Behind The Scenes (Jun. 1973)

by Bert Whyte

This column is usually concerned with some specific event or subject ... something with a central theme. There are occasions however, when there are a number of matters clamoring for attention and I am compelled to deal with them in what might be charitably called a "bits and pieces" column. This present effort is of that genre, so if this is not your "cup of tea", you can always turn to the pithy and pungent comments of our dear Editor, or catch Canby's latest musings, or even read our classified ads ... a fascinating glimpse into the microcosm of audio exotica.

The hi-fi industry has a number of trade publications, notably "Audio Times" and "High Fidelity Trade News", that at regular intervals surveys business conditions of audio retailers throughout the country. While the surveys of the past few months reflected the overall state of business, there was heavy concentration on the impact of quadraphonic sound and it's contribution to sales. It was interesting to note the diversity of opinions and the experiences of dealers in various sections of the country. In some stores where quadraphonic sound has been enthusiastically accepted and aggressively merchandised, it has accounted for as much as one third of total sales. This is the exception rather than the rule, with percentages of sales in most stores appearing to run between 5 to 15 percent. There are also a distressing number of stores in which quadraphonic sound is given the "Bah!-Humbug!" . . . "Who needs it" kind of treatment. They are entitled to their opinion of course, but one rather suspects that type of outlet still offers sharpening services for cactus needles! All kidding aside, the surveys showed that there was a general acceptance of quadraphonic sound as a fact of life, and as a distinct marketable entity. However, there was also universal concern that the quadraphonic disc war was causing much confusion among their customers, fomenting fears of equipment obsolescence.

Well, the dealers can take heart, because their laments have not fallen on deaf ears. I pointed out several months ago that at the Consumer Electronics Show in June, we would almost surely see receivers with built-in SQ, QS and CD-4 facilities. It is now certain that this will be the case, although by no means across the board with the products of all receiver manufacturers. What precipitated this as much as anything, was the signing of the Warner record group to the CD-4 system. Even the most obtuse could see that both the matrix and the discrete camps have plenty of clout, and that co-existence is the order of the day.

Obviously the customer is going to pay more for such expanded facilities, and with the fragile inter-national money situation, the rise could be quite considerable. But whatever the ultimate cost of these units, their mere existence can allay the fears of obsolescence. In essence, the ball will be tossed back to the dealer, and it will be up to the dealer to effectively demonstrate all the quadraphonic modes of these new units and turn his customer's apprehensions into sales.

The next item on the agenda will be short and to the point. I get more mail from readers asking where they can purchase pre-recorded open reel tapes, than almost anything else. I have furnished this information before ... ye Editor has proffered it as well, but here it is again. The King Karol Record Shops in New York specialize in tape in all formats, and operate a mail order service. The Sam Goody shops, have similar service, with not quite the depth of stock. Columbia has not issued any open reel tapes for some time (more's the pity) but catalog items can be obtained in these shops. The open reel situation at RCA is somewhat similar, except that they have made a deal with a company called "Magtec", to issue catalog items (which incidentally will return to the original 7 ½ ips speed, instead of the 3 3/4 ips of latter years)

as well as new productions, including, it is rumored, quadraphonic tapes. Both of the aforementioned stores carry items from the Ampex Stereo Tapes catalog, but for some time now Ampex has been operating a successful open reel mail order service which is said to offer 24 hour "turnaround" on orders. You can get an Ampex catalog covering 6000 some selections on over one hundred different record labels by sending 50 cents and writing to ... Ampex Catalog Offer, Box 178, Elk Grove Village, Illinois 60007. Keep those open reels rolling! Speaking of Ampex Stereo Tapes, it is a pleasure to announce that they have decided to issue quadraphonic open reel tapes. In fact I have the first six productions. From the London catalog there is "Chacksfield Plays Bacharach"; "Annunzio Paolo Mantovani", 25th Anniv. album; "A Salute To Glenn Miller", Ted Heath Orchestra; and a sampler entitled "The Quadraphonic World of Phase 4 Stereo". From Vanguard their by-now-familiar "Surround Stereo" sampler, and from Enoch Light's Project 3 label, "Four-Channel Dynamite". Admittedly, not much in this batch for the classical buff, but they will be coming along as quadraphonic masters are made available to Ampex. In the meanwhile, this first effort is very well done, with excellent processing, including fairly low hiss levels, although it is obvious that Dolby B noise reduction would be as helpful here as it was in the recent issue of Vanguard "fore and aft" Dolby tapes. London's approach to quadraphonic seems a bit more conservative than the dynamic "freewheeling" philosophy of recording espoused by Enoch Light. They use surround techniques, obviously mix downs from 16 track material, but I have a feeling that none of the productions were originally conceived for quadraphonic sound. Nonetheless, their tapes are quite effective, certainly produced with a sharp ear for musical values. On the sampler is a richly sonorous and spectacular excerpt from "Victory At Sea" and a vividly atmospheric arrangement of the "Russian Cavalry Song", with parts of Borodin's "Prince Igor" interpolated into the score. The Glenn Miller tape uses all the old familiar arrangements, which are played almost by rote, but this will not bother those who want a literal re-creation, if not the spirit of the "Miller Sound". All in all, an auspicious debut for Ampex quadraphonic open reel tapes.

