This wee beastie is a Mu-Stage.

Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

In Reply to: I need help understanding a circuit posted by hifitom on March 28, 2002 at 17:30:43:

This input circuit is called a mu-stage, and was developed (in modern times, anyway) by Alan Kimmel in the mid '90's. It's a triode amplifier loaded with a pentode current source, whose multiple grids and monster plate resistance give it some technical advantages over, say, a mu-follower or SRPP. I think some of Ron Welborne's gear uses it. The 390ohm resistor in series with the 33K resistor from the cathode of the pentode (current source) to ground form the voltage divider that biases this tube (the link is the 1Meg resistor to G¹). The 1µF cap from this node up to the base of the 47K resistor at the pin of G² is a smoother-outer shunt that keeps AC rubbish off the screen (which is another control grid of the tube, after all). The cap marked '0.1µF - 1µF' on the way to the output is a normal AC coupling (DC blocking) cap.
'Eh?
Poinz

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

Sonic Craft

Follow Ups Full Thread

Topic - I need help understanding a circuit - hifitom 17:30:43 03/28/02 (8)

Re: I need help understanding a circuit - Jan Comitas 04:27:41 03/29/02 (0)

try this link - Joost Riphagen 02:03:55 03/29/02 (1)

whhoops.. got that one allready.. - Joost 02:05:23 03/29/02 (0)

Many thanks guys - hifitom 21:42:03 03/28/02 (1)

Welcome; and thanx yerself. - Poindexter 21:53:57 03/28/02 (0)

This wee beastie is a Mu-Stage. - Poindexter 03/28/0218:20:48 03/28/02 (0)

Re: I need help understanding a circuit - Kurt Strain 18:12:37 03/28/02 (1)

they sound pretty good too <nt> - Chris O 19:02:56 03/28/02 (0)

Follow Ups

This wee beastie is a Mu-Stage. - Poindexter 03/28/0218:20:48 03/28/02 (0)

You can not post to an archived thread.