Output coil on power amp... - diyAudio
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 4th August 2006, 09:27 AM   #1
Skorpio is offline Skorpio  Denmark
diyAudio Member
 
Join Date: Mar 2004
Location: Denmark
Default Output coil on power amp...

If i try to remove the output coil on my NAD3020 power amplifier, could it means that the amp will blow?

I know that is is there to secure stability in a NFB amp, but what does it actually do? Is it for extreame cases and special speaker cables? All speakers do have a coil af input for the woofer.

Some amplifiers does not have this coil....Pass, Hiraga Class A, etc.....why?
  Reply With Quote
Old 4th August 2006, 12:53 PM   #2
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
It is mainly to damp the effects of a capacitive run of speaker cable, ie long cable runs, to prevent oscillation. In most cases leaving it out will do no harm.

Why remove it though?
  Reply With Quote
Old 4th August 2006, 06:56 PM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
just follow me for a moment.

NAD sell very competitively priced amps.

The designer decided his amp did not need a Thiel network on the output.
The sales department said the amp would sell better if a Thiel network was added and would leave more margin for profit by allowing NAD to sell the amp at a higher price.

I think not.
__________________
regards Andrew T.
  Reply With Quote
Old 4th August 2006, 07:17 PM   #4
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
The way I see it, in a consumer market amp, they have to cater for all kinds of events, such as the user having 10 metre cables and such nonsense.

DIY or enthusiast amps such as Pass's amps know that the user is going to be (fairly) sensible and not do such things.

Whether there's any audible difference between the two is another matter. I usually add them "just in case".
  Reply With Quote
Old 4th August 2006, 08:34 PM   #5
diyAudio Member
 
destroyer X's Avatar
 
Join Date: Feb 2004
Location: Recife - Brasil Northeast
Default Using simulators, a big damaged in the amplifier performance can be perceived when we

miss this output filter....that coils with paralell resistance.

Maybe simulators are crazy, but i am afraid that it really does some effect in performance.

regards,

Carlos
__________________
Power supply; ripple, filter, noise, stability and the use of capacitance multiplier... Portuguese and English; https://www.youtube.com/watch?v=sSm0ku1eIgg
  Reply With Quote
Old 4th August 2006, 09:09 PM   #6
mikeks is offline mikeks  United Kingdom
Account Disabled
 
Join Date: Jun 2004
Location: Animal farm
Default Re: Using simulators, a big damaged in the amplifier performance can be perceived whe

Quote:
Originally posted by destroyer X
......... i am afraid that it really does some effect in performance.

Carlos

Depends on construction of coil...and choice of values, of course.
  Reply With Quote
Old 4th August 2006, 09:24 PM   #7
CBS240 is offline CBS240  United States
diyAudio Member
 
CBS240's Avatar
 
Join Date: Aug 2005
Location: K-town
In the real world, this coil rejects the extra phase shifting caused by adding components to the output such as complex reactive loads and long strands of wire. Having said this I digress to Mike B in post 35 of this thread: Amp distortion

and also rt7085 for post 46.
__________________
All the trouble I've ever been in started out as fun......
  Reply With Quote
Old 4th August 2006, 09:30 PM   #8
diyAudio Member
 
Join Date: Sep 2002
Location: Sweden
Coils are expensive components. If the manufacturer of an amp was absolutely certain that the amp couldn't oscillate under any imaginable load condition, it would skip the coil. Serious manufacturers are probably cautious, though, so the cases where the coil is really needed may be rare, but on the other hand, they may not. It depends on the particular amp.
  Reply With Quote
Old 4th August 2006, 09:38 PM   #9
diyAudio Member
 
destroyer X's Avatar
 
Join Date: Feb 2004
Location: Recife - Brasil Northeast
Default That is it folks...really we need them.

Thank you all by the informs..they are always usefull.

regards,

Carlos
__________________
Power supply; ripple, filter, noise, stability and the use of capacitance multiplier... Portuguese and English; https://www.youtube.com/watch?v=sSm0ku1eIgg
  Reply With Quote
Old 4th August 2006, 09:39 PM   #10
poobah is offline poobah  United States
diyAudio Member
 
poobah's Avatar
 
Join Date: Nov 2005
Sometimes people ask me if I have an extra cigarette. I examine the pack carefully pretending to count. I then say, "No, there are no extras".

  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
EV SP12C with too-low output and too-high coil DCR... jon_010101 Multi-Way 2 21st June 2009 09:31 PM
Output coupling - Choke-coil method? danielle Tubes / Valves 3 15th February 2006 09:57 PM


New To Site? Need Help?

All times are GMT. The time now is 03:14 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