Mono Vinyl Playback on a Modern Stereo Audio System

February 17, 2017 /
Since its introduction in the 1950s, the stereo audio format has become an inseparable part of listening to recorded music. This two-channel standard has been implemented on such a universal scale, the terms “stereo” and “audio system” are virtually interchangeable today in everyday language. The original theory of sound recording was a little different though. Mono, short for monaural, is the single-channel format fundamentally connected to the invention of recorded sound. Mono enjoyed an unchallenged half-century reign in the music industry until stereo came along to dominate and drive the senior format to the point of commercial extinction.

For someone who grew up in the stereo age, mono recordings can sound primitive and cramped when compared to the wider, more spacious aspects of stereo sound, and this heightened sense of realism is what ultimately won over the music-buying public back in the 1960s. But not only are some of history’s greatest music performances only available to us as mono recordings today, time has proven that the antiquated format possesses an allure that continues to charm music lovers of all ages. When done right, mono recordings demonstrate a great sense of cohesion and power, and the best of them also do an ample job of establishing a sense of depth and space. Though creating a mono recording that checks all of these boxes is no small technological feat, the great audio engineers of yesteryear have managed to hand down to us a treasure trove of work in mono that is both breathtaking and timeless.

If you’re a vintage jazz record collector, you’re probably aware of the fact that all mono LPs are compatible with today’s stereo audio equipment. While this is true, playing a mono record on a stereo audio system without making the proper adjustments leaves room for improvement. This article is designed to help you get the most out of playing your mono LPs in a modern stereo world.

What Exactly Is a Mono Record?

The answer to this question is potentially quite complicated. The difference between mono recordings and mono masterings of recordings needs clarifying, as does the difference between mono records cut before and after the death of the mono format in the late 1960s. For the purpose of this article though we can settle for a simpler definition of a mono record being a record that is intended to produce the same exact audio signal (noise aside) in both the left and right channels of a stereo audio chain. True, without any fuss a listener will hear roughly the same thing coming from both speakers when they play a clean mono record on a stereo audio system, but our goal is to hear the exact same thing from both speakers and in the process lower distortion and improve the signal-to-noise ratio of the overall listening experience.

Knowing If a Record Is Mono

Before we get started, let’s be sure that our records are even mono in the first place (by all means, if this is a no-brainer for you, feel free to skip this section). The easiest way to tell if a record is mono is if there is some indicator on either the front or back of the album jacket. In some instances, the absence of the word “stereo” will point to a mono record. (For example, any vintage Blue Note pressing not brandishing the word “STEREO” on the record labels is mono.) The next easiest way to tell is simply by listening, and the best way to achieve this goal is with headphones. If all the music is more or less in the “center” of the stereo field while surface noise is clearly audible on the far left and far right of that spread, your record is mono. Note that the loudest parts of a worn mono record may distort “in stereo” so you need to focus on the quieter parts of the music. Finally, to state the obvious, if there are instruments or sounds distinctly positioned to either the left or right side of the stereo spread, your record is stereo.

What’s Wrong with Listening to a Mono Record in Stereo?

If you’ve been listening to mono records in stereo your whole life, there are two significant ways in which your listening experience can be improved. First, surface noise can be reduced and made less noticeable. Many marks on the surface of a vinyl record manifest as out-of-phase noise on the far left and right of the stereo field. When listening to a mono record on a stereo audio system, these pops and ticks are heard in a very different position than the actual music, which lies directly in the center of the stereo field. By listening in mono though, not only does the out-of-phase nature of this noise lead to its reduction in relation to the volume level of the music, much of whatever surface noise remains will be masked by the music in the center of the would-be stereo field.

Presented here are two audio clips. The first is of a mono record being played in stereo, the second being the same record played in mono. In the second clip, notice how the surface noise has collapsed to the center of the “stereo field” and is more difficult to discern once the music kicks in:

Horace Silver, “Finger Poppin'” (Original 1959 mono pressing of Finger Poppin’ with the Horace Silver Quintet)

Stereo Playback:

Mono Playback:

Second and similar to surface noise, groove wear on vintage mono records also often manifests as out-of-phase (stereo) noise. This distortion can also be reduced by listening in mono, and the fuzzy, smeared sound that would be heard listening in stereo becomes a tighter, more focused central image. The following audio clips emphasize this type of improvement:

Lou Donaldson, “Avalon” (Original 1962 mono pressing of Gravy Train)

