Not sure you mentioned this, but this was a "super-compact" portable VTR for field recording. On the studio models, the tape reels were "side-by-side" rather than stacked, and they probably accepted larger reels. In modern VTRs (starting with Sony's 3/4" U-Matic), they put the head drum at an angle, instead of the tape - this allowed both reels of tape to be on the same plane inside the cassette. (Several early formats such as "Catrivision" had the reels stacked inside the cartridge).
You are totally wrong. If you don't have a control track your playback servo will never lock onto the tape, it will go into free run mode, and you will end up with head switching point running through the picture on 2 head (VCR) machines. On single head systems, like the 1" you are working on there won't be the head switch problem (on the 2 head machines the CTRL pulse is used to lock in the tracking for the A field. On a single head machine, technically it is possible to play the tape back if the machine is genlocked to station sync, where the servos can get a reference, but still since there is no reference on the physical tape the tracking can drift in cases where the tape has stretched.Copy protection has had a few different systems tried. The earliest was modification of the video sync, where most, but not all of the vertical sync was stripped. This caused the recording machine that was being used to bootleg a copy to have a heart attack and the result was generally servos falling out of sync and going into free run mode. The result is the copy has head switching point slowly drifting through the picture. The later forms of copy protection was macrovision, which the added severely over recorded pulses to the luminance channel in the vertical blanking area. They would record on a machine with manual video gain controls and record white video at up to 150IRE, and drive the opposing black pulse down below 0IRE into the blanking area on the first dozen or so lines of video following vertical blanking. This caused the AGC on the recording machine to go crazy trying to set record levels and resulted in a picture that blinked bright dark, bright dark and the color to be messed up.Later versions of macrovision, called color stripe made changes to the timing of the color burst which resulted in thin color bands across the picture.Its a beautiful machine. Would love to have one of those in my collection. Carried one for years when I was in broadcast.The term "stiction" was used frequently, and it refers to worn tape that the binder or back coating is "sticking" to metal parts. On playback these tapes would start to screech as they played, and the picture would get lots of wiggly lines caused by these vibrations on the tape. Was a big problem with Ampex tapes.
You're mostly correct, with one minor quibble: you absolutely need the control track to achieve playback servo lock on this machine, because it lacks the R/P sync head 30° offset from the R/P video head -- so the tape is actually missing the vertical interval between lines 4 and 16. This pretty much prevents the machine from discerning where the track actually is with relation to the video lines. On a machine with the sync head you can theoretically identify the start of a field... but in practice the only machines that pull this off are the ones with dynamic tracking heads like BVH-2000s (and even they get upset if they don't see the control track).
Its Funny that the leader in magnetic recording made the worst tape pros almost always used 3m stock as it was very good, uniform quality. Fuji made great tape (on quads) but after 6-7 passes it degraded fast. It was good for camera masters as input to edit. On some machines such as the AMPEX AVR-1&3 and ACR series could easily playbackna tape with no control track. It derived rhe control track from the frame rate. All u needed was a few frames so the internal oscillators locked on. The machine knew what the frame rate should be and opon playback would try the control track if that was bad it derived it from the frames Also I want to point out that a control track was a tone (normally 240hz) not pulses, tha sole purpose was to lock the capstan (or vertical lock) on playback. The control track was derived from vertical sync as it was imperative that the control track was locked to the frame rate. In addition one company I worked for was one of the largest vhs duplication companies in the USA, we devised a copy protection system that would randomly place extra sync pulses on the video signal. It was no problem on playback. Bor was it a problem for tv sets, but when the video signal was fed to another recorder in which the capstan speed was set based upon the vertical interval, all hell would break lose on tbe record machine. All of these copy protection schemes wwre broken fast by pirates
Re: Copy protection. I don't know if the control track method was used on all video tape systems, but the copy protection schemes I know of work by inserting 'loud' signals during the blanking intervals of the video signal to confuse the AGC (Automatic Gain Control) of the recording VCR. Also, not all video tape systems record the video straight onto the tape, but use various modulation and superheterodyne techniques to accomplish it, and sometimes for Hi-Fi audio as well. Just FYI :)
This is a great way to explain how rotary head digital audio recorders worked, it's relation to video technology and how quadruplex 2" machines differed. Denon even used 2" for early 70s digital audio recordings. These are great videos. Thanks
Brought back so many memories of High School and early college... Editing on an AV3650 and AV8650 RtR Video... Cleaning the heads (and yes, they spin up fast) with Xylenes (and don't break them - they're more fragile than a soap bubble), 3 twists on the take-up, 10 seconds (minimum) of leader run. Getting both machines in sync, and we haven't EVEN gotten into PVS's and the old-school analog SEG's... The Panasonic 3085 Porta-pak was awesome - you had a camera, the VTR on a strap on one shoulder, and the battery pak either (hopefully) on a belt pack, or hanging off the other shoulder (and squeezing the sides of your neck) - because the on-board NiCad was worthless for recording time. And you're right - once you do it enough times, threading is awesomely fast and smooth. Thank you for bringing me back to the good old days!
Control track pulses are like a metronome keeping time. Tape speed is never perfectly constant so the recorded pulses help the VTR mimic the recording's tape speeds during playback. It's never perfect, so these Time Base Correctors you may have heard about can be used to electronically finesse the video timing. The whiteboard anim and that VTR are both a joy to behold. Love this vid!
