Comments | captain18: Outsmarting Sony (or, Stupid U-Matic Tricks!)

captain18

Outsmarting Sony (or, Stupid U-Matic Tricks!)

Jan 12, 2011 00:45

So, part of the reconfiguration of my edit suite/man cave has been to recable everything to use S-Video instead of composite video for the highest quality video I can get from my collection of professional and prosumer gear. This was pretty easy on the S-VHS front since that's where S-Video was developed to begin with, and my Betacam deck does S- ( Read more... )

Comments 53

(The comment has been removed)

Re: Great U-Matic Tricks captain18 February 3 2011, 00:49:14 UTC

The best way to actually convert Y/C 688 to S-Video is to stalk eBay. Options include:

Y/C Plus has the YCP-688 which is a bi-directional transcoder.

Digital Processing Systems (Leitch) has two products that might do what you want as well, the DPS-210 (a transcoder) and the DPS-295 (a TBC and transcoder).

Panasonic has the UTP-2, a re-badged DPS-210 transcoder.

Prime Image has the Excel 6.5, also a TBC/Transcoder combo.

The upside to the converter is you don't need to open your VO-9850 at all. And if you get one with a built-in TBC you've killed two birds with one stone. The downside is you're taking the 3.58mHz Chroma signal, converting it to 6.88kHz, then converting it back to 3.58mHz so you have the potential for signal degradation. There's also the waiting for one of the units to actually show up and be affordable ( ... )

passwordisfail October 26 2013, 20:09:31 UTC

[Hoping I won't get marked as spam this time.]

The JVC KM-F250 Frame Synchronizer could be another good option. The Y/C dub input and output can both be switched between S-VHS/U-Matic, and there's even component outputs. As a bonus, it claims to feature U-Matic dropout compensation.

( ... )

captain18 October 27 2013, 01:17:23 UTC

This looks promising, yeah. The only thing is, it uses the locking 7-pin DIN, so in order to take advantage of S-Video output to modern gear you'd need to build an adapter.

Thread 5

BVU-950 board location to get Chroma? / baking tapes? turnkit April 19 2011, 04:19:17 UTC

THANK YOU FOR POSTING THIS! I am pretty amazed ( ... )

Re: BVU-950 board location to get Chroma? / baking tapes? captain18 April 22 2011, 04:05:32 UTC

Here's the breakdown of what most of those boards are based on the BVU-870 descriptions:

TBC - (Time Base Corrector)
DM - (Demodulator)
SV - Servo control
AU - Audio rec/playback
BC - Control timing generator
MD - Y/C modulator

The BVU-870 has a YD (Luma Decode) and CD (Chroma Decode) boards, based on the nomenclature, DM is almost certainly a combined Demodulator board. So that'd be a place to start.

I can only see two reasons not to do this (apart from already having a DPS-210). For one, you have to adjust your chroma timing at the TBC. For two, based on the CD-32A schematic, the spot I'm stealing the signal from is before the noise reduction circuit so the chroma may not be as smooth as it otherwise would be. This may or may not be an issue for the BVU-950.

Re: BVU-950 board location to get Chroma? / baking tapes? turnkit April 22 2011, 07:33:46 UTC

But when you say "you have to adjust your chroma timing at the TBC" how would I go about adjust that to fix the problem that the "horizontal timing on the Chroma will be a little off from the Luma"?

If I am using a DPS-295, for instance, is there a way to adjust the chroma timing to put it back in sync with the luma signal?

Stephan, the fellow who posted the instructions for getting S-VIDEO off the VO-9800 board said he'd try to look through his BVU-950 book to find the signal points there. Hoping he can...

But what's your prediction? In (signal) theory-land, would the DUB YC688 chroma have greater bandwidth over the S-VHS signal?

Do you think the superior signal would come from the pre-TBC'd signal transported via DUB+NTSC2 or via S-VIDEO soldered hack?

I almost want to create both signal paths now just to test.

I've got hundreds of tapes I'm going to be digitizing so I'd like to do it once and know I did it the best way possible.

Re: BVU-950 board location to get Chroma? / baking tapes? turnkit April 22 2011, 08:13:12 UTC

Do you think the extra wavy lines shown in your checkerboard (in the S-VIDEO signal path) are due to bypassing the noise reduction circuit?

Thread 9

DPS-295: High-band or Low-Band turnkit April 20 2011, 19:13:49 UTC

Anyone know if the DPS-295 is expecting high or low-band signal ( ... )

DPS-210 / UTP-2 vs. DPS-295 turnkit April 20 2011, 21:05:36 UTC

Notice that the DPS-210 / UTP-2 has a front panel switch to select the Hi vs. Lo setting for the YC688 modulation which reads: Y/C-688L vs. Y/C-688H

http://picasaweb.google.com/lh/photo/sF9Lbtj07_FNAqBSnStBFg

More pics here: https://picasaweb.google.com/turnkit/PanasonicUTP2AndDPS210Transcoders?feat=directlink

The DPS-295 doesn't seem to have a way to select the high vs. low setting. I think this is why I am only getting black and white on the DPS-295.

Anyone know how to if it's possible a DPS-295 High/Low-Band (modulation) setting?

Re: DPS-210 / UTP-2 vs. DPS-295 captain18 April 21 2011, 03:29:30 UTC

I don't think this is a Hi-Band/Lo-Band issue, simply because you are getting color from the Composite output. The "band" being referred to is the amount of chroma bandwidth being encoded: A Hi-Band recording will play back in monochrome on a Lo-Band machine because the color circuits don't recognize the expanded signal. Given that the chroma signal splits off to feed the Dub connector prior to being encoded for composite output, it should be an all-or-nothing proposition ( ... )

jvraines May 4 2012, 18:41:34 UTC

If I may jump in with another year-after tidbit . . . now that I'm deep into U-matic transfers with the DSP-210/UTP-1, I have found that the "688L" setting appears to shift the levels up a suspicious 8 IRE or so. Most tapes play correctly on "688H," but a few only have correct black levels on 688L. Perhaps these were recorded without NTSC setup and that's what the L(ow) setting fixes.

captain18 May 4 2012, 23:03:31 UTC

The "L" and "H" refer to the bandwidth used for non-SP U-Matic. So-called "Low-Band" U-Matic is the original format spec. In the late '70s Sony upped the luminance, resulting in "High-Band" U-Matic. I believe the changeover was with the Series VIII machines (ie, VO-7xxx) but I haven't found a good source to back that up.

That's cool that you were able to establish a good visual benchmark for identifying which system was used for recording.

Thread 7

a clue... now perhaps an interpretation??? turnkit April 22 2011, 07:24:31 UTC

As I read your response I was thinking... perhaps Chroma could come from the composite signal -? But I don't understand the electronics well enough to know if that would make sense ( ... )

Re: a clue... now perhaps an interpretation??? captain18 April 22 2011, 12:43:25 UTC

Actually, taking the chroma off of composite would be an elegant solution, if you think about it. Any TBC by design is going to split the chroma and luma from the composite signal to begin working with it. Since the luma is already S-Video compliant, DPS saved themselves some circuitry by pulling the chroma from composite rather than adding the extra bits to transform the 688 kHz color to 3.58 mHz ( ... )