Not fadeing

[LightUp]

Yes, you're right barnaby. Apparently it uses an SCR, which is unidirectional.

You want a fullwave rectified, pulsating voltage for dimming for least flicker. If using a bridge, make sure you don't add filter capacitors on the output, or the SCR won't turn off, thereby ceasing to dim lights.
Not knowing the SCR max. voltage, it is uncertain whether it can be used on a 220VAC supply, so don't use it for 220VAC supplies until it is confirmed that it is within the rated SCR max. voltage.

EDIT:
Since the SCR conducts in one direction (like a diode), the 1/2 wave LED strings will only work if attention is paid to voltage polarity. A fullwave bridge isn't needed for those types of strings. I haven't tested this "SCR" version of SSR board, so I'm not speaking from experience.

 

[Technician37]

I'm also new to Vixen. I'm using an Arduino Mega 2560 to control 48 Channels. I have 4 8-Channel SSR relay boards that are zero crossing, but I would like to have some channels that allow dimming so that I can leverage other Basic Vixen Effects (Pulse, Twinkle, Spin) for those channels. Can you recommend an 8 channel relay board that has non zero crossing relays and can be controlled by the Arduino, or do I need to buy a completely separate controller board to accomplish dimming.

 

[LightUp]

There is no SainSmart board I know of that does dimming. Due to pixels taking over the Christmas lighting world, there are fewer sales of triac AC controllers. Many here build their own. There may be some kits available like; http://www.diyledexpress.com/index.php?main_page=product_info&cPath=35_34&products_id=221
, or people selling their old units. So watch for AC SSR sales on this forum.

The other thing you need for AC dimming is a sketch that uses a zero crossing hardware circuit, which you may need to build yourself, as such former kits have been discontinued. Dirkcheap AC SSRs were popular for awhile but the site claims non in stock.

EDIT: Sketch was here last I looked, the one on the right.