Mono recordings - two questions...

If we're talking great mono, I also recommend any of the LPs sold via "Sam's Club", which is based in France.  I forget the name on the label of the production company.  All the Chet Baker recordings are to die for, in mono.  (Recorded during Baker's sojourn in Paris, I think.) They've produced maybe 8 or 10 LPs thus far, no losers among them.
Also, the original "Ella and Louis" recordings are sublime.

Back to mono baby !

Well recorded and well reproduced vintage mono recordings sound wonderful.  Many are surprised at the sense of depth and realism possible with a mono LP.   You can hear layering among instruments, space around musicians, and studio ambiance.  While everything happens in the middle, you can hear so much depth that it sounds like the back of the recording reaches all the way to the horizon.

I am a proponent of using true mono cartridges to play pre 1960 mono LPs. There are very few true mono cartridges sold today.  Most described as mono are in fact stereo cartridges modified to output a mono signal. The modifications can be as simple as internal summing of connections, or as complex as reorienting the pair of existing stereo coils.  With either (or both) the cartridge still responds to and generates a signal from vertical content which can potentially affect what is heard by the listener.  A true mono cartridge only responds to horizontal content.

Cost can be less than $100 to several $1000 for a true mono cartridge.  At the low end, many are happy with the venerable GE VRII for which new styli are available.   The Denon 102 is available for less than $300.  Ortofon CG25DI MKII lists for about $900 but is available for much less.  

If your intent is to play pre 1960 LPs, then the investment in a true mono cartridge may be justified (but only you can make that decision).

If you expect to play mono LPs from the mid 60's forward, and current mono reissues, then a new mono (modified stereo) cartridge would be fine.

 The modifications can be as simple as internal summing of connections, or as complex as reorienting the pair of existing stereo coils.  With either (or both) the cartridge still responds to and generates a signal from vertical content which can potentially affect what is heard by the listener.

as for current mono options, I agree that the summing will pick up and attempt to offset any vertical content but if the coils are oriented so they are in the lateral and vertical plane and only the lateral ones are used then I do not see any pickup of the vertical info.  The one big difference found in "vintage" mono pickups is there is little vertical compliance which is the origin of the rumors that playing a stereo record with a mono cartridge will surely destroy it.  I am not aware of any recent manufacture cartridges that fall into the "lateral compliance only" category.

dave

... from an audiophile perspective, how does one listen to mono recordings? For example, does ’imaging/soundstage depth’ matter and is it accomplished through a well-mic’d mono recording? Obviously tonal balance, impact, resolution are all qualities that should shine through...

Basically, you listen to mono recordings as you would stereo recordings--for the music. Most of the the traits you mention--soundstage depth, tonal balance, impact, and resolution--are strengths in mono recordings. If, however, you derive much of your listening pleasure from 3D imaging of each voice and instrument, you won’t find that on mono recordings.

But mono recordings have strengths that stereo recordings don’t. Generally they have a richer tonal balance, stunningly real-sounding midrange, and perhaps the biggest surprise, a deep soundstage, particularly on sacred vocals recorded in a cathedral or instrumentals in an auditorium.

Would appreciate recommendations of well recorded MONO LP’s -- recently bought a Julie London LP in mono it sounded surprisingly nice/natural... not so hot as many later stereo pop recordings... my musical preference would be for vocals in pop, jazz and soul/r & b realms..

If you think about it, many recordings from the mono era (1949 to mid 1960-is) feature vocals with instrumental accompaniment. This was the heyday of Sinatra, Bennett, Crosby, Ella Fitzgerald, Sarah Vaughan, and Nat King Cole. I have a mix of mono recordings--originals from the ’50s and ’60s rescued from thrift shops, and high quality mono reissues such as the wonderful EMI/Parlophone Beatles mono reissues of Sept. 2014, plus several Beach Boys releases by Capitol, as well as a 45 rpm 3 LP set by Acoustic Sounds of Nat King Cole. Nothing puts Nat in my living room like that one.

If you are into hunting down vintage mono releases, you are in for a treat if you get a mono cartridge to go with it. Apparently most of the surface noise of an LP occurs in the vertical axis. I have several genuine mono albums from the ’50s and ’60s (some all the way out to 1969) that are unlistenably noisy with a stereo cartridge which are dead quiet with a mono cartridge.

After a year of listening to my 2014 Beatles mono reissues, I decided to get a mono cartridge. I chose the Audio Technica AT-MONO3/LP, available from US authorized dealer LPGear.com for $189.99. It’s a high output moving coil cartridge with a conical stylus, which seems--to me--most appropriate for original mono recordings from the ’50s and ’60s. I opted to get mine from a Japanese storefront on eBay for $112 and change, but currently they’re around $117. Search Amazon for Audio Technica AT-MONO3/LP and you'll get several returns in that price range.