transformerless tube mic

[analag]

[quote author="penquista"] it appears that the first half of the ECC83 triode provides the gain while the second half works in ?cathode follower? mode to lower impedance. The ECC82 is used as a phase splitter to provide the balanced output, making transformer and solid-state output circuitry unnecessary.[/quote]

It appears whoever wrote this has no idea about what they are talking about. Gain stage then CF then phase splitter? And this is supposed to provide balance and low impedance. Not possible.

Here is another quick one with line level output. Much can be done to this to optimise it to suit your particluar need including lowering the output level.

analag

 

[Gus]

That looks like fun

Maybe a pot at the output tap to adjust some asymmetry at the PI for some distortion as an effect?

Cap across R7

Some might not like the the PI feedback but who cares?

 

[FredForssell]

Not being a sim guy, the question comes up in my mind...

Are vaccum tube models accurate enough to indicate space-charge effects (1 gig grid-leak resistor)?

Just curious...

Cheers

 

[analag]

[quote author="FredForssell"]Not being a sim guy, the question comes up in my mind...

Are vaccum tube models accurate enough to indicate space-charge effects (1 gig grid-leak resistor)?

Just curious...

Cheers[/quote]

1 gig resistors are the usual culprits in a lot of tube mics, the ones I have built with them sound just fine.
I don't depend on simulations for deep analysis of tube circuits, I use it as a sketch pad where I can manipulate voltages and connections quickly thus helping me to commit to a design idea sooner than later.

analag