Stereo Playback:

Mono Playback:

For a visual account of these improvements, the following two diagrams illustrate how listening to mono records in mono can provide an improved listening experience (the circles represent music and the curved lines represent surface noise):

Stereo playback of a mono vinyl LP

Mono playback of a mono vinyl LP

It should be noted that when compared to various digital formats, it can take more effort to get vinyl sounding great, and playback of mono recordings is one scenario where this is true. In the digital domain, both the left and right channels of a mono digital file are (in theory) perfect copies of each other, and our goal of hearing the exact same thing in both channels is instantly realized. Record collectors have a little more work to do, but the experience of hearing quality mono vinyl playback will certainly make the vinyl enthusiast’s efforts worthwhile.

The Solutions

Now that we’ve identified the ways in which playback of your mono LPs can be improved, how do we achieve this? Everyone has different equipment situations so there is no one-size-fits-all solution, but surely there is a sensible option for everyone.

If you have a tonearm with a removable headshell, the most obvious hassle-free solution is to acquire a mono cartridge. Luckily, getting a mono cartridge doesn’t mean you need to hunt down and restore a vintage one. Cartridge manufacturers like Ortofon, Grado, Lyra, Miyajima, and Dynavector all currently provide quality mono cartridge solutions for a modern stereo audio system.*

Ortofon Quintet Mono cartridge

While a mono cartridge will produce identical signals in both channels of a stereo system (a duplicated “mono signal”, if you will), simply summing the left and right channels in a stereo audio chain can actually produce comparable results (for more information, see the appendix at the end of this article). One easy way to do this is with an amplifier with a mono button. Another summing option is using a “double Y-cable” configuration, which involves placing a pair of RCA adapters in the signal chain. (The method is outlined here in this Steve Hoffman Music Forum thread by the host himself, and advice on where to place the adapters in the signal chain can be found here.)

Will either using a mono cartridge or summing provide more favorable results? Though the answer to this question certainly depends on which cartridges you are using, here we offer up one of these comparisons. The first is the result of playing a vintage mono record with a Grado MC+ mono cartridge and the second is a clip of the same record being played with a Shure M44-7 stereo cartridge and the mono button engaged on an integrated amplifier:

Johnny Coles, “Jano” (Original 1964 mono pressing of Little Johnny C.)

Grado MC+ Mono Cartridge:

Shure M44-7 Stereo Cartridge with Channels Summed:

A final, less popular option is to use a “left channel only” or “right channel only” setting on an amplifier. Unlike a mono setting that sums the channels, these settings will duplicate one of the two stereo channels in both signal paths. While this method typically fails to improve the signal-to-noise ratio of the signal, it is preferable in some rare instances. For example, if a record was played many times on a turntable with severe anti-skate problems, one groove wall may be in much better shape than the other, and listening to one channel or the other may prove more desirable than summing.

McIntosh MA6200 integrated amplifier with mono, L-to-L&R, and R-to-L&R settings

Vintage vs. Modern Mono Records & Stylus Size: Is Bigger Always Better?

The only other variable that modern mono lovers need to consider is stylus size. Today’s stereo (and mono) LPs are cut with a groove width optimized for playback with a modern stylus tip measuring approximately 0.7 mils at its longest radius (1 mil equals 0.001 inches; in the metric system, 0.7 mils is equivalent to 18 microns, where 1 micron equals 0.001 millimeters). However, vintage mono LPs dating back to the 1950s were actually cut with the intention of being played back with a larger 1-mil (25-micron) stylus. What this means is that while a more modern 0.7-mil stylus will be compatible with all mono records, only the oldest mono LPs were cut with the intention of being played with a 1-mil stylus.

Generally speaking, all mono LPs manufactured in the 1950s can be played with either a 1-mil or a 0.7-mil stylus, and all mono LPs manufactured after around 1970 should only be played with a more modern 0.7-mil stylus.** As for the 1960s, there is unfortunately a great deal of uncertainty as to when each record label would have made the change from the wider to the narrower groove spec. I don’t see any reason why mastering engineers would have started cutting mono records with a narrower cutting head in the ’60s as long as the mono format was still a viable product, but beyond using a special microscope likened to that of a mastering engineer’s, you might want to play it safe with a 0.7-mil stylus for records pressed in the ’60s, and unless stated otherwise by the manufacturer most modern styli fall into the 0.7-mil category, the styli on modern mono cartridges included. (Ed. Note: Special thanks to Deep Groove Mono visitor rl1856 for advancing and improving this section of the article.)

