What does you reference rig do better than your vintage rig or vice versa?

I’ve reached that critical point where flutter can be detected if the combination of phono pre output level and receiver volume are too strong. 

That sounds more like you are having feedback issues at higher volumes.

What is your vintage tt, arm and cartridge ?

@dover, I’ve got an AKAI AP-A50 Linear Tracking tt with an Audio-Technica DR250 cartridge. 

Unfortunately, my room is less than stellar for hifi playback. I’ll mess with speaker placement and consider adding bass traps. I’ve added a thick, heavy slab of calico hickory underneath the tt. That helped to be able to increase the volume before the flutter shows up.

I could also upgrade the tt. However, I have been impressed with generally how good the tt does sound. I also love the automatic return and stop!

Great / beautiful systems. Looks like both could benefit enormously from careful room treatments and possibly positioning. 

You're going to hear every imperfection on your reference rig. 

My vintage rig in a vacation home in Vermont (DCM Time Windows 3, Pioneer SX 828, Thorens TD161/Stanton 681 EE, Linn Unidisc SC.  Plays music warm, fulfilling and comforting like mom’s Sunday meatballs and sausage gravy over spaghetti.

My reference rig (see profile) plays music with the fresh clarity to the pallet, dynamic busts of flavor, emotion and elegance of the tasting menus at Le Bernardin in Midtown Manhattan, NY.  

The reference system brings me closer to memories of live, acoustic performances.   Closer, but still distant.  

Regarding issues with less than stellar recordings, reference rigs do to lower noise floors, detail retrieval, and extended frequency response are not tolerant of less than stellar recordings.  You hear all of the engineering faults clearly that are masked on vintage systems.  

I agree @dover that vinyl distortion at high playback levels is usually not flutter (speed inaccuracy) but rather acoustic feedback.  I would look first at TT isolation and speaker placement relative to the TT.  If it is flutter, it should be evident at low volume as well as high volume. This does not seem to be the case since you state “it sounds so good” … until you turn it up.  

@dover, @jsalerno277, Yes, my mistake. It definitely was loudness feedback rather than flutter. 

I moved the speakers towards the front wall 1 foot, they're still almost two feet into the room. I’m able to listen now still with great sonics. Now I can turn the volume nob to 12 o’clock where as before I could only get it up to 10 o’clock without noticing the feedback. I’m still getting a nice center image too.