Responses from don_c55

Big issues found in Magnepan crossovers!
BS YouTube video.There are thousands of satisfied 1.6 and 1.7 owners.Good way to screw up these Magnepans! 
DAC finalist please help
I have the Gungnir multibit 5 and I love it.Warm and big sound stage, with very good detail.Could not be happier. 
Is Radio Paradise the only free CD quality internet radio station?
Linn Jazz is 320 Kps low res. 
The OP is obviously hates Apple.Ignore this post.Apple TV 4K is great if you are in the Apple eco system.Best picture quality over the cheap Roku or Amazon cube.I have owned both.All the apps you could ever need.Get the 64gb model you will need th... 
Tube Replacement Problem - Audio Research SP9 MKiii- V1 Tube Goes Dark w/ new V2 installed
I have owned all the SP9s and currently use a MK3 in my home theater.The Amperex tubes are a popular choice and should work great.Sovtek tubes are junk IMO. They are reliable but sound very cold!Most owners of the various SP9s threw out the stock ... 
How would you characterize the VAC tube amps?
Electrostatic speakers sound best with tube power amps.I suggest you look at atmosphere or VTL.They  are both popular with sound lab owners. 
XLR balanced cables, best bang for t ht e buck?
Canare quad star pro balanced from MarkerTek onlineInexpensive  and can not be beat IMO. 
Power Conditioning / Surge Protection
https://www.changlightspeed.comBest solution I have found for surge protection, and conditioning (power line noise reduction).Better than AC regenerators or conditioners with coils.No residual artifacts at all.Power factor Correction included.    ... 
Audio Research D400 mk2 amp
The amp is over 25 years old!Time for a PS cap replacement IMO. 
Am I too big of a jerk,even for audiogon?
Yes you are a jerk!You make little sense as usual.You seem to be a want to be engineer type. 
It’s a pleasure.
Good atitude!  Enjoy what you have, after all, it is the pleasure of listening that counts! 
Macbook Air to dac
NoYou need a short (1.5 meter) USB to the DAC for best sound quality.Get a DAC with Balanced (XLR) output, and run a long XLR cable to your system.Long RCA cables=poor sound quality IMO.Does the Rouge have balanced input? 
Analog or Digital and why?
Analog for recordings made before 1981, digital for after. 
Do Tonearms need servicing
If the arm works to your satisfaction you do not need service on the arm. 
Does the first reflection point actually matter??
IF you own box speakers yes.If you own panel speakers no.