[barpc]

I have three (compound) questions regarding the Monogram:

1.  Isn't the cathode follower in the phono stage overkill?  Since the impedances, capacitances and resistances are known, and fixed, or, stated another way, you don't have to worry about driving an interconnect of unspecified length and specifications into an unknown line stage, wouldn't the Monogram be well if not better then easier or at least possible without a cathode follower?  Could I build it with a paralelled 12AU7 instead?

2.  In an unrelated post, you teased with a suggestion of what sounded to me like a super linear cathode follower (ala Vacuum State Electronic's Allen Wright) using transistors on the anode and cathode.   If so, and especially if the answer to my first question is "no", have you worked on such a design, would it be suitable in the Monogram and are you ready or  willing to share it?

3.  Finally, I wonder why, even as an upgrade option, you do not discuss or show regulated supplies for the Cornet (Monogram), Clarinet, or Cymbal.

TIA.  You'd think I didn't care that you;ve just returned from vacation.  Actually, these questions have been piling up as I struggle to learn.

[hagtech]

Isn't the cathode follower in the phono stage overkill?

It drives the volume pot.  Sure, the impedances are known, and it could be done without, but the circuitry was already there (Cornet).  In the Cornet, the buffer is needed to unload the passive EQ.

build it with a paralelled 12AU7 instead?

You can try anything you want.  I chose a circuit that was relatively easy to build on the existing circuit board.  Hence the paralleled input tube.  The board should be flexible enough to try other various options.

super linear cathode follower (ala Vacuum State Electronic's

Allen makes a crazy follower.  Maybe crazy good.  I've never heard it.  It's just a bit too complicated for my tastes, and involves a number of local feedback loops which scare me.

do not discuss or show regulated supplies

I was trying to hit a reasonable price/performance point with the Cornet series (all the "C" machines).  I also didn't want to use feedback, which regulators liberally employ.  So I designed the circuit with huge power dissipating voltage drops to get passively clean supplies.  I drop anywhere from 50V to 100V depending on the circuit.  Then large filter capacitors do the job of regulating voltage.  And then, designing the amplifier stages themselves to be as constant current as possible makes the whole thing work.  So basically, I removed the signal path from having to go through a feedback regulator.  Nothing but capacitor (electrolytics bypassed with very critical films).  

On the other hand, there are applications that demand super low noise regulated supplies.  The perfect example being the HagClock.  Solid, stable references for maintaining jitter performance over a very wide range of frequencies.

jh