Mainbow + recurBOY issues

[hellocatfood]

I recently purchased a Mainbow and I’m having a bit of trouble feeding video into it from a recurBOY.

When I plug the output of the recurBOY into the video input on the Mainbow it shows the video correctly. However, when I turn up the Alpha Symmetry instead of the generated pattern all I see is a grey/white overlay. See video below

Mainbow/recurBOY

What I should be seeing is demonstrated in the demo video. I have feeding video in from other devices and it worked fine, so I’m guessing it’s something to do with the recurBOY/Raspberry Pi? Both the recurBOY and Mainbow are set to PAL (I’m in the UK).

I don’t think Russel Kramer/Chroma Couldron is on here but I’ve also reached out to him via e-mail but any insights anyone here can give (paging @cyberboy666) would be warmly received.

[PigPin]

Somewhere else in these forums there was a signal issue with the output from a Mainbow that was fixed using a Kramer 104L Proc Amp… Maybe be the Mainbow would play nice with the recurBOY signal if you used a Proc Amp to amplify the signal from the recurBOY into the Mainbow. Just a thought if you have one laying around to try it with and report back.

[looseopinions]

Hi, I have both a Mainbow and a recurBOY, so I tried your test. I do not have this issue… recurBOY into the Mainbow input works fine.

Good to know someone else with a similar rig. Lets stay in touch and trade notes.

[cyberboy666]

hi @hellocatfood - thanks for reporting this issue you are observing. having never used a mainbow myself i cant be sure exactly why this is happening, however here is the previous post mentioned about b/w issues with mainbow output into v8:

Mainbow > Roland V-8 output is B&W

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 show…

although this is other way around i guess could be mainbow having trouble locking on to the recurboy sub-carrier…

one thing you could do is test putting something else (like a distribution amp or tbc) between rpi and the mainbow to see if that makes a difference.

it could be that this issue is unique to pal if other users are reporting these two working together ok - so could be worth testing both with ntsc if possible.

finally another (slightly round-about) option could be to take the hdmi output from recurboy and convert this to composite with an hdmi->composite adapter and see if this would solve your problem

i would like to build a mainbow one day (and am also in PAL land) so if i ever do will be able to test this for myself also

[hellocatfood]

@looseopinions are you using PAL or NTSC?

@cyberboy666 thanks for the tips! At the moment I don’t have any of the devices you mentioned so I can’t test it but I probably will need a hdmi > composite adapter soon so will purchase one and let you know.

It’s not all that urgent anyway, just looking forward to when I can do most of my visuals without the ol’ laptop!

[looseopinions]

I’m on NTSC. Also I’m the person that had trouble with Mainbow showing up B&W on my Roland V8, and putting a dist amp inbetween those two to amplify the signal fixed that issue. However, I’m able to go straight from recurBOY into Mainbow with no amplifier. Definitely worth a try though. I’ve found a little amplification between things has helped other issues throughout my analog signal chain.

[hellocatfood]

@cyberboy666

it could be that this issue is unique to pal if other users are reporting these two working together ok - so could be worth testing both with ntsc if possible.

I finally found a moment to test and I can confirm that if I put both the Mainbow and recurBOY into NTSC mode it works as expected. Yay, I guess? Would this suggest that the issue appears to be the PAL signal being generated by the recurBOY?