Mono vs Stereo LP's

I recently purchased a 1958 mono issue of Art Farmer's "Farmer's Market" on the New Jazz purple label (New Jazz was a Prestige specialty label) The record looks to be in near mint condition and was carefully cleaned by me with a record vac. The recording, however, plays with a constant background noise or hiss. The dealer who sold me the record has a reputable history and is telling me the noise is because I need to play the record with a mono cartridge rather than my stereo Shelter 501. I have read the threads on Audiogon regarding mono cartridges which say they can sound better, but don't suggest there would be the type on noise I am hearing with stereo. I have many other mono records of similar vintage and have never encountered this before. Anyone have a similar experience to this?
Here is a thread that might help to answer your question:
Stereo cartridge w/mono records?
In addition to the excellent discussion thread referral by Cincy bob, I have found that using Audio Intelligent Vinyl Solutions two step process may be an answer for your particular record. Excellent for mono, or stereo records, in comparison to other cleaning products used with record cleaning machines.
Thanks to both of you for the info. As it happens, I do use Audio Intelligent Vinyl Solutions which I would agree is an excellent cleaner ... the best I have ever tried. I cleaned this record before playing and then again after noticing the noise with no significant difference which suggests it is not dirt. The record was also cleaned on a record machine by the dealer who sold it to me and appears in very good condition with good luster and no scratches.
Perhaps it's the recording.
Lots of old recordings had hiss (from tube electronics and pre Dolby/DBX tape recorders). To overcome this most preamps had noise filters, to roll off response as low as 6000 Hz. The best noise filters were "dynamic" (they cut in and out according to whether the music was loud or soft) and the very best dynamic noise filter was a thing called "Autocorrelator" invented by Bob Carver.

Why don't you just sit back and enjoy that authentic 1950s sound?
I have the same record and the same "problem", though I don't consider it that problematic. Your dealer is correct, the hiss will be probably be markedly reduced through use of a mono setup. I agree with Eldartford, though, there are a lot of records of that vintage with hiss and they are still enjoyable. I think the key word in your post is "constant" hiss. No record cleaner will remove that, it is part of the recording.
Ooops, I was under the impression that the LP I have was issued in 1956, so maybe we have different pressings. Anyway, it has the same hiss. Does your pressing have the release issue NJLP 8203 (which I am assuming) or PR 24032?

I THINK that this title was released in the OJC series. Wonder how it sounds. I ask because I have a Horace Silver LP which has similar, very mild hiss on the original recording but it is gone on the OJC re-release, though the re-release is far less "earthy" and less enjoyable.
4yanx..."No record cleaner will remove that, it is part of the recording".

Have you heard the "record cleaning" that can be done by digitizing the signal and processing it with a computer? Absolutely amazing. I am talking about recordings made almost 100 years ago, barely audible in original form, but where the cleaned up version sounds almost acceptable today.
Well, if you're going to argue semantics! :-) ha!
I tried a little experiment this evening based on suggestions here and the Asylum. I got two Y connectors at Radio Shack with reversed male and female RCA connectors and used them to blend down the stereo outputs to mono and then in to the phono pre ins. This produced a clear 50+% reduction in the noise. I had read that the noise is out of phase between the channels and some will cancel out. The level is now quite low and easily makes the record quite enjoyable. I think, however, that a good mono cartridge may be in my future.
BTW 4yanx, the record is the plrp 8203 purple label (also identified as New Jazz. This is listed as 1958 issue, the same year as the more coveted (but more expensive) Yellow Label. Goldmine shows a number of NJLP 8203 for these but my record has prlp 8203 on the label. The Prestige 24032 was supposedly released in the 70's.
Glad you got some resolution, there, J.
Fair enough on the pressings. Mine is a yellow and was originally my father's who bought it new. Farmer was born in Iowa as was my dad and I. They shared some mutual friends, and Farmer was one of his favorites. He swears the LP came out in 1956, and it won't be me that argues the point with him! Ha!
Glad for you if you have that recording 4yanks! According to Allmusic Jazz, Farmers Market was a compilation of sessions that Art made in the mid 50's which explains the date ambiguity. Love that Art Farmer!! I also recently picked up a 10" original issue of prlp 209 "Art Farmer Quintet" with Gigi Gryce from 1955. Interestingly this mono recording is quite quiet (except for a little scratch on side 2) with my stereo cart and benefits only slightly from the mono mixing described
That stuff with Gigi is good stuff, man. Wish I could find more of that stuff (along with a few thousand others). As I have chronicled before, my dad lost what was then a small, and what is now a princely fortune when our house burned in the late 60's along with nearly all of his 1,000-odd Jazz LP's - and I'm talking those that everyone (mostly the rich) clamors for now. The Farmer is one of a scant few saved and I would not sell it for any price. I have spent the better part of the past 5 years finding some of them and, when he visits, playing them for him like he's never heard them before. He's cried in the process and that's something for an old B-25 pilot who's seen it all.
1000 melted classic jazz albums! That was a sad day indeed!