For Sale: VIC-20 S-Video Cable

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Oge_user
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For Sale: VIC-20 S-Video Cable

Post by Oge_user »

For sale is a VIC-20 S-Video Cable available in SCART (as picture) and Mini-DIN versions. Its lenght is of 1,6MT. and it is compatible with ANY VIC-20 with a DIN A/V connector. ;)

Yes, S-Video. :)

PICTURE:
Image

PRICE:
€9,80
SHIPPING: EU (€6,40); Outside EU (€8,20)

Cheers,
Oge
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mrr19121970
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Re: For Sale: VIC-20 S-Video Cable

Post by mrr19121970 »

Oge_user wrote:Yes, S-Video. :)
:D

NO S-VIDEO OUT ON A VIC20
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Oge_user
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Re: For Sale: VIC-20 S-Video Cable

Post by Oge_user »

If you highpass Composite Video in two different steps, one step for Luminance and one step for Chrominance, you can obtain S-Video from a VIC-20.

I discovered that by accident while trying to reduce Chrominance leakage on Luminance signal onto the Commodore 64.

I strongly suggest to use a good old CRT capable of S-Video. How to know if this Cable will work is quite simple: if you are able to display S-Video from a Commodore 64, then this Cable is good for you as well.

If anyone is interested in testing it using a LCD I may sell one with free shipping. :)


Cheers,
Oge
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Mike
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Re: For Sale: VIC-20 S-Video Cable

Post by Mike »

Oge_user wrote:If you highpass Composite Video in two different steps, one step for Luminance and one step for Chrominance, you can obtain S-Video from a VIC-20.
You're talking bullshit here.

An unmodified VIC-20 only outputs composite. A cable can't make this S-Video. It's a normal function inside a display unit to separate the Luma and Chroma signal out of a composite signal by low- and high-pass filtering. But at this point, the "damage" is already done: the chroma signal of the VIC-20 has strong components outside of the normal chroma range, which leads to pixel tearing. And the filtering process will reduce the bandwidth of the luma signal far below of what's possible with S-Video.

See also: http://sleepingelephant.com/ipw-web/bul ... &start=103
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tokra
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Re: For Sale: VIC-20 S-Video Cable

Post by tokra »

Mike wrote:
Oge_user wrote:If you highpass Composite Video in two different steps, one step for Luminance and one step for Chrominance, you can obtain S-Video from a VIC-20.
You're talking bullshit here.
Well, logic dictates his answer is correct, he did not say how good the S-Video will look :D

Of course you can split a composite-signal into Luma and Chroma if your display device only has such inputs. I used such an adaptor for many years to be able to connect my VIC-20 to a Commodore 1901-monitor which only has separate Luma and Chroma inputs. I even remember that the cable put a 100pf capacitor into the Chroma-line, otherwise the picture would look very poor.

If you want S-Video-quality output you need to modify your VIC with an S-Video-mod of choice.
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Oge_user
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Re: For Sale: VIC-20 S-Video Cable

Post by Oge_user »

On the CRT TVs used for the tests the quality was pretty good.

Dunno about LCD TV Sets at the moment but I can say that:
1) They also struggle with plain S-Video signal out of a C64;
2) S-Video signal of the C64 is out of specifications as well (Chroma signal being too strong and Luminance with severe leak of Chroma signal)


Cheers,
Oge
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Mike
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Re: For Sale: VIC-20 S-Video Cable

Post by Mike »

The main motivation of the S-Video mod is to get rid of the checkerboard patterns, that most prominently appear with the colours Red, Cyan, Purple and Green (and also Orange) and their light variants over white or black background.

Set the character colour to cyan, and put a vertical, single pixel wide, line on screen, as with [SHIFT] + [-]. On a PAL machine, you won't get that line, but rather something more resembling this:

Code: Select all

 **
*  *
 **
*  *
 **
*  *
 **
*  *
This pattern is steady on a PAL machine. On a NTSC VIC-20, it will exchange after each 1/60s of a second with this pattern:

Code: Select all

*  *
 **
*  *
 **
*  *
 **
*  *
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... making the checkerboard effect less apparent. On PAL, this pixel tearing can reduce certain letters in the aforementioned colours to an unreadable pulp. Just check with your cable, whether these artifacts are still present. You can use my program 'Colour Test' to check this for all combinations of background and foreground colours.

The S-Video mod prevents those patterns by not mixing the chroma into the luma signal to obtain the composite signal in the first place. A true S-Video signal can then also use the extra bandwidth available in the luma signal to produce a sharper image.

Some monitors and TV sets do a fairly good job at separating the colour information and luminance without too much degradation of sharpness, by applying a comb filter. They can already do this with just a supplied composite signal. :)
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Oge_user
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Re: For Sale: VIC-20 S-Video Cable

Post by Oge_user »

Thank you, Mike.
Some monitors and TV sets do a fairly good job at separating the colour information and luminance without too much degradation of sharpness, by applying a comb filter. They can already do this with just a supplied composite signal. :)
I've seen that the quality is slighty higher feeding S-Video (rather than Composite) but my CRT and some other models tested may be not enough. Would someone wish to test it? I offer free shipment in this case.


Cheers,
Oge
Barney
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Re: For Sale: VIC-20 S-Video Cable

Post by Barney »

I'd like to buy one. I would like the 5 pin din (on vic side) to s-video mini din (on tv side). Do you take paypal? Thanks
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