Mono record sounds like stereo

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.  

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 

@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

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 !

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

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

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.