Mono record sounds like stereo

So I have been playing stereo records for 40 years.  I’ve recently acquired some Verve Japanese reissues. Listening to Metronome All stars tonight and there is clearly separation. I hear horns predominantly on the left and xylophone and drums on the right.  This is on an Ortofon SPU synergy stereo cartridge. Is this normal ?  I’m sorry.  I’m new to Mono.  I bought about 50 verve and Blue notes last week and got some monos on accident.  My system is balanced and the room has extensive treatment so I’m lost !   


Welcome to the jungle. Nowhere in audio can you find more conflicting information than on the subject of mono reproduction and mono cartridges. To begin with most modern mono cartridges are stereo cartridges that have been modified in one way or another to produce mono. Very like flipping the mono switch on your preamp.

Yeah, that’s gonna be an interesting read because that SPU has a conical stylus I believe. So much smaller profile of my blackbird would not duplicate the problem.

I just wanted to confirm if my AT-33 mono is MC as I bought it a long time ago

this popped up, it happens to be my combo of MC Stereo and MC Mono


Audio Technica AT33PTG/II and AT33 MONO

Post by omegabri » 10 Jan 2018 10:49

Hi guys

I've just finished putting my new Audio Technica AT33PTG/II and AT33 MONO MC cartridges on to two matching Pro-Ject aluminium Signature headshells, and setting them up on my turntable.
I've moved up from an AT440mlb MM cartridge. Having briefly listened to a mixture of lp's, using the new carts, I can say that I am extremely pleased!
The AT33PTG/II gives more positioning of instruments than the AT440mlb (which is still an outstanding cartridge). The sound stage portrayed by my speakers seems to have more depth, the response of the MC cart seems sharper, and draws out more detail.
The AT33 MONO is, to me, simply astonishing! I've never had a dedicated true mono cartridge before, and listening to mono now just blows my mind. Outstanding isn't a good enough term. I'm definitely looking forward to dragging all my mono lp's out now!


Also mentioned above, I am using my old but nearly new AT-440ML on my Office TT. I used to alternate it with Shure's V15Vxmr, preferred the Shure due to it's damped brush (helped with my flexible flyer wood floors), and it's beryllium cantilever, until I looked sideways at the beryllium and it shattered.

AT's current version of the AT440 is the VM540ML, it is the one I recommend as a 'starter' upgrade MM Stereo cartridge, due to advanced stylus shape, tight channel balance 1.0 db, fairly wide channel separation 28db, fairly light tracking force 2.0g.

@adrianleewelch , first off let me say nice setup. My 311 horns are dwarfed next to those 15s...

Last week I pulled the trigger on an Otho Cadenza Mono. Being I have about 60+ Mono’s original pressings of Jazz & Big Band. I love how the drums are in front of me, instead of coming from either the R or L speakers. Every instruments is delivered with authority in my system. IDK what the hell I was waiting for?

Enjoy the music everyone!

To be honest I had never heard, nor been interested in Mono. I just never had exposure. Now I’m really intrigued. All I need is another rabbit hole !!  It will be interesting to take it a step further with a suitable arm and cart.  I really appreciate all of the responses to this thread.  Adrian

Mono LPs can sound absolutely wonderful, and in some cases, you don’t miss stereo. This is because your brain is doing the work of supplying a stereo- like image. Your brain knows where the horns are usually located in an orchestra, and likewise where the violins are located, etc. In addition to that the recording, even with a mono microphone and mono mode picks up phase differences among instruments, and the many sources in an orchestra, and that may contribute to the sensation of a stereo image. However, if you interrogate yourself, while you’re listening, you will realize it’s a feaux image, although nevertheless, satisfying. 

