[Hammarlund] HQ-150 question

[Les Locklear]

I recently acquired an early HQ-150, serial number B5096. On the chassis the 1st af/bfo tube is clearly marked 12AU7. The manual copy shows it as a 12AX7. 
The Q-Multiplier uses a 12AX7, perhaps there was a running factory change? Does anybody have a manual they can look at to see if there might be an earlier
version or perhaps a different manual?


The receiver works fine, but needs an alignment after replacing a couple of bad tubes.

Thanks,

Les Locklear
Gulfport, Ms.
Dx'ing since '57