First thing to do is get the impedance load between the cartridge and the pre-amp matched. The Magus has a nominal impedance of 47K which is fine for most MM cartridges but not for most MC cartridges which run best somewhere between 500 and 100 ohms.
Find out what the manufacturer recommends for the load of the cartridge. Then find a techie who will make a couple of male RCA plugs with resistors with the load values - then plug them in. You'll note the proper female RCA's on the back of the Magus right next to the Phono RCA's. That what they are for and that alone could solve your entire problem (well most of it anyway). And it is highly recommended in any event. Either that or get a MM cartridge. A MC cartridge with a 47K load will more often than not sound bright and thin.
Re tubes - I'm not enthused by EH 12AX7's at all and warm they are not. Unfortunately the tubes I use are practically unobtainable now. NOS Mullards should/could work well but are spendy. Before you go that far I'd buy some new production JJ's for all tube positions and see if that tone would work for you. If so at least you have a benchmark for further exploration if you want to fine tune it further. And these four tubes would cost less than $60 total.
Re VTA, save that for last unless you can find out what exactly that cartridge likes. Some cartridges like to be set up so that the rear of the arm is a degree or so lower than the cartridge. Another fine tuning thing - but don't get to anxious about it, as different records will sound different depending on their thickness, and how they were initially cut. Also the shape of the stylus plays a big role in the sensitivity of it to VTA as well.
BTW, I know some will disagree, but using a phono pre with a volume control is similar to using a standard phono pre with a passive volume control. Even though using a phono pre w/VC may avoid a couple of issues of the latter you still loose the dynamics that an active pre-amp will add.
As I mentioned before, this little Magus is a fine unit! Just learn how to use it. Getting vinyl right ain't a Sunday walk in the park :-)
Hope that helps a little bit.
Find out what the manufacturer recommends for the load of the cartridge. Then find a techie who will make a couple of male RCA plugs with resistors with the load values - then plug them in. You'll note the proper female RCA's on the back of the Magus right next to the Phono RCA's. That what they are for and that alone could solve your entire problem (well most of it anyway). And it is highly recommended in any event. Either that or get a MM cartridge. A MC cartridge with a 47K load will more often than not sound bright and thin.
Re tubes - I'm not enthused by EH 12AX7's at all and warm they are not. Unfortunately the tubes I use are practically unobtainable now. NOS Mullards should/could work well but are spendy. Before you go that far I'd buy some new production JJ's for all tube positions and see if that tone would work for you. If so at least you have a benchmark for further exploration if you want to fine tune it further. And these four tubes would cost less than $60 total.
Re VTA, save that for last unless you can find out what exactly that cartridge likes. Some cartridges like to be set up so that the rear of the arm is a degree or so lower than the cartridge. Another fine tuning thing - but don't get to anxious about it, as different records will sound different depending on their thickness, and how they were initially cut. Also the shape of the stylus plays a big role in the sensitivity of it to VTA as well.
BTW, I know some will disagree, but using a phono pre with a volume control is similar to using a standard phono pre with a passive volume control. Even though using a phono pre w/VC may avoid a couple of issues of the latter you still loose the dynamics that an active pre-amp will add.
As I mentioned before, this little Magus is a fine unit! Just learn how to use it. Getting vinyl right ain't a Sunday walk in the park :-)
Hope that helps a little bit.