Reply to Ex turntablist getting back in

Hi.Needles ex turntablist from the early 2000s and local DMC champ who's been totally out of the game for 10 years plus. I want to build a new setup incorporating a DVS system. I've never used Traktor or Serato. My old setup was two Gemini 500s and a Vestax 06 mixer.

Important hardware concerns for me are :

1. The fader. Must be smooth as silk, hamster button, realllly durable, and have curve adjust.
2. Transform switch ideal but not mandatory
3. I would like to be able to sample something I play quick and loop it (maybe a scratch beat or quick juggle) and the layer other live samples over top. Do I need a separate box, or do some mixers do this stock?
4. Computer. I have an old AMD dual core laptop, and realize I will probably have to upgrade. Are macs 100% necessary? I prefer windows but don't mind switching. What about something like Rain?
5. DVS. Are there say big differences between the two? Can both handle really technical scratches and juggles? Could I throw my old DMC set at either one without a hiccup?
6. Needles/cartridges. I used to use shure m44-7 (or - g). Have better ones come out. Should I consider the long skinny ortophone type?

I've done a bit if reading and my mixer choices seem to be

Rane 56/57
Rane 61/62
pioneer 909
pioneer t1
traktor z2

I realize if I get a non - DVS mixer (eg. 909) I will have to get the interface box too. What are the pros and cons of integrated interface/standalone box. If I got say a 57, could I use it with traktor? And vice versa with the t1?


Thanks a lot for all the help.