Actually it was not pulses but a tone of 240hz that was made from the incoming veils rate of 60hz. This tone was like sprocket holes on film. The tone was then used on playback to lock the capstan speed. Simple
I used to maintain one of these BVH-500s, as well as our studio BVH-2000s and 2500s. Amazing machines, especially the portable 500. With the internal battery pack, it weighed something like 80 pounds, so every time I took it for a field recording shoot (we did a show from a bowling alley every week), I got a real workout. Good to see one running again, though I was cringing to watch how you threaded it. Generally speaking, you would pull about three feet of tape off the end of the supply reel and thread it through the tape path -- you don't pull it through, especially through the video head assembly. Pulling the tape through not only damages the tape (you can see the puckering in the tape surface where you snagged the entrance guide), putting tension on incompletely seated tape risks chipping one of the video head tips. Aside from being better and safer practice, it's also much faster -- I used to do it in about ten seconds. Finally, you want to trim off damaged tape ends, because they will get caught between the spinning drum and the entrance and exit guides -- there's only about two tape thicknesses of clearance at that point. Studio machines like the BVH-2000 had retracting guides that would move away from the spinning drum as the tape was about to unthread, but the guides are fixed on these portable machines.
You never worked on a poetable quad I bet. It could only record 20 min videos. Had no room for an erase head so you had to use a degaused tape to record on. In addition the tension arms were actually air dialectic caps. So the humidity had to be just right.. The heads rotacts at 14,000 rpm and used ball bearings which wore out. The studio quad machine had the headwheel on air bearings
Yep, that's a BVH-500. I've used one before. You want to try threading without touching the face of the tape to keep the oils of your fingers off the transport. Also it's common to trim off the damaged tail of the tape. If the creased part of the tape goes through the drum, it can damage the spinning heads. Take a look at an Ampex VPR-5. The last and greatest 1" portable helical VTR.
Great machine! One word about the helical scanning, the ‘why’. It’s not about using the full surface of the tape. Video required much higher frequencies to be recorded (compared to audio), for which you need extremely high tape speeds. The helical scanning delivers just that: the tape speed as seen by the head is mostly determined by the rotational movement of the head drum. And because of the very high frequencies a narrow head will do, which also enables packing the tracks closer to each other. Altogether the tape surface is more densely packed with information, but it’s the high frequency recording that requires a high relative tape speed, obtained by the helical scanning.
Believe it or not, standard VHS tape only has a single mono audio track. SVHS has "HiFi" Stereo on the helical data. One of the features of SVHS was increased bandwidth due to better formulations. They encoded the audio subcarrier into the helical strip itself but left the mono audio carrier for reverse compatibility. It's really neat.
***** S-VHS used a 6 head recording system, though incompatible with 4-head jobs, could play regular VHS tapes. Standard tapes made for regular 4-head jobs still had a HI-FI stereo track. Look at the spine of any old film and you'll see that listed in the information on the back. I should know, I grew up with the things.
The scanner has the record/play head and the erase head. The third "head" is called a dummy head, it doesn't do anything and it's only there for balance. Audio, control track and linear time code is recorded on a stationary stack heads. Control track is not really time code, it's more like sprockets on motion picture film. The control track is what lines the scanner play head up to the recorded video track. Some machines also record vertical interval time code, which is laid down with on the video track. VITC time code can be read at slow speeds or even when the machine is in still mode, longitudinal time code, like audio, can only be read at speed.
@@BertGrink On a studio machine like the BVH-2000, that third head position was for dynamic tracking playback: a special head mounted on a quartz substrate that could move slightly when a control voltage was applied. This allowed the machine to produce clean still-frames and variable speed playback from -1x to +3x speed. A machine without the DT head still needed dummy tips, because they maintain the correct drum circumference.
Well close. The control track is an audio tone of 240hz not pulses. This tone is a mutiple if the frame rate (60hz) agreed this is like sprocked holes on film, however film speed is mostly. VERY lax, and varies greatly inless its a professional projector. The control track tone is there to merely set the capstan speed on playback. Tracking sets the the spinning heads phasing from the control track. BOTH tape speed AND head speed must be in sync
I used to work with these type video recorders back in the day at TV stations. They were very dependable to use. The huge broadcast video recorders/playback unit were also great to work with.
I worked at a TV station in 1990 that had one of these that our commercial production division used. They were the only ones that were allowed to use it. News use 3/4" U-matic VCR. We also had 3 big studio 1" VTRs that were used to edit commercials. Fun times.
Sorry Chris you were slightly wrong about the control track, without the control track there is no sync, therefore nothing to track the video too. The tracking then hunts trying to sync making the pic roll or jump. So the control track is very necessary. Also out if interest the early 2" Quadruplex format recorders would wright the information in tight horizontal lines, they would edit the tapes using fero fluid and a razor blade like film :) .
I worked on EVERY machine AMPEX maded and it makes me chuckle when I hear people refer to the control track as pulses. A control track is a tone of 240hz. It is a multiple if the field rate if 60hz. It acts like sproket holes on film. On playback the capstan speed is derived from this tone, it is also used to govern head speed. The two must be in perfect sync with each other. Tbe tracking control refers to the phase difference between recorded control track and head speed. The control track has nothing to do with a sync signal, that comes from the recorded video. With TBCs rhe sync I usually striped off the recoded video and replaced by a clean signal generated by the TBC. Some analog video switchers also did the same thing. They ignored incoming sync and regenerated it. The poor quality video mixers did not refer sync signals and were always a problem AMPEX AVR series of QUAD machines could very easily playback a tape with no control track. It only needed a few frames to get in sync as it took the timing off the video itself as the circuitry woukd determine where the head should be for max RF output. It would multiply the video frames to obtaon both the tape speed and headwheel speed. The video didnt even need a sync signal! Truely an amazing feat if anakog video engineering
Oh I'd love to have a reel to reel video recorder for putting my DVD movies to reel and then watch them outside like an old drive in movie for the neighborhood kids.
