Valley & Wallman) and the authors of "A Single-ended Push-pull Amplifier," Proc. IRE, Vol. 40 1952 (Peterson and Sinclair) and the author of the MJ Stereo Technic "Sidewinder" article that contains 20 formulae for evaluating the SRPP circuit falsely think it was push-pull in nature?
   Moving away from psychology to electrical engineering, if this circuit is truly single-ended, how is it possible to deliver (into an external load) current swings (in both directions) in excess of the idle current? How is this possible with a single-ended circuit, let alone one with a constant current source?
   If your answer is something along the lines that people once thought the world was flat, but today we know better, here is some troubling news. Just the other day I picked up the latest issue of Glass Audio, wherein you will find an excellent article titled, "SRPP's Harmonic Cancellation Capabilities." The author, Mr. Stefano Perugini, writes
  "Figure 1 is the schematic of an SRPP. The
   circuit operation is such that: Io = Ip1 - Ip2." Push-pull in a nutshell. Later, he goes on to say

   The next argument is that since the SRPP circuit was originally designed for high-speed digital computer circuits, calling this a push-pull circuit would be a misnomer. I fear that I do not follow this argument at all. Are you saying that circuits designed for high-speed digital computer circuits can never be push-pull, and as this circuit was designed for such an application, it cannot be push-pull? If so, why? (As a historical aside, this circuit was designed as a DC amplifier that would be immune to power supply fluctuations and it found its widest use in TV sets.)
   Push-pull operation entails anti-phase current conduction between the output devices, which even by your own analysis obtains in this circuit,
  "As the input voltage on the bottom triode   
  increases (V1 grid), the current drawn across
  Rak increases, so the voltage across Rak drops
  and so to the voltage at V2 grid must drop. As
  the voltage at V2's grid drops, the current
  through V2 decreases..." (our italics.)
   (By the way, if the current decreases, how is it constant?) Since all the current flowing through resistor Rak must also flow through V1, the current through V1 must also increase. Since the triodes are experiencing a different current conductions, where does the difference in current flow go other than the load? If this circuit were single-ended in operation then while the currents through the triodes could differ in magnitude, they would at the very least be in phase with each other.
   If the SRPP is not push-pull in nature, where did everyone go wrong when analyzing this circuit? Was it the two triodes that threw us off? Was it that we had not seen enough digital IC schematics? Not to argue from word etymology (by definition God must comprise all perfections and it is a closer approximation to perfection to exist than not to exist; therefore, God must exist), but what do you think compelled someone to put the "PP" in "SRPP?" Was it for "Push-Push" or "Pull-Pull" or "Perfectly Pleasing" perhaps? Why did its inventor and all the writers of electrical engineering textbooks (Seely, Millman & Taub,

"From this it becomes clear that the greatest    potential of SRPP, as a shunt type push-pull, is obtained when, by varying R or Rl, you make Ip1 and Ip2 out of phase. This peculiarity of the SRPP circuit was well understood by its inventor; unfortunately, in most cases, we now use it like a kind of common-cathode amplifier with an active load and a low output impedance."

Yes, quite unfortunately, as the actual load driven has been left out of the equation.
   As for the Constant Current Draw Compound amplifier, this circuit has been so beaten to death in previous GlassWare Tube Circuit of the Month articles that I glossed over the details of its operation. From the Circuit of the Month: September 1998:

"Once again, this leaves the Constant Current Draw Grounded Cathode (CCDGC) amplifier as a good candidate. Besides