Ohmage question

[pwcopy]

Wanted to post this in the Yamaha Owners Thread, but it won't let me. Anybody know how to join it?

Two weeks ago (3.5 months out of warranty), my Yamaha RX-v481 AVR started hissing in the audio channels of both HDMI and RCA inputs/outputs. Don't have a digital audio cable to test if it's there as well. This noise was accompanied by high distortion of the audio playback from a blueray source, a CD player and thru the headphone jack.

The Yamaha Owners Manual states “Minimum Impedance 6Ω.“ The Martin-Logan Motion 20 Speaker Owners Manual states “Impedance 4Ω, compatible with 8Ω, 6Ω AND 4Ω rated amplifiers.” Is it at all probable that my speakers damaged my amp?

Many thanks for your help, PW
VIZIO M50
Yamaha RX-v481 AVR (toast)
Martin Logan: > Motion 20 F > Motion 8 C > Motion 4 R
Definitive ProSub 60

 

[Speedskater]

NO.
Your receiver should have a circuit to protect itself, when connected to low Ohm speakers played at a very high volume for a long period of time.

 

[PENG]

Wanted to post this in the Yamaha Owners Thread, but it won't let me. Anybody know how to join it?

Two weeks ago (3.5 months out of warranty), my Yamaha RX-v481 AVR started hissing in the audio channels of both HDMI and RCA inputs/outputs. Don't have a digital audio cable to test if it's there as well. This noise was accompanied by high distortion of the audio playback from a blueray source, a CD player and thru the headphone jack.

The Yamaha Owners Manual states “Minimum Impedance 6Ω.“ The Martin-Logan Motion 20 Speaker Owners Manual states “Impedance 4Ω, compatible with 8Ω, 6Ω AND 4Ω rated amplifiers.” Is it at all probable that my speakers damaged my amp?

Many thanks for your help, PW
VIZIO M50
Yamaha RX-v481 AVR (toast)
Martin Logan: > Motion 20 F > Motion 8 C > Motion 4 R
Definitive ProSub 60

You should do a factory reset first and go from there.

 

[pwcopy]

You should do a factory reset first and go from there.

I did a factory reset and a firmware update, with no change in the problem. Forgot to put that in my original post. Thank you for reminding me.

 

[pwcopy]

NO.
Your receiver should have a circuit to protect itself, when connected to low Ohm speakers played at a very high volume for a long period of time.

I've cranked the system up a few times, for just 5-10 minutes. I hope that doesn't qualify as "a long time", but even if it did, the circuit should have popped. That would render it inoperable, not just malfunctioning, correct? Many thanks for your reply, PW

 

[TLS Guy]

I've cranked the system up a few times, for just 5-10 minutes. I hope that doesn't qualify as "a long time", but even if it did, the circuit should have popped. That would render it inoperable, not just malfunctioning, correct? Many thanks for your reply, PW

If you hear it on your headphones, then there is a fault in the preamp or more likely the power supply if it is on all channels.

I suppose 4 ohm speakers could have stressed the power supply, but I suspect this is a component failure.

We the complexity of gear now, I think we have to move form consumer grade components to auto grade components, or at least industrial grade. Consumer grade components are allowed a 10% failure rate over 1 to 3 year. So with the thousands of components in a receiver it is getting to be that statistically failure will be more common than long term reliability.

This is what I posted recently about this.

 

[Speedskater]

Take it to a friends house and try it there.

 

[pwcopy]

“I suppose 4 ohm speakers could have stressed the power supply, but I suspect this is a component failure.

We the complexity of gear now, I think we have to move form consumer grade components to auto grade components, or at least industrial grade. Consumer grade components are allowed a 10% failure rate over 1 to 3 year. So with the thousands of components in a receiver it is getting to be that statistically failure will be more common than long term reliability.”

TLS Guy, thanks for your reply. Interesting observation about the quality of components. When originally shopping for an AVR (my first), and looking for a potential replacement for the Yamaha if the company won't give me another one, I noticed that all the major brands seemed to have about 10% of purchasers complaining about premature failure. This is what I've been observing in the auto industry, of which I'm a part, over the last 20 years as vehicles have grown exponentially more complex. I have a 20+ year old surround-sound receiver that sounds as good today as it did new. Now I don't know what to buy.

 

[Speedskater]

Any good hi-fi component (like a Yamaha) should be able to deal with a short circuit across the speaker terminals.

 

[TLS Guy]

Any good hi-fi component (like a Yamaha) should be able to deal with a short circuit across the speaker terminals.

Well up to a point.

It is not a good idea to trip protection. You really don't want to trip protection. A unit can certainly fail if you do trip it, and will fail of you do it often enough and may be the first time.
It is a bit like saying that if you get run over by a bus you don't necessarily get killed!

There is a common misunderstanding about protection, that its primary purpose is to protect the unit itself. Actually that is only its very secondary purpose. The main purpose of protection is to stop the rail DC voltage flowing through damaged power transistors and burning out the woofer voice coils, and even starting a fire..

 

[TLS Guy]

“I suppose 4 ohm speakers could have stressed the power supply, but I suspect this is a component failure.

We the complexity of gear now, I think we have to move form consumer grade components to auto grade components, or at least industrial grade. Consumer grade components are allowed a 10% failure rate over 1 to 3 year. So with the thousands of components in a receiver it is getting to be that statistically failure will be more common than long term reliability.”

TLS Guy, thanks for your reply. Interesting observation about the quality of components. When originally shopping for an AVR (my first),and looking for a potential replacement for the Yamaha if the company won't give me another one, I noticed that all the major brands seemed to have about 10% of purchasers complaining about premature failure. This is what I've been observing in the auto industry, of which I'm a part, over the last 20 years as vehicles have grown exponentially more complex. I have a 20+ year old surround-sound receiver that sounds as good today as it did new. Now I don't know what to buy.

Well I assume it is under warranty, so that is the first place to start. No, I see it is 3.5 months out of warranty. So at the cost of the unit $400.00 on Amazon, then I doubt the cost of repair will be worth it. You will be up to that in labor in not time before we get to parts.

This is exactly what has to change. I think it will take legislative action, as if a brand went to auto grade components, they would be uncompetitive unless made to do so by law.

I suspect there will be legislative action on this before much more time goes by. This will probably come from the EEC as they have minimal electoral oversight. Anyhow that will effectively mandate it here. This is definitely on the radar in Europe, where the environmental lobby is significantly more powerful and active than in the US. What people won't like is the substantial price increases.

If they won't replace your receiver, I don't think any other brands will be better, and Onkyo/Pioneer definitely worse. Actually Yamaha is probably still the best for reliability.

I would consider moving up the food chain a bit though.

 

[PENG]

Yamaha's are supposed to be more reliable than others but they can fail too. I think the OP should do more test just to be sure. For example, check all the connections, especially if banana plugs are used. Taking it to a nearby friend's place and try it on his speakers and wires is an excellent idea. The RX-V4XX should be under 20 lