The AMPEX MM-800's cast-magnesium base plate is strategically ribbed for rigidity. It rests on a special, three-point suspension system to mechanically ensure that there will be no warping while the big 10.5-inch reels with their 1-inch tape are in motion. Further, the lightweight magnesium is an excellent heat sink. It eliminates hot spots, making the MM-800 a cool-running machine and helping keep the tape-path elements in precise alignment.Message Board - AMPEX MM-800 General Discussion
You'll find that the MM-800's simplified servo-controlled drive system gives excellent tape speed control. The motor shaft itself is the capstan. The shaft is machined to extremely close tolerances (±0.0001) and it is the only internal variable in the system that affects tape speed. You switch speeds electrically (15 and 30 ips, or 7.5 and 15 ips) quickly, quietly.
And tape speed is always accurate. A special integral capstan- speed servo system continuously samples both frequency and phase of the capstan tachometer and compares them with an internal standard frequency. The output is used to provide extremely accurate capstan speed control. The combination of capstan control and precise tension control introduces speed accuracy rarely obtained in audio recorders.
Overall excellence of MM-800 system design is demonstrated by its superior tape handling characteristics. Smooth and gentle braking and completely interlocked control circuitry eliminate possible tape stretch or breakage. Front accessibility provides easy routine preventive maintenance.
Innovation in tape recorder technology improves the breed. Yet, an innovative recorder must stand alone and prove its own worth. The MM-800 is ready for the challenge. We've brought together the ideal transport for one-inch tape and the quietest, cleanest electronics available the sweetest marriage you'll ever come across in eight channels.
Experience the MM-800. You'll find it the smoothest tape handling transport you've ever operated. Tape threading is simple and straight forward. In the fast forward and rewind modes, tape lifters raise the tape from the heads, increasing tape life and reducing head wear Controls are simple and convenient for finger-tip command operation. Designed specifically for eight-channel requirements the MM-800 is not offered in other versions.
For the best electronics, we didn't have to look beyond the MM-1000. Yes. the MM-800 uses the same electronics recording engineers and mixers swear by in both the MM-1000 Series and the AG-440B Series recorder/reproducers. Solid-state? Yes . . . but more importantly, these electronics give maximum S/N and a distortion free dynamic range. And the MM-800 records and plays back 30 - 18,000 Hz at 15 ips. All electronics modules plug into the front of the chassis for easy rapid accessibility. Playback, record, and bias amplifier boards afford you front-panel adjustments. Special logic-and-control circuitry eliminates intolerable editing "pops" when switching record amplifiers. All eight channels' electronics are mounted on an overbridge above the transport tor easy operation. Large illuminated easy-to-read VU meters can be switched to read record input, output, and bias current. A special control allows easy calibration of record and playback levels.
The Ampex pioneered Sel-Sync® system (selective synchronization) that made creative multichannel mastering possible is standard in MM-800 electronics. The Sel-Sync system allows selective switching of recording heads to playback operation giving you the freedom to develop the right sound, and add new dimensions to the sound, even after the talent has gone home.
New Sel-Sync system logic improves S/N and frequency response while in that mode. And control backlighting in the remote control makes it easy to use. Lighted color codes indicate the mode of each track. Inter-channel beats are eliminated by a special master bias oscillator. A 150k Hz bias frequency is fed to all eight channels assuring stable record/reproduce performance. Foundational text and photos courtesy of Ampex Corporation.
Dale Manquen, at MANCO, shares his thoughts on the Ampex MM-800:
By the time I arrived at Ampex in August 1971 there was nothing left of the MM-800.
There were two markets for an 8-track machine. We normally think of the recording studio market, but there were also a lot of 1" machines used to take duplicating masters for 8-track consumer cartridges. The AG440-8 had lots of users in this duplicating market.
Reading between the lines, I would guess that the MM-800 was intended to use some of the components that had been developed for the ABR-10/15 Automated Broadcast Recorder/Reproducer. The casting for the AG440 servo motor came from that era, but the ABR-version servo motor packaged the servo controls onto a circular PC board (or two?) that was attached to the motor. The ABR also had tape tension controls since it was intended for reels up to 14 or 15 inches in diameter.
The ABR program was a huge can of worms. There were bad problems in the field, and on a few occasions the machines were replaced with AG440s. I killed the ABR to get it out of our hair, but there were so many parts for the ABR in inventory that they tried to design a duplicator with the parts.
The idea was to build an intermediate-speed duplicator for radio program syndication and moderate-volume duplicators. Okio Hosada was the designer of duplicator. It was also a failure. AD-15??
The MM-800 description alludes to what sounds like the cal pots on the later 440/MM1000 electronics modules, and maybe the relay-controlled monitor switching for SelSync. I don't see a picture of the remote control with internal illumination. Maybe this used the Switchcraft leverlite switches used on the MM1000.
When I got to Ampex in '71, they were running around like a bunch of chickens with their heads cut off, scared to death of the 2-head Scully 100. The MM1100, originally called the M500 as half of an MM1000, was to be a low-cost 2-head machine for that market - a Volkswagen. Fortunately, we introduced the machine as a 3-head version.
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