If you are at all serious about tape recording, sooner or later you come to the realization that the two line and mic inputs provided on most tape machines are a decidedly limiting factor.

The answer to more mic and line inputs is the use of an accessory mixer. These come in all sorts of sizes, degrees of sophistication and prices. I have used a number of popular mixers over the years, all of which had their virtues, and all of which lacked certain features, which from my viewpoint at least, would have been desirable.

For some time now I have been using a Prokit SM-6A mixer made by Gately Electronics of Havertown, PA. This unit is available as a kit at $299.00, or factory-wired at $499.00. It is well worth the money in the wired version, and if you have the time and the dexterity to put the kit together, it's a real bargain. Being a lazy type cat, I opted for the factory version. If you are tired of lugging equipment on location recordings, the first endearing feature of this mixer is that it measures a mere 17 in. wide, by 3 1/2 in. high. by 9 in.

deep, and weighs in at about ten pounds. Small as it is, it is loaded with facilities, many of which are not available on larger and more expensive mixers.

The Prokit will mix up to six signals simultaneously, either line or mic inputs, which are pushbutton selectable on the front panel. Since the SM-6A is a stereo unit, any of the six signals can be assigned to either channel A or B output.

Inputs 5 and 6 on the unit can be switched to provide phono preamplification with standard RIAA equalization.

Line or mic inputs one through four can be switched to channel A or B, or both ... the latter point being of particular value to me. Control over each input is via silky-smooth pots, and there is a master pot for each output channel.

Two VU meters are provided, which in the factory-wired version are set up so that a "0" VU indication results in a +4dBm output. Additional taps are provided so that a "0" VU indication can be either 0-dBm or +8dBm. On the rear panel of the Prokit, the mic preamp gain can be switched between 35 or 55 dB on each input, such range covering most dynamic, ribbon, or condenser mics. There is also a switch that can provide a low frequency cut at about 100 Hz on each input. A connection for stacking units in parallel is provided, to gain additional inputs. An accessory EQ-6 equalization kit can be plugged into the rear to provide equalization on all inputs. A headphone jack accepts 600 ohm phones.

The Prokit uses top quality components such as Allen Bradley pots, UTC input transformers, Switch-craft XLR connectors, Centralab push-button switches. Plug-in integrated circuit operational amplifiers are a feature of the unit. Mic input impedance is 150 ohms balanced bridging, line input impedance 100K unbalanced, and the phono preamp is typical 47K unbalanced. Output impedance is less than 50 ohms, and output capability is +20dBm (8 volts) into 600 ohms or higher. Distortion is a very low 0.5 percent at +8dBm (2 volts) and noise is inaudible at -127 dBm on mic channels. Even with the master gain control half-open, the noise is -65dBm.

This "bare bones" description doesn't tell you what a pleasure it is to use this versatile unit. Now I frequently have friends visiting me for listening sessions, and just to titillate them, I play some 15 ips three-channel half inch master tapes. Inevitably they want copies of these, but most of them do not have half-inch 3 channel machines.

Mixing down from 3 to 2 channels before I acquired the Prokit, was a real pain. Other mixers I have used, while of generally excellent quality, usually had an input configuration of 6 mics and but 2 lines. With the Prokit, I simply assign the left channel of my master tape to line input one, channel A output; the right channel of the tape to line input three, channel B output; the center channel of my tape goes to line input two, with both A and B channel outputs. All done by manipulating pushbuttons! Of course, when my friends playback the copy on their two channel stereo machines, the "hidden" center channel is "reconstituted" and appears between their loudspeakers.

Recently I had to make some radio commercials, with source material from a tape machine, from discs, and live voice on mic. No trouble at all with the Prokit. Just plug in everything (including direct pre-amplified phono) push the right combination of buttons, "ride the pots", and the job is done.

Truly, the Prokit is a delight to use and performed flawlessly. If I have a few quibbles, they are that I would like to see either a pilot light showing the unit is on, or illuminated VU meters.

(Good thing too, in dim locations.) Also, while it is nice to have master pots on the outputs of the two channels, things would be handier if there was an overall master pot controlling the level of both channels simultaneously. Needless to say, this function would be especially valuable if you were using two Prokits for quadraphonic recording. Enough of nit-picking. Try one, you'll like it!

(Audio magazine, Jun. 1973; Bert Whyte)

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