The Sherwood Micro/CPU-100 tuner does damn near everything else. It's the latest in microprocessor-controlled digital tuners and one of the most expensive FM tuners you can buy. What do you get for $2000? Simply put, you get an excellent piece of audio gear and one of the most fun toys of the year.

Let's get the audio part out of the way quickly. In terms of specs and performance, the CPU-100 is a winner. A scan of the spec sheet reveals sensitivity of 1.7 uV or 9.84 dBf. For 50 dB quieting, the figure reads 2.1 uV or 11.7 dBf with a normal IF bandwidth and 30 uV and 13.5 dBf with the IF band switch in a wide position. THD figures for stereo reception are nothing short of remarkable. They show 0.2% at 100 and 1,000 Hz and .25% at 6,000 Hz. With the IF band switch on wide, the figures read .15% for all three frequency check points. Signal-tonoise is listed at 75 dB for normal or wide IF in the mono position and shows a loss of only three dB (down to 72) for stereo. Capture ratio is shown at 1.0 dB for normal IF and 0.5 for wide. Alternate channel selectivity measures 80 dB for normal and 18dB for the wide setting. Stereo separation (the measure of how good the stereo effect really is) yields figures of 40dB for 100 Hz, 45 at 1,000, 35 at 10,000 and 30 from 30 to 15,000 Hz, For the wide IF position, increase the results five dB for each category. These are truly impressive statistics for any tuner.

That's what the paper shows, but the real question is one of perfor-

mance. Doss two grand worth of sophisticated electronic components actually give me something far in excess of what I can get for a tenth of that? The answer is a resounding yes.

I used the Micro/GPU-100 with the B.I.C. Beam Box indoor antenna and got results that matched and in many cases exceeded any tuner I had in the house. On some stations I heard music for the first time. I live in a particularly difficult section of Manhattan (from a radio point of view) and the Micro/CPU-100 was able to pick its way between signals and their doppelgangers with reasonable facility and to discriminate between signal and nonsignal with almost unfailing precision.

I have chosen to stress specs and performance rather than features first because this is a most feature-filled tuner. It is unique. It's a state-of-theart audio use of microprocessor digital technology. The Micro/CPU100's spec sheet list semiconductors as follows: 76 ICs (8-bit CMOS microprocessor, 768 x 8 bit Read Only Memory, 256 x 8 Random Access Memory and 1 ASCII character generator); 48 transistors; 3 J-FETs; 3 MOS-FETs; 31 LEDs; 4 LED alpha numeric displays; 6 varactor diodes; 7 power diodes; 2 solid sate infra-red interrupters. Impressive?!

You better believe it is. But what does it do? Well, to begin with, the tuner digitally synthesizes frequencies. That is, there is no tuning capacitor. That means there need be no tuning meter either, for each frequency is, by definition, perfectly tuned as it is synthesized by the tuner. The Micro/ CPU-100 has, however, two large meters, one for signal strength and the other for multipath (the audio equivalent of TV's "ghosts"). It also has a conventional looking tuning dial in addition to the digital station frequency readout. The reason the dial is only conventional looking is that while we see a dial, we see no dial pointer. Instead the tuner has a series of LEDs which light up to tell you

where on the "dial" you are tuned. And if two indications (the frequency numbers and dial location) are not enough, this tuner will give you a programmable alpha numeric readout of up to 48 four-character stations. If your area has more than 48 receivable FM stations, you're just going to have to make some decisions about which ones will be without tell-tale call letters.

Programming call letters is accomlished rather simply by tuning in a station either via the tuning knob or the automatic scanning system and pressing the Alpha touch control that puts an "A" in the first position. By rotating the tuning knob (which instantly converts from tuning to programming function) you can go through the alphabet, numbers and a series of signs as well. Once you've selected the first character, a "W" for the call letters in much of the country* you press the Store touch control and repeat the process until all four slots are filled. You've now got a station's call letters permanently synched with the frequency. For instance, 93.9 in New York is WNYC. That combination is now locked into the tuner's memory and will appear when the tuner is manually tuned to the frequency or autoscans the band and comes to it. You can also place the combination into one of the four

touch-to-tune memories.

The fun comes in programming other things into your alpha readout. 106.7 in New York (WRVR) is devoted to a certain 20th century American musical idiom; my Sherwood informs me "JAZZ" when it arrives at that frequency. Likewise, 94.7 (WFME) is a local religious outlet and winks "OGOD" at me as I tune by. A station devoted to classical music could readout "CLAS" or, more interestingly, "BACH," while a more contemporary station would read "ROCK." The possibilities are almost endless because of the numeric and sign capabilities of the readout.

Fun is fun, but what of the other controls and features of this remarkable tuner? Well, we've already touched on the auto scan touch tuning which will go from wherever you are on the band either left or right (up or down). If it does not hunt out a usable signal it will come back to its starting point and go the other way. You can also, with a touch, set the unit to accept only stereo broadcasts. An-

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other touch and it handles mono as well.

The lower part of the front panel has a swing open door. When opened, the door dimly reveals a set of two knobs which control output and muting level and five flip switches handling muting (in/out), selectivity (normal/wide), filter (iq/out), mode (stereo/mono), de-emphasis (normal/25 usee). Here is the only bone I have to pick with Sherwood. The control section is handsomely designed with blackfinished interior and white lettering and black controls. However, because of the black and the controls' location within the body of the tuner, the controls are difficult to see and manipulate. I would have been happier had the company interlocked a light panel above the controls. This would have illuminated the-^ controls and maintained the design and human engineering of a very fine unit. Really, how much more would it have increased the Yost of a $2000 tuner? Perhaps in the next model...

All of this quality is quite fabulous, but once you have it, you are struck by one almost overwhelming fact. Radio stations had better clean up their acts. Those with better quality tuners have known for some time that the signals sent out by stations are inferior to what the best consumer electronics engineering can make available to the listener. That gap is increasing and as the technology filters down, we are faced with a situation of having marvelous receivers that we don't want to turn on because we can't abide the crud we hear. Sherwood, a nice job.