Ampex 175 2-inch Quadruplex Videotape Demonstration

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This demonstration tape was released by Ampex in the late 1960s or early 1970s. It was designed to showcase the performance of their 2-inch quadruplex videotape over multiple generations. The videotape recorder used is an Ampex AVR-1, which for many years was the highest quality videotape recorder available. If interested, there is some good info about the AVR-1 at this site: www.lionlamb.us... -- scroll down until you find the AVR-1 section. This thing was a beast!
This copy was sourced from an original 2-inch tape provided by Ampex. Using hardware, I upconverted it to 720p in order to maintain the smooth 60fps frame.

Опубликовано:

11 сен 2024

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Комментарии : 33

@deepred6502 3 месяца назад

The performance is from the Red Skelton Hour, recorded on 18 Nov 1969: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-EMuYAkvD1AU.html

@fmphotooffice5513 10 месяцев назад

10 to 15 years later in the mid 80s they were still used as workhorses along with 1"", though by then the queuing by audio was arcane, uneven head wear caused banding problems, daily playback of older recordings were shredding needing constant attention. Nevertheless, this amazing demo shows the quality in an interesting way. Remarkably it took almost 10 generations to really ruin the quality.

@christopherrippel2463 10 месяцев назад

Interesting! You can see generation lines around the shoulder starting on 8th Gen.

@VectraQS 2 года назад

Always wondered if anybody ever did Quad generation loss. Interesting to see it in action. The degradation is apparent but the geometry is a lot more stable than any other format I’ve seen.

@cysjunk Год назад

Next I'd want to see a Betamax or U-Matic generation loss.

@altebander2767 7 месяцев назад

Well the geometry problems are caused by jitter. They disappear on decent VTRs with TBC... even on VHS. The main reason those do not exist on professional VTRs is that they get their sync from the studio. Therefore the sync-pulses you see on their outputs are typically not the sync pulses that came from the tape. So they are pristine. This of course means that the VTR has to sync its mechanics to the studio sync on playback. For colour video in NTSC (and to a lesser extend PAL), the remaining errors in the mechanics are to big to be used directly, so they have a TBC based on an LC-low-pass filter with varicap diodes as capacitors... hundreds of them! Some Quad VTRs also had glass delay line based TBCs for less stringent mechanical requirements.

@jourwalis-8875 2 месяца назад

Unbelievable! But who needs a 15:th generation?

@altebander2767 Месяц назад

Looking at the video in detail, I would say that most of the image degradation comes from the VTR not the tape. For example you can see the chroma shifting because the VTR has a slightly non-linear phase response which adds up more and more over the generations. Also the linearity of either the modulator and the demodulator seems to be slightly off, creating problems with graduation. I'm not sure if this was noise reduced before uploading it here, but it has virtually no noise which I would attribute to the tape. The tape seems to perform better than the VTR.If I'd have been alive and a broadcast engineer when this came out, I'd make a comment like "nice tape, shame about the VTR".

@domfjbrown75 10 месяцев назад

I NEED to see the rest of that track... It's oddly amazing!!

@tomcarlson3913 7 месяцев назад

I suspect that might be from the TV show Lawrence Welk ran.

@deepred6502 4 месяца назад

@@tomcarlson3913 The song is "Summer Me, Winter Me", and a number of artists covered it. The show is actually The Red Skelton Hour - a variety show in a similar vein to Lawrence Welk - and the episode aired somwhere in 1969-1970: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-EMuYAkvD1AU.html

@jeffhartman7000 9 месяцев назад

Interesting to see the chroma delay as it increases. I wouldn’t have expected that from a direct color recording.

@altebander2767 7 месяцев назад

Well such Quad recorders used essentially a low-pass filter made from capacitive diodes and inductances to create a variable delay. It seems only natural for that to have a slight group delay distortion which becomes apparent after many generations.

@jeffhartman7000 7 месяцев назад

@@altebander2767 Good point. I was forgetting about the AMTEC / Colortec or its RCA equivalents.

@user-nk8ke4qk5h 9 месяцев назад

The tape stock is 175. The machine is an AVR-1.

@VPR2B 9 месяцев назад

True.

@VintageTVMemories 2 года назад

By 15th generation, the degradation was VERY apparent. But still just as good as (if not better than) first generation VHS on EP.

@VPR2B 2 года назад

True!

@fmphotooffice5513 10 месяцев назад

This WAS broadcast tape, not the house of cards VHS. The 1" helical replaced quad, but the standard was the same. The side-by-side 1" machine was the ""VPR2B" used as the name of this channel.

@altebander2767 7 месяцев назад

@@fmphotooffice5513 Well actually the 1" helical standards were quite different to quad. Essentially a completely different standard. For example some of them (like C) didn't record the vertical blanking interval. Also some of them (like C) recorded a whole field (or even frame) in one track, allowing for a primitive form of trick-play without frame stores.

@fmphotooffice5513 7 месяцев назад

@@altebander2767 I meant the 525-line standard was the same. The tape rooms in the 1980s had 1" helical machines and older 2" quad machines side-by-side doing different things.

@jourwalis-8875 2 месяца назад

The Sony U-matic system barely coped with third generation copies. After that is was a mere catastrophe!

@altebander2767 7 месяцев назад

I find it fascinating that audio seems to degrade much more than the video.

@tyx823 Год назад

this might be early 70s because the music gives me the 70s vibe

@cysjunk Месяц назад

Generation timestamps: 1:18 5th generation 1:39 6th generation 2:01 7th generation Audio starts to peak in some spots 2:22 8th generation Color bleeding starts to become noticeable near the edge of the left side of the screen 2:42 9th generation 3:03 10th generation Audio is noticeably softer and has less fidelity than the 5th generation 3:23 11th generation Audio starts to lose sync with the video and peaks more frequently, ringing effects start to appear 3:43 12th generation Ringing starts to become more prominent, video quality starts to become softer 4:05 13th generation 4:25 14th generation Colors start to shift and look inaccurate 4:46 15th generation Audio is now completely low-fidelity and out of sync by 2 to 3 seconds, colors look even more inaccurate

@jourwalis-8875 2 месяца назад

What is a "High Speed Duplicator"? Never heard of.

@janovlk 9 месяцев назад

The sound is almost the same over all the generations. I think they redubbed the audio track as it is slightly out of sync form 11th gen. I don't think the audio would survive that much generations.

@mrnmrn1 4 месяца назад

The audio clearly got more and more distorted and had less and less bandwidth over each generation. I also noticed it came out of sync but don't know why. What I found odd is that the noise floor hasn't elevated as much as I expected it will.

@culturanime 8 месяцев назад

Qual é o nome da música?

@djslavatv Месяц назад

По сравнению с VHS, очень хорошо выдерживает копирование. Но, сдается мне, что в 90-е на Российском ТВ (на не очень крупных каналах) могли использовать иногда 10-е копии, т.к. тоже изображение немного двоилось.