I'm sure it can happen -- just a sign that you did a good job and got all the soldering done well, and then the c4s will asdd some extra current draw on startup, and possibly a bit more when in use too, so that could account for the difference.
Now just kick back and listen...
-- Jim
Jim Rebman -- recovering audiophile
Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).
s.e.x. 2.1 under construction. Want list: Stereomour II
All ICs homemade (speaker and power next)