Ortofon OM cartridge fitted with a D25M 1-mil stylus

Once more, we have two audio clips to offer up for comparison. The first is a vintage mono LP played back with an Ortofon OM cartridge sporting a D25M 1-mil conical stylus (still in production), and the second clip is the same record being played with a Shure M44-G cartridge with a 0.7-mil conical stylus (both cartridges are stereo, channels summed for both clips):

Donald Byrd, “Lover, Come Back to Me” (Original 1959 mono pressing of Off to the Races)

Ortofon OM Cartridge with D25M 1-Mil Stylus tracking at 3 grams:

Shure M44-G Cartridge with 0.7-mil Stylus tracking at 1.5 grams:

Note that stylus size in and of itself has no bearing on whether a record will play mono or stereo; the inner workings of the cartridge are what ultimately determine this.


Despite stereo’s current reign as the industry’s standard format, mono sound has certain qualities that distinguish it from stereo and make it special. When done right, mono can be a highly enjoyable listening experience. Mono recordings have a simplicity that give them character. Their “punch” is intrinsically tied to the limitations of the format, and the same can be said of the way the elements of a mono mix meld together into one cohesive whole. My hope is that this article has explained how to get the most out of your mono records and has also provided you with a practical, affordable solution in your quest to obtain the finest mono vinyl playback possible.

* Advanced collectors will appreciate a note regarding the difference between single-coil and dual-coil mono cartridge design. In theory, a single-coil mono cartridge design will provide an even higher signal-to-noise ratio than a dual-coil design, though it should be noted that implementing a single-coil cartridge (vintage or modern) may require collectors to make costly modifications to their current equipment. Additionally, mono carts with no vertical compliance like Ortofon’s SPU Mono CG 25 Di MKII may also produce superior results, but note that stereo records should never be played with a cartridge with no vertical compliance. (Special thanks again to visitor rl1856 for this additional information.)

** There are a handful of exceptions to this rule, three of which I know are the Classic Records mono Blue Note reissues, the more recent Beatles mono reissues, and albums reissued by The Electric Recording Company label. These LPs are cut with wider grooves to duplicate original pressings to an exacting degree and thus can be played with a 1-mil stylus without compromise.


“Stereo information” in a stereo record is information that is not equally present in the left and right channels of a stereo signal, and it is determined by the unique vertical modulations cut into each groove wall. “Mono (centered) information” is equally present in both channels and is determined by horizontal modulations in the groove only. Since surface marks on a record generate both horizontal and vertical motions of a stylus, playing a mono record with a stereo cartridge will not only reproduce noise related to the vertical motions of the stylus, that noise will usually be more noticeable because it will be in a very different position than the music in the stereo field. Using a modern mono cartridge will certainly cure this ailment, but summing a stereo signal from a stereo cartridge will produce noticeable improvements as well. The reason for this is because much vertical noise in a record’s groove is “out-of-phase”, meaning that the voltages produced by the cartridge’s left and right channels are to some extent polar opposites of each other, so when they are summed together, not only is the volume of this (stereo) noise reduced, the relative volume of the mono information i.e. the music is slightly boosted as well.

To illustrate this, the screenshots below show various waveforms in a digital audio workstation. The first shows the left and right channels of a mono record being played in stereo, while the second shows the same record played with the left and right channels summed using the mono button on an amplifier (both clips use the same stereo cartridge):

Lead-in groove of a mono record being played in stereo

Lead-in groove of the same mono record being played with channels summed to mono

Additional Resources:

(1) “Ortofon True Mono Cartridges”: Fantastic article on the Ortofon website discussing the history of monophonic playback

(2) “RCA Victor Announces Living Stereo”: 1958 short film explaining the science of stereo records (YouTube link)

(3) Stereo Cutting Head GIFs: Awesome GIFs explaining the science of stereo cutting heads, courtesy of

  • DaveS

    Great stuff as always. Giving me something to think about changing up, that’s for sure.

  • bopmodalfree

    Hi Rich,

    Thank you for posting this very informative piece. I’ve been up against this issue for a few years now. For reasons I won’t go into I ended up with a phono stage that doesn’t have a mono button. I have a removable headshell on my Technics TT so I have an Ortofon 2M mono cartridge that I can switch in. It’s a bit of a hassle (not to mention the cost) to do this, but I think I would be equally bothered by constantly detaching and attaching the Y cabling you describe, and I would be quite irritated if the connections eventually wore out. I would also fear that this would degrade the sound quality with two extra connections introduced, but I must admit that I couldn’t detect a meaningful difference between your mono cart/Y cabling clips. I’m constantly switching between stereo and mono and would be interested in your thoughts regarding the practicality of the various types of switching.

