interresting amp question

shagone · 10th May 2008, 12:52 AM

i have an older model smaller 2-channel earthquake amp that i'm working on (black with gold emblem) that powers on and outputs audio on my bench when i run it through a 2 ohm current limiting resistor. when i try to power it on directly without the limiting resistor the power led flashes on and off every couple of seconds and never stays on. it also causes my test head unit that is connected to the same power supply to flash on and off.

What could be the cause of this? i pulled the board and it has some questionable solder joints but i tried to touch most of them up and it still flashes on and off.

has anyone ever seen this happen before?

theAnonymous1 · 10th May 2008, 03:24 AM

Your power supply is a SMPS I bet.

ifrythings · 10th May 2008, 05:35 AM

Sounds like your power supply is too weak to power both the deck and the head unit a t the same time when running a 2 ohm load, I would try a bigger power supply before your start looking for problems.

Perry Babin · 10th May 2008, 09:50 AM

How much current is it pulling through the resistor?

If you're using a head unit for your signal source, you should get a small, dedicated supply for it. A computer power supply will work. It's a pain to have the head unit reset every time you cause the 12v power supply to shut down.

theAnonymous1 · 10th May 2008, 01:59 PM

It's more likely that the supply (SMPS?) doesn't like the highly capacitive load the amp presents; not so much that it is under powered.

I have some 12v 12A switching supplies and they do the same thing if I try to connect a car amp directly to them. They work fine if I insert a 0.1R resister in series with the power wire.

MatthewS · 10th May 2008, 03:08 PM

The Earthquake he described is from the 'Thrust' family and it's PWM.

Hope that helps.

- Matt

theAnonymous1 · 10th May 2008, 04:46 PM

Sorry, I didn't mean the amps power supply being a switching supply; that's pretty much a given. I meant the external supply.

shagone · 10th May 2008, 07:39 PM

my bench supply is a nice B&K 25 amp conventional power supply not a smps. it has seperate 2 amp tie points that i run the head unit from. i have a spare 13.8 volt 20 amp ham radio supply that i'll hook the head unit to and try.

Perry Babin · 10th May 2008, 08:03 PM

How much current is it pulling through the resistor?

shagone · 10th May 2008, 08:09 PM

Quote:

Originally posted by Perry Babin
How much current is it pulling through the resistor?

good question? i'll check on that. i don't remember it being very high though.

10th May 2008, 12:52 AM	#1
shagone diyAudio Member Join Date: Apr 2007	interresting amp question i have an older model smaller 2-channel earthquake amp that i'm working on (black with gold emblem) that powers on and outputs audio on my bench when i run it through a 2 ohm current limiting resistor. when i try to power it on directly without the limiting resistor the power led flashes on and off every couple of seconds and never stays on. it also causes my test head unit that is connected to the same power supply to flash on and off. What could be the cause of this? i pulled the board and it has some questionable solder joints but i tried to touch most of them up and it still flashes on and off. has anyone ever seen this happen before?

10th May 2008, 03:24 AM	#2
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	Your power supply is a SMPS I bet. __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

10th May 2008, 09:50 AM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	How much current is it pulling through the resistor? If you're using a head unit for your signal source, you should get a small, dedicated supply for it. A computer power supply will work. It's a pain to have the head unit reset every time you cause the 12v power supply to shut down. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

10th May 2008, 01:59 PM	#5
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	It's more likely that the supply (SMPS?) doesn't like the highly capacitive load the amp presents; not so much that it is under powered. I have some 12v 12A switching supplies and they do the same thing if I try to connect a car amp directly to them. They work fine if I insert a 0.1R resister in series with the power wire. __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

10th May 2008, 04:46 PM	#7
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	Sorry, I didn't mean the amps power supply being a switching supply; that's pretty much a given. I meant the external supply. __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja


	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

10th May 2008, 05:35 AM	#3
ifrythings diyAudio Member Join Date: Oct 2005	Sounds like your power supply is too weak to power both the deck and the head unit a t the same time when running a 2 ohm load, I would try a bigger power supply before your start looking for problems.

10th May 2008, 03:08 PM	#6
MatthewS diyAudio Member Join Date: Feb 2008	The Earthquake he described is from the 'Thrust' family and it's PWM. Hope that helps. - Matt

10th May 2008, 07:39 PM	#8
shagone diyAudio Member Join Date: Apr 2007	my bench supply is a nice B&K 25 amp conventional power supply not a smps. it has seperate 2 amp tie points that i run the head unit from. i have a spare 13.8 volt 20 amp ham radio supply that i'll hook the head unit to and try.

10th May 2008, 08:03 PM	#9
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	How much current is it pulling through the resistor? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Interresting Quiz. Which tube is this?	Radioman62	Tubes / Valves	5	28th December 2008 12:41 PM
do i REALLY need a crossover?? and an amp question. and an ohm question	legendaryfrog	Multi-Way	4	29th October 2006 01:39 AM
nothing interresting..	Rocky	Everything Else	8	23rd April 2006 10:48 PM
newbie with input tran. question and wiring question	imo	Solid State	0	18th January 2006 10:10 PM
old speaker question, bullet midrange question & link to speaker project	wallijonn	Multi-Way	10	5th November 2002 06:03 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read