It also avoids the expense and quality of the additional cables required. The important difference between this approach and the external passive control concept is merging the two sections into one unit solves the impedance-matching problems. All you need is a volume control and input selector and the amplifier is complete. Simply, the power amplifier gain is raised to increase the input sensitivity from (typically) a volt or so to a quarter of a volt, accommodating a standard range of audio sources. The original practice of integrating a preamplifier and small power amplifier in one casing, generally for reasons of economy, is modified by removing the active part of the onboard line preamplifier, so shortening and simplifying the signal path. The second alternative has become popular over the past decade and is frequently seen in moderately priced audiophile-grade integrated amplifiers (footnote 1). Though such devices are highly demanding of source and load matching on grounds of both impedance and signal voltage, it is nevertheless possible to achieve very good sound in compatible audio chains, to the serious embarrassment of many costly active-control units. This may well look and act like a preamplifier, but it lacks an active gain stage or unity-gain impedance-matching buffer. On the other hand, sensible choices have to be made when analog disc is a key component of a system this source, in addition to amplification and RIAA equalization, generally requires a form of line-level control.Īn intermediate strategy is to use a passive controller. There are unmistakable gains in fidelity with such systems, and it takes a truly exceptional combination of separate line controller and interconnect cable to compete. When these include their own volume controls, either in the digital ( eg, Wadia 850 and 860, dCS Elgar, Meridian 518) or the analog (Krell KPS-20 i/l) domain, their audio outputs can be directly linked to the power amplifier, eliminating the controller and its cabling. One sidesteps the problem of input selection and lets the aspiring audiophile concentrate on his main source of audio replay, usually digital: an input-versatile CD player or DAC. This part of the chain is completed, albeit inflexibly, by a hand-soldered pair of high-quality resistors per channel, these serving as a system's ultimate, fixed-level volume control. Some enthusiasts even resort to changing signal source by manually switching out interconnect cables: sources are chosen with sufficient power and voltage to drive the power amplifier directly. I say "hair-shirt" because, on the face of it, audiophiles require the facilities a line controller offers: control of system volume and input selection. Some hair-shirt enthusiasts have gone all the way, attempting to eliminate the line controller altogether. These losses result from the necessary cable runs, the plugs and sockets, the input selector, the volume control (however well executed), and the active amplifying device. While in general this is true, some losses in signal quality are inevitable when using a preamp. The search for signal transparency has led to much experiment and debate concerning losses in fidelity that can be traced to the preamplifier or-as it's more often and awkwardly called these days when the phono stage is omitted-the "line controller."įew preamps these days are burdened by analog disc inputs, and in consequence should logically be either cheaper or better, or both.