One More Time: "True Mono" Carts vs. Mono Buttons/Y-Cables

Discussion in 'Audio Hardware' started by 2xUeL, Oct 4, 2013.

Thread Status:
Not open for further replies.
  1. rl1856

    rl1856 Forum Resident

    Location:
    SC
    A true mono cartridge has only one coil and is designed to respond to lateral signals only. It does not respond to vertical signals. A stereo cartridge strapped or otherwise manipulated to become a mono cartridge still responds to vertical signals. The introduction of the vertical signal causes distortion and phase anomolies that are not fully canceled by summing the 2 signals. The anomolies are audible. That is why many consider a true mono cartridge (one coil only) to be superior to a stereo cartridge adapted to mono.

    The Denon 102 is a unique cartridge. It has only one coil, thus only generates signal from lateral modulations, but the stylus has vertical compliance, ie- it responds to vertical grooves in the record. However no signal is created or generated from the vertical grooves. The cartridge was produced by Denon in the 60's for Japanese AM radio stations. The inclusion of vertical stylus compliance allowed the stations to play stereo records with a mono cartridge and not damage the grooves.

    There are many opinions regarding the optimal stylus size and profile for a mono record. My opinion is that most mono records from back in the day were played with needels that had more in common with nails than with modern low VTF profiles. 1mil conical profile was the most common shape back in the day. A modern .07mil profile will track a portion of the groove that may have been untouched by the primative cartridges of 50+yrs ago.

    Best,

    Ross
     
  2. 2xUeL

    2xUeL Forum Philosopher Thread Starter

    Location:
    Albany, NY
    That was probably the most helpful, thorough, to-the-point answer I have ever gotten for such a technical question...exactly what I was looking for. I will probably give the DL-102 a shot at some point, add it to my A/B comparisons. Again, great post! :righton:
     
    Gordon Johnson likes this.
  3. Wally Swift

    Wally Swift Yo-Yoing where I will...

    Location:
    Brooklyn New York
    What vertical signals are present in mono records with only lateral grooves?
     
  4. mesaboogie

    mesaboogie Forum Resident

    Location:
    USA
    Its not a signal from recorded sound intentionally put there so much as just an imperfection in cutting/pressing as I cannot image cutting a groove that long will be perfectly flat...they can barely machine metal without any variation...pvc that was stamped out would be impossible.
    Thats my uneducated take.
     
  5. action pact

    action pact Music Omnivore

    Not only that, but he is 100% correct. :agree:
     
    Gordon Johnson and 2xUeL like this.
  6. MikeyH

    MikeyH Stamper King

    Location:
    Berkeley, CA
    Noise, wear.

    I had precisely one LP that played cleanly whatever the mono switch position. The others, not so much - mono cartridge or mono switch made them better.
     
  7. Wally Swift

    Wally Swift Yo-Yoing where I will...

    Location:
    Brooklyn New York
    Right, but the noise and wear are made evident by the stereo amp [and reduced by summing], not a vertical signal from the record.
     
  8. 2xUeL

    2xUeL Forum Philosopher Thread Starter

    Location:
    Albany, NY
    For lack of better terms, the wear on a vintage mono record creates both a lateral and vertical signal. This vertical signal deriving from wear is not made evident by the amplifier, it is made evident by a stereo cartridge or (to a lesser degree) a stereo cartridge wired for mono; a true mono cart will only acknowledge the wear from the lateral signal because it's not even picking up a vertical signal to begin with. Though of course there is already a small vertical signal even with a near mint vintage mono record, because no mono record was ever cut perfectly in the lateral direction without any vertical variation.
     
    Last edited: Oct 9, 2013
  9. Wally Swift

    Wally Swift Yo-Yoing where I will...

    Location:
    Brooklyn New York
    For wear to produce a vertical signal in a mono LP wouldn't the styli that caused the wear have to be hitting and damaging the bottom of the groove? Are you sure it's not just the smaller styli on a stereo cartridge scraping the bottom of the wider groove? If a true mono cart as you say doesn't pick up a vertical signal it's probably because of the size and shape of the stylus, not the fact that it's a mono cart. A proper stylus on a stereo cart with a mono switch engaged should produce the same results. Damn, now I want to buy a mono cart to experiment.
     
  10. 2xUeL

    2xUeL Forum Philosopher Thread Starter

    Location:
    Albany, NY
    I think you're confusing two separate ideas here. The first is the idea of a true mono cartridge vs. a stereo or stereo-wired-for-mono cartridge, and the other is a 1-mil stylus vs. a .7-mil stylus. One point that Ross made above is that, while summing reduces the vertical noise inherent in the groove, a true mono cart doesn't even acknowledge it. In a way, that is a separate matter from the .7-mil/1-mil debate.

