The farthest back Philbecks I have are:
George Philbeck Sr. b.1764 Scotland, died probably in Rutherford county,NC, wife's name unknown.
children:
1) William b.1790 Scotland
2) Nella b.1790 Scotland
3) Sarah b.1792 perhaps in Rutherford,NC (not sure)
4) George b.1793 b.SC
5) Richard b.22 jul 1811 Rutherford,NC

(Note Rutherford county is on the NC/SC boundary)

George b.1793 married Demassa Randall (b.1804)
Their children:
1) Robert b.1824 of,Rutherford,NC
2) Sarah b.1826 of,Rutherford,NC
3) Sinah b.19 Jun 1828 of,Rutherford,NC, d.6 Aug 1900 Cleveland,NC
4) James b.1831 of,Rutherford,NC
5) Temperance b.19 Mar1832 Rutherford,NC, d.26 Mar 1920 Gaffney,Cherokee,SC

Richard b.1811 married 1st Elizabeth Womack b.1813 RUtherford,NC d.1841 Rutherford,NC (dau of Anderson and Frances [Dobbins] Womack).
Their children:
1) Mary L. b.19 apr 1834 Rutherford,NC d.8 aug 1869 Rutherford
2) Alma E. (female) b.1836 Rutherford,NC
3) John Philip b.5 Oct 1837 Rutherford,NC, d.27 jan 1919 Cleveland,NC
4) Sinah Frances b.9 oct 1839 Rutherford,NC, d.23 Jun 1935 Cleveland,NC
5) William A. b.20 jan 1841 Rutherford,NC

Richard married 2nd Nancy Davis b.8 sep 1813 Cleveland,NC (dau of William Failsen and Sarah [Womack] Davis)
Their children:
1) Thomas Fernilson b.27 jan 1844 Cleveland,NC
2) Sarah W. b.1846 Cleveland,NC
3) Delphia S. b.8 Oc t1847 Cleveland,NC
4) James Pinkney b.18 Mar 1849 Cleveland,NC d.4 Apr 1898 Cleveland,NC
5) Daniel Johnson b.20 may 1852 Cleveland,NC

I have lots more on this family, but it doesn't appear to be the same Philbeck family as yours.
Hope you find what you are looking for.
Oh, by the way, I have one other Delphia Philbeck in my database: She married 6 Nov 1825 Benjamin Washburn b.1860. I have nothing more on her. Ben's 2nd wife was Mary Dobson b.1820. They had: 1) Mary b.1855 and 2) John b.1856. Ben was the son of Gabriel and Priscilla (Jones) Washburn.