Some other Source Follower Configurations

As promised.
Protos only, not final version.


Patrick
 

Attachments

  • DAO-STD PCB 1.JPG
    DAO-STD PCB 1.JPG
    498.8 KB · Views: 636
  • DAO-TCS PCB 1.JPG
    DAO-TCS PCB 1.JPG
    427.6 KB · Views: 545
  • DAO-XCS PCB 1.JPG
    DAO-XCS PCB 1.JPG
    503.8 KB · Views: 498
I tried an LTSpice simulation based on the schematic provided by Patrick in post #4, but the I cannot get the offset voltage to be near zero with reasonable values of R1 and/or R2., and the distortion results are much worse than shown in this thread. I suspect that the spice models I am using are inappropriate. Can anyone point me to spice models that work for this circuit?
 
My simulations were not done with LT SPice, but real device measurements then calculated in Excel.

You probably need to trim the values of the 2SJ103 model until you get Idss of 8mA, but even then it is still not reality.

There is no easy way other than to build, I am afraid.


Patrick
 
Is DAO follower with Taylor a Class-A Quasi-Comp topology?

What distinguishes the circuit of post #4 from a Quasi-Complementary circuit? It has all of the attributes:

. Upper output FET operates in common-drain (ie. source follower) mode

. Lower output FET operates in common-source mode

. The combination of Q1 and Q3 forms a phase-splitter.
 
The Taylor current source is a form of quasi-pushpull, except that the main driving device (the upper FET) is driven directly by the signal, and the current source is modulated by the current of the top device sensed by Q3. In a quasu complementary, both devices are driven by the phase splitter.

For more details of the working principle, please google "tubecad taylor current source".


Patrick
 
No, let me finish off the F5X first.
No time right now, next to full time job, business travel, looking after elderly parents, family, ....

When in 5 years time, I can afford to retire to do Audio (for fun) full time, then there will be more progress at an acceptable pace.


Sorry,
Patrick