    A second question I have is if you think more of a difference between Y-cabling and mono cart would be perceived with records that have a greater degree of wear, especially groove wear. I’d like to think that the mono cart might have an advantage but this is mostly wishful thinking on my part.


    • Hi Drew,

      I was hoping someone would comment on the audio clips–to my ears, the mono cart and summing clips sound very similar, as do the .7-mil and 1-mil styli clips. I suppose it’s true that a mono button offers even more convenience than switching cartridges; certainly, the Y-cable is the most inconvenient option. (Note that my “summed” clips are done with a mono button, not a Y-cable.) It sounds like you’d prefer the added convenience of a mono button/switch but don’t see yourself buying a new preamp/amplifier. The only other option I can think of is something like what London Jazz Collector uses, it’s a custom-built in-line mono-stereo switch box. You should contact him to find out more about that. 🙂

      I’ve done the above comparisons with more heavily worn records and couldn’t hear much of a difference in those cases either. In fact, I did this whole study back when I first started collecting when I was buying a lot of worn records. The hope was that either a mono cart or a 1-mil stylus would do a better job than summing but unfortunately I didn’t find that to be the case.

      • bopmodalfree

        I think I did forget that you use a mono button. Thanks for the xtra info on worn records…I think this will be really useful for newcomers to vinyl who want to play both mono and stereo. I’ll have to continue to switch mono and stereo cartridges, which doesn’t bother me too much because I really love my mono-buttonless phono stage. One other thing I forgot to mention was that when I began spinning vinyl (again) a few years ago, I favored stereo, but now that I have better sound quality overall, I’m really beginning to enjoy the natural beauty of mono.

  • Alvaro Pinto

    I will begin by thank you for this great article. I also include in my jazz collection both mono and stereo albums. My general tendency is to follow the technical ‘advances’ and thus if a recording was originally 2 track I don’t even bother to look for the mono release. Of course the opposite also applies. This being said I have a couple of cartridges (mono and stereo) that I switch whenever is appropriate as at the same time I select the mono/stereo button on my amplifier and it seems to work fine for me. I realised that for my old mono records, specially the 10inch ones, the use of my ortofon 25M cartridge reduces wear noise significantly. My only doubt here is (as I own a great deal of Japanese mono pressings), should I avoid my mono cartridge on this ones since they were pressed in the 70ies. All the best!

    • Hi Alvaro,

      Interesting that you notice a difference with a 25-mil stylus on older ten-inch records. Are these records at all worn or are they in pretty good shape?

      Question: Does your mono cartridge have a 25-mil stylus? I’m a little confused because the Ortofon D25M stylus is actually made for use with stereo OM cartridges. In any case, I’m pretty sure that you should not be playing your Japanese reissues with a wider 25-mil stylus since they were made in the ’70s or later.

      • Alvaro Pinto

        I’m sorry but it seems that I wasn’t clear enough once more (sometimes it’s hard with my English). I don’t have a mono cartridge I just switch from the “regular” one to the 25M cartridge every time I put on a microgroove mono record. I don’t know exactly why but it must be because of the wider size of the stylus getting in touch with a less worn part of the groove, I don’t know. I have this really old and worn Chet Baker record with so many scratches and scuffs that I thought it would be forever unplayable and suddenly when I got the 25M and played the record it sounded much better.

  • rl1856

    Industry conversion to stereo from mono, also included conversion to a standard .7mil groove width. Meaning that mono records from the 60’s should be be played with a modern .7mil stylus profile. You *can* use an older 1mil stylus but it wont sound correct. Rule of thumb is after 1960, use a modern stylus profile.

