22 there is no bass and when I say none, I mean my floor standers sound like a pair of satellite speakers. I've been told on countless occasions the amp exhibits a flat response, but surely the last two amps can't be so out of kilter that they had way too much artificially increased bass ?

I think I'm going to remove the extra stuffing though not sure what that will achieve. The speakers have shown they can do bass, surely it must be the amp ?
All other things being equal, then it has to be the amplifier. I imagine it has a very high output impedance, like many of the pricier Arcam amplifiers, and while a claimed Qt of 0.40 means the Jordan's won't be as badly affected by this as some other FR / WR units with their much more powerful motors, it probably will still make a difference. The other possibility of course is you've got a duff example of the amp, though I suspect that's unlikely. Arcam units err toward the 'tonally mediocre but reliable' end of the scale. Try ripping all the damping out of the last 15 - 20in of the line, which should bring the LF up a bit.