Best investment; cartridge or line stage?

btw,

Those speakers are 92 db sensitivity, and the bass is self powered: thus not needing a lot of power.

You might someday consider going all tube, i.e. sell the McIntosh Hybrid.

Perhaps get a Stereo model that can also be used as Mono, so you can double your power in the future if you fall in love with some inefficient speakers (don’t even listen to inefficient speakers if you know what’s good for you).

And, the speakers are 4 ohm nominal, if you ever change to all tubes, look for an amp that doubles it’s power for 4 ohms.

@terry9 I am really looking forward to your first attempts at producing a cutting edge design Mycelium / Soya Resin Impregnated  Wand.

The world of Soya Resin is quite established, with the world of the 'Myc’ being the one that is fast closing in.

I have now found Speaker Cabinet/Enclosure produced from 'Myc', as well as  Acoustic Panels, the usage of this material is ’mushrooming’ 😁.

@elliottbnewcombjr "don’t even listen to inefficient speakers if you know what’s good for you"

I suspect that what you mean is, "Some are so good that you will fall in love," like ESL's or Magnepans. But some could take your words as dismissive. Perhaps you could clarify?

@pindac That’s going on the back burner for now, because I’m building an active crossover for some Magnepan DWM woofers and my isobaric sub.

This is an intriguing question, but I suspect that upgrading just the phono stage or just the cartridge will leave you wondering about how much improvement you will hear from upgrading both. It is also worth noting that the interconnects from your phono stage will also play a part. Based on my own journey, I suspect that the cartridge upgrade will produce an immediate benefit, but that a new phono stage should be the next move. Another idea is to try and demo a new phono stage in your system, as this will give you a sense of the change (and is obviously more practical than trying to "demo" a cartridge!) If you like the improvement, buy it, knowing that a new cartridge at a later date will only create further gains. 

@elliottbnewcombjr Elliot, buy the time he can afford the phono stage the cartridge will have worn out. Phono stages last a long time and the great ones are not cheap. The cartridge is usually less expensive than a great phono stage so it is quicker to save up for. Many of us have to push it financially to get into the better equipment. If money was not an issue he'd buy both now.