The reason for a spinning head has got nothing to do with data density and everything to do with frequency. The maximum recordable frequency on magnetic tape is directly related to the head gap and the speed of the tape. (F= Head gap / Tape speed) The frequencies required for video are in the megahertz range (unlike audio which maxes out about 20khz) and even with the smallest head gap possible the tape would have to be moving ridiculously fast to record signals in the MHz range. So instead of having a tape moving at 60mph they make the head do it and record across a tape moving at a more manageable rate.
I read up on pro videotape, and the type your recorder uses is called Type C, and there are many different manufacturers of the actual tape (not sure who is currently manufacturing the tape though) but I do see a *lot* of 3M Scotch brand tape, and probably Ampex as well.
There are numerous analog delay lines in old hardware like this. Those delay lines are used to delay the audio or the video. Look it up on wikipedia, some interesting articles on that.
Actually, no. The audio R/P head is a fixed distance from the video track, and that is part of the SMPTE type-C standard. I just dug up the training manual from when I went to Sony BVH training school some 30 years ago, and the audio R/P head is 116.63mm from the portion of the video track as it transitions from line 24 to line 25. Analog delay lines were commonly used in quad videotape machines like the Ampex VR-2000 as part of the AMTEC and Colortec units, essentially pre-digital time base correctors.
Cool video! The stacked reels are so strange! Some audio recorderts used stacked reels. They never worked very well. Channel Master, Westinghouse and Craig had a "cartridge" audio recorder where the cartreidge was two reels stacked.
Even though this video was shot a decade ago. Im still wondering if any one in Australia still has one of these portable recorders for sale or give away.
I was one of those "guys" but not a gorilla (made Steadicam seem light weight) and you don't even mention the weight of the batteries since the 1" sucked power like nothing short of the cameras which we could use as a food warmer on cold days! Generally the smarter among us wound up making various carts and so forth to carry all the junk. By the way the portables could only play heterodyne color back and not "real" color. To play in the field it required another box which was a color adapter.
The control track has nothing to do with copy protection. Each pulse denotes the start of a video track so 60 for NTSC sand 50 for pal. It locks the vtr servos which set the tape speed and head servo lock.
Did you initially thread the take up spool the wrong way. Made me cringe when put manual tension on that spool,too much back tension equals wrecked video heads. So easy break beautiful equipment like that.
Untrue. I work in EVERY machone AMPEX made ceom the VR-1000 to the VPR series. Control track is a tone of 240hz. It is multiple of the field rate of 60hz. This control track, because of its very nature of coming from the field rate would make itnlike sprokwt holes on film. After the control track is layed on the tape and during playback, this set the capstan speed for the tape forward motion. Tracking was derived from maximum RF coming od the tape. They call it RF Because the video signal was Frequency Modulated (or FM) that was very high in frequency this allowed from praxtically DC TO 6MHZ to be recorded on tape
@@Geebax2 haha BVH stands for Broadcast Video Helical Just like the came as BVP atand for Broadcast Video Photo (or camera) BVM stand fir. Broadcast Video Monitor etc Sont had a division that was called Broadcast Video
I always wondered if there is a vertical tension on the tape which travels from down reel to top reel. Since the tape path is not parallel to hubs (because tape ramps up at some point) the tape is being stretched on one edge while being collapsed on the other. Am I missing something here?
The 8 track has got 8 tracks, not 4. Yes, it is 4, just like he drew, but each track consists of 2 separate tracks (L and R channels for Stereo sound), 4x2 = 8.
I was watching the Stargate SG! and Atlantis recently and discovered they are using a couple of Ampex VR 1200 or 2000 chassis as props. It triggered a Pavlovian response of my yesteryears.
You are totally wrong about control track. You were doing good until the control track and footprint section. You are lost. Control track is analogous to sprocket holes on film. The CTL pulse provides picture lock to video track. On the 500A there was also a frame pulse recorded on very other CTL pulse used for color frame editing. This was the improved BVH-500A servo but the biggest improvement over the 500 was the connectors used for internal interconnect. Gold contacts! The 500's connectors would oxidize and you would sometimes make the machine work by dropping the machine from a couple of inches. Many failed remotes back in the day! Stiction is rubbing noise from the tape lubricants not performing keeping the proper air gap between head tip and tape! Tape backing, binders can fail, especially with Ampex tape. Glad you finally noticed 3 audio tracks since you left that off your footprint diagram. Track 3 is for time code, recorded next to the CTL track.
Actually the control track is not pulses at all. Its tone of 240hz. The purpose is set the speed of the capstan and thus tape speed during playback. I worked on EVERY AMPEX machine since the VR-1000. Went to AMPEX school in redwood Calif too
No, there are two separate motors driving the reels through concentric shafts. Tension arms send a sensing voltage to the reel drive servos so that the correct torque is applied to each reel to maintain consistent tension.
The NTSC version used in the United States was 525 lines overall, of which about 486 were active. In todays digital world, the closest equivalent would be 640h x 480v.
a Videotrack from a Video-Head (A) have never a Angle of 45°. The Videotrack is more flat and for PAL625 you have one Videotrack from one Head(A) to the next Head(B) with the length of the half round of the circle (this is the silver thing) the VHS have a relative Tape to Head Speed from around 7,02m/s this machine have much more so the SNR is times better then from VHS. maybe 20m/s because on this machine is the Head A to Head B more then 90% from the Circle of the Videoscanner.
