Mainbow > Roland V-8 output is B&W

Hi, I am relatively new to video synthesis and I am running a variety of inputs into a Roland V-8 mixer with no issues. However, when I connect my Mainbow video synth to an input of the V-8, the output is black and white. What is weird is that the V-8 allows me to directly monitor the input and the Mainbow input monitor shows as color. There is something being lost internally between the input and the output of the V-8.

If I remove the V-8 from the middle, the Mainbow outputs to my monitor fine. If I put a Videonics M-1 mixer between the Mainbow and the V-8, the color is restored and everything is fine. But I don’t want to haul an extra mixer to a gig so I’m hoping I can track down the issue that is happening inside the V-8. Any thoughts?

Sounds like maybe one device is on Pal and the other ntsc? Worth a double check anyway

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The V-8 is very picky with the signals it will take. I have a home-built video synth that I think is similar in its guts to the Mainbow and I have the same issue with it going into my V8. The Videonics mixers (I have an MxPro) seem to be much more forgiving, and mine also will take my video synth signal and pass through the color no problem. Sorry that’s not a solution, but I don’t think it’s just you. I now have a rescan station with a camera pointed at a CRT so that I can get the full beauty of the synth because even the Videonics kind of dulls the output.

I had the same issue. I’m in the process of trying a few less noisy solutions, but the $20 soltion that’s currently working was sending the output to an av2hdmi, and then back to another hdmi2av before going into the v-8. I have a few other things i want to try though so i may have a better solution eventually.

Yep, same. Videonics MX-1 in the middle restores color but it definitely dulls the output.

Is there a piece of hardware I could put in the middle, like some sort of signal amplifier, that could help the V-8 see color or the Videonics not dull the color?

there are proc amps out there that allow you to bump contrast and brightness and color, etc, but I haven’t tried them for this. rescanning off of a CRT has been my solution, but it takes up space and requires some fine-tuning to get the frame right, etc

Sounds like the V8 has trouble locking to the color subcarrier from Mainbow, iirc the input monitor out on V8 is just a passive loop-through, which would be the same as bypassing the V8 entirely, and the monitor is probably a bit more tolerant to subcarrier frequency deviation.

Does it change if you input an external video source into the Mainbow? As the Mainbow will lock to the external signal subcarrier, which may be a bit more in-spec with what V8 expects.

If it does lock properly (and shows colors), but goes back to black and white when no external signal is present at the Mainbow input, you can try adjusting the IS (Internal Subcarrier Frequency Adjust) parameter on Mainbow until the V8 picks up colors.

Then, if it doesn’t lock to the external signal subcarrier (output is still black and white), you can try adjusting GC (Genlock Coarse) parameter, while leaving the GF (Genlock Fine) to AUTO. And then try to adjust IS again once no external signal is present at the Mainbow input.

Else, if you’re not able to get colors whatever the parameters on Mainbow are set to, as other suggested, a digital device (like AD/DA converters) in between Mainbow and V8 could help, in order to recreate a subcarrier which may be closer to the specs V8 expects.


Update: Kramer 101L video line amplifier fixed b/w output. small. fits in the palm of yer hand device. much smaller than an extra mixer or rackmount tbc. i found one for $25 on the bay.

Thanks @donchampsound I went with a very similar solution, using a vintage Showtime Video Ventures distribution amplifier. It corrected the Mainbow b&w problem, but it is a very large extra piece of equipment.

Thanks for this tip. I just picked up a very similar device, a Kramer 104 L 1:4. Much smaller than the Showtime.