    The idea is that, if a mono record was played back in the day with a worn and/or heavy 1-mil stylus, playing that record today with a new, modern 1-mil stylus will reproduce that wear, which turns out to be higher on the groove wall. The stylus doesn't "grip" the tight curves of higher frequencies as well; it "drags" over them, out of the groove, and creates tracing distortion. But if you use a .7-mil stylus, it may still "grip" those higher frequency turns better and more accurately because it's "sitting" below the wear. But that theoretical improvement in tracing comes at a cost: the stylus is riding lower in the groove so it is more likely to respond to dirt at the bottom. I always figured if a record is clean, I'd rather the stylus avoid the wear caused by an old stylus. It's not as if the stylus would then be "scraping" the bottom of the groove, it would still be suspended above the bottom of the groove but it would be sitting lower on the groove walls, I'm positive of that based on diagrams I've seen.

    You are bringing up an interesting point though, one that I hadn't thought about before. I've always understood tracing distortion in terms of the lateral movement of the stylus, but it makes sense that tracing distortion does cause the stylus to vibrate vertically because it's coming up "out of the groove" a little bit because of the worn curves. So the wear from a 1-mil stylus will create vertical noise upon playback with a 1-mil stylus, though a .7-mil stylus may avoid it.

    I think the bottom line here is this:

    1. A true mono cart will, in theory, give you the best results with a vintage mono record, since the cartridge does not respond at all to any vertical imperfections in the groove (Denon DL-102).

    2. Summing the left and right channels [using a stereo-wired-for-mono cart (Grado MC+) or a stereo cart paired with a mono button on an amp] will have a significantly higher S/N ratio than using a stereo cart without a mono button.

    3. If a record has been worn by a vintage 1-mil stylus, a modern 1-mil will reproduce that wear (both lateral and vertical), while a .7-mil will in theory trace the groove more faithfully. Provided the record is clean, one will get better results with the .7-mil cartridge in this case.

    Through all of this, I couldn't hear a difference between 1-mil and .7-mil conical styli, though I did hear a slight improvement in tracing distortion with an elliptical. But I look forward to comparing the Denon DL-102 with with my current configuration.
     
  11. Wally Swift

    Wally Swift Yo-Yoing where I will...

    Location:
    Brooklyn New York
    I put a .7mil conical stylus on my new modded SL-1200 [details of mods here; http://forums.stevehoffman.tv/threads/audiophile-modded-technics-sl-1200mk2.329839/#post-9424209] to check a 1973 stereo LP that skipped with my elliptical stylus. While I have the .7mil conical in action I pulled out a 1950's LP that I'm very familiar with and gave it a spin. Immediate differences I noticed: weaker midrange, slightly shrill highs and an overall leaner sound. And this is on a modded 1200 as opposed to a stock 1200 with a 1mil conical stylus. Right now I am spinning a 1967 RCA mono LP that was still sealed before this spin. This sounds perfect with the .7mil conical. Just my observations this evening.
     
  12. 2xUeL

    2xUeL Forum Philosopher Thread Starter

    Location:
    Albany, NY
    Why not perform these tests using both styli on the same LP?

    I may actually get around to posting links to MP3s of my A/B comparisons.

    BTW: very cool that you're using a 1200. :thumbsup:
     
  13. hvbias

    hvbias Midrange magic

    Location:
    Northeast
    To throw a monkey wrench into the works here is what Jonathan Carr (Lyra cartridges) replied to me:

    Dnath: If you use a single-coil cartridge in a stereo system, chances are good that you will end up with hum. If you have a dedicated mono system - only one channel from head to tail - a single coil cartridge will work fine.

    The key issue for mono playback is not the number of signal coils - but their angular orientation, which determines whether they are sensitive to vertical groove modulations or not. A coil design that does not pick up any vertical modulation in the first place gives better sound than picking up the vertical modulation, then attempting to cancel it out later.

    IME, what works best in a normal stereo system, is a cartridge with two mono coils. This eliminates any sensitivity to vertical groove modulations, yet avoids the hum issues that a single-coil cartridge may be prone to.

    hth, jonathan carr
     
    MrRom92, MikeyH and 2xUeL like this.
  14. action pact

    action pact Music Omnivore

    FWIW, I have used a GE VR-II mono cartridge in my stereo system - on the same SL-1200MK2 that Wally Swift now owns - with no hum.
     
  15. 2xUeL

    2xUeL Forum Philosopher Thread Starter

    Location:
    Albany, NY
    This hum thing is news to me. I understand that Carr is a design engineer for Lyra but I can't take a statement like that at face value without an explanation. Terminology like "chances are good" isn't very convincing either.
     