The audio record/play (R/P) head is always a fixed distance from the video track: 116.63mm to the transition between video lines 24 and 25. Since that distance doesn't change -- it's part of the standard for this tape format -- you can record a tape on one machine and play it back on another, and the audio will be exactly in time with the video. Conceptually, it's no different from sound-on-film, where the sound drum with its optical sensor is 26 frames beyond the gate (28 frames for mag stripe film).
Mostly fruitless answering questions years later, but... There is no "delay" between the video and audio heads. The fact that the video and audio where recorded on separate locations on the tape will be "matched" during playback. The location of the heads will stay in sync... just as recorded. Audio and video will both reach the monitor in sync with each other without need to be "fixed" or "compensated."
What delay? There is a standard od the ohysical properties of the 1" C. It specifies the physical distance from the first video track to the audio stacks. As long as manufacture adhered to this standard that was no delay at all in fact film audio LEADS the picture and ib video the audio lags the video tracks
+allan fulton The head of a tape is probably sacrifical, like leader on a film print. Rewind tends to beat up the header and damage slowly creeps up the tape. I wonder whether a splice would pass through the machine without damaging something. So compared to what is recorded, tape stock is very cheap.
"this may be why we got this donated" hah... That or it's just OLD technology. I've thrown away a bunch of those BVH-500's and the large rackmount version, the BVH-1000. BTW, hit the STANDBY button (top right) to spin up the heads and keep them spinning. Then you can push other buttons to do what you want and not have to wait for it to keep spinning up/down. Most 500's dont have a color corrector, so playback is fairly useless.... but they did record nicely!
It's certainly going to be expensive especially virgin tape. But a lot of companies made that back in the day. Ampex, Fuji, Sony, Kodak, AGFA/BASF and scotch/3m were some of the companies. I bet you can find a lot of tape on eBay but who knows what shape it'd be in.
As a professional vtr operator for over 55 yrs u are making a mockery of video recording. First off a control track is an analog tone that is layed down the same time the video is layed down. On playback the tone is used to set the tape speed. It is also used to set the head speed. The phase difference is called tracking. A control track has NOTHING to do with time code! A LTC. (Lineear tine code) is recorded on channel-3 where channel1&2 is used for audio. I cringe watxhing this video! Btw BVH stands for Broadcast Video Helical Amoex made the first the first broadcast VTR. The phrase VIDEO TAPE is coined by Ampex. Your explanation of how video is recorded they way it is is totally wrong. I would be happy to be a technical advisor if you want to re-do rhis video. I have wprked on every machine Ampex built from quads to 1"-C
ruclips.net/video/TEdGo1eGYEw/видео.htmlm37s Isn't the linear audio track on a VCR only mono? When the 4 Head VCRs came they started writing the audio track into the diagonal video track as well, but kept the mono linear audio track for compatibility reasons.
pre Digital/1990's hifi was the best...all this wireless this and BlueTooth that bores the living shit out of me. Ok I do admit that I do have a few ultra modern machines like a CameraDrone and a few Quadcopters so these are useful but when it comes to physical Audio machines...I like them BIG n BULKY with SPAGHETTI hanging out😜
Not sure you mentioned this, but this was a "super-compact" portable VTR for field recording. On the studio models, the tape reels were "side-by-side" rather than stacked, and they probably accepted larger reels.
In modern VTRs (starting with Sony's 3/4" U-Matic), they put the head drum at an angle, instead of the tape - this allowed both reels of tape to be on the same plane inside the cassette. (Several early formats such as "Catrivision" had the reels stacked inside the cartridge).
You are totally wrong. If you don't have a control track your playback servo will never lock onto the tape, it will go into free run mode, and you will end up with head switching point running through the picture on 2 head (VCR) machines. On single head systems, like the 1" you are working on there won't be the head switch problem (on the 2 head machines the CTRL pulse is used to lock in the tracking for the A field. On a single head machine, technically it is possible to play the tape back if the machine is genlocked to station sync, where the servos can get a reference, but still since there is no reference on the physical tape the tracking can drift in cases where the tape has stretched.Copy protection has had a few different systems tried. The earliest was modification of the video sync, where most, but not all of the vertical sync was stripped. This caused the recording machine that was being used to bootleg a copy to have a heart attack and the result was generally servos falling out of sync and going into free run mode. The result is the copy has head switching point slowly drifting through the picture. The later forms of copy protection was macrovision, which the added severely over recorded pulses to the luminance channel in the vertical blanking area. They would record on a machine with manual video gain controls and record white video at up to 150IRE, and drive the opposing black pulse down below 0IRE into the blanking area on the first dozen or so lines of video following vertical blanking. This caused the AGC on the recording machine to go crazy trying to set record levels and resulted in a picture that blinked bright dark, bright dark and the color to be messed up.Later versions of macrovision, called color stripe made changes to the timing of the color burst which resulted in thin color bands across the picture.Its a beautiful machine. Would love to have one of those in my collection. Carried one for years when I was in broadcast.The term "stiction" was used frequently, and it refers to worn tape that the binder or back coating is "sticking" to metal parts. On playback these tapes would start to screech as they played, and the picture would get lots of wiggly lines caused by these vibrations on the tape. Was a big problem with Ampex tapes.
you are right on every point.
Hi 12VoltVids, excellent informative explanations, thank you for taking the time to clarify it, Ciao, L
You're mostly correct, with one minor quibble: you absolutely need the control track to achieve playback servo lock on this machine, because it lacks the R/P sync head 30° offset from the R/P video head -- so the tape is actually missing the vertical interval between lines 4 and 16. This pretty much prevents the machine from discerning where the track actually is with relation to the video lines. On a machine with the sync head you can theoretically identify the start of a field... but in practice the only machines that pull this off are the ones with dynamic tracking heads like BVH-2000s (and even they get upset if they don't see the control track).