    The mono vs. stereo cartridge debate is contentious. Some feel that a stereo cartridge can be used, and adapted for monophonic playback through use of an appropriate stylus or “mono” switch (or Y cable). A case can be made that the best reproduction of a pre 1960 mono pressing occurs when using a true monophonic cartridge. Most modern “mono” cartridges (like the Ortrofon pictured above) are actually stereo cartridges modified for a mono signal. Internal coils are shifted 45′ to reduce response from vertical signals, and the coil outputs are “summed” to cancel out any residual vertical content. However the cartridge coils are excited by the vertical signals (if they were not, then why sum to remove the content?), and the summing process introduces phase anomalies that can be audible. A true mono cartridge has a single coil, that is set up to respond to horizontal signal only. The stylus may have vertical compliance, but the coil response comes from lateral movement. Nothing to “sum” nothing to “cancel out”. The resulting sound is considered to be bigger, bolder and more direct than the sound from an adapted stereo cartridge. And surface noise is reduced even more than what is achieved with an adapted stereo cartridge. It is easier to adapt an existing design than it is to create a sub model that will have limited appeal, thus the few ‘true mono” cartridges available tend to be highly priced. Many collectors seek out vintage mono cartridges, and have them restored. Fairchild 225a, ESL Concert and C60, Elac, Decca London are a few examples that have great reputations among collectors. Ortofon actually makes a “true mono” cartridge the CG25di MKII; which is an updated version of their original mono moving coil cartridge from the early 50’s. This model is separate and distinct from the “SPU-Mono” which is the normal SPU cartridge adapted for mono. Something to think about.

    • I stand by my comment about it being okay to play mono records prior to the late ’60s with a 1-mil stylus. The Ortofon article I link to above explains that The Beatles’ original mono LPs were cut with wider groove widths for 1-mil styli. That would include Pepper in ’67 so I’m willing to say that all Platylite-era Blue Notes can be played with a 1-mil stylus. This would also make sense in light of Capitol not releasing a Beatles album (in the US) in stereo only until 1968 (The White Album). This seems to mark a pivotal moment the industry’s acceptance of the victory of the stereo format. Only then do I see mastering houses giving up on 1-mil mono cutting heads. You know what though? It would be interesting to take a mono Blue Note from around 1965 and take a look at the groove width under a mastering engineer’s microscope. I’ll be Kevin Gray would be willing to do just that.

      I chose to avoid the gross intricacies and technicalities behind what constitutes a “true” mono cartridge here in part for the sake of brevity but more importantly because I don’t find it to be very relevant or useful when it comes to the average person playing mono records on a modern stereo system, which is in all likelihood someone who will not be motivated to go through the process of restoring vintage mono cart and making the appropriate modifications to one’s stereo system to do so. Depending on one’s definition of a “true” mono cartridge, modern mono carts are or are not “true” mono cartridges. If a cart needs to have a single coil to be a “true” mono cart, yes, modern mono carts are not “true” mono carts. But in my opinion, that seems largely irrelevant here. Yes, most modern mono carts have two coils but manufacturers still (rightfully, I believe) refer to them as “true” mono carts because of the realignment of the coils (magnets in the case of a moving coil design?). To be clear, the coils (magnets) in modern mono carts are re-aligned to be perpendicular to the record surface in the exact same way as a vintage single-coil mono cart. You seem to be under the impression that they are at 45-degree angles. I am certain that is not true in the case of Grado and Ortofon, and I have evidence by way of email exchanges with those companies.

      You’re going to need to provide evidence that the perpendicularly re-aligned coils of a modern mono cart react to vertical modulations of a stylus more so than the single coil on a vintage mono cart. If you want to create your own blog that provides side-by-side audio comparisons, by all means, I encourage you to do so and let me know when it’s available. Regarding your point about summing, my understanding is that the signal is not summed on these newer mono carts and that each coil’s signal is sent independently to each channel…I will need to double-check that but I recall this being info relayed from either Grado or Ortofon or both. I would also argue that the phase anomalies created by summing are purely noise and are reduced or nearly cancelled, meaning that no musical information will be unwantonly altered, cancelled, or reduced by summing.

      Thank you for providing your information on restored vintage mono carts. Are those carts compatible with modern stereo turntables/tonearms/headshells? I admittedly don’t know much about vintage mono carts, but in my defense this article is not about vintage all-mono, single-channel systems. I would agree that your comments are something to think about if you’re willing to go through the process of restoring a vintage cart and making it compatible with a stereo audio system. My assumption here was that the reader will be in a similar situation to someone such as myself and not be so ambitious as to undertake this task, and I tried to make that clear at the outset…perhaps the intro could use some rewriting and I could make that even clearer: vintage, single-coil cart restoration is off the table for this conversation. 🙂

      Finally, this article took numerous unpaid hours to research, write, and fine-tune before its release. Your comments seems to have no reverence for that so please just consider that in your future comments here, thank you.

