John Curl's Blowtorch preamplifier part II - Page 21

KSTR · 4th July 2009, 07:15 PM

Not the speakers themselves are the concern here, Joshua, rather the side-effects of RF leaking into the amp via the normally unshielded speaker wires -- especially when the amp is a typical global NFB design. Output inductors don't help much unless they are split into two parts, one per each single wire.

http://www.diyaudio.com/forums/showt...73#post1419373

- Klaus

Joshua_G · 4th July 2009, 07:23 PM

Thanks.

cliffforrest · 4th July 2009, 07:47 PM

Quote:

Originally posted by Joshua_G
How does RF impact speakers?

It doesn't directly, but the speakers and cables are an easy way for RF pickup to be directed back into the amplifier.

john curl · 4th July 2009, 08:18 PM

It's called IIM distortion, also studied and written about by Matti Otala, (and me) about 32 years ago.

PMA · 5th July 2009, 03:38 PM

You knew it all

janneman · 5th July 2009, 03:47 PM

Quote:

Originally posted by PMA
You knew it all

... except that RF ingress via the speaker cables is not interface intermodulation in this context.

See

http://www.aes.org/e-lib/browse.cfm?elib=2817

and

http://www.aes.org/e-lib/browse.cfm?elib=11887

... and I guess John refers to this:

http://www.aes.org/e-lib/browse.cfm?elib=3765

The AES lists only one conference paper with John Curl as co-author here:

http://www.aes.org/e-lib/browse.cfm?elib=2229 which is not related to IIM.

Jan Didden

dimitri · 5th July 2009, 04:26 PM

Dig deeper, Jan
http://www.aes.org/e-lib/browse.cfm?elib=3379

janneman · 5th July 2009, 05:23 PM

Quote:

Originally posted by dimitri
Dig deeper, Jan
http://www.aes.org/e-lib/browse.cfm?elib=3379

This is the same article as the 2229; one is the conference paper, the other is the JAES article.

I think there are some more articles on TIM and IIM with John as (co) author, possibly IEEE? John?

Jan Didden

dimitri · 5th July 2009, 05:27 PM

Omitted factors in audio circuit design
Curl, J.
Acoustics, Speech, and Signal Processing, IEEE International Conference on ICASSP '78.
Publication Date: Apr 1978
Volume: 3, page(s): 263- 266

janneman · 5th July 2009, 05:34 PM

I have no access to IEEE papers.

Edit: What are the omitted factors? Can you quote the abstract?

(I did find out recently that I can become a member of the local university library that will give me that access. It's on my to-do list

Jan Didden

5th July 2009, 05:34 PM	#210
janneman diyAudio Member Join Date: May 2002 Location: Where Germany, The Netherlands and Belgium meet Blog Entries: 6	I have no access to IEEE papers. Edit: What are the omitted factors? Can you quote the abstract? (I did find out recently that I can become a member of the local university library that will give me that access. It's on my to-do list Jan Didden __________________ /Another new issue: Linear Audio Volume 3!

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4th July 2009, 07:15 PM	#201
KSTR diyAudio Member Join Date: Jul 2007 Location: Central Berlin, Germany	Not the speakers themselves are the concern here, Joshua, rather the side-effects of RF leaking into the amp via the normally unshielded speaker wires -- especially when the amp is a typical global NFB design. Output inductors don't help much unless they are split into two parts, one per each single wire. http://www.diyaudio.com/forums/showt...73#post1419373 - Klaus

4th July 2009, 07:23 PM	#202
Joshua_G diyAudio Member Join Date: Nov 2008 Location: Israel	Thanks.

4th July 2009, 08:18 PM	#204
john curl diyAudio Member Join Date: Jul 2003 Location: berkeley ca	It's called IIM distortion, also studied and written about by Matti Otala, (and me) about 32 years ago.

5th July 2009, 03:38 PM	#205
PMA diyAudio Member Join Date: Apr 2002 Location: Prague, Kitakyushu, Fukuoka	You knew it all

5th July 2009, 04:26 PM	#207
dimitri diyAudio Member Join Date: Oct 2002 Location: retired	Dig deeper, Jan http://www.aes.org/e-lib/browse.cfm?elib=3379

5th July 2009, 05:27 PM	#209
dimitri diyAudio Member Join Date: Oct 2002 Location: retired	Omitted factors in audio circuit design Curl, J. Acoustics, Speech, and Signal Processing, IEEE International Conference on ICASSP '78. Publication Date: Apr 1978 Volume: 3, page(s): 263- 266

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