Tube DIY Asylum

RE: NOVICE SRPP problem please help

98.59.249.131

Paul Joppa

P

In Reply to: RE: NOVICE SRPP problem please help posted by 6dj8triode@gmail.com on May 21, 2024 at 08:43:58

I'm agnostic about current sources - they all have their own strengths and weaknesses. The cascoded depletion-mode MOSFET designs are widely discussed on the various tube forums, so that might be a good place to start.

TK's suggestion to use a plate choke is a reasonable option. It kind of depends on the context, i.e. the rest of the circuit and power supply.

(For my Bottlehead designs, I use the Camille Cascode Constant Current Source, a.k.a. C4S, licensed from the late John Camille. But it's not well documented in the public domain.)

Follow Ups:

RE: NOVICE SRPP problem please help - PakProtector 16:00:20 05/21/24 (2)
It seems Mr. Blencowe allows the mu follower to have an output at both the voltage amplifier plate, and at the load tube's cathode. After seeing Gary Pimm refer to the source/cathode output of his MOSFET designs as the 'mu' output, using the lower output Z seems a reasonable way to go... :)
The cascode MOSFET current regulator can be used as a load, with output at the plate, and with output at the lower device source. The current regulator Paul mentioned has no low Z output.
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

Edits: 05/22/24 05/22/24
- RE: NOVICE SRPP problem please help - Paul Joppa 07:42:19 05/22/24 (1)
  As I noted above, every option has its pluses and minuses. I use the C4S in my kit designs to avoid adding a trimpot to set the current, giving up the "mu output" because many (including me) think the lower-plate connection sounds slightly better. YMMV :^)
  
  A complete discussion of all the pluses and minuses of all the options seems beyond the scope of a single post.
  - RE: NOVICE SRPP problem please help - PakProtector 01:27:11 05/23/24 (0)
    no trim pots here... :) Those do sound a wee bit iffy to me.
    
    Douglas
    Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors:

Parts Connexion