Are Pre-Amps necessary?

@atmasphere  I only meant straight wire comment as a theoretical. I've long found my active pre's superior to passives and dac direct. Bass, impact, as you mentioned, much superior with the two actives I've owned.

in the real world of rat race fatigue, pre-amps with their sound adjustments are just what the doctor ordered, the spectral tilt control in old quad pre-amps a case in point, some days you just need more mellow. some noisy old recordings could benefit from a true mono switch [discards the stereo difference signal and not just a mere fold-down] or groove selector to choose the quieter groove of a mono recording. a balance control for people with uncooperative listening room dimensions and poor/inflexible juxtaposition of listener and speakers within the room. EQ to improve listenability of subpar recordings and rooms acoustics. straight wire with gain is both a clear window AND a window in need of a shade at times. 

And to all, active preamps have volume controls as well, and most times not as good quality as the better passives pre's usually use. Also active pre's use many other distorting/colouring components in them.

At least passive pre's usually only have a quality pot, which is why they are the closest in sound to going direct (a straight piece of wire) when used correctly.

And balanced is not needed if you only use <3mts interconnect, and in many case better as the balance inputs and outputs on many pieces of equipment, are opamps to make them balanced, when their true circuit is not, so your better off using the single ended inputs on those, again a more direct path, instead of going through opamp etc for balanced

This entire post is false. Many active preamps employ custom multi-position switches rather than pots, built up with fancy resistors to create a volume control. MBL does this, CAT, Atma-Sphere and many others. The first 2 paragraphs thus debunked.

The '<' symbol means 'less than' but I am assuming that in the quote above George meant to use the '>' symbol.

The benefit of balanced operation is there even if the cable is only 6" long. Anyone familiar with motion control can tell you that... the rejection of noise induced in the cable does not matter how long the cable is. It relies on the Common Mode Rejection Ratio at the input of the receiver (amplifier). Most solid state amps made today are actually fully balanced and many of them have differential inputs. Some are executed with opamps, some are not. Opamps can have extremely high CMRR values, in excess of 120dB, and set up with unity gain they offer no coloration whatsoever. There are places where opamps are not a good idea, such as the input of a phono section (where the input circuit can be overloaded quite easily) but as an input to a solid state amp they can work quite well. Opamps made in the 1960s, maybe not so much. The main thing you might encounter is increased noise floor if a cheap opamp is used. But if a nice one is used the circuit will be quiet even on horns.


We've been making fully differential balanced amps and preamps since 1987 and not used any opamps for input or output, just FWIW...


George frequently quotes Nelson Pass, who is one of the top designers in high end audio today. Nelson's designs feature differential inputs without opamps for their balanced operation. His are not the only like that by any means. The last paragraph is debunked; the entire post is rubbish.