Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 22nd November 2002, 02:02 AM   #1
diyAudio Member
 
MRehorst's Avatar
 
Join Date: May 2002
Default Speaker cable in amp feedback path

I see a lot of amplifiers with extra terminals to allow "buy-wiring" to the speakers, but if you're going to put two sets of terminals on the amp anyway, why not put one at the amplifier output and the other at the feedback input. You then biwire using two identical sets of wire to the speaker and let the amplifier's feedback take care of minimizing any speaker cable effects...

Anyone ever tried this?

MR
  Reply With Quote
Old 22nd November 2002, 03:44 AM   #2
halojoy is offline halojoy  Sweden
On Hiatus
 
Join Date: Nov 2002
Default The idea is good.

It would be like messuring resistens accurate with 4 wires.
This makes the resistens of the wires "invisable".

I do not know what it would do to the stability of the amp.

But the closer to you ear the feedbackpoint is located the better.
A technique used sometimes is acustic feedback,
a device mounted on the speaker cone,
senses the movement of the cone.
  Reply With Quote
Old 22nd November 2002, 05:17 AM   #3
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Kenwood made some amps that used this trick. basically a Kelvin connection. The return to the feedback loop doesn't have to be the same wire as the speaker feed, since it's carrying miniscule amounts of current.
  Reply With Quote
Old 22nd November 2002, 06:32 AM   #4
edm is offline edm  Netherlands
diyAudio Member
 
Join Date: Nov 2002
Location: The top of the Netherlands
Isn't this contradicting a little bit that one normally wants to have short feedback paths? I wonder what the experts have to say about this one, if this will help or not.
  Reply With Quote
Old 22nd November 2002, 08:14 AM   #5
diyAudio Member
 
Join Date: Sep 2002
Location: Sweden
I have been thinking about this trick too, but it is probably not a
good idea when considering stability, risk for TIM etc. One
possibility might be to split the feedback loop so we feed back
both from the speakers and from the amp output. If we then
use a low-pass filter on the speaker feedback, and balance this
with a suitable HF boost on the OPS feedback then perhaps
we could avoid the problems. What I mean is a double feedback
la the Leach amp, but moved one step further, from driver/OPS
to OPS/speaker. One problem is that this would have to be done
individualle for each system, since we must know the electrical
properties of the speaker cables to get this right.
  Reply With Quote
Old 22nd November 2002, 11:16 AM   #6
Werner is offline Werner  Europe
diyAudio Member
 
Join Date: Jan 2002
Location: Belgium
As said above, Kenwood tried that: Sigma series in the eighties.

I think DNM also did it for a while. If not DNM, then some other British outfit.
  Reply With Quote
Old 22nd November 2002, 12:17 PM   #7
diyAudio Member
 
Join Date: Mar 2001
Location: Brazil
Default Speaker feedback

This arrangement was suggested by Richard Marsh, in The Audio Amateur 3/85.

The speaker feedback was implemented through a 0.15ohm resistor.



Carlos
Attached Files
File Type: zip feedbck1.zip (29.3 KB, 59 views)
  Reply With Quote
Old 22nd November 2002, 12:21 PM   #8
diyAudio Member
 
Join Date: Mar 2001
Location: Brazil
Default SPEAKER FEEDBACK

These are some measurements made on a speaker horn, using a JBL D-130 15" speaker.

It was published on the same TAA article to show how distortion specs were improved.


Carlos
Attached Files
File Type: zip feedbck2.zip (36.0 KB, 41 views)
  Reply With Quote
Old 22nd November 2002, 01:52 PM   #9
jam is offline jam  United States
diyAudio Member
 
jam's Avatar
 
Join Date: May 2001
Location: Auburn, CA, USA
Using the same idea Hafler used to put the speaker fuse inside the feedback loop. The idea was to reduce non-linearities of the fuse or in the case above speaker wires by the use of feedback. The idea never got popular though.

Jam
  Reply With Quote
Old 22nd November 2002, 03:54 PM   #10
diyAudio Member
 
Join Date: Mar 2001
Location: Brazil
[QUOTE]Originally posted by jam
Using the same idea Hafler used to put the speaker fuse inside the feedback loop. The idea was to reduce non-linearities of the fuse or in the case above speaker wires by the use of feedback. The idea never got popular though.

Jam


I think the emphasis here is on being able to make the cable part of the feedback, due to the resistor from ground. If you take the fuse away, the feedback will still be there.

Carlos
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
cheap cat5e cable for speaker cable fishline Full Range 6 19th May 2009 07:42 PM
DC blocking cap in feedback path or DC servo? roender Solid State 27 19th September 2007 09:40 AM
Transformer on feedback path NIC1138 Solid State 3 9th May 2007 06:41 AM
problems with speaker cable as power cable pjpoes Parts 11 14th January 2007 08:24 PM
Cheaper path to speaker quality? walker Multi-Way 29 29th October 2002 12:55 PM


New To Site? Need Help?

All times are GMT. The time now is 09:08 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2