Best investment; cartridge or line stage?

@terry9 ,

You made those tonearms??!

Extremely impressive. Do you have a background in materials engineering?

I wouldn’t have a clue where to start...

The Rega P6 has a very acceptable arm. I think you have to think of this differently. A phono stage is a long term investment and can easily last decades. Cartridges are expendable devices, they wear out. If your cartridges still has some life in it go for the phono stage. The Sutherland Locos are fine stages. When the cartridge wears out change it. 

@thecarpathian 

Thank you for the kind words. Most courteous.

Made some parts, subcontracted others. Turntable and tonearm, all my designs, my fabrication, subcontract much of the woodwork. The latest wands are natural fibre composites, for which I make the cores and subcontract the epoxy work. Off-the-shelf whenever possible: e.g. New Way air bearings and shafting, Igus carriages. Battery power supply is more complex than it looks, my design, layout, and fabricating. Same with power supply for the main monoblocks. Other electronics, mainly my layouts, parts selection, fabricating, and a better man's amplification schematics.

Not engineering - math and science. Now retired and learning some of the stuff my more practical father could have taught me.

I also think the Rega Tonearm is 'good enough', until you move up to a far superior TT.

You will DEFINITELY hear an improvement, BETTER, with a new cartridge with an advanced stylus shape.

A different Phono Stage? I would love to hear the existing and new cartridges thru that Sutherland TZ Vibe Phono Stage, your system or mine.

If the Sutherland sounds great, why even think about changing it? Have you heard something elsewhere that makes you think it is not great? Unless a POC, phono stage differences  are about PREFERENCE, not better..

I highly recommend, after you break your new cartridge in, and saved some money, buy a Phono Stage with return privileges. It may prove how great your Sutherland is.

Don't forget, the Sutherland has adjustable gain settings. Medium/High/Low

Compared to other sources, streaming, CD: where is the Preamp's volume setting when playing Vinyl? If preamp volume is higher than the others, change Sutherland to higher gain. It preamp's volume is higher than the others, try lower gain.

@milo0812   Just when you thought it was safe to go back in the water ...

Another county heard from. Everyone hears differently. I think that you should listen to other systems and other components as much as possible - but you already knew that. One last piece of advice - don't hurry! Good equipment will still be available in 6 months or a year.