Ampex ACR-25 Commercial Player Question

[TVBeeGee]

How many former Ampex ACR-25 folks are here? If you never used one or saw one, you would be amazed to see it work. All the threading was done by differential air pressure. No mechanical arms ever pulled at the tape. Through a careful ballet of various vacuums, tape seemed to magically leap out of its cassette and fly into position on the transport. You really missed something if you never saw one work.

There is a video on youtube showing ACR-25 transports in action, but it is too short and too low in resolution to give those not familiar with the machine a good idea of how it worked. It really was amazing.

Other than the relatively rare mechanical or electrical failure, about the only problem I ever saw with the ACR-25 was that the cassettes seemed to develop a cluster of dropouts at the beginning and ending of where a spot was typically recorded. I always wondered if this might have been caused by the video heads nicking the tape at the point where the head's vacuum guide rose or was retracted. The threading was extremely gentle, but this encouraged the cassettes to be used for many hundreds of plays and perhaps a very tiny amount of wear built up over time. For those of you who worked with the ACR-25, did you ever see these dropout clusters? Do you know what caused them?

[TVBeeGee]

Nobody remembers the ACR-25?!?!?

[NewVista]

I watched the 'low resolution' video you refer to. It shows cassette Ferris-wheel shunting back & forth with great torque! This early attempt at robotics would have been hazardous to work on (as all mechanical robotics can be hazardous to humans), this one designed by Ampex (in Silicon Valley)(not renown for mechanical engineering), so one sees at one point in video they use a lot of off-the-shelf Ledex Rotary Solenoids doing their thing, making a lot of noise..

[TVBeeGee]

You bet! I worked at a station where all engineers were required to wear neck ties. The only exception was if working inside the ACR-25. (For obvious reasons!) The design is late 1960's. The machine debuted at the 1970 NAB Convention. It did include a heavy safety bar that came down into the carousel path when service doors were opened to prevent the carousel from moving if the mechanism was exposed.

Cassettes were driven into and out of the carousel by a pneumatic piston, one on each side, below each of the two transports. This is some of what you hear making that characteristic clunking noise as cassettes are shuffled in and out of the carousel.

The ACR-25 was an absolute wonder of the video world at the time it premiered. Unlike the RCA competition, the Ampex machine shuttled at 600 inches per second and used time code (not beep tones) for cueing, and required only 30 ms (one video frame) preroll. The TBC had a window of one full video line. Price was $160,000 in 1970...over one million US dollars in today's money. The station I worked for owned two machines, with four transports total.

Note that the vacuum guide that holds the tape around the video heads fully retracts BELOW the tape path during threading and unthreading. The Mark XX video head was the only quadruplex scanner ever marketed that had this feature and was also used on Ampex's incredible AVR-1 open real VTR. The Mark XX featured an eight phase head motor.

[NewVista]

Its carousel prob driven with a notched belt from a hi-torque-reversing ~1hp motor? Otherwise standard 'industrial-electronics' type tech. Price no object as they shared a duopoly with RCA, Ampex probably having 80% of market. Today a $100 android device could perform same function - programmed random access to stored videos - a 10,000:1 price reduction.

[TVBeeGee]

Very true about the $100 replacement! But I miss those days when there was real money in television. Back then, when one called a manufacturer with an urgent need for a strange part, it wasn't necessary to explain how the downtime was costing your employer thousands or even tens of thousands of dollars per hour. Often, the manufacturer would return to the phone to say that the part had already been dispatched to a human courier, who was already on his/her way to the airport, and that the part would be arriving on flight xxx counter to counter air at your local airport in three hours. Overnight was not good enough.

For the same reason, excellent engineers and technicians, who could find and fix a problem quickly, were worth very high wages. Now, thanks to the fragmentation of audiences and the likes of the $100 playback device, many operations don't employ any real tech people anymore and the few that do treat them like janitors. Simply throw it away if it breaks.

Today's technology is utterly amazing, but a lot of the humanity is gone. It was more like a big league team sport long ago.

[NewVista]

Then Ampex, filled with the kind of confidence only a monopolist could have, launches the high tech/high priced ACR-225 leviathan!

[kf4rca]

As I understand it most stations on the east coast were RCA. Ampex dominated on the west coast. RCA won an emmy in'69 for the first tape cartridge machine:
https://worldradiohistory.com/ARCHIV...ws/RCA-153.pdf
The first ACR I ever saw was at WFBC (Greenville SC) in '72 (about) but they didn't have it running 100%.
I've heard that RCA had most of the market. The TCR was about $160K and the ACR was $225K. The TCR parts were interchangeable with earlier TR70 machines. The ACR parts were not.
I helped install the TCR at WCBD (Charleston SC) in May of '76. It was the first TCR in the market. Overnight our air "look" cleaned up and blew the other stations away.
The only ACR I ever worked with was at CNN in the early 80's. I fixed an RF warning light (AFC problem) on it on my overnight shift.
The chief called me the next day to congratulate me when I was half asleep.
All I can remember telling him was that ACR is just RCA backwards. And he chuckled.