  16. 2xUeL

    2xUeL Forum Philosopher Thread Starter

    Location:
    Albany, NY
    Can we settle the coil thing once and for all? What's going on with the damn coils inside all the carts? One thing I read says a true mono (DL-102) has one coil, another thing I read says it has two. One thing says stereo carts have two, another thing says they have four...:confused::shake:

    Also, I'm very confused about these mono carts that have "more" coils than the Denon DL-102 (the Grado MC+, the Lyra, the Ortofon 2M, etc.) but still claim they are "true mono" carts that yield "better" results than summing the channels with a stereo cart paired with a mono button or a Y-cable. I've read about there being a different way to "align" or "wire" (?) the coils that works "better" than summing. Presumably, these internal alterations either do not pick up any vertical signal (like the DL-102) or they just reduce the vertical signal more than summing but don't quite eliminate it completely??

    :help:
     
  17. 2xUeL

    2xUeL Forum Philosopher Thread Starter

    Location:
    Albany, NY
    FTR, the following dialogue between Grado and our buddy action pact is about as telling as anything else I have come across in my research:

    (http://forums.stevehoffman.tv/threa...rado-re-their-mono-carts.228295/#post-5816348)

    So is the idea that the realignment of the coils makes the cart function just like the DL-102 in the sense that the coils in the Grado are only picking up the lateral signal while producing two signals, one for each channel, opposed to the Denon which produces one signal, in which case the wires on the headshell need to be connected to two pins instead of four?
     
  18. hvbias

    hvbias Midrange magic

    Location:
    Northeast
    I think it might be one of those demons, where either you might have it or not. I am most interested in the Miyajima mono cartridges... it's hard to tell what exactly they use given the poor translation on their website.
     
  19. action pact

    action pact Music Omnivore

    The Denon only has two output pins and is a single coil cartridge. It can be played with stereo records because the cantilever can wiggle in all directions, not just side to side.

    I'm not sure what the story is with the Grados though...

    You might find this useful:
    http://www3.sympatico.ca/murraya/DenonMonoPage.htm
    "As can be seen in this photo, the cartridge consists of a single solenoid wound moving coil mounted between fixed parallel pole pieces."
     
    The FRiNgE and 2xUeL like this.
  20. THE BEATLES-HEY JUDE!.jpg THE BEATLES-HEY JUDE!!.jpg THE BEATLES-HEY JUDE!!!.jpg I was jonesing for a dedicated mono turntable because my preamp has no mono switch, so I just used Steve's trick with the Y-cables & presto! The resulting playback with mono-mixed records is astonishing on every level. I simply can't believe how wicked these LPs sound. And one huge bonus for me is being able to playback some stereo-mixed LPs in mono. There are a quite a few stereo-mixed LPs I've got where I don't dig that left/right/center weirdness, but once played on the mono turntable they groove like hell. Example: that 'Hey Jude' compilation LP that's in stereo by The Fab Four. I played that one on my mono turntable & it's unbelievably awesome in mono. Crank it to 11, sit in your 'sweet-spot' & try not to get up and dance...
     
    Last edited: Oct 14, 2013
  21. rl1856

    rl1856 Forum Resident

    Location:
    SC
    Grado and many other "mono" cartridges are stereo cartridges adapted to monophonic reproduction. They contain *2 coils*. However the coils are oriented such that vertical signal level is attenuated. The stylus and cantilever still respond to vertical signal and still transfer a vertical signal to the coils. Vertical signal level is very much reduced, however it is still present and still capable of introducing phase anomilies and distortion.

    The Denon 102 has a single coil and 2 connection pins. The connection pins are much longer than those on other cartridges and allow for the stacking of connections; IE 4 wires attached to 2 pins. Other than a vintage GE VR, the Denon 102 is the cheapest true mono option available that delivers reasonable fidelity without harming vinyl.
     
    action pact and 2xUeL like this.
  22. hvbias

    hvbias Midrange magic

    Location:
    Northeast
  23. McLover

    McLover Senior Member

    The DL 102 was of all things, made for broadcasting use. It was made for the Japanese NHK radio and made to be compatible also with Stereo records and mono cut on Stereo cutting heads without damage. The DL-103 was also designed for the NHK for FM Stereo station use. It excels at 1950's microgroove pop, jazz, and classical. It is also one heck of a 45 RPM cartridge for pre 1965 singles.
     
    Last edited: Oct 14, 2013
    2xUeL likes this.
  24. hvbias

    hvbias Midrange magic

    Location:
    Northeast
    But at least the DL-103 offers very close to full frequency response (I think my pamphlet spec'd it to 18 Khz). And IMO after owning one of them even mounted to an old school heavy tonearm it's too tonally grey compared to better modern MC cartridges.
     
  25. 2xUeL

    2xUeL Forum Philosopher Thread Starter

    Location:
    Albany, NY
    Ok, major progress here in my understanding, so I'm pretty sure this is my last question: is there any difference then between a mono cart with two coils realigned and summing with a mono button? I would think there is a difference in theory, though in my tests it wasn't audible to my ears.
     
Thread Status:
Not open for further replies.

Share This Page

molar-endocrine