|Scott 260 stereo integrated amplifier|
THE EQUIPMENT: Scott 260, a solid-state integrated preamplifier-power amplifier. Dimensions (in metal case supplied): 15 by 12½ by 4 inches. Optional feet raise height to 4¾ inches. For knob and rear connections, about 2½ inches should be allowed. Price: $259.95. Manufacturer: H. H. Scott, Inc., Ill Powder Mill Rd., Maynard, Mass. 01754.
COMMENT: One of Scott's newest products is the Model 260 combination amplifier, a solid-state transformer-less unit that is handsomely styled, has a full complement of controls, and is truly a splendid performer in every respect. It easily meets or exceeds its specifications, is loaded with useful features, and has a superb listening quality.
Mounted on the gold-anodized front panel are six slide switches for tape monitor, rumble filter, scratch filter, loudness compensation, speakers off/on, and power. In addition there are six control knobs. A four-position input switch selects tape head, phono, tuner, or extra. To its right is the versatile mode control: in its BAL. L or BAL. R positions, signals coming in on both left and right inputs are combined and sent to either the left or right speaker, respectively. When used in conjunction with the balance control, the BAL. L and BAL. R positions of the selector switch enable the user to equalize the volume of the two speakers. Both STEREO and REV. STEREO positions of the selector switch provide stereo operation, but the latter position reverses the two channels. In addition, the L. INPUT and R. INPUT positions of this switch feed the input signal from either the left or right input through both amplifier channels and into both speaker systems.
The bass and treble tone controls are dual-concentric; they may be used on each channel independently, or inasmuch as they are friction-coupled—they can regulate both channels simultaneously if desired. A large volume control is located in the upper right-hand portion of the front panel. A low impedance stereo headphone jack is located just under the speaker switch, and a pilot lamp is placed below the power switch.
At the rear of the amplifier are the four pairs of stereo inputs that correspond to the settings of the input selector control. In conjunction with the phono inputs is a phono sensitivity switch that allows three choices of phono input impedance, and which can be set to maintain the amplifier at constant volume level when switching between different program sources. There also is a pair of tape feed jacks, and a pair for signals from a tape recorder on playback. Also on the rear is a jack for feeding an A + B signal to a separate monophonic amplifier for centre-channel fill, or to pipe a mono version of a stereo program into another room.
Speaker connections are made from a pair of barrier-terminal strips, and each output has an impedance selector with one position for 4-ohm speakers and the other for 8- to 16-ohm speakers. There are three fuse-holders: one each to protect the speaker output and one slow-blow type for the AC line. The power cord and two AC outlets (one switched) complete the rear complement.
The circuitry of the Model 260 is built around twelve transistors per channel, plus additional solid-state devices in the power supply. The only "iron" used is the power transformer; there are no interstage or driver transformers in the amplifier.
In tests conducted at United States Testing Company, Inc., the Model 260 proved to be an outstanding performer. Power output, which extended beyond the "normal" audio band, was high and clean enough to drive the lowest efficiency speakers; distortion was extremely low; signal-to-noise ratio excellent on all inputs. Frequency response was virtually flat to 100 kc at the high end, and to about 10 cps at the low end. The IM characteristic was one of the most linear yet encountered in any solid-state amplifier, remaining very low up to the rated output. It was best at 8 ohms, which is of course the most widely used speaker impedance. Actually, however, the IM at all three impedances, combined with the amplifier's power reserves and stability, would recommend the 260 for use with any speaker available.
Equalization characteristics, for both RIAA (disc playback) and NAB (tape head playback) requirements, were excellent. Unlike many combination units, in which the NAB curve is somewhat compromised, the 260 provides highly accurate equalization for tape heads and thus is one of the few amplifiers that can be used, if desired, for direct playback from a tape deck that has no built-in preamplifier. A minor feature this, but another indication of the careful design of this equipment. Square-wave response of the 260 also was noteworthy: the 50-cps response had some tilt, but still was better than average; the 10-kc response had fast rise-time no ringing, and indeed approached the ideal in shape
Listening tests confirmed the measurements. The Scott 260 had a clarity and ease of reproduction that satisfied all listeners and made it the inevitable choice over a tube amplifier of similar power output. It had that "clean transistor sound" and, like other topflight solid-state amplifiers, seemed capable of getting maximum performance from any speaker it was connected to.
Without doubt, the 260 is one of the best-integrated amplifiers available; indeed its performance is of an order that suggests, or even exceeds, what used to be obtained from separate preamps and power amps.