Its Funny that the leader in magnetic recording made the worst tape pros almost always used 3m stock as it was very good, uniform quality. Fuji made great tape (on quads) but after 6-7 passes it degraded fast. It was good for camera masters as input to edit.
On some machines such as the AMPEX AVR-1&3 and ACR series could easily playbackna tape with no control track. It derived rhe control track from the frame rate. All u needed was a few frames so the internal oscillators locked on. The machine knew what the frame rate should be and opon playback would try the control track if that was bad it derived it from the frames
Also I want to point out that a control track was a tone (normally 240hz) not pulses, tha sole purpose was to lock the capstan (or vertical lock) on playback. The control track was derived from vertical sync as it was imperative that the control track was locked to the frame rate.
In addition one company I worked for was one of the largest vhs duplication companies in the USA, we devised a copy protection system that would randomly place extra sync pulses on the video signal. It was no problem on playback. Bor was it a problem for tv sets, but when the video signal was fed to another recorder in which the capstan speed was set based upon the vertical interval, all hell would break lose on tbe record machine.
All of these copy protection schemes wwre broken fast by pirates
Can you make a video on one of these (sorry for my bad english i speak spanish)
Re: Copy protection. I don't know if the control track method was used on all video tape systems, but the copy protection schemes I know of work by inserting 'loud' signals during the blanking intervals of the video signal to confuse the AGC (Automatic Gain Control) of the recording VCR. Also, not all video tape systems record the video straight onto the tape, but use various modulation and superheterodyne techniques to accomplish it, and sometimes for Hi-Fi audio as well. Just FYI :)
This is a great way to explain how rotary head digital audio recorders worked, it's relation to video technology and how quadruplex 2" machines differed. Denon even used 2" for early 70s digital audio recordings. These are great videos. Thanks
Brought back so many memories of High School and early college... Editing on an AV3650 and AV8650 RtR Video... Cleaning the heads (and yes, they spin up fast) with Xylenes (and don't break them - they're more fragile than a soap bubble), 3 twists on the take-up, 10 seconds (minimum) of leader run. Getting both machines in sync, and we haven't EVEN gotten into PVS's and the old-school analog SEG's... The Panasonic 3085 Porta-pak was awesome - you had a camera, the VTR on a strap on one shoulder, and the battery pak either (hopefully) on a belt pack, or hanging off the other shoulder (and squeezing the sides of your neck) - because the on-board NiCad was worthless for recording time.
And you're right - once you do it enough times, threading is awesomely fast and smooth. Thank you for bringing me back to the good old days!
Control track pulses are like a metronome keeping time. Tape speed is never perfectly constant so the recorded pulses help the VTR mimic the recording's tape speeds during playback. It's never perfect, so these Time Base Correctors you may have heard about can be used to electronically finesse the video timing.
The whiteboard anim and that VTR are both a joy to behold. Love this vid!
Actually it was not pulses but a tone of 240hz that was made from the incoming veils rate of 60hz. This tone was like sprocket holes on film. The tone was then used on playback to lock the capstan speed. Simple
I used to maintain one of these BVH-500s, as well as our studio BVH-2000s and 2500s. Amazing machines, especially the portable 500. With the internal battery pack, it weighed something like 80 pounds, so every time I took it for a field recording shoot (we did a show from a bowling alley every week), I got a real workout. Good to see one running again, though I was cringing to watch how you threaded it. Generally speaking, you would pull about three feet of tape off the end of the supply reel and thread it through the tape path -- you don't pull it through, especially through the video head assembly. Pulling the tape through not only damages the tape (you can see the puckering in the tape surface where you snagged the entrance guide), putting tension on incompletely seated tape risks chipping one of the video head tips. Aside from being better and safer practice, it's also much faster -- I used to do it in about ten seconds. Finally, you want to trim off damaged tape ends, because they will get caught between the spinning drum and the entrance and exit guides -- there's only about two tape thicknesses of clearance at that point. Studio machines like the BVH-2000 had retracting guides that would move away from the spinning drum as the tape was about to unthread, but the guides are fixed on these portable machines.
You never worked on a poetable quad I bet. It could only record 20 min videos. Had no room for an erase head so you had to use a degaused tape to record on. In addition the tension arms were actually air dialectic caps. So the humidity had to be just right..
The heads rotacts at 14,000 rpm and used ball bearings which wore out. The studio quad machine had the headwheel on air bearings
@@rty1955 At the TV station I worked at in 1984 we had a "Quad in a briefcase." I remember the ball bearing head assembly.
Yep, that's a BVH-500. I've used one before. You want to try threading without touching the face of the tape to keep the oils of your fingers off the transport. Also it's common to trim off the damaged tail of the tape. If the creased part of the tape goes through the drum, it can damage the spinning heads.
Take a look at an Ampex VPR-5. The last and greatest 1" portable helical VTR.
Great machine! One word about the helical scanning, the ‘why’. It’s not about using the full surface of the tape. Video required much higher frequencies to be recorded (compared to audio), for which you need extremely high tape speeds. The helical scanning delivers just that: the tape speed as seen by the head is mostly determined by the rotational movement of the head drum. And because of the very high frequencies a narrow head will do, which also enables packing the tracks closer to each other. Altogether the tape surface is more densely packed with information, but it’s the high frequency recording that requires a high relative tape speed, obtained by the helical scanning.
