Two Amp Fire Balls... Please Tell Me Why

[ltjenkem]

Listen I just had the worst night of my life.
I finally got my garage to fill up for a music show and then
2 hours in a loud crackling noise sounded... I looked to the right and fire was bouncing around inside of my amplifier (or a spark)... Then my speakers went out...

If this isn't enough, I said "O.k, b/s, amp is bad"... "I'll get my second one one sec guys! The party will go on"...

Then 20 minutes in on my SECOND amplifier it bursts into flames almost identically!!! The right channel completely toasted (all safety lights on)...


This was horrendous, expensive, scary, and embarrasing. I ruined my first "show" that people were in to...


What went wrong? How can I prevent this in the future when I get new amplifiers...


My bass amplifier on the same power outlet never blew up though ... Thank god... That one is 2400 RMS and I love it sooooo much...


1. My outlet?
2. Wired speakers wrong?
3. wut?

[pinkmouse]

Need much more info. What were the amps, what was the input, what speakers, cabling etc. Was it the same channel each time?

[ltjenkem]

An Ashly CFT 1800
and back up PYLE PTA 1400

I believe it was the same channel each time, but I also believe the whole amp shut down (both of them motionless)... But I'm scared to turn them on.

The input was unbalanced RCA to a DJ mixer, unbalanced from DJ mixer to active crossover... Then unbalanced active crossover to amp.

The speakers were one 8 ohm pyle 10" horn / woofer daisy chained to
an old school radio shack 8 ohm of the same sort. (250 rms pyle, 250 rms radio shack)

The cabling was just speakerwire.


My only guess is I messed up the daisy chaining somehow? and that would explain it frying both amplifiers... I mean how cruel is that? Would something like that result in blowing an amp up?


The power outlet used was run to a power strip and all three of my amplifiers were running off of it...

[AndrewT]

Daisy chaining.
Explain.
Diagram and/or pics

[sakis]

one think is that you actually send to or connected to the output of the left ch. together with the output of the right channel

if the level and music they play is absolutely identical (Theoretical approach) you might gate away with it ... now if the level of any channel is lower then this channel becomes from an amplifier to a load for the other channel....

Also to answer your next question and that will be
"""why the protection didn't kick in ?"""

Cause the protections are designed to detect a number of things except music .... if its music that you want they let free to pass .... In your case... music coming from the other channel is simply undetectable

kind regards sakis

[Zero Cool]

unless the speaker actually blew first causing and internal short which caused the amp to blow, then when you connected the second amp, it blew for the same reason.

[dillmeister]

Sakis may be on to something. I almost had a disaster with a situation similar to what he described. I was testing a phono preamp and I had one the positive inputs from one channel on the common negative. Fortunately I could smell something was getting really hot and shut it down. Amp was just about to the point where it was too hot to touch. Protection did not kick in and it actually did not sound horrible. I am sorry for your loss.

[jkuetemann]

Since the fault occurred in the same channel I'd suspect an impedance drop or short in the cabling or the speaker. Check with a DMM to see if the left and right are the same and I'd suggest the DC resistance should be no lower than 3ohm if the speakers are wired in parallel (an 8ohm nominal speaker often has about 6ohm DC resistance), and should be quite a bit higher if wired in series. I would suspect you likely used a parallel connection, amplifier positive to speaker positives and amplifier negative to speaker nagatives. With a seies connection one speaker shorting out wouldn't likely toast the amp. If the cabling is pinched or stapled you should be able to determine that by disconnecting the speakers and checking just the wire with a DMM.

[ltjenkem]

I do not know much "tech talk" outside of very very basics...

Most of the posts above need to be translated to my level (a dumb persons level)


I just don't want to blow more amps...

And someone googling for this may gain help if they are in my same situation...


Would "power conditioners" have saved my problem? Also... What's the cheapest way to get new reliable amps.. any recomendations?

[Brian Oshman]

Low impedance or a short or both.