finding the weak link

The biggest change the OP can have would be a different pair of speakers. How about some Ohm Walsh's? I have a pair of the Sound Cylinders and OMG do they fill a room with 3-D SOUND! The performers are RIGHT THERE in the room! Ohm in Brooklyn can build a pair of Sound Cylinders in any finish the OP desires!

Oh, I'd like to hear those speakers!

Thank you all for your responses, they are very appreciated!

For those who asked, the remaining details of the system:

Dr. Feickert Volare Turntable,  Origin Live Mk3A select tonearm,  Hana E Series MC Phono Cartridges - EL

MoFi Electronics UltraPhono MM / MC Phono Stage × 1

Tube upgrade:

Brimar CV4003 / 12AU7 (2)

Tung-Sol KT 150

Cables and Power

              Kimber 12TC speaker cables

Audioquest

Sydney (interconnect)

Niagara 1200 Low-Z power/noise dissipation system

Wind series Monsoon power cable

NRG-Z# power cable (2)

Rocket 88 Speaker Cable

Morrow Audio

SP6 Speaker Cables

MA4 Interconnect Pairs (2)

Nordost

Ax Angel RCA Interconnect

Frey 2 Interconnects RCA

No obvious weak links.

You could try going to a separate pre and power amp.

Your speakers go down to 28hz. You will be surprised at how much more info will be extracted from your main speakers when you ad a subwoofer. Add 2. You won't be disappointed. my speakers are rated to 20hz. yet the subs were probably my biggest improvement.

then your phono preamp is not up to the task. Do NOT underestimate the importance of a GOOD phono preamp. The OL Silver arm is OK and actually hits above its price level as ALL the OL arms do. At some point you might want to upgrade to something like an Illustrious which is supposedly their sweet spot.  I have one that I bought for my Teres TT as a temporary arm. That was 12 yrs ago. I just upgraded to a TriPlanar. Yes it was better. But the OL has absolutely no shame when placed alongside the Tri. keep your eye open. i have it on good authority that there will be one for sale sometime soon. You have a good system in the PL and speakers. i would not consider changing the PL until you take care of the problems I mention.

BTW, like others have said, the KT66 & 6L6 tubes are something to consider. My own favorite is the 7581 tungsol. Fantastic freq response and the prettiest blue glow you have ever seen. They have the same specs as the KT66 as I understand