33rpm vs 45rpm - which is better

Yes. Absolutely. The answer to this and every other single question is…….

Streaming!       LOL 

@holmz

Maybe get them both and put the less liked one onto Disc cogs?

Wow, that didn't occur to me.  Guess I'll do that - $26 + $30 ain't much nowadays.  Thanks.

@lalitk

You didn’t say anything about your analog setup, does your system allows you to discern differences between 33 1/2 and 45 RPM vinyls? 

It should be - still assembling.  VPI Avenger>Etna/VDH Grand Cru/VHD Grail SB/Constellation Inspiration Pre+StereoAmp>Vimberg Mino D (just purchased AXPONA demo). Waiting for my 3 tonearms delivery (4point,Schroeder CB-L,Schlick) and about to purchase Siltech interconnects.

I usually assume that 2x45rpm is always superior to 1x33-1/3, but the single 1x45 had me perplexed.

Wow, that didn't occur to me.  Guess I'll do that - $26 + $30 ain't much nowadays.  Thanks

@kennyc - save the packing… You’ll need the packing to ship it.
(And we can work out a price off-line.)

in my experience, 45 sounds "airier" [cleaner extended trebles, greater sense of EASE from bottom to top esp. towards the inner grooves] than 33 but that it also has a slightly higher volume of surface noise, what noise there is in higher in pitch and more audible to me, the effect is similar to being outside in the wind and you hear the wind pick up. 

NOT a crap shoot.

Correctly engineered the 45 will always sound better because the higher speed enables more faithful recording of the music.  Compare with reel to reel tape - 7.5ips is better than 3.75 and professional studios often used 15ips.  Some of those recordings remain the best masters we have.

Consider - an LP should not contain more than around 20 mins music per side.  More than that requires compression of the grooves which reduces dynamic range (but look at the brilliant job Decca did on the Stones' 'Aftermath' that runs 52+ minutes) .  Do the maths - cutting less than about 9 minutes on a 45 side allows the engineer to cut at a higher level without crashing the grooves.  But if you try to cram more than that, then the advantage is gradually lost..

I bought a lot of used 45s in the 80s and 90s, mainly 70s and early 80s rock.  As others have posted, many of these are the best sounding vinyl I have.  A particular favorite is Frank Zappa's Stairway to Heaven b/w Ravel's Bolero - both outtrageous over-worked parodies of the originals.  I also have singles by most of the 80s big names.

@emrofsemanon    If some of your 45s are noisier, it is because they are dirtier, or perhaps they were played a lot or mishandled by a DJ in the day.