Well I swapped one end of the RCAs and of course it moved the horn section to the opposite speaker.  I played it on my other table and it was balanced left to right so I realized it was the SPU cartridge contributing. I switched the preamp to Mono and it corrected it.  I’m thinking I need to set up that arm again. It’s an SME 3009 unimproved. It was rebuilt by SME last year and has the extra weight system for the SPU. What I forgot is that I added a fluid damper to the arm without readjusting anti skate. I bet it has way too much pull to the outside of the record.  I likely should have backed off on the anti skate when I added the trough. Well at least I know what’s likely happening.  It’s odd though that I never sensed a channel imbalance prior to this.   Adrian

adrianleewelch OP

Definitely, without doubt, put the stereo cartridge on the long arm. Pick an arm with removable headshell if possible, gives you flexibility now and in the future.

Does your 9" have a removable headshell?

My 12.5" long arm is fixed cartridge, used for my MC cartridge. Only change it when worn.

My 9" has both removable headshell and extremely easy arm height adjustment, so it is most flexible. I  have several cartridges I alternate, MC, MM, and now an alternate Mono. And we play my friend's cartridges on it. SUT handles various MC impedances, and has Pass for MM.

I added a 3rd arm for mono, fixed. Limiting, but my 9" arm saves the day regarding flexibility.

My Grado Mono is elliptical, on the 3rd arm. I'm very happy with it. I'm not looking for perfection, or even 'best', just gaining the advantages of playing mono lps with a true mono cartridge.

I just had VAS put a new boron/shibata on an AT33PTG Mono Body. For modern Mono, Haven't used it yet. He played it at his shop, we all were impressed, no comparison here yet.

3 arms: MC, MM, Mono all ready to go in seconds in any listening session.

The compliance of the cartridge and the mass of the tonearm must ’avoid a problem’.

Today’s equipment, I would simply put my existing stereo cartridge (likely high compliance) on my new long arm (likely not too heavy) and expect no problem.

Perhaps, before you buy it, pick an arm you want, tell the members here about it and your cartridge, get their help.

To be more specific not the whole cable but just the input to each component ,

if anything unplugging and plugging help clean the connections. 


Get a 12" with a removable head-shell so you can easily swap cartridges. I'm not sure it matters which arm hosts the mono. Try both and report back. I have 12" and 9" arms on my main table. 

Oh dang. It never occurred to me to swap the RCAs as a quick test. I’m going to try that now. TBH I’m not even sure if my Preamp has a mono setting. I’m going to check that as well.    Thank you !

I like to say what a beautiful system or systems !

I just played Metronome All-Stars 1956 1974 Japanese pressing and did not hear the separation that your are hearing , it is only available in mono so I am assuming the it was recorded in mono .  Going with elliottbewcombjr's # 3 that is a possibility , looking at your room your left and right speakers are not equidistant from the side wall so maybe ?  Cartridge alignment ? Swap cartridge TT cables to preamp  L & R from preamp to amp L & R as your last test .

Have your tried other mono pressings yet ? I have some early 50's jazz that heavily favor the right speaker ( giving the #3 impression ) .  If you like the Beatles try the mono pressing of Sgt. Pepper , this is one of the best examples of mono I have ever heard .

Good Luck

@adrianleewelch ,

You might want to check out the recordings from pre-war 1930's Germany.

I have always been amazed at how much sound they could get out of those microphones.


@elliotbnewcombjr.  I have the option of adding a 12” arm to one of my tables. I’m using a Sumiko blackbird and an SPU on 9” arms currently.  If I added the 12” arm, would it be better to run the mono cart on it and leave the stereo cart on the 9” ? Or would I benefit more from the stereo cart on the 12”, and the mono on the 9”?  Adrian

I learned about listening to Mono LP’s here.

1. Get thee a true Mono Cartridge. It makes a little, some, a lot of difference depending on the LP.

Mono picks up horizontal movement only. It will not pick up anything from the inadvertent vertical movement: slight warps, up and down from dust in the grooves, surface dust, scuffs that are small but make some vertical happen.

I sell LPs, and I advise mono lp buyers: slight scuffs are not too apparent using Mono Cartridge, retains an involving musical experience. Play same LP with Stereo cartridge, the noise from the slight scuffs is essentially doubled, hard to enjoy the music.

