BSP midi problems with Volca Sample when going thru Keystep

[JoyMonkey]

I have a BSP at the beginning of my midi chain, going something like this...

BSP Midi Out -> Keystep Midi In
                Keystep Midi Out -> Midi Splitter -> Korg Volca Sample Midi In
                                                  -> Roland SH-01A Midi In
                                                  -> Korg Monologue Midi In

I have configured the Drum section of the BSP as seen in this Arturia video, so pads 1-10 are assigned to midi channels 1-10, which the Volca Sample uses. I have configured the other synths so their channels are 11 and 12. I have configured the Keystep so Midi Thru is on.
This way I'm able to control the synths using either the BSP or the Keystep, however the BSP Drum section isn't controlling the Volca Sample. The Sample just sits there sad.

When I connect the BSP Midi Out directly to the Volca Sample it behaves just fine.

Any ideas why midi channels 1-10 don't appear to be getting to the Volca Sample from the BSP when going through the Keystep?

[megamarkd]

Which MIDI splitter are you using?
Is the Keystep set to MIDI THRU?

[JoyMonkey]

Which MIDI splitter are you using?
Is the Keystep set to MIDI THRU?

The Keystep is set to Midi Thru.
I'm using a passive midi splitter - I'm thinking this is the root of my problems; splitting the signals too many ways, weakening it too much for the amount of devices I have in line. I'm going to build a better splitter that offers buffering for each output; similar to the Banana Split. I'm thinking this will fix my problems.
Thanks!

[megamarkd]

The Keystep is set to Midi Thru.
I'm using a passive midi splitter - I'm thinking this is the root of my problems; splitting the signals too many ways, weakening it too much for the amount of devices I have in line. I'm going to build a better splitter that offers buffering for each output; similar to the Banana Split. I'm thinking this will fix my problems.
Thanks!

Bingo!  Passive splitters tend to split the current and voltage also.  From what I've seen, passive splitters only work for a single split and after that the data signal becomes too weak and is corrupted.
Sonic State, as great as their video reviews are, have done the MIDI world a disservice by posting a tip on using Belkin-like stereo headphones splitters as a MIDI splitters.  Every few months or so someone posts somewhere on the 'net about their Volca set-up not running on MIDI correctly while using a technique they thought should work as they saw it done in a Sonic State video......(the vid never actually shows more than one device running at one time).

Hotchk155 makes some nice MIDI tools, but they are always sold out when I've had the money and the need for any of them.  I have a Phil Rees V3 splitter which runs on a 9v battery and I think I've changed the battery three times in the 18yrs I've owned it for.  Unfortunately Phil Rees has retired, his site is still up as a resource but the products are now collector's items, not even showing up on eBay that often.