      • rl1856

        Your site is obviously a labor of love and for someone your age, you have acquired a wonderful record collection.

        From 1960 (or so) to 1968 (last mono pressings sold) there was a lot of crossover as to what was 1mil and what was .7mil. Hard to really know unless one examined grooves with a microscope. Some labels changed immediately, some did not. Existing 1mil presses and stampers were used at first, then replaced with newer .7mil for standardization. I defer to Jonathan Carr, owner and designer for Lyra Cartridges regarding which size stylus to use:

        “I believe you must first consider which records you will be playing before buying a mono cartridge. From reading I’ve done, here are my conclusions. Note this applies only to 33 LPs, not 78s. Dates refer to master cutting, not performance date for reissues. This is a function of the groove shape created by the cutter head.

        Pre-stereo era monos (roughly ’48-’57), select a 1.0 mil conical stylus. Early stereo era monos (roughly ’58-’68), select a 0.7 mil conical stylus. Recent mono reissues (mid ’90s to present), select a mono cartridge with a modern narrow stylus profile.”

        I use 1960 as a cut off to make it easier for me.

        Regarding cartridge construction, a stereo cartridge is constructed with 2 coils set 90′ apart from each other, aligned so that each coil is 45′ either side of vertical…..visualize this as the upper half of an “X”. A mono adapted cartridge has coils that are rotated 45′ so that one coil is vertical, and once coil is horizontal. Thus one coil responds to the horizontal signal, and one coil responds to the vertical signal *with an attenuated response* The outputs are then connected with the vertical coil signal out of phase relative to the horizontal coil, so that the vertical signal is effectively canceled. However the signal was initially present, the stylus and coils were initially excited, and it is this aspect that leads to the phase anomalies that some listeners can hear. The Ortofon cartridge released in conjunction with the Beatles Mono Box and the Ortofon OM25, along with all Grado mono cartridges, and most mono cartridges available, are modified stereo cartridges. The Ortofon CG25di MKII, Denon DL102, several Miyabi, and several Lyra cartridges are single coil only. Professional listeners/reviewers such as Michael Fremer and Art Dudley (Stereophile) have reported that single coil cartridges sound better than adapted models. They note a significant reduction in audible surface noise- in some cases disappearing, with some of the noise remaining audible when using an adapted cartridge. Most listeners who have made the comparison agree with their assessments.

        You are correct that for the average listener with an average system, playing a mix of modern mono reissues, and vintage pressings, a modern mono cartridge may be the best compromise. However, your record collection, as featured in your blog, indicates the expenditure of considerable time (and probably expense). At some point, you would benefit from the investigation of a true mono cartridge. At best your vintage mono pressings will sound much better, at worse they will sound the same. I note you use a Technics SL1200, which has a detachable headshell. You can mount a mono cartridge on one shell, then install as needed. Some listeners like to find vintage mono cartridges and have them rebuilt. With patience this can be accomplished for less than the cost of new single coil mono cartridge. 2 of the most popular vintage cartridges are the Fairchild 225a, and ESL C60. Both can be purchased for less than $300 (with patience), and a rebuild would be another $300-$350. Total expense is cheap for some, expensive for others, but it is a viable alternative.

        • Hi again Ross,

          Well I went back to read a very informative thread I started in the Steve Hoffman Forum about 3 years ago (, and lo and behold, it appears that you were one of the most helpful commenters in that thread! I’m happy to hear back from you now and would like to make a couple remarks:

          1. I’m still going to bet on the theory that mono records cut through 1965 at least and probably as late as 1968 were cut to be played with a 1-mil (or 0.7-mil by default) stylus. So long as labels were releasing both mono and stereo versions of albums to the market–until the late ’60s–why would they change the width of the groove on the mono records so as to essentially make them incompatible with older mono cartridges, especially in light of the fact that one never sees warnings on older mono albums saying anything like, “Warning: This mono LP can only be played with a stereo cartridge and cannot be played with a mono cartridge”…right??

          2. When it gets down to the nitty gritty of the internal workings of cartridges, I must humbly plead the fifth. I’m a mathematically and scientifically-minded person with professional experience as an audio engineer and a hobbyist interest in electronics but I can’t really contest your comments about the inner workings of cartridges because I really don’t know ultimately. The thread I linked to above gets into the ugly details of the topic but at the end of it all I still can’t say I’m very clear on the coil stuff. Correct me if I’m wrong but I believe your general point to be that “single-coil” mono cartridges (modern or vintage) can at the very least in theory provided even more improvements than summing or “dual-coil” mono carts. That might be a worthy comparison to make some day but for now I’m contempt with the most obvious/economical choices currently on the market (ex. Ortofon moving magnet) and will keep the article the way it is for now.

