Driving an EL34 amp without driver stage ?

[Blitz]

I had recently a brief discussion with John Broskie and he gabe me the hint, that construting a poweramp without driverstage is the trick, so that the linestage directly swings +-35v. Well, I am not yet sure how you would do this...an Aikido with this voltage swing ? currently I use his unbalancer with a 12au7 doing the upscaling of the small signal from the sabre dac 9018 to something like 2 V. But 35v ? 70v p-p ? Would this not result in another stage in the linestage simply ? I guess it only makes sense when you can save a stage and get rid of coupling caps etc...

 

[DF96]

EL34's do not need a driver, just a voltage amplifier. You could call this a line stage if that makes you happy. Better in my opinion to call it a voltage amplifier and put it on the same chassis as the EL34, then no line stage is needed.

 

[Blitz]

Well, i guess its all about defining different interface standards, not the typical 2v for the power amp for example. And I guess must be something about saving stages..like with Nelson Pass F4...

...in my case I am already driving directly the el34 from menno

http://www.mennovanderveen.nl/images/ul40s2-bias/UL40-S2 in ST mode + auto-bias.jpg

with john's unbalancer

http://www.tubecad.com/2011/03/22/Unbalancer Schematic.png

So, even if I would use the setuo differential and not se, not sure how to save the 6922 driverstage in the el34 poweramp...

 

[Ketje]

You have a balanced signal,then an unbalancer,and to drive the PP you balance the signal again ????
What's the use of all this
Mona

 

[rmyauck]

Here's an EL84 one he posted yrs ago.

Tube CAD Journal: Tube balanced phono stage, July 1999

 

[Blitz]

You have a balanced signal,then an unbalancer,and to drive the PP you balance the signal again ????
What's the use of all this
Mona

I know, i know. its on the list. the ul-40s2 has been a kit...with Se input. I am currently building three different line stages fully balanced and than switch the ul-40s2.

It is about understanding what is possble and not changiing too much at the same time.