Nope. The SRX is originally a Stax design from the 1970s that was given to the DIY community. I named my version the SRX Plus to honor the original Stax circuit, and to indicate that it was an optimized version of it. The SRX Plus circuit is almost exactly the same as the SRX, but updated with the addition of constant current sources or loads to improve its function and drive capability. The MOSFET constant current sources/loads set the circuit parameters but the active devices are tubes. The fact that such a "simple" circuit, when updated, is still sonically competitive with some of the best designs today is a testament to the talent of the Stax engineers who designed it. The T2 shares the skeleton of the SRX, as described in the previous post, To say that all the intervening transistor circuitry merely replaced the two coupling capacitors is somewhat of an oversimplification, as the output stage of the T2 is a common grid rather than the SRX's common cathode configuration, and the former requires an extra driver stage. In fact the BHSE uses a similar output stage configuration which was inspired by the T2.