Two Receiver Dead in One Day

The "new" woofer arrived early (today) so ive been able to install that. It also gave me 3.6 so the same as the other one. The back terminal reading also gave me 3.6 so i have a matching pair. Going to plug them in and give them a whirl.
 
Hi all, so one day I went to go play some music (which started to play) but after 30 seconds the speakers cut out. The unit stayed on but now no sound goes to the speakers. Where is the best place for me to start to try and solve the mystery of whats gone wrong?
 
It sounds a bit low, but not necessarily too low. If the speaker element functions correctly -- the battery test is a good way to check -- then it's fine.

These should show infinite resistance when the reading stabilises, though they may initially show a resistance value as the capacitor charges up. Make sure to test them with the speaker elements disconnected, or you may be measuring the resistance of the speakers rather than testing the capacitors.

Wanted to follow up on your previous comments. I am trying to see if my speakers are the bad egg causing all my receivers to die. Both speakers give me 3.6 Ohms still, which does seem low for an 8 ohm speaker? When the receiver and speakers DID work, they sounded AMAZING. Should I be worried about the 3.6 reading? and is there any other way of testing if the speakers are bad? Maybe a cheap digital receiver to see if they trip?

Thanks

Joe
 
Wanted to follow up on your previous comments. I am trying to see if my speakers are the bad egg causing all my receivers to die. Both speakers give me 3.6 Ohms still, which does seem low for an 8 ohm speaker? When the receiver and speakers DID work, they sounded AMAZING. Should I be worried about the 3.6 reading? and is there any other way of testing if the speakers are bad? Maybe a cheap digital receiver to see if they trip?
3.6 ohms static resistance is fine for a 4 ohm (impedance) speaker, assuming it's not wired in series or parallel with any other speaker element. An 8 ohm speaker is usually about 6 ohms static resistance, and a 16 ohm speaker is about 12 ohms static resistance. Usually.

Boston CR9 speakers are rated as 8 ohms impedance, but that's a nominal value and to a certain extent independent of static (DC) resistance. Maybe they are nominally 8 ohms impedance, or maybe they fly well under 8 ohms impedance given certain frequencies, which at high volume levels (how hard are you cranking these things?) may be a strain on amplifiers not built for sustained high volume levels or low impedance. Neither the Sony 6055 nor the Yamaha CR-840 are particularly beastly, so maybe the combination of an actually-less-than-8-ohm speaker and high volume is a bit of a strain?
 
3.6 ohms static resistance is fine for a 4 ohm (impedance) speaker, assuming it's not wired in series or parallel with any other speaker element. An 8 ohm speaker is usually about 6 ohms static resistance, and a 16 ohm speaker is about 12 ohms static resistance. Usually.

Boston CR9 speakers are rated as 8 ohms impedance, but that's a nominal value and to a certain extent independent of static (DC) resistance. Maybe they are nominally 8 ohms impedance, or maybe they fly well under 8 ohms impedance given certain frequencies, which at high volume levels (how hard are you cranking these things?) may be a strain on amplifiers not built for sustained high volume levels or low impedance. Neither the Sony 6055 nor the Yamaha CR-840 are particularly beastly, so maybe the combination of an actually-less-than-8-ohm speaker and high volume is a bit of a strain?

Thank you for your reply. Never really went over 50% on the volume knob with either receiver. Im just trying to find out ways if my speaker is the cause to all my amp issues or not
 
In a typical speaker, the woofer is wired with an inductor in series with it. A multimeter reading DC resistance will see that as just a coil of wire with almost zero resistance, so you're looking at the woofer voice coil only when you test at the rear input terminals. Mids and tweeters have capacitors in series with them which do not pass DC and will read as infinite resistance to the meter.

It's somewhat unusual for an 8 ohm nominal woofer to read 3.6 but since they are both the same it's probably normal. Something else is going on.

Let me go back and scan the thread.
 
OK, there are several items that were brought up that we didn't get clear answers to.

