The older Mills 12w (shiny black) has a bit more detail and has fast, clean high frequencies and is slightly lean in the upper bass although it has tight, powerful deep bass. They also have a slight edginess in the highs. The newer version (dull brown) is warm, not lean, slightly soft and dull, and doesn't have quite as much detail. At least that's how I recall them from a couple years ago.
i have two types of mills mra12
- the first one is dull brown and marked : "mills 1ohm mra12f 1019"
- the second one is shiny brown and marked : "mill mra12 1ohm 1% m1713 mexico"
what is the newer between the two that " is warm, not lean, slightly soft and dull, and doesn’t have quite as much detail " (salectric cit.)?
I cant comment on how the newer ones sound compared to the older ones made in the USA but I would not call the newer brown shinny ones slightly dull and warm. I replaced the sand resistors in my Dynaduio S 25,s with them and they do not sound dull and warm to me compared to how the s 25,s sounded before quite the contrary I would call them fast, detailed, tonally correct with alot more micro dynamics.
I know I’m probably jumping in here late, but I’m doing some research on resistors for a project I’m planning next year. The "Vishay Mills" is on my short list.
The older NOS "Mills" resistors are black in color.
The newer "Vishay Mills" resistors are brown in color.
The only difference I have been able to determine are that the older black "Mills" have the silver-plated copper alloy end-caps.
The newer "Vishay Mills" brown have just copper alloy end-caps (no silver). This would seem to coincide with salectric’s feedback that the older black Mills have more of a fast/clean sound in the high frequencies and lean bass.
I would personally go with the newer brown resistors for overall tonal balance unless you are really after that "silver" signature that pushes the upper mids / low highs -- or if you need to replace resistors in an old circuit that uses original Mills and need to match sonic signature.
These are the specs for the new Vishay Mills MRA resistors.