
I know Spectors and have owned four and currently own three (including one neck-thru Korean NS2A). varied over the years but they are all the same component values, same dual op-amp, all have balance (with center detent), volume, bass and treble (both with cut/boost and center detent) all in the same circuit. That was just the Spector preamp circuit for many years before they (more recently) went with the Tone Pump (inferior, IMO) preamp. The preamps in those asian neck-thru Spector basses (NS2A) may not have all been manufactured by HazLab (some may have been built under license) but they are the same circuit. The components of the HazLab preamp are inexpensive. The HazLab preamp is ridiculously expensive now but that's just what they charge for them (now). I also believe those NS2A basses were all made in and around the 1980's.).

The Japanese and Korean NS2A basses all had the HazLab preamp (BTW, I believe ALL NS2A's came from asia.