Verifying correct original woofers - I assume the replacement woofer you got matched the originals, visually and any numbers stamped on it? Probably so or you would have said so. So that rules out having the wrong woofers in your speakers to begin with. Unless there were 4 and 8 ohm versions of this speaker (or woofer).

Testing crossover components - someone asked what setting you were testing capacitors with. Some meters have a cap test function, but if yours does not, testing a cap for DC resistance will give a value that rises up as the cap charges, eventually to infinity, slower or faster depending on the capacitance. The numbers you quoted did sound like capacitance (4.6, 10.5, 0.8, 0.3). Trouble is the crossover pic you posted has caps 1, 6, 10 and 16 uf. The 0.8 is close to 1 uf but none of the others are close if those are capacitance readings. And if they are resistance readings, that's also a big red flag because they should climb to infinity. So we'll need a clarification on that.

You might want to check the DC offset on the receiver you are using. Disconnect speakers, set your meter on DC volts. Turn on the receiver, crank up the volume all the way (again, NO speaker leads connected), and measure the DC voltage across the red and black output jacks for each channel. Usually this should be in the low millivolts - less than 50 mV.
 
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crank up the volume all the way

A bit OT, but I can't remember ever seeing this advised before, and I'm curious. Is the idea to maximize the effect of any DC leakage at the input of the power amps? I could see that being a useful diagnostic check. But I think most manufacturer's procedures for actually adjusting a power amp's DC offset call for the volume to be all the way down, no?

Thanks,

chazix
 
A bit OT, but I can't remember ever seeing this advised before, and I'm curious. Is the idea to maximize the effect of any DC leakage at the input of the power amps? I could see that being a useful diagnostic check. But I think most manufacturer's procedures for actually adjusting a power amp's DC offset call for the volume to be all the way down, no?

Thanks,

chazix

Hmm, I could be wrong about that.
 
Hey all,

I have been using my setup for about a year without any complication until one day I had two receivers die on me, so below is the curious case of the dying receivers.

My initial setup was a Sony STR-6055 Receiver with Boston CR9 speakers and an Audio Technica lp120 turntable.

The only previous issue I had was one of the channels in the receiver didn't work so I had both speakers connected to the right channel.

All of a sudden when I went to go change a record and put the needle on, the receiver let out a bang, a puff of smoke came out of the top and then a loud humming noise sounded through the speakers. Whilst the receiver turns on, the only sound through the speakers is the loud feedback.

So I go to my local music store and pick up a Yamaha CR840 which has just been restored. Take it home, plug it in, sounds beautiful! Then all of sudden, again when I go to change a record, the sound dies. No smoke or feedback or noise this time but just nothing out of either channel.

Then I take my friends Pioneer Digital Receiver - looks like a 90s black receiver, nothing special and plug in the speakers - we are back up and working! However, if the volume goes above say 25% the receiver shuts down automatically. A little bit of testing tells me that one of the speakers is making the receiver trip, so I rewire it to see if that fixes things, the same story, so I just run one speaker and keep the troublesome speaker disconnected.

So my question/thought is that one of the speakers is causing the receivers to trip/blow - but how does that happen? Or is it something else?

My knowledge in this space is pretty limited but hoping someone can help.

For context, the Sony 6055 produces smoke from the power amp board and the Lower or Upper channel components give me a zero reading on the ammeter. With the Yamaha its gone into protection mode and the SDK chip seems to be dead - zero reading on the ammeter.

Thanks in advance for any help that can be provided.

Joe

PS - Wasnt sure where to best post this so apologies in advance if this is in the wrong place
Might wanna invest in a More powerful amplifier, or power amp surround amp combos.
All channels stereo is nice if you want to run lots of speakers , or get a 2 ch and run a& b don’t try Running speakers parallel etc unless you do it properly.
I have a 5 ch surround stereo amp it even goes into protection mode it’s old as dirty Dolby prologic 1. I cannot use digital no 5 ch input on my DVD player .
 