I have a vintage Mono LP, Chicago Jazz, late 28’s, early1930’s, includes some early Louis Armstrong and many others. Play with Stereo, it was like a history lesson, where’s Louis? I would never play it again.

Got mono cartridge, what a difference. Not imaging, but clear distinction of the various instruments, that’s a trombone, that’s a trumpet. There’s Louis. I play it for my friends, they get it right away.

2. MONO MODE if your preamp/amp has a choice. You still want to start with a Mono Cartridge.

3. Speakers ’Perfectly’ Balanced, Frequencies matched L to R. IF your ’speakers output’ are not perfectly balanced, or speakers perfect but the actual received frequencies ’in the space’ are not perfectly balanced a random slight stereo effect will occur, left speaker or side of the space emphasizing part of the frequencies of some instruments, right speaker likewise. Just unbalanced enough to give some imaging.

I have 2 L-Pads: ’presence’ to adjust the volume of the mid horn to the woofer and ’brilliance’ to adjust the tweeter to the mid horn. OMG is it hard to get it right. I use a SPL meter on a tripod, a test CD with 29 frequency bands, do some, take a break, do some more, sleep on it, finish in the morning. Get each balanced individually, then both playing revise things, then L to R balance.

Casandra Wilson’s (others) voice cannot move slightly off center in either direction as frequencies change.

4. Listen to only one speaker. This is how the early music was listened to. Eliminates item 3 above, and you can listen anywhere in the room, space, out on the porch, ... you get the idea. It is hard to turn off our search for imaging, listening from somewhere else takes that habit away.

5. Some Mono LPs are curiously partly stereo, some imaging does occur. Miles Davis, Sketches of Spain is an example of: Is this Mono or did they take Stereo and mix Mono? Those Castanets are definitely from over there! Part of the aural confusion:

"Some percussion instruments are tuned and can sound different notes, like the xylophone, timpani or piano, and some are untuned with no definite pitch, like the bass drum, cymbals or castanets."

I bought a new Sketches of Spain LP, random effects same as my old one.


The better your system ’images’ in Stereo, the more it will reveal, some stereo effects, if Mono: when it reaches your ears, is not perfectly balanced

Essentially: get a mono cartridge, and if some stereo is distractingly apparent, turn one speaker off.

The tiny horns were made by Markus Klug. They are for 1” compression drivers. I’m using Faital HF10AK tweeters. My crossovers are a Hiraga inspired 3 way design built by Pete Riggle. It helps the Altecs up top and you can flip a switch and turn the tweeters off if you want the classic sound.  

Wow! That's not a room, thats a temple for the God of speakers, stunning! Even a radio jingle will sound great in that setup.

Might be more trouble than it's worth, but you can "strap" the phono outputs if your system doesn't offer a mono switch. With a mono switch strapping is then done in the pre-amp. What I do is run two turntables in two different systems. The dedicated mono unit is 1, an e-bay and then overhauled Pioneer 1150. The Pioneer runs the Grado MC+ (there is a new upgrade MC+), the other, 2, is a Pro-Ject Debut Carbon DC with a Audio Technica MC cartridge through the P-J S box, that cart has since been obsoleted and supplanted. You can play mono with a stereo cartridge, each side of the cart will feed "stereo" outputs to your system. I have noticed the effect you mention when playing a Shibata stylus. Do not play your stereo records with a mono cart. For Jazz and Classical I prefer Mono, it gives a more "sitting in the front row" experience for me, not to mention going back to the days of mono systems.

A well recorded mono LP is an attention getter.

Period press of straight ahead Jazz on Contemporary, World Pacific and Riverside are a few of the other labels that do the magic.



I’m listening on an Altec A5 horn system and I was so impressed with the sound quality of this mono record.  Thank you for the response. I thought I was crazy or my preamp was broken LOL 

Mono records sound great of axis. Once you get in the right listening position a mono record will sound as if you are listening through a crack in the door. If this is not happening one would have to assume there is a problem with your system's stereo imaging.