|Fisher TX-200 integrated stereo amplifier|
THE EQUIPMENT: Fisher TX 200, a solid-state preamplifier and power amplifier on one chassis. Dimensions: front panel, 15¼ by 4¾ inches; depth behind panel, 12 inches. Price: $279.50. Manufacturer: Fisher Radio Corp., 11-40 45th Rd., Long Island City, N.Y. 11101.
COMMENT: Solid-state and using no output transformer, the new Fisher TX 200 amplifier is a high-performing unit that offers a full panoply of control features as well as high, clean power across the audio band. The gold-anodized front panel, divided into two horizontal areas by a decorative ridge, presents a neat and well-ordered appearance. The upper row of controls includes: a six-position program selector; a mode switch (mono, stereo, reverse); a channel balance control; and a pair of dual-concentric, friction-coupled tone controls (so that bass and treble can be adjusted simultaneously or independently on each channel, as desired). The larger knob at the upper right is for power off/on and volume.
The lower half of the escutcheon contains six rocker switches for: tape monitor; main speakers off/on; remote speakers off/on; low filter; high filter; and loudness contour. Centred between the rocker switches are three pilot lamps which indicate what mode of operation is being used, a stereo headphone jack, and a tape jack that permits hook-up to a stereo tape deck directly from the amplifier's front panel.
At the rear of the chassis are two sets of barrier terminal strips for speaker connections; two switched AC convenience outlets; seven stereo pairs of input jacks; another pair for feeding to a recorder; and four fuses for the set's eight output power transistors (one fuse for two transistors). A slide switch selects the speaker output impedance (4, 8, or 16 ohms). In addition, there are special input and output jacks for connecting an external reverberation unit; normally, these jacks are kept shorted.
The back panel of the TX 200 serves as the heat sink for its eight output transistors. Individual bias controls are provided on the chassis for each set of two output transistors, making four adjustments in all; these are factory preset and not normally used by the owner.
In tests conducted at Nationwide Consumer Testing Institute, Inc. (a subsidiary of United States Testing Company, Inc.) the TX 200 shaped up as a very clean performer, with characteristics that would suit it for driving any known speaker system of any efficiency.
The measured performance data, shown in the accompanying chart and graphs, all follow the manufacturer's specifications very closely and indicate an honestly rated, well-engineered product. The IM characteristic is representative of many solid-state integrated chassis, in which distortion measures higher at lower power output levels. However, at the levels most often used the IM doesn't rise much above 0.5 per cent. The amplifier's damping factor is a very favourable 10, and its harmonic distortion is very low across the audio band.
Both the RIAA (disc) and the NAB (tape head) equalization characteristics are excellent, and this is one of the few integrated amplifiers encountered that can supply accurate playback direct from tape heads, if desired.
Tone controls, filters, and loudness contour all functioned smoothly and exhibited very favourable characteristics from a music-listening standpoint. Sensitivity and signal-to-noise ratios of all inputs were very good. The high-frequency square-wave response showed no ringing and good transient characteristics; the low-frequency square-wave showed some tilt, reflecting the rolloff in the extreme bass (below 20 Hz) that is typical of integrated amplifiers. The stability of the TX 200 was found to be excellent.
A versatile unit, the TX 200 is also a clean-sounding one, and another example of how solid-state design can achieve superior performance in an attractive and relatively compact format. It should be of interest to anyone seeking a substantial control amplifier at a fairly reasonable cost.