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Review: Shelter 501 II mono moving coil cartridge

Larry Deniston | Published on 12/1/2016

This effort, and it was more of an effort than I believed it would be, began after reading some reviews of mono cartridges and stereo magazine contributors having opined on the benefits of playing mono records with mono cartridge. So, I thought I’d like to check this out as I have some nice mono albums and assumed it would be a relatively easy comparison to make: purchase a mono cartridge and a second arm tube for my VPI Prime to simplify cartridge swapping and have a listen.

After some research of reviews on mono cartridges and searching Audiogon and eBay, I purchased a nice, used Shelter 501 II mono for a reasonable price. I also purchased an extra 10″ arm tube (metal, not the 3D printed type) for the VPI Prime. The Shelter cartridge is a true mono configuration with four pins to connect to the tone arm wires.  After mounting and getting the Shelter set up on the tone arm I ran into an issue before even being able to truly listen to any music – hum, and not by any means a minor amount of hum. The hum was loud enough to be clearly heard during music playback and that wasn’t going to be acceptable.

At this point I was not a happy camper, at first thinking there was an issue with either the cartridge or the arm. I was able to rule out any issues with the arm by mounting a stereo cartridge on the arm and finding no hum with that combination. After trying the suggestions from the person that I bought the Shelter and doing some internet searches I found that hum with mono cartridges is not an uncommon problem. Assuming it was a ground loop problem I tried lifting the ground between the turntable and phono stage, grounds on various power cords, lifting the ground on one of the phono interconnects, and tying the two ground legs from the cartridge together all to no avail. A friend and fellow audiophile pointed to some articles online referring to the use of two sets of “Y” cables which sum the channels and then send the summed signals to the left and right channels of the preamp. I bought and installed some inexpensive Y cables and this reduced the hum to a level where it was only audible when music was not playing. Not optimal by any means, but this configuration at least allowed me to listen to some of my mono recordings. One additional fix I tried was putting in a different phono stage; I replaced my reference Aesthetix Rhea with a Transcendent phono stage and there was no hum, albeit a reduction in sound quality.  A call to Aesthetix is in my future to try to find out if there is a way to further reduce the hum in the Rhea.

Comparison of cables with the Ortofon yielded more of an organic and cohesive sound with the “Y” cable set up, but did not provide the same clarity and resolution as my current reference interconnect cables (Synergistic Research Element Tungsten) between the phono stage and the preamp. For cartridge comparison going forward I elected to use the “Y” cable set up, thus removing a variable in the equation. I’m planning on making my own “Y” connectors with some interconnects I have that are not being used.

My thoughts on the comparison between my stereo cartridge (Ortofon A90) and the Shelter 501 II are below, but there are a number of variables including arm tube material, output and price point that make a strict comparison not valid, but the intent was to compare and contrast a stereo vs. a mono cartridge playing mono records, i.e. is there anything to all the fuss about mono records with mono cartridges?

Mono Music used as a reference:

John Coltrane Blue Train Blue Note Mono 33 rpm re-issue by Music Matters MMBLP-1577

Original issues:
Howard Rumsey’s Lighthouse All-Stars Vol. 6 – 1955 mono recording. The album was recorded at the Lighthouse jazz club on the pier in Redondo Beach, California.
Bob Brookmeyer And Friends, Stan Getz, Herbie Hancock, Ron Carter, Gary Burton and Elvin Jones. Columbia Records CL 2237 recorded in 1964.
Ortofon observations: Circle of sound mostly within and between the speakers. On the Coltrane album the sax was clear and central, nice cymbals and bass.  The drums and piano appeared to be recessed, but fairly well defined. The Rumsey album had a more open sound with the music extending slightly beyond the speakers with the drums and piano being better defined. The bass is somewhat muddy, but the instruments seem to be interspersed on top of each other.
Shelter observations: With both the Coltrane and Rumsey albums I heard very good tonal make-up of the mid-range, nice highs, and good attack with the drums and piano. The bass has good weight and presence to it, but not quite as well defined as the Ortofon. The Brookmeyer album sounded great with both cartridges, but shined with the Shelter cartridge. You can hear the saxophonist’s (Stan Getz) breathing and the pad strike as the sax is being played – awesome! Additionally, it appeared that the Shelter was able to put a little more space between the instruments. Overall the there is an organic, natural tone to the Shelter cartridge that is engaging and draws you into the music.

While I still have some work to do to get the best out of the Shelter through the Aesthetix phono stage, I’m enjoying this new facet of my system and the music produced from the mono recordings. So much so that I just ordered John Coltrane The Atlantic Years in Mono box set and I think Santa may be bringing me a Beatles mono box set.

Cartridges being compared:
Ortofon A-90 specs:
Output voltage: 0.270 mV
Channel separation: >22dB
Frequency range: 10Hz to 80kHz
Stylus type: 5/100 special polished nude Ortofon replicant
Cantilever: boron
Tracking force range: 2.3g (2.0 to 2.5g)
Recommended load impedance: >10 ohms
Weight: 8g
Shelter’s specs:
Output: 0.4mV
Stylus profile: 0.65 Mil Conical
Weight: 8.1 grams
Recommended Tracking: 1.4-1.8 grams
Recommended Loading: 47k
Frequency Response: 20Hz-20kHz, +/-2dB
Separation: 25dB at 1kHz

VPI Prime turntable, Aesthetix Rhea phono stage, PS Audio BHK Signature Preamp, Conrad Johnson MV60se power amp and Wilson Duette speakers. Interconnects, speaker cables and power cords are primarily synergistic research. Power conditioning with Synergistic Research Power Cell 10 III and a PS Audio Power Plant Premier.