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Bipolar vs MOSFET vs J-FET

I know many people here believe that "properly designed" amplifiers have no sound of their own. Thus it's impossible for two amplifiers to sound different at matched levels if each has high input impedance, low output impedance, flat frequency response, low distortion, low noise floor, and is not clipped.

For this discussion let's leave out tubed amplifiers and refer ONLY to solid state amplifiers, ok? I was under the impression that different manufacturers choose to use different solid state amplifying devices such as op-amps, J-FETS, MOSFETS or Bipolar because they prefered the "sound" of one these devices over another. I definitely remember when people were speaking about MOSFET mist or Bipolars as sounding warm.

Then there's Steve Bench's article on The "Sound" of Capacitors. Steve states: Many people believe there is a distinct sound to different types of capacitors. This article covers this topic by examining the linearity (or deviations from linearity) associated with different capacitor types. I've expanded this report and slightly re-arranged it to keep the load times reasonable. Steve's article can be read by clicking on the link below.

My question is "IF" these devices in and of themselves can have a distinct "sound" why then wouldn't the amplifier that's built using them not also have a distinct "sound" as well? I suppose this is really a question for the manufacturers and DIYers to answer, but has anyone here built the same amp using just different amplifying devices or different capacitors? If so did changing from a J-FET to a MOSFET or Bipolar device in and of itself change the "sound" of the amp? What about using different capacitors types such as electrolytics, tantalum, ceramics, paper-in-oil, polycarbonate, mica, polyester or polystyrene in the same circuit? Did any of you notice a difference when just replacing a polystyrene with ceramic or paper-in-oil cap?

I'm particularly curious as to what those who actually build amps for themselves such as the manufacturers and DIYers amongst us have to say about this topic.

Thetubeguy1954

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Topic - Bipolar vs MOSFET vs J-FET - thetubeguy1954 05:58:39 01/26/07 (121)
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