Diode on output? - 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 9th September 2002, 07:57 PM   #1
CryingDragon
Guest
 
Default Diode on output?

What would happen if i were to put a Diode on the output of my amp (hybrid)Faceing out(ie the current can flow out but not in)? Would it mess it up? my idea is i want to make some circuitry that measures the resistance the the positive to negitive connections of each speaker terminal when you first hook them up so if the load ever drops below 8Ohms it lets the groud of my power in relay float so it turns off and turns the amp off beofre damage can be done.
  Edit/Delete Message Reply With Quote
Old 9th September 2002, 08:25 PM   #2
diyAudio Member
 
Holger Barske's Avatar
 
Join Date: Jan 2001
Location: Ruhrgebiet
As an amplifier is an AC source, you would build a rectifier.
The amp's output voltage is referenced to ground and it definitely swings from positive to negative polarity and back. Means: the current doesn't just flow out of the amplifier, ist is also "coming back".
So I would say: not quite perfect, your idea.
  Reply With Quote
Old 9th September 2002, 08:26 PM   #3
trwh is offline trwh  United Kingdom
diyAudio Member
 
trwh's Avatar
 
Join Date: Apr 2002
Location: UK
Hi

"Would it mess it up?"

For the time the diode was in circuit, the sound would be very distorted - you'd only be reproducing one half of the audio waveform. Not only would this sound bad, but it wouldn't do your speakers any good either. I say stick to more conventional protection circuits.

See ya,
Tim.
  Reply With Quote
Old 9th September 2002, 09:28 PM   #4
CryingDragon
Guest
 
Well i really kinda liked my idea about cutting the power off if the risistance was too low and could damage the amp (i had an AiwA that did this once it was the shiznit you could do anything to that radio and not hurt it) any circuit suguestions? i really want to protect my amp from overdraw
  Reply With Quote
Old 9th September 2002, 10:11 PM   #5
skaara is offline skaara  Slovenia
diyAudio Member
 
Join Date: Jun 2002
Location: Europe, Slovenia
Only one diode wont do it.
  Reply With Quote
Old 10th September 2002, 12:35 PM   #6
diyAudio Member
 
Join Date: Aug 2002
Location: connecticut usa
Cool Output stage protection

Output stage protection is often done with two current monitors, typically measuring the voltage dropped across the emitter (or source) ballast resistances of the source and sink devices. Overcurrent in either device, as indicated by excessive voltage across the resistor, causes the overcurrent circuitry to steal drive from that device.

Once you developed the "overcurrent" signal, you could then use it to inhibit the entire amplifier if you wanted to, but the above approach works well.

Joe
  Reply With Quote
Old 10th September 2002, 02:44 PM   #7
e96mlo is offline e96mlo  Sweden
diyAudio Member
 
Join Date: Apr 2002
Location: Helsingborg, Sweden
A few years back Elector published an amplifier with an interesting protection circuit. It had an output relay and before it was switched on, the protection circuit measured the DC resistance of the speaker. If the resistance was above a certain value, then the relay was closed.

I'm not sure but I think it monitored the output emitter currents aswell and, of course, DC voltage on the output.

Perhaps that is what you are looking for?

/Marcus
  Reply With Quote
Old 10th September 2002, 07:42 PM   #8
CryingDragon
Guest
 
Talking YEA!!

Thats what i need!! Can you direct me to it???
  Reply With Quote
Old 10th September 2002, 07:45 PM   #9
trwh is offline trwh  United Kingdom
diyAudio Member
 
trwh's Avatar
 
Join Date: Apr 2002
Location: UK
CryingDragon, here is an article that should answer your questions:

http://sound.westhost.com/vi.htm
  Reply With Quote
Old 10th September 2002, 07:51 PM   #10
e96mlo is offline e96mlo  Sweden
diyAudio Member
 
Join Date: Apr 2002
Location: Helsingborg, Sweden
The problem is that I can't remember the amp or the issue!

Probably wouldn't be too hard to design from scratch though. Why don't you give it a try?

/Marcus
  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
diode bridge - 10000uF cap - diode tube - small cap - HV+ engels Tubes / Valves 5 29th January 2008 10:16 PM
hybrid power supply: diode bridge into diode tube engels Tubes / Valves 8 24th September 2007 09:18 AM
diode vca - build and measured. what amplification for output signal? Domplotz Parts 10 22nd April 2007 02:45 AM
Laser diode output lands? buddha Digital Source 8 25th September 2005 02:56 PM
output diode bridge confusion Danko Power Supplies 4 17th August 2005 10:45 AM


New To Site? Need Help?

All times are GMT. The time now is 07:21 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