Believe it or not, standard VHS tape only has a single mono audio track. SVHS has "HiFi" Stereo on the helical data. One of the features of SVHS was increased bandwidth due to better formulations. They encoded the audio subcarrier into the helical strip itself but left the mono audio carrier for reverse compatibility. It's really neat.
***** There are tapes with stereo linear tracks, I use to have one but it didn't sound very good, especially when playing SLP.
***** S-VHS used a 6 head recording system, though incompatible with 4-head jobs, could play regular VHS tapes. Standard tapes made for regular 4-head jobs still had a HI-FI stereo track. Look at the spine of any old film and you'll see that listed in the information on the back. I should know, I grew up with the things.
+Nick sargente That's generally true with VHS, although some VHS machines are stereo on linear tracks.
The scanner has the record/play head and the erase head. The third "head" is called a dummy head, it doesn't do anything and it's only there for balance. Audio, control track and linear time code is recorded on a stationary stack heads. Control track is not really time code, it's more like sprockets on motion picture film. The control track is what lines the scanner play head up to the recorded video track. Some machines also record vertical interval time code, which is laid down with on the video track. VITC time code can be read at slow speeds or even when the machine is in still mode, longitudinal time code, like audio, can only be read at speed.
+MurrTV Yeah i was thinking the third "head" was for mechanical balance as well.
@@BertGrink On a studio machine like the BVH-2000, that third head position was for dynamic tracking playback: a special head mounted on a quartz substrate that could move slightly when a control voltage was applied. This allowed the machine to produce clean still-frames and variable speed playback from -1x to +3x speed. A machine without the DT head still needed dummy tips, because they maintain the correct drum circumference.
Well close. The control track is an audio tone of 240hz not pulses. This tone is a mutiple if the frame rate (60hz) agreed this is like sprocked holes on film, however film speed is mostly. VERY lax, and varies greatly inless its a professional projector. The control track tone is there to merely set the capstan speed on playback. Tracking sets the the spinning heads phasing from the control track. BOTH tape speed AND head speed must be in sync
Oh, and a note on the audio. There were 3 full channels and a cue. Most used the 3rd channel for time code.
I used to work with these type video recorders back in the day at TV stations. They were very dependable to use. The huge broadcast video recorders/playback unit were also great to work with.
U mean quads... :)
Would be wild if the recording on that tape was Johnny Carson's first Tonight Show in color from October 1, 1962.
That format, Type C, was not standardized until ‘79. Most of the early Carson shows got recorded over because no one thought they should be saved.
I worked at a TV station in 1990 that had one of these that our commercial production division used. They were the only ones that were allowed to use it. News use 3/4" U-matic VCR. We also had 3 big studio 1" VTRs that were used to edit commercials. Fun times.
"Blanking and sync and fields and RAAARGH!" I was laughing after that. :)
You make very informative videos, thank you.
Thank you for watching! :) There's a lot more coming!
I LOVE THE CASETTE TAPE SHIRT, AWESOME
That was very educational and very well presented. Chris Boden reminds me of David Tenant from Doctor Who.
Sorry Chris you were slightly wrong about the control track, without the control track there is no sync, therefore nothing to track the video too. The tracking then hunts trying to sync making the pic roll or jump. So the control track is very necessary. Also out if interest the early 2" Quadruplex format recorders would wright the information in tight horizontal lines, they would edit the tapes using fero fluid and a razor blade like film :) .
I worked on EVERY machine AMPEX maded and it makes me chuckle when I hear people refer to the control track as pulses. A control track is a tone of 240hz. It is a multiple if the field rate if 60hz. It acts like sproket holes on film. On playback the capstan speed is derived from this tone, it is also used to govern head speed. The two must be in perfect sync with each other. Tbe tracking control refers to the phase difference between recorded control track and head speed. The control track has nothing to do with a sync signal, that comes from the recorded video. With TBCs rhe sync I usually striped off the recoded video and replaced by a clean signal generated by the TBC. Some analog video switchers also did the same thing. They ignored incoming sync and regenerated it. The poor quality video mixers did not refer sync signals and were always a problem
AMPEX AVR series of QUAD machines could very easily playback a tape with no control track. It only needed a few frames to get in sync as it took the timing off the video itself as the circuitry woukd determine where the head should be for max RF output. It would multiply the video frames to obtaon both the tape speed and headwheel speed. The video didnt even need a sync signal! Truely an amazing feat if anakog video engineering
Oh I'd love to have a reel to reel video recorder for putting my DVD movies to reel and then watch them outside like an old drive in movie for the neighborhood kids.
Actually I've heard the term "striction" used to describe tape sticking to head drums and stationary audio heads.
I'm the field-op who's done it 10,000 times.
The reason for a spinning head has got nothing to do with data density and everything to do with frequency. The maximum recordable frequency on magnetic tape is directly related to the head gap and the speed of the tape. (F= Head gap / Tape speed) The frequencies required for video are in the megahertz range (unlike audio which maxes out about 20khz) and even with the smallest head gap possible the tape would have to be moving ridiculously fast to record signals in the MHz range. So instead of having a tape moving at 60mph they make the head do it and record across a tape moving at a more manageable rate.
I love it when people who are smarter than me teach things in the comments. Thank you! :)
I read up on pro videotape, and the type your recorder uses is called Type C, and there are many different manufacturers of the actual tape (not sure who is currently manufacturing the tape though) but I do see a *lot* of 3M Scotch brand tape, and probably Ampex as well.
3m was the standard in the industry, the was Fuji, AMPEX, Maxwell. But 3m produced the most consistant brand of tape
There are numerous analog delay lines in old hardware like this. Those delay lines are used to delay the audio or the video. Look it up on wikipedia, some interesting articles on that.
