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Old 11th Nov 2019, 7:09 pm   #1
Henenen
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Default A truly analogue semi-pro vision/effects mixer?

I used to use things like the Panasonic WJ-MX10 and MX12 in the late 80s/early90s, but these mixers were digital and the effects they applied look digital.

Was there ever a semi-pro vision mixer that wasn't digital?

Something that could do chroma-keying or applying a block-colour to the luminance? (eg. Effects like this.)
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Old 11th Nov 2019, 10:14 pm   #2
cmjones01
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Default Re: A truly analogue semi-pro vision/effects mixer?

There probably was, but I imagine it will have been big, heavy, noisy and unreliable. Anecdotally, some friends and I cleared a load of junk when the Pye TVT premises in Cambridge became Varian TVT and downsized somewhat. The time was around the 'great storm' in 1987. Amongst it were various things which were clearly video-processing related, and even then they were all digital.

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Old 12th Nov 2019, 12:45 am   #3
Henenen
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Default Re: A truly analogue semi-pro vision/effects mixer?

I'm starting to wonder if such tech was just so expensive pre-digital that no prosumer equipment was ever really available?

Am hopeful there was something.

I found this Panasonic WJ-5500A which looks to be analogue: https://www.youtube.com/watch?v=hiJbT27cK9Y
But it doesn't do Chroma or Lumakey, just wipes and cuts. And has issues with genlock/TBC from what I read.
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Old 12th Nov 2019, 1:47 am   #4
Graham G3ZVT
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Default Re: A truly analogue semi-pro vision/effects mixer?

I seem to remember seeing, in the mid 80s, Chromakey functionality retro-fitted into an existing studio mixer at Granada, in a way that looked to me rather primitive and home made.
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Old 12th Nov 2019, 6:55 pm   #5
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Default Re: A truly analogue semi-pro vision/effects mixer?

There were lots of purely analogue vision mixers around in the 60's & 70's. I regret disposing of the ones I had.
The main manufacturers that I remember were Nivico,(JVC) the company I worked for was the sole importer of these. The keying & effects were all analogue, - quite complex circuitry.
Also Sony, Shiba Electric (Shibaden / Hitachi) and National (Panasonic) produced analogue mixers & effects generators. I seem to remember that had large encapsulated circuit blocks (Like a Lego brick with wires!), not unlike the Elliot Mini-log blocks. Some of these encapsulated circuits were analogue, whilst others were things like flip-flops & Schmidt triggers, but the mixers were essentially analogue. I used to save money by chipping out the encapsulation & repairing the innards!

All good fun & a long time ago!


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Old 12th Nov 2019, 7:22 pm   #6
Malcolm G6ANZ
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Default Re: A truly analogue semi-pro vision/effects mixer?

I inherited an EMI mixer and effects generator many years ago . Reputedly from HTV studios in Bath Road Bristol after a fire when it was refurbished.
It gave a selection of wipes and fades, and possibly chroma key, although I never got that working.
It is now in the possession of Brian Summers.
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Old 13th Nov 2019, 12:47 pm   #7
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Default Re: A truly analogue semi-pro vision/effects mixer?

Analogue vision mixers are, in the way they work, very different from digital mixers.

Simplistically, timing is the problem. In an analogue (colour) mixer the inputs have to be timed so that each of the start of picture is within say 5n/sec of each other. This requirement led to the use of a master sync pulse generator to lock and time each camera etc. A complex system soon developed.

Digital mixers solved this by the use, internally, of a synchroniser unit, whereby each random input was clocked into and read out of memory to be in time with the other sources. All became much simpler at this point.

A whole book could be written on this subject. A brief note about genlock in the attachment.

So analogue mixers are not for the faint hearted! BTW Sony did a small 2 input? analogue mixer for use with the Betamax SL5 ? It got round the timing by having a special "locked camera" ala Genlock.

If you really want an analogue mixer look at a Grass Valley 110 a nice and still sought after mixer but you will still have to time the inputs

Picture https://www.broadcaststore.com/store...l.cfm?id=10838

Good luck.
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Old 13th Nov 2019, 5:06 pm   #8
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Default Re: A truly analogue semi-pro vision/effects mixer?

I agree with Brian, not for the faint-hearted.

Sony actually made a number of quite large multi-input vision mixers/FX generators. I also used to be involved with the Grass Valley ones, and also Echo-Lab.

Most of the early ones didn't just require a genlock, i.e. black & burst synchronising reference, but needed line drive, field drive, mixed blanking, mixed sync, PAL ident, subcarrier & burst gate.
When installing these my fingers used to ache from making off all the interconnecting cables using either PL259's or BNC connectors! Imagine, 7 or 8 cables, just for synchronisation, plus say another 12 for source inputs, plus key, preview & outputs. It's probably why I have bad arthritis in my left hand now!

We used a huge quantity of cable, and timing was indeed fun, but interesting. But then so was setting up the 3-tube cameras of that era, it guaranteed a job for us engineering staff, as all cameras used to be set up very regularly to maintain tightly required parameters.

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Old 13th Nov 2019, 6:06 pm   #9
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Default Re: A truly analogue semi-pro vision/effects mixer?

Quote:
Originally Posted by beamcurrent View Post
Analogue vision mixers are, in the way they work, very different from digital mixers.

Simplistically, timing is the problem. In an analogue (colour) mixer the inputs have to be timed so that each of the start of picture is within say 5n/sec of each other. This requirement led to the use of a master sync pulse generator to lock and time each camera etc. A complex system soon developed.

Digital mixers solved this by the use, internally, of a synchroniser unit, whereby each random input was clocked into and read out of memory to be in time with the other sources. All became much simpler at this point.

A whole book could be written on this subject. A brief note about genlock in the attachment.

So analogue mixers are not for the faint hearted! BTW Sony did a small 2 input? analogue mixer for use with the Betamax SL5 ? It got round the timing by having a special "locked camera" ala Genlock.

If you really want an analogue mixer look at a Grass Valley 110 a nice and still sought after mixer but you will still have to time the inputs

Picture https://www.broadcaststore.com/store...l.cfm?id=10838

Good luck.
Re digital mixers. The inputs can’t actually be ‘random’, they have to be on the same set of reference pulses as the vision mixer itself and also within half a TV Line of being correctly timed into the mixer. The input buffers of these mixers generally have +/- half a tv line of buffer to accommodate this but, and this is big ‘but’, the output of the mixer will be delayed by one tv line with respect to the reference pulses to soak up these potential delays on the inputs as you can’t make time go backwards! This makes it impossible to correctly time the output of the mixer into another point (think here perhaps of a studio needing to be synchronous with a transmission suite) so it was common practice for the pulse chains in a digital studio to be advanced by 1 tv line with respect to the destination to allow the studio to become synchronous with the destination. A good example of this ‘technique’ was the digital Sony DVS8000 mixer used by LNN News in London whereby the entire studio was working one tv line in advance of the rest of the building to accommodate the one tv line delay through the mixer. Like Vintage Engr, I also used to work on large professional vision mixers like Grass Valley and Sony. I loved it, and, they paid me too!

Last edited by red16v; 13th Nov 2019 at 6:19 pm.
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