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Amiga computer related discussion => Amiga Marketplace => Topic started by: ZeBeeDee on October 31, 2008, 12:06:19 AM

Title: 15Khz RGB to VGA Converter Scaler
Post by: ZeBeeDee on October 31, 2008, 12:06:19 AM
A possible contender for those who can't use the Indivision AGA 1200?

Not cheap, but a viable alternative by all accounts.



*Link removed*  See full thread why
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: InTheSand on October 31, 2008, 06:10:40 AM
Quote

From the auction item:
Supports 16-bit and 24-bit color depth


I wonder if it's true 24-bit?

 - Ali
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: alexh on October 31, 2008, 07:31:10 AM
It's not. This is a Cypress CM-397 (http://www.cypress.com.tw/product.php?PId=87936&CId=010&CName=PC%20Multimedia/Scan%20Converters&SR=0). We've had them apart. The chips inside are 16-bit only.

Not only is it 16-bit only. Cypress said the Digital->Analog->Digital->Analog conversion process had an effectiveness of 12-bit
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: InTheSand on October 31, 2008, 07:54:02 AM
OK, thanks for the info - good to know these things!

 - Ali
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: alexh on October 31, 2008, 07:54:49 AM
Unless they've re-done the internals, which I doubt it.
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: tonyyeb on October 31, 2008, 09:54:54 AM
Funny how these boxes seem to pop every so often, this is third time i've seen them mentioned on amiga.org and each time the result is Alexh saying they are pants!

Step away from the crap FlickerFixer people!
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: ZeBeeDee on October 31, 2008, 03:21:52 PM
Didn't know they'd already been discovered and rejected as crap - thanks for the heads-up alex!

Link removed - not giving the seller any potential sales from here.

Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: HopperJF on October 31, 2008, 04:41:33 PM
I just bought one of these:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=180301378360

To use with my Acorn multisync monitor. I'm hoping it is alright but if it isn't, it was only £15 so no big deal.  :-)
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: tonyyeb on October 31, 2008, 04:46:21 PM
Quote

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=180301378360



Alex? Any good?
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: alexh on October 31, 2008, 04:53:57 PM
Quote

HopperJF wrote:
I just bought one of these:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=180301378360

To use with my Acorn multisync monitor. I'm hoping it is alright but if it isn't, it was only £15 so no big deal.  :-)

Depends which Acorn Multi-sync monitor it is. AKF50 and AKF52 will work and AKF85 I think works too.

This is a purely passive device. Just wires. Also known as a Sync-Dongle.

http://bboah.com/cgi-bin/showhardware.cgi?HARDID=733
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: tonyyeb on October 31, 2008, 04:55:16 PM
So just to get things in my head, the monitor would still need to be able to do 15Khz?
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: alexh on October 31, 2008, 04:57:00 PM
Correct.

Early Acorn monitors were made by the infamous monitor company Microvitec. Well known for making 15-31KHz multi-sync monitors. Later ones which came with RISCPC's were AFAIK standard PC monitors (i.e. 31KHz)
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: tonyyeb on October 31, 2008, 05:01:56 PM
So if you wanted a TFT monitor that could do 15Khz... no chance? Better buying an LCD TV?

Is it the horizontal frequency that people should look at? Is that the 15Khz/31Khz?
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: HopperJF on October 31, 2008, 05:09:40 PM
As long as it displays bog standard AGA I am happy, since I have no gfx card. I just want a solution to display 640x512 flicker free.

Edit: I was told the Acorn monitor I have is multisync, I will go check the model number.
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: alexh on October 31, 2008, 05:11:24 PM
You'll never find a PC monitor which support 15KHz horizontal scan rate and 50Hz vertical refresh rate through the VGA socket.

LCDTV or Plasma would be a better way to go but remember you'll need to connect via the SCART socket.
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: alexh on October 31, 2008, 05:12:32 PM
Quote

HopperJF wrote:
Edit: I was told the Acorn monitor I have is multisync, I will go check the model number.

Multisync does not mean anything these days. All it means is the monitor is not a fixed frequency monitor. Back in the old days it meant it support 15KHz and 31KHz but now it could be 31KHz+.

Multisync no longer means a monitor supports 15KHz
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: HopperJF on October 31, 2008, 05:13:06 PM
Just checked, it is an AKF53 model
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: alexh on October 31, 2008, 05:15:24 PM
http://acorn.chriswhy.co.uk/docs/Monitors/Acorn_AKF506070.pdf

As you can see from this document, AKF5x series supports 15KHz will work fine with a sync dongle and an Amiga.
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: HopperJF on October 31, 2008, 05:16:57 PM
Quote

alexh wrote:
http://acorn.chriswhy.co.uk/docs/Monitors/Acorn_AKF506070.pdf

AKF53 will work fine with this sync dongle and an Amiga.


Hurrah!!

Have a drink on me  :pint:
Title: Re: 15Khz RGB to VGA Converter Scaler
Post by: alexh on October 31, 2008, 05:18:36 PM
It will however flicker enough to trigger an epilepsy seizure when displaying 50Hz interlaced modes. :-)

The flicker will be much more apparent than say a CRT TV using RGB SCART due to the low persistence phosphor of the monitor. (But it will also be a lot sharper!)