Actually, no. The audio R/P head is a fixed distance from the video track, and that is part of the SMPTE type-C standard. I just dug up the training manual from when I went to Sony BVH training school some 30 years ago, and the audio R/P head is 116.63mm from the portion of the video track as it transitions from line 24 to line 25. Analog delay lines were commonly used in quad videotape machines like the Ampex VR-2000 as part of the AMTEC and Colortec units, essentially pre-digital time base correctors.
Haha what arr you talking about there is ZERO delay lines in these machines. The only microsend delays are in a Time Base Corrector or TBC
very cool. I wonder what the break down rate on these were out in the field with the banging around it may get.
Ooh the animations are really great!
Cool video! The stacked reels are so strange! Some audio recorderts used stacked reels. They never worked very well. Channel Master, Westinghouse and Craig had a "cartridge" audio recorder where the cartreidge was two reels stacked.
Even though this video was shot a decade ago.
Im still wondering if any one in Australia still has one of these portable recorders for sale or give away.
The shipping would be hell, but this one is for sale for the right price.
How much in Australian dollars including shipping.
Email me and we can discuss details.
Absolutely amazing! I've never seen a video recorder like that before, that was incredible :) You must try and get video off of it for a future video!
I own one fully operational
watching him set up that tape around up and down made me think of bad days of trying to set up the boardgame Mousetrap as a kid
I was one of those "guys" but not a gorilla (made Steadicam seem light weight) and you don't even mention the weight of the batteries since the 1" sucked power like nothing short of the cameras which we could use as a food warmer on cold days! Generally the smarter among us wound up making various carts and so forth to carry all the junk. By the way the portables could only play heterodyne color back and not "real" color. To play in the field it required another box which was a color adapter.
good explanation. thanks.
The control track has nothing to do with copy protection. Each pulse denotes the start of a video track so 60 for NTSC sand 50 for pal. It locks the vtr servos which set the tape speed and head servo lock.
Did you initially thread the take up spool the wrong way. Made me cringe when put manual tension on that spool,too much back tension equals wrecked video heads. So easy break beautiful equipment like that.
Excellent video! THX ;-)
Did you ever hook a monitor up to it to see if there was any video on the tape?
control track is the track that guid the heads to the tape. if you donts have control track you see drops at video and non stable audio
Untrue. I work in EVERY machone AMPEX made ceom the VR-1000 to the VPR series.
Control track is a tone of 240hz. It is multiple of the field rate of 60hz. This control track, because of its very nature of coming from the field rate would make itnlike sprokwt holes on film. After the control track is layed on the tape and during playback, this set the capstan speed for the tape forward motion. Tracking was derived from maximum RF coming od the tape. They call it RF Because the video signal was Frequency Modulated (or FM) that was very high in frequency this allowed from praxtically DC TO 6MHZ to be recorded on tape
The Omega system was early over passed by Alpha system more stable, non need for artificial sync neither for TB correction
The B in the model number stands for beta which describes the way it wraps around the video drum.
No it does not, it stands for Broadcast, and the V is for Video. The H was used for all Sony recorders, while a P was for cameras.
@@Geebax2 Moreover, one-inch machines used an Omega wrap.
@@Geebax2 haha BVH stands for Broadcast Video Helical
Just like the came as BVP atand for Broadcast Video Photo (or camera)
BVM stand fir. Broadcast Video Monitor etc
Sont had a division that was called Broadcast Video
I always wondered if there is a vertical tension on the tape which travels from down reel to top reel. Since the tape path is not parallel to hubs (because tape ramps up at some point) the tape is being stretched on one edge while being collapsed on the other. Am I missing something here?
The 8 track has got 8 tracks, not 4. Yes, it is 4, just like he drew, but each track consists of 2 separate tracks (L and R channels for Stereo sound), 4x2 = 8.
BVH-500A is so awesome, I'm going to get me one right away. Long live 1" Type-C format. Cheers!
Long live quad!!!
Damn thats a cool unit!
I was watching the Stargate SG! and Atlantis recently and discovered they are using a couple of Ampex VR 1200 or 2000 chassis as props. It triggered a Pavlovian response of my yesteryears.
You are totally wrong about control track. You were doing good until the control track and footprint section. You are lost. Control track is analogous to sprocket holes on film. The CTL pulse provides picture lock to video track. On the 500A there was also a frame pulse recorded on very other CTL pulse used for color frame editing. This was the improved BVH-500A servo but the biggest improvement over the 500 was the connectors used for internal interconnect. Gold contacts! The 500's connectors would oxidize and you would sometimes make the machine work by dropping the machine from a couple of inches. Many failed remotes back in the day! Stiction is rubbing noise from the tape lubricants not performing keeping the proper air gap between head tip and tape! Tape backing, binders can fail, especially with Ampex tape. Glad you finally noticed 3 audio tracks since you left that off your footprint diagram. Track 3 is for time code, recorded next to the CTL track.
Actually the control track is not pulses at all. Its tone of 240hz. The purpose is set the speed of the capstan and thus tape speed during playback.
I worked on EVERY AMPEX machine since the VR-1000. Went to AMPEX school in redwood Calif too
This is amazing!
The reels spinning opposite ways looks like it uses a differential to keep tension on both reels.
No, there are two separate motors driving the reels through concentric shafts. Tension arms send a sensing voltage to the reel drive servos so that the correct torque is applied to each reel to maintain consistent tension.
Its belt driven
I remember the slow video machine.
There new new episodes coming out with this machine in the future. :)
Aha! A slow motion machine not a slow video machine, may be.
