The Mod Squad's standard Line Drive, the one that's become the passive control preamplifier, costs a mere $500; Steve McCormack is the first to admit that it is a value-oriented design. His ultimate goal, however, was to construct a passive control system that would be sonically identical to plugging a source component directly into the power amplifier. The Deluxe AGT version represents Steve's best shot yet at that goal: a slam-dunk of a shot in which nothing has been spared to wring that nth…
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John Atkinson reviewed The Mod Squad Deluxe Line Drive AGT in January 1989 (Vol.12 No.1):
Sidebar 1: JA's System Details
The fundamental listening tests involving The Mod Squad Line Drive were carried out in a system consisting of the VTL 100W Compact monoblock amplifiers driving Celestion SL700 loudspeakers, though I also used the combination for all the loudspeakers that I tested for this and the next issue of Stereophile. In addition, the pair of Thiel CS1.2s reviewed by Larry Archibald in this issue spent a considerable amount of time in my system.
Line-level source components included my stock Revox A77 for master tape replay, CD players from The Mod Squad and…
Sidebar 2: Measurements
The only measurements relevant to the Line Drive are the crosstalk between channels and its input and output impedances, which will affect compatibility with source components and interconnect cables. The input impedance on all inputs is a lowish 8200 ohms, which could lead to a lightweight bass with high–output-impedance, capacitor-coupled tube preamplifiers. The Line Drive's output impedance will depend on the volume control setting; the resistance of the conductive-plastic track between the wiper and ground and the wiper and the signal input will be in parallel…
Sidebar 3: Specifications
Description: passive control unit with five line-level inputs, two tape loops, and two main outputs. Input impedance: 8200 ohms. Output impedance: variable according to volume-control position, reaches a maximum of approximately 2100 ohms not including impedance of selected source. Channel separation: 86dB (20Hz), 83dB (1kHz), 72dB (20kHz).
Dimensions: 16.5" W by 10.75" D by 2.5" H. Estimated weight: 3 lbs.
Price: $400 (1987), $500 (1989), $900 (1989, Deluxe version); no longer available (2009). Approximate number of dealers: 115.
Manufacturer: The…
Thomas Alva Edison may have had a fully equipped laboratory, with a team of assistants slaving every day over ideas to be adopted when ripe as those of the great inventor, but the image of American ingenuity which rings true to me is of the lone tinkerer, working alone and mixing a generous dose of good ol' Yankee know-how with the sweat of his brow—a lot of it. These days, with the faithful PC and a hardworking CAD program at his side to do the math, the lone tinkerer seems to be thicker on the ground than ever, to judge by the humongous numbers of small companies selling high-end hi-fi…
Following the electricity from the wall in its transformation from industrial muscle to music, the captive mains lead feeds a small toroidal transformer from the UK manufacturer Cotswold Electronics, the output of which is rectified and smoothed before being fed to a pair of LM317T/LM337T regulator chips. These drop the supply voltage from ±37.5V to ±26.5V, and, as they carry the entire current required by all the active circuitry, run pretty hot. They therefore use the bottom panel of the chassis as a heatsink, which has the advantage of heating the enclosure to a steady temperature. The…
Sidebar 1: JA's System Details
The fundamental listening tests involving The Mod Squad Phono Drive were carried out in a system consisting of the The Mod Squad Line Drive Deluxe VTL 100W Compact monoblock amplifiers driving Celestion SL700 loudspeakers, though I also used the combination for all the loudspeakers that I tested for this and the next issue of Stereophile. In addition, the pair of Thiel CS1.2s reviewed by Larry Archibald in this issue spent a considerable amount of time in my system.
Line-level source components included my stock Revox A77 for master tape replay, CD…
Sidebar 2: Measurements
The Phono Drive had a measured output impedance of 60 ohms from its direct-out sockets, and an even lower 50 ohms from its line stage. Neither outputs should have any difficulty driving long or highly capacitive interconnects. The input impedance of the line section I measured to be 11k ohms; again, no problem except with some antique tube components or the Mk.I version of the CAL Tempest CD player, which had a 5.6k-ohm output impedance.
The gain structure of the Phono Drive appeared to be around 20dB from the MC headamp, followed by 44dB at 1kHz from the…
Sidebar 3: Specifications
Description: Dedicated MC/MM phono preamplifier, with separate line-level amplifier with volume and balance controls. Measured specifications: Frequency response (phono): 5Hz–110kHz, –3dB. Frequency response (line): DC–85kHz, –3dB. Output impedance: 60 ohms at 1kHz (phono direct); 50 ohms (line out). Input impedance: 45k ohms (MM); either 10, 20, 40, 100, 200, 1000, 47k ohms, or user selectable (MC); 11k ohms (line). Phono Sensitivity: 5mV RMS for 775mV output (MM); 0.5mV RMS for 775mV output (MC); 125mV RMS for 775mV output (line). S/N ratio ref. 775mV out (…
A psychological theory (footnote 1) that I've always been fond of is the one that proposes the perceptual/personality dimension of Sharpening vs Leveling. As defined by the early Gestalt psychologists, Sharpening is an exaggeration of differences, Leveling a minimization of differences. In visual-perception research on this topic, when test subjects were presented with an asymmetrical figure, some later recalled it in ways that exaggerated the figure's asymmetry (Sharpeners), while others minimized or eliminated it (Levelers).
It seems fair to say that—like those who have a strong…