AudioRoundTable.com: Thermionic Emissions » Class A, AB1, B, C Operation/Modes

Home » Audio » Thermionic Emissions » Class A, AB1, B, C Operation/Modes (How Class A, AB1, B, C Modes Work and Their Strengths and Weaknesses)

Show: Today's Messages :: Navigator :: Polls
E-mail to friend

Re: Class A, AB1, B, C Operation/Modes [message #96474 is a reply to message #96471]

Sun, 05 March 2023 08:05

Wayne Parham
Messages: 18683
Registered: January 2001

Illuminati (33rd Degree)

I connect signal ground to chassis ground, but at only one location.

Any device that is remote must be isolated in some way, without having grounds connected. The isolator can be a transformer or something like an opto-isolator.

Where this can become tricky is in the definition of "remote." Some might think of this as a physical distance, and in fact, that is often the case. But in fact, what makes a device "remote" is the resistance and reactance of the ground conductor.

If all devices had a hypothetical perfect zero resistance connection between grounds, there would be no possibility of the condition we call a ground loop. What causes the problem is the difference between the local ground potentials at each device. And this is due to the resistance between them.

So I try to limit resistance between ground connections everywhere that's possible. That's the case inside a chassis as well as outside. But if resistance cannot be reduced to very, very low levels - close to perfect zero ohms - then isolation is necessary.

And that includes reactive effects too, which makes things even trickier. A resistance of zero ohms at DC doesn't matter much if the circuit is operated at 10Mhz and there is reactance in the ground conductor, making it higher than zero ohms in the passband of the circuit. Where there is any resistance or relevant reactance in the ground conductor, we must abandon the approach of connecting the circuits and instead completely isolate them by transformer or opto-isolator.

Report message to a moderator

[Message index]

		Class A, AB1, B, C Operation/Modes By: positron on Sun, 05 February 2023 20:40
		Re: Class A, AB1, B, C Operation/Modes By: Wayne Parham on Sun, 05 February 2023 20:54
		Re: Class A, AB1, B, C Operation/Modes By: gofar99 on Mon, 06 February 2023 20:38
		Re: Class A, AB1, B, C Operation/Modes By: positron on Tue, 07 February 2023 16:13
		Re: Class A, AB1, B, C Operation/Modes By: gofar99 on Tue, 07 February 2023 19:33
		Re: Class A, AB1, B, C Operation/Modes By: positron on Tue, 07 February 2023 20:37
		Re: Class A, AB1, B, C Operation/Modes By: gofar99 on Thu, 09 February 2023 21:01
		Re: Class A, AB1, B, C Operation/Modes By: positron on Thu, 09 February 2023 21:35
		Re: Class A, AB1, B, C Operation/Modes By: positron on Tue, 28 February 2023 19:04
		Re: Class A, AB1, B, C Operation/Modes By: Wayne Parham on Wed, 01 March 2023 08:28
		Re: Class A, AB1, B, C Operation/Modes By: gofar99 on Wed, 01 March 2023 19:45
		Re: Class A, AB1, B, C Operation/Modes By: positron on Sun, 05 March 2023 00:33
		Re: Class A, AB1, B, C Operation/Modes By: Wayne Parham on Sun, 05 March 2023 08:05
		Re: Class A, AB1, B, C Operation/Modes By: gofar99 on Sun, 05 March 2023 08:10
		Re: Class A, AB1, B, C Operation/Modes By: positron on Mon, 06 March 2023 19:01
		Re: Class A, AB1, B, C Operation/Modes By: positron on Sat, 06 May 2023 22:32
		Re: Class A, AB1, B, C Operation/Modes By: gofar99 on Tue, 09 May 2023 21:30
		Re: Class A, AB1, B, C Operation/Modes By: positron on Thu, 11 May 2023 00:26
		Re: Class A, AB1, B, C Operation/Modes By: positron on Tue, 05 September 2023 23:48
		Re: Class A, AB1, B, C Operation/Modes By: gofar99 on Fri, 08 September 2023 21:12
		Re: Class A, AB1, B, C Operation/Modes By: BreakneckRedneck on Sun, 24 September 2023 00:42
		Re: Class A, AB1, B, C Operation/Modes By: positron on Thu, 12 October 2023 11:21
		Re: Class A, AB1, B, C Operation/Modes By: positron on Fri, 03 November 2023 12:22
		Re: Class A, AB1, B, C Operation/Modes By: gofar99 on Fri, 03 November 2023 20:58
		Re: Class A, AB1, B, C Operation/Modes By: positron on Sun, 05 November 2023 01:38
		Re: Class A, AB1, B, C Operation/Modes By: positron on Thu, 07 December 2023 23:12
		Re: Class A, AB1, B, C Operation/Modes By: gofar99 on Mon, 18 December 2023 20:20
		Re: Class A, AB1, B, C Operation/Modes By: positron on Tue, 16 January 2024 21:32
		Re: Class A, AB1, B, C Operation/Modes By: gofar99 on Wed, 24 January 2024 20:31

Previous Topic:	Source loop
Next Topic:	New Production Tung Sol 6550, Penta KT88s

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Sun May 05 22:48:29 CDT 2024