That's awesome! What's the resolution on that? 240 lines like a VHS or more?
The NTSC version used in the United States was 525 lines overall, of which about 486 were active. In todays digital world, the closest equivalent would be 640h x 480v.
300+ lines
Good
I love the simplicity of tape lol.
11:00 I have the same reaction when dealing with normal reel to reel and the tape gets out like that
no video ? :-(
The cover is missing.
a Videotrack from a Video-Head (A) have never a Angle of 45°. The Videotrack is more flat and for PAL625 you have one Videotrack from one Head(A) to the next Head(B) with the length of the half round of the circle (this is the silver thing) the VHS have a relative Tape to Head Speed from around 7,02m/s this machine have much more so the SNR is times better then from VHS. maybe 20m/s because on this machine is the Head A to Head B more then 90% from the Circle of the Videoscanner.
So, any idea what was on that tape?
Jeeze guys, can you find a worse acoustic environment? How about a racquet ball court?
This was probably a $20,000 VTR at the time.
Closer to $50,000-$75,000
....and they were a true bugger to repair! I was a much bigger fan of the VPR-3
How does the recorder deal with the delay between the video head and the sound head, or does it just record with a delay the has to be fixed later?
The audio record/play (R/P) head is always a fixed distance from the video track: 116.63mm to the transition between video lines 24 and 25. Since that distance doesn't change -- it's part of the standard for this tape format -- you can record a tape on one machine and play it back on another, and the audio will be exactly in time with the video. Conceptually, it's no different from sound-on-film, where the sound drum with its optical sensor is 26 frames beyond the gate (28 frames for mag stripe film).
Mostly fruitless answering questions years later, but...
There is no "delay" between the video and audio heads. The fact that the video and audio where recorded on separate locations on the tape will be "matched" during playback. The location of the heads will stay in sync... just as recorded. Audio and video will both reach the monitor in sync with each other without need to be "fixed" or "compensated."
What delay? There is a standard od the ohysical properties of the 1" C. It specifies the physical distance from the first video track to the audio stacks. As long as manufacture adhered to this standard that was no delay at all in fact film audio LEADS the picture and ib video the audio lags the video tracks
thats pretty modern
8:29 "RAAAARRH" - Rotational Azimuth Automatic Adjustment And Record-Replay Harmonization.
Alternatively, RAAAARRH DON'T TOUCH THE HEADS!
Is there ever a lot of wasted tape starting one of these up.
+allan fulton The head of a tape is probably sacrifical, like leader on a film print. Rewind tends to beat up the header and damage slowly creeps up the tape. I wonder whether a splice would pass through the machine without damaging something. So compared to what is recorded, tape stock is very cheap.
"this may be why we got this donated" hah... That or it's just OLD technology. I've thrown away a bunch of those BVH-500's and the large rackmount version, the BVH-1000. BTW, hit the STANDBY button (top right) to spin up the heads and keep them spinning. Then you can push other buttons to do what you want and not have to wait for it to keep spinning up/down. Most 500's dont have a color corrector, so playback is fairly useless.... but they did record nicely!
Is that AMPEX tape hard to find?
Regular 1/4" tapes are expensive as kidneys, 1" tapes, man, hard to find and expensive as exclusive top-class hooker.
I've got stacks of NIB Ampex 407 1/4" if anyone wants some... No sticky shed on these.
It's certainly going to be expensive especially virgin tape. But a lot of companies made that back in the day. Ampex, Fuji, Sony, Kodak, AGFA/BASF and scotch/3m were some of the companies. I bet you can find a lot of tape on eBay but who knows what shape it'd be in.
I have 4 cases of 3m 1" 60min stock also a BVH-2000 and a BVH-500A
uses the same reel design. as a cantata 700
As a professional vtr operator for over 55 yrs u are making a mockery of video recording.
First off a control track is an analog tone that is layed down the same time the video is layed down. On playback the tone is used to set the tape speed. It is also used to set the head speed. The phase difference is called tracking. A control track has NOTHING to do with time code!
A LTC. (Lineear tine code) is recorded on channel-3 where channel1&2 is used for audio.
I cringe watxhing this video!
Btw BVH stands for Broadcast Video Helical
Amoex made the first the first broadcast VTR. The phrase VIDEO TAPE is coined by Ampex.
Your explanation of how video is recorded they way it is is totally wrong.
I would be happy to be a technical advisor if you want to re-do rhis video.
I have wprked on every machine Ampex built from quads to 1"-C
ruclips.net/video/TEdGo1eGYEw/видео.htmlm37s Isn't the linear audio track on a VCR only mono? When the 4 Head VCRs came they started writing the audio track into the diagonal video track as well, but kept the mono linear audio track for compatibility reasons.
+Philip vB That's generally true with VHS, although some VHS machines are stereo on linear tracks.
Thanks for that, didn't know that one...
Actualy, they're stéréo non hi-fi and hi-fi totalling 4 distinctive channels on broadcast s-VHS and BetacamSP.
Head number 3 is for sound, probably stereo.
Show something on the tape!
I want his shirt :D
awesome :D
pre Digital/1990's hifi was the best...all this wireless this and BlueTooth that bores the living shit out of me.
Ok I do admit that I do have a few ultra modern machines like a CameraDrone and a few Quadcopters so these are useful but when it comes to physical Audio machines...I like them BIG n BULKY with SPAGHETTI hanging out😜
What for with no video? Poor video heads!
This escelated quickly into a school lesson and not a nerdy talk about tape. The guy in the red shirt is lame..
OMG. Too many touches to tape. :)
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Нехерасе,не видел такого аппарата!