CRT RGB monitor hack to increase contrast and color saturation

[LambdaMikel]

I added a composite to RGB (csync) converter to my Amstrad CTM 644 monitor because I wanted to use it with composite video computers such as the Atari 400 or ZX Spectrum. However, there are only two composite to RGB converters on the market, and both have their issue: this first one has bad contrast with washed colors, and the second one produces a rolling picture that I can't lock on to by adjusting V-HOLD. Weird. So I decided to fix the bad contrast and color saturation problem by adding a TI THS7316 video amplifier. And - this really makes a huge difference! Here is a little video:

The captured video doesn't do the much improved picture quality justice (very hard to capture CRT). But trust me when I say - the difference / improvement is stunning! Highly recommended little "hack" for vintage RGB monitors.

 

[cj7hawk]

That's pretty cool - But if you go full RGB from a Spectrum 128, it gets even better.

It's a shame they never added a RGB option to the Spectrum, but I don't think they ever expected it to be as big as it was, or to get the serious use that it did. They should have stayed with the z80 and moved up to faster Zilog chips for the QL. Splitting their customers was a bad idea.

The QL was a nice machine, but it lacked support. I don't think Sinclair ever figured out that it was their customer base who wanted to get the latest spectrum that they left behind. No one is going to throw out three years of collected games just to move up to an unsupported computer. The QL needed a z80 based CPU and backwards compatability to the Spectrum - and it lacked that. If they went that way, the QL would have been very successful as a low cost business machine, much as the Amstrad PCWs were.

It didn't help any that the QL microdrive cartridges were 20% faster than the Spectrum format, and flipped the interleave, so it wasn't even data compatible.

 

[LambdaMikel]

That's pretty cool - But if you go full RGB from a Spectrum 128, it gets even better.

I actually have a Spectrum +2a which has RGB, a ZX-HD (HDMI), as well as a Peritel RGB for the original Spectrums... so no shortage of RGB / HDMI output for the Speccy, but just nice to have a bigger CRT monitor that can also do composite. My Sony Triniton next to it can do both composite, S-Video, RGB, (Scart, ...), obviously, but I am attached to the CTM - my childhood monitor. So I like using it. Compare it to the Commodore 1701 - just with an RGB input option as well.