Sounds that way to me too. The first receiver had two speakers in parallel on one channel, which right away is half the impedance and twice the load. Add in a shorted or partially shorted voice coil on one woofer, and you've got very low impedance and a recipe for overloading the amp channel.

The Yamaha really should have gone into protection BEFORE the STK module fried, that's what protection is supposed to do, but apparently it didn't work in this case. Bummer.

What exactly are you measuring when you get 'zero reading on the ammeter', and with what device on what setting?
Yeah that will fry anything that’s not a powerhouses amplifier. One set of speakers is much smarter or get surround amplifier and bi amp .
Unusual sorry loss for two amps, maybe don’t hook up so many speakers to a 2 ch amp ?
 
So I went ahead and bought a cheap, working "modern digital" receiver just to test the speakers with and to actually have something to listen to music with. Seems like the speakers are okay.

I then went ahead and bought some STKs to replace the ones in the Yamah CR 840. Tried a few, none of them give me the "click" that I need to get the receiver working again.

A little out of my depth and not sure where to do next. Might just have to toss the Yamaha to the scrap heap and stick with the modern plastic crap :(
 
OK, there are several items that were brought up that we didn't get clear answers to.

Verifying correct original woofers - I assume the replacement woofer you got matched the originals, visually and any numbers stamped on it? Probably so or you would have said so. So that rules out having the wrong woofers in your speakers to begin with. Unless there were 4 and 8 ohm versions of this speaker (or woofer).

Testing crossover components - someone asked what setting you were testing capacitors with. Some meters have a cap test function, but if yours does not, testing a cap for DC resistance will give a value that rises up as the cap charges, eventually to infinity, slower or faster depending on the capacitance. The numbers you quoted did sound like capacitance (4.6, 10.5, 0.8, 0.3). Trouble is the crossover pic you posted has caps 1, 6, 10 and 16 uf. The 0.8 is close to 1 uf but none of the others are close if those are capacitance readings. And if they are resistance readings, that's also a big red flag because they should climb to infinity. So we'll need a clarification on that.

You might want to check the DC offset on the receiver you are using. Disconnect speakers, set your meter on DC volts. Turn on the receiver, crank up the volume all the way (again, NO speaker leads connected), and measure the DC voltage across the red and black output jacks for each channel. Usually this should be in the low millivolts - less than 50 mV.


Hey toxcrusadr - apologies I think I totally missed this post. So I never got the Yamaha working again, tried two different STKs - either they have been replaced too many times (the board when I opened it up was pretty burnt around the solder contacts) or its something else.

I recently bought an Onkyo TX-860 and the same thing has now happened to that. Worked for a few weeks, now I get no output from the speakers. Starting to think something is up with these speakers and its killing every receiver I buy?
 
I recently bought an Onkyo TX-860 and the same thing has now happened to that. Worked for a few weeks, now I get no output from the speakers. Starting to think something is up with these speakers and its killing every receiver I buy?
An intermittent short is possible, but very, very unlikely to hit both channels at once.

Old amplifiers needing a rebuild that get hot and die under load?

More likely.

How loud were you running these amps?
 
An intermittent short is possible, but very, very unlikely to hit both channels at once.

Old amplifiers needing a rebuild that get hot and die under load?

More likely.

How loud were you running these amps?

About 30% volume. And it wasn't like they cut out during listening. I just turned it on one day and no sound came out. Very odd
 
About 30% volume. And it wasn't like they cut out during listening. I just turned it on one day and no sound came out. Very odd
Sounds like you might have a different problem with the Onkyo. Have you done any investigative troubleshooting yet? E.g., checked fuses, incorrect positions of tape monitor & speaker switches, etc.?
 
Sounds like you might have a different problem with the Onkyo. Have you done any investigative troubleshooting yet? E.g., checked fuses, incorrect positions of tape monitor & speaker switches, etc.?

Not yet. Need to read into that receiver a little more and take it apart this weekend. I just thought with this being the 4th receiver that has now died on me, maybe its the speakers?
 
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