The Birch-Stolec era AC-30 was the earliest effort to build an AC-30 using printed circuit construction techniques. The chassis, slider board and control panel from the JMI and VSEL era AC-30 were adapted by Birch-Stolec to accept their new twin printed circuit board design. Rectangular holes in the chassis provided access to the printed circuit board mounted tube sockets.
The tube complement remained unchanged from the original JMI design. It included five ECC-83 and one ECC82 in the preamp area (these tubes were removed from the amp in the photo above), four EL-84 for the output stage and one GZ-34 rectifier tube.
Various books have reported that the Birch-Stolec AC-30 was the first AC-30 redesign to eliminate the GZ-34 tube recitifier. This appears to be only partially true. The pictures shown here offer evidence that the GZ-34 rectifier tube was included in some Birch-Stolec era AC-30 Top Boost amplifiers.
Please note the "Lemark" label on the choke seen above. Lemark Industries was another company owned by Birch-Stolec Ltd.