Some other Source Follower Configurations

iko

Ex-Moderator
Joined 2008
Here you go:

*model D1N5314 anode cathode
.subckt D1N5314 1 2
j1 1 2 2 jx
.model jx NJF(Beta=750u Betatce=-.5 Rd=1 Rs=0 Lambda=531.9u Vto=-2.506
+ Vtotc=-2.5m N=2 Xti=3 Cgd=6p Is=10f M=.5 Pb=1 Fc=.5 Af=1)
* Motorola pid=NKO case=DO7
* 88-07-25 bam POVmax=100
* 88-12-16 pwt
.ends
 
> 1. is this a unity gain amp (or not)?

Yes.

> 2. could I put a potentiometer in the input?

In principle yes.
Suggest you also try to add a JFET buffer (like the B1) to compare.

> 3. what is the [maximum] acceptable preceding stage (source or pre-amp) impedance before the DAO?

I would not want to have more than 500R, but most source or preamp should have much less.

It all depends on how much bandwidth you would like to have.


Patrick
 
would it be a good idea to move the zener bypass cap after the mosfet gate resistor to form a low pas filter, i.e. put the cap between the mosfet gate and output for the top mosfet, between mosfet gate and V- for ccs mosfet ? i m not sure but thought i might ask.
 
Last edited:
this is what i meant just in case
 

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very good question.

i m kind of beginning to learn how electricity works and didnt not bother with learning LTspice...yet.

just thought i might ask for some guidande first. i would eventually have tried it to judge from my ears but they never tell me me if it is proper implementation.

i also dont have a scope yet.

i ll probably spice it or mod it and let you guys know :)
 
If you want another 2 or 3 months or so, we have a newly made PCB for the standard version, plus daughter boards for the TCS version and a new modulated current source (we nicknamed XCS).

We already have the boards, but we want to build the prototype first before posting. So it will take a while.


Patrick
 
If you want another 2 or 3 months or so, we have a newly made PCB for the standard version, plus daughter boards for the TCS version and a new modulated current source (we nicknamed XCS).

We already have the boards, but we want to build the prototype first before posting. So it will take a while.


Patrick

Gr8. I think I will wait so, and play some more with my ZEN amp.
Thank you.
 
Euvl,
Any chance for PCB's for a balanced version? Either the X version or Circlotron?

I will probably order the standard + TCS when you have them ready, but I would really prefer a balanced version.

So far too lazy to learn to make my own, but I might try a breadboard if nobody is making PCB's.

Mark
 
> Any chance for PCB's for a balanced version? Either the X version or Circlotron?

Not planned at this moment. If at all then circlotron.

> I will probably order the standard + TCS when you have them ready,

You have no choice.
It comes as a 3-board pack (standard DAO + TCS / XCS daughter boards).

> but I would really prefer a balanced version.

We did it for ourselves, plus the majority would want SE first.
So you'll just have to wait till we have time for the circlotron version.

> but I might try a breadboard if nobody is making PCB's.

If you don't want to wait, then you should.
We do this for fun, not for money.
And I already have a circlotron prototype.

:)


Patrick
 
Thanks Patrick,
I look forward to the PCB set availability! If you are starting a list, please add me to it, but I'll understand if it's too early for that.

Once I have the SE amp working then I'll decide if I want to give the balanced version a try to compare!

Did you ever put together a circlotron DAO follower schematic that you could share? I am sure I'm not the only one that would be interested. But if you have not, no big deal, like you said more to life than this hobby.

Care to comment on the circlotron prototype? Impressions, or comparisons to the new prototype you are building would be greatly appreciated. Do you know if others have been built?

Cheers!
Mark