Luxman PD121A - PD441

Do all the Seiki 505s use the din to rca connectors?

As far as I know yes.

And is the MK3 a good purchase in terms of options for carts in your opinion?

I had one and it was great, even though low mass Gallibrier demoed a 505mkIII with a low compliance Denon 103 at a show and it was fine.

The only thing to be wary of is that this model is less common and spare arm tubes are hard to find. Japan auction sites are best here. The mkII and mkIII arm tubes are not compatible.

The 441 come with an TP-MT mount. The 505 MKIII should fit correct? 

Yes.

@dover 

Very much appreciate this info!

Any suggestions besides the Denon for an all round good cart for this arm?? If there is such a thing at a none crazy amount of money. 

And is there a place where all the arm boards can be seen with hole dimensions? I have been looking but cant seem to find any.

So if i buy a din to rca cable I imagine the cable quality will be a major factor on sound?

@chridabs 

Yes - I have been running an old Audio Technica AT33 whilst my Van den hul Calibri XGW is off for service - it has really surprised me. AT33E ( elliptical ) or AT33PTGII ( micro ridge styli ) are great bang for the buck - better than the slightly more expensive OC9 series. They would be a better match than the Denon 103.

If you want high output - Soundsmith and Grado are great options.

Yes the old micro cables can be bettered at modest cost - better quality connectors and cable today. Get your cartridge choice first - if you buy a moving magnet you will want a low capacitance phono cable. If you run a moving coil then capacitance is not an issue.

The AT33 is mono???

@chridabs 

No 

see here

https://www.audio-technica.com/en-eu/cartridges/line-series/at33-series?_gl=1*3n3jrk*_up*MQ..*_ga*MTI1NDc1NTg3Ni4xNzUzODQwMjI1*_ga_9B1Z5FDEW6*czE3NTM4NDAyMjUkbzEkZzEkdDE3NTM4NDAyNDgkajM3JGwwJGgxMzM4MjgzNzA3

Recommended AT33EV and AT33PTGII.

Plenty available on line at great prices new.