Hi James,
A few questions about the SP4:
1) No headphone jack?
2) D/A conversion is only 24 bits, not like 32 bits as the BDA-3? Who is manufacturer of the D/A chip, model?
3) No balanced Analog Inputs, SP3 has two inputs?
4) No AES inputs, SP3 has two inputs?
5) No Unbalanced Analog Inputs-2 channel equipment?
6) Cooling Fan, always on or with a set temperature trigger? Noisy?
7) USB ports, two units on rear panel, USB 2 or 3? Any chance to have one on the Front panel?

Ethernet port - 100MB only, not 1GB? Direct streaming capabilities?
9) What are the possible expansion boards for this SP4?
And will it be demo presentation at a local Audio dealer in the coming weeks?
Luigi