Velleman K4700 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 March 2008, 12:07 PM   #1
dome406 is offline dome406  United Kingdom
diyAudio Member
 
Join Date: Mar 2004
Location: uk
Default Velleman K4700

I am building this speaker protection circuit and just wondered the purpose of R23, R24, R25 and R26 (see attached diagram) and weather i need to include them.

In the instruction manual (see instructions1) it says to include them if:

Quote:
If the amplifier to which the module is to be connected has a simple power supply (asymmetrical supply) i.e. an amplifier with output elcos, the following resistances has to be mounted...
My amplifier is a non inverting lm3875 with a regulated 18V 0 -18V power supply so i am guessing it doesnt need these resistors since the supply is symmetrical ?

What confuses me is what elcos mean i thought it might mean electrolytic capacitors? but am unsure. Also my amplifier has 2.2uF non polarised capacitors if this makes any difference.

Hope someone can explain

Thanks very much
Attached Images
File Type: jpg diagram.jpg (62.3 KB, 330 views)
  Reply With Quote
Old 22nd March 2008, 12:12 PM   #2
dome406 is offline dome406  United Kingdom
diyAudio Member
 
Join Date: Mar 2004
Location: uk
Heres the other image.
Attached Images
File Type: jpg instructions1.jpg (66.5 KB, 305 views)
  Reply With Quote
Old 22nd March 2008, 09:16 PM   #3
Thago is offline Thago  Belgium
diyAudio Member
 
Join Date: Nov 2006
Location: Asse, Belgium
Hi

I used the same Velleman K4700 kits in Pass Aleph 2 monoblocs, which have a symmetrical +45V - 0 - 45V power supply, thus meaning that both + and - are 'hot' (see attachment).
I did'nt use the resistors you mentioned, the K4700 works fine.
Attached Images
File Type: gif ale2-pwr.gif (9.7 KB, 276 views)
  Reply With Quote
Old 23rd March 2008, 11:38 PM   #4
dome406 is offline dome406  United Kingdom
diyAudio Member
 
Join Date: Mar 2004
Location: uk
thank you Im still not quite sure what they are needed for but will try without the resistors.
  Reply With Quote
Old 24th March 2008, 12:14 AM   #5
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
these resistors are needed for bleeding output caps , which are certainly used if amp is made with non-symmetrical PSU ;



better to charge/discharge them through resistors , than through speaker coils, don't you think?
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM
  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
K4700 PCB (Speaker Protection) GeorgeP1111 Multi-Way 2 3rd February 2014 10:08 PM
FS: heatsinks, velleman K4700, bosoz PSU, etc cowanrg Swap Meet 6 17th January 2007 02:15 PM
velleman k4700 speaker protection circuit cyteen Solid State 6 27th May 2005 03:16 PM
speaker protection velleman k4700 wuffer Multi-Way 2 1st March 2005 05:09 PM
Velleman K4700 kit problem supernet Parts 2 5th November 2004 07:13 PM


New To Site? Need Help?

All times are GMT. The time now is 07:31 AM.


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