Just to be clear on these matters, to get the best results you need both a POWERED HDMI splitter (one HDMI IN and two OUT) and a POWERED HDMI to COMPONENT converter (red, green and blue for video and red and white for audio) . You can use a powered HDMI to COMPOSITE converter (scart or RCA white, yellow and red), but the picture quality through the Slingbox (any model) will be MUCH poorer than using component and since all recent Slingbox models (can't confirm this for Slingboxes prior to the PRO HD) have component IN connections as well as composite, there is no reason at all to use the composite unless you are connecting to two different devices such as a Tivo/V6 AND another device such as a Freeview box or a DVR.
An HDMI lead should be connected between the Tivo or V6 HDMI OUT and the HDMI splitter IN. A second HDMI lead should be connected from one of the HDMI OUT sockets on the converter to your TV and a third HDMI lead should be connected between the other HDMI OUT socket on the converter to the HDMI IN socket on the POWERED HDMI to COMPONENT converter. Finally you need to connect the 5 output connections on the component converter to the component input sockets on the Slingbox. The splitter and converter must both be permanently powered ON.
I use 2 Slingbox Pro HD's, two Slingbox M1's, six Slingcatchers and two Amazon Firesticks around the world with the above configuration and have never had any problems.
Using any unpowered splitters or converters WILL NOT WORK.
Both of mine are powered,will try with component rather than composite when it arrives. The odd thing is the exact same set up (Powered HDMI splitter, powered hdmi to scart connected tot he scart composite connector supplied with the M1) works fine with my Sky+HD box, yet the left hand edge of the image is off the edge of the screen and doesn't reach the R side of the screen in sling player (Windows, Android or ipad) when plugged into the V6 box. Tinkered with the video settings and image layout of the slingbox with no benefit.
Firstly using component connection is NOT an option on the Slingbox Classic - this box only has composite and video-s inputs. The video-s input is working fine by the way.
As I said before I am NOT using a splitter. I unplugged the HDMI from the TV and plugged it into the HDMI2AV converter.
The issue is when I plug the HMDI2AV output component cables (3 x RCA Male to male ) into the Pro HD - Slingplayer on the PC works fine. When I plug the composite cables into the Classic box ( 3.5mm to 3 x male RCA) I get a black and white picture but sound is fine. I wondered if it was a problem with the 3.5mm to 3 x male RCA cable that is used with the Classic but this it NOT the case since it worked ok with a different source device ( Humax Freesat )
The HDMI2AV converted is powered on throughout the test and when unplugged I get NO picture in Slingplayer so that is not the issue here.
It seems to be some difference with the output from the HDMi2AV vs the "normal" PAL output from say my Freesat box. 50/60 Hz a possibility ?
I don't know about Slingbox but it's a general rule that ancient devices can be troublesome in our digital age, so I'm not surprised that you have a problem with an HDMI to composite converter going into to a Classic box with neither supporting 576i50.
It seems to me that it's best to use just the Pro HD with an HDMI to component converter.
Back in January, my set-up which is almost exactly the same as yours and which had been working flawlessly for about 3 years, stopped working while we were away from home and the Slingbox!
I am now home and see the red light on the HDMI-Component adapter flashing. I contacted the supplier of the converter and they sent another... and the light on that is flashing too! I tried connecting the HDMI lead from the converter directly into the Tivo, bypassing the powered splitter - but it doesn't work.
I guess the flashing light on the converter shows it is not working... but I am at a loss to understand why. Can the first unit be faulty, and the second one also?
I did read somewhere Virgin had added software to the Tivo to prevent splitting of the signal.. but I haven't had that confirmed yet.
Hope you can help, by letting me know if your set-up is working. Hopefully it is and I can just buy another Converter!