The only thing common to these two capacitors is the MFD values and physical dimensions.
Our # 284320-2 is a traditional can capacitor design made for us here in the US by CE-Distribution and sold through Antique Electronics and others. These traditional style capacitors are made on the original Mallory equipment.
Our # 284320-6 is basically an aluminum can with (4) discrete modern F&T low ESR electrolytic capacitors fitted within the can. Three sections are rated for 550 vdc continuos 600 vdc surge and the remaining 30 MFD section rated for 525 vdc continuos 575 vdc surge.
We selected this German made capacitor for our Dynakit Mark III amplifier.
I have not personally compared these two capacitors to each other in either the ST-70 stock unit or Mottram's VTA upgrade. Most who purchase the # 284320-6 use this in the MK III amplifier. I doubt you will hear any measurable difference.
I would suggest you pose this same question to Bob Latino at the Dynaco Tube Forum. I believe he has tried both of these can capacitors in his VTA upgraded ST-70. [/i]
Does anybody have experience with this capacitor in both stock and VTA boarded ST-70 amps?