Alternatives to 12BH7 in Eros shunt regulator

[ALEXZ]

Dear Bottleheads:
Please explain, are there any potential  issues with running 12AU7 in the Eros power supply ?
Here is some math around Eros (we are talking about one side of the amp):
Tape repro runs at 350v HT, therefore to keep 12BH7  bellow the max. plate dissipation, it passes maximum 10ma.
3 tubes of the repro are running at ~15ma.  I.E. shunt regulator tubes runs at 2/3  current of the load.  Actually, if the PS in the repro has the same 23ma C4S as Eros (I

 

[Doc B]

The only issue is that you will wear it out faster. Reducing the current thru the regulator might change the sound. You would simply have to try it. Another way to go might be to set it up for a 6CG7/6FQ7 as regulator. We considered this instead of the 12BH7 during development. It does require some changes, the particulars of which I don't have readily at hand.

It's the same for the 6DJ8/6922 discussion - the 6DJ8 will work fine, but it may not last as long due to a lower max plate voltage rating. And it does pull more heater current than a 6922.

The Repro uses a different setup with the large half of a 6CM7 as regulator, or in later iterations, a 6BX7.

 

[ALEXZ]

Thank you, Dan. 
I yesterday  loaded PS in Eros with additional 39K resistor per side and put 12AU7 . All voltages are OK, but I did not have time to listen  to it.  Another temptation is to convert to octal socket. That opens whole bunch of  possibilities

 

[ALEXZ]

This Eros thing seems to have very balanced design. I did reduce current through shunt tube to let 12au7  have longer life, but all of the magic that I was getting with this tube in the PS is gone, so back to  12BH7.
Another  change that I tried is to add capacity to the PS filter. In a way it the same direction as replaicing  filter resistor with choke. Works well.
Thanks,
Alex