[NewVista]

That's a good edition of RCA B.N. magazine. In various pictures of cameras & other equip, it's alarming how low the parts-density was on PC boards back then, making repair possible. Also the TCR seems to have more accessible manual cartridge loading, like later machines with X-Y type storage - accessed from the other side of the frenetic robot mech for obvious reasons.

[TVBeeGee]

Many of the parts in the Ampex ACR-25 were also used in the Ampex AVR-1 reel to reel machine, including the Mark XX video head, the signal system and the TBC (buffer) boards, plus many other parts. Many network and broadcast facilities had both models. The AVR-1 featured 30 ms lockup time with any reel size, exquisite tape handling, and could also play tapes smoothly with damaged or even totally missing control track. Shuttle acceleration in the AVR-1 reel to reel machine was limited to 300 inches per second per second...unless you were Compact Video...who modified their machines to shuttle and cue at the same 600 ips speed as the ACR-25. This made for astonishingly fast checkerboard auto-assembly online editing for numerous network tape shows in the 70's.

[kf4rca]

But the ACR headwheel panel would not work in a VR1200 or 2000 where TCR heads would also work in a TR70, TR60 all the way down to a TR3 and 4.
I remember studying the manual on the ACR while at CNN. It used an 8 pole DC servo motor for the headwheel panel. The TCR used a 3 phase AC servo motor. That DC motor was how the ACR achieved fast lockup.
Turner would end up with 6 ACR's. Two for CNN, 2 for Headline News, and 2 for Superstation WTBS.
WSB bought one of the first TCR's Never buy anything when it first comes out. It turns out the harness for the logic bay was too short. When they extended it on the rails they wires popped out of the connectors to the mainframe. Oops.

[TVBeeGee]

I never worked with the TCR, but saw many and heard a lot of stories. Probably the most famous TCR story was the emergency popsicle stick repair for the cart handling fingers. Right?

Probably the most infamous aspect of the ACR was when something would go wrong with a vacuum column/reel servo. It was rare, but when it did happen the ACR had enough power to rip the tape right out of the cassette. This malfunction was usually heralded by a wailing turbine sound, soon followed by a very loud WHACK!

Working on the RF was a little less dramatic. Congrats on your AFC fix! The chief had good reason to be impressed. Nice work, especially if you were new to the machine.

I was a student in the last AVR-1 training class in Redwood City, early 1978. The training class was quite helpful. The analog TBC (one full video line of buffer...in analog) was quite complex, but as usual it seemed most of the failures in practice revolved around power supplies and servos.

[kf4rca]

The real advantage I saw with the TCR was that you could load it while it was running since you had full access to the carousel at all times. It was sequentially programmed which was easier than the ACR.
One of the problems CNN had was with the operators. They were non technical people. The were recent journalism school graduates and wanted to be reporters and anchors. They felt that "running tape" was akin to slavery. They were making minimum wage. They learned early on that if they did a bad job they would get transferred out of there. I brought this up to the CE and he said it was out of his area of responsibility.
I remember one of the girls crying over the intercom when things went bad. I reassured her that this was just like real television.

[TVBeeGee]

So true. Fortunately, I worked at operations where all the operators reported to engineering, belonged to the engineering union, and were members of the engineering team. We all wore ties and dress shirts and took a lot of pride in our air product. We had Nielson 60 shares for local shows. Big profits. Expensive equipment.

MUCH has changed. Severe audience fragmentation, brought about first by cable, then followed by streaming, turned broadcast dollars into Internet pennies.

[kf4rca]

CNN was under-capitalized from the beginning. I think Ted Turner thought he would get more advertisers than he did. Consequently he ran too many PI spots which didn't pay the bills.
I remember transponder time was $500 an hour (C-band). And they didn't give out checks till after 4PM on Fridays. Insiders called it Charity News Network.
The stations who had ACR's were 5,11, and Turner (17, CNN, Headline News).
The TCR stations were 2 and 46.
I moved on to 46 when it was clear that Turner was in trouble. I got a dollar an hour raise. 46 had two TCR's. They were the 4th news station. They were owned by Tribune and a CBS affiliate.
Their Corporate Engineer was a "rock star." His philosophy was,we were going to stay on the air, no matter what, just short of a direct nuclear strike. It was great seeing all the new equipment rolling in!
He even had pocket protectors made up with the corporate logo after an unfortunate experience with a pen at the NAB. I wore mine proudly at the local SBE meetings.
And we always had beer in the transmitter building's refrigerator.
What a guy!