          I am interested in reading what Fremer and Stereophile have to say about single-coil designs but I’m skeptical I would be able to hear what they’re hearing. I find myself more often than not at odds with audiophile opinions and what seems to be their “mysterious” abilities to hear differences I cannot, but nonetheless I’m open to giving anything a try within the substantial constraints of my budget.

          In times of doubt such as these, it’s reassuring to know that we can always fall back on what we hear and whether or not the theory matches up with the listening experience. The difficulty arises when we are put in a position to consider things we have never experienced. For me here, this means trying a single-coil design. I honestly can’t say I feel there’s anything “wrong” with what I’m currently hearing from my mono LPs but that doesn’t rule out the possibility that it could be even better. Again, time, money, effort and patience permitting, you may see me giving this single-coil thing a try but I’m not sure I’ll ever have the patience to pursue the restoration of a vintage mono cart and the potential setup changes that may come along with that.

          In conclusion, I think I have a much better sense of what the scope of my article is. It’s really for people using integrated amps and turntables with stock tonearms. The options you’re putting forth seem to all require either a moving-coil phono stage, a replacement tonearm or a combination of both.

          (PS: I would be shocked to learn that after all of your persuasion you don’t use a single-coil cart. 😉

          • rl1856

            Hello again. I own a Ortofon CG25DI MK2….a single coil mono cartridge. I use a separate TT (Technics SP15 / AT 1503 arm) with a detachable headshell. I can switch between cartridges in about a min. I also have a TT with a stereo MC cartridge. I realize my solution is not feasible for everyone. We moved into a new house last year. I personally moved all of my records and all of my equipment. The exercise forced me to consider the value of what I had accumulated. I realized that my collection was such that I could justify setting up a separate TT for mono use. In your case, you have already accumulated a nice collection. At some point you may ask if it is worth your time (and money) to try to retrieve the best sound possible from your vintage mono LPs. Only you can answer the question, but the justifiable case can be made if you are routinely spending upper 2 to 3 figures on vintage mono LPs, or have amassed a sizable collection. The cartridge I have is sometimes available as a used cartridge at a fraction of the MSRP, making it almost an economical option.

            A stereo MC cartridge has 2 coils, oriented in a X pattern, reflecting sensitivity to the 2 channels embedded in a stereo record groove. An adapted stereo cartridge has 2 coils, oriented in a + pattern to enhance sensitivity to horizontal groove content. The outputs of each coil are summed to cancel out any residual vertical content, to yield a mono signal. A single coil mono cartridge has a single coil, oriented for maximum sensitivity to horizontal content. Moving iron, or moving magnet cartridges operate according to the same principals. The main difference is the orientation of the moving parts.

            Steve Hoffman, who is a well known mastering and recording engineer, has reported encountering mono LPs pressed as early as 1961 using .7mil grooves, and as late as 1965 using 1mil grooves. There was a lot of crossover during the 60’s as parts/equipment etc were replaced. This time frame also encompassed an industry changeover from tube to transistor equipment, and the changes often encompassed the entire cutting chain from mastering boards, to recording preamps, to cutting amps, to cutting heads. I err on the conservative side by using 1960-61 as a demarcation line.

            Keep up the good work.

          • Okay, I think I understand more now. I was under the assumption that a MC cart had one coil and two magnets. Thank you also for your more detailed explanation of what’s happening when these companies realign the coils of a stereo cart to make the cart mono. In light of this it does makes sense that they would sum internally.

            Perhaps I would be able to hear a difference between single-coil and dual-coil mono carts. I would rather not be required to invest in either a new tonearm or an entirely new turntable-tonearm setup to do this, however.

            So your CG 25 is fitted with a 25-micron stylus, does that mean you only play vintage LPs manufactured prior to 1961 with that cart? If so, what do you play vintage mono LPs pressed in the ’60s with?

            Finally, if Hoffman claims he’s seen 18-micron mono LPs as early as 1961, I suppose I can’t doubt that. I have made the appropriate changes regarding both mono cartridges and stylus size above, thank you.

          • rl1856

            I use the CG 25 for pre 60-61 mono LPs. I use a .7mil cartridge for everything else, unless I can prove to my satisfaction that a 60’s mono pressing has a 1mil groove width. This is grey area that is slowly becoming of more interest to hobbyists. I liken it to the growing discussion regarding the correct EQ curve to use for pre 1958 recordings. Over time, more information is becoming available to help clarify the subject. Enjoy.

        • As a follow-up question, I continue to be perplexed by the “single coil-dual coil” comparison. The modern mono carts that tout single coils all seem to be moving coil carts. Aren’t those single coil by default, meaning are there any MC carts in existence that aren’t single coil, stereo or mono? Second question: When we talk about single coil vintage mono carts, aren’t we usually talking about moving magnet carts? Third and related, when we talk about moving coil mono carts, shouldn’t we be more interested in the positioning of the magnets than the number of coils? After doing some research today, it appears that the function of the single coil in a vintage moving magnet mono cart may incorrectly be getting equated with the function of the single coil in a moving coil cartridge. In other words, don’t the coil(s) in a moving magnet cart serve the same purpose as the magnets in a moving coil cartridge?

  • thebeathunters

    looks like i’m a year late on this one… i’m quite new to mono playing – while collecting mono pressings for about 10 years so it was time to finally enjoy it. it’s mostly fifties/ early sixties Lps xcept for a few Blue Note “late” UA mono/microgroove faves, which belong more to the stereo crate, recorded as mono but pressed in stereo grooves.
    i chose an ortofon OM 25M cart to start, because it’s a 1 mil stylus, which i thought was best for microgrooves and very affordable to test if my small dedicated system was working. sl1200mkII+DIY phono-pre switchable to mono+heathkit ma12 EL84 monoblock+1955 philips vintage mono corner speaker (9710A+satellites) that’s it ;-D
    i couldn’t help but notice on your OM25 test that you settled for a 1,5g tracking force – same as the other cart – whereas ortofon advise up to 3g – and an eminent fellow at LencoHeaven forum was enthusiastic at 4,5g. it could make quite a difference in reading the 1 mil groove.

    • Hi again beathunter! That’s very perceptive of you, noticing that I had listed the tracking force for the D25M as 1.5 grams. Long ago I made a decision on principle to always track at the highest recommended tracking force, which I now see is 3 grams for the D25M, and I’ve always been very attentive to tracking force. These files were made several years ago and I actually don’t have a note for the tracking force of the D25M for the test, so I’m assuming the test was actually done at 3 grams and I’ve made the appropriate changes in the article above.

      Years ago I also did scrupulous A/B comparisons of records being played with various tracking forces, and while clean records didn’t seem to sound much different (provided the lower tracking force was adequate enough to track the groove), for record with more surface marks, make no mistake about it, a higher tracking force ‘cut through’ the pops and ticks more successfully and made the records sound quieter (on the contrary, I found that groove wear can be mildly reduced with higher forces but never by a significant amount that I felt genuinely improved the listening experience).

      Somebody wrote me recently and asked the same question about NY USA Blue Note pressings and groove width, I’m assuming it wasn’t you. It turns out a lot of people are curious about this, including myself. My guess is that Van Gelder used a mono 1-mil cutting head for all Blue Note mono pressings he mastered, he just cared too much about his work and mono specifically to make a haphazard decision like that to use a stereo cutting head to cut mono records…though I have no evidence. The only way to know for sure at this point would be to look at the groove widths under a mastering engineer’s microscope. I actually have the connections to do that but I haven’t had the time or energy to reach out and make the trip to the mastering studio, perhaps mainly because I’m content for the moment with using a modern 0.7-mil stylus.

      • thebeathunters

        hi and thanks for your detailed answer about mono matters.
        when i was deciding what mono cart i will choose, i read mixed up feedbacks about denon DL102.
        on the good side: “true” mono cart, 0.7 mil stylus AND able to play stereo grooves, too. especially old noisy ones
        bad side: developed for japanese AM radio stations to read mono and stereo, it could sound quite limited on low/high frequencies.
        i’m very tempted to give it a try and solve the BN, late mono pressings issue and stereo too

        • The thing about the 102 is it’s a moving coil so you need a MC preamp.

          • thebeathunters

            it’s a high output MC which actually seems to play pretty well thru MM mode/load. i’ll keep you posted. btw, did you ever see late 60’s stereo records which say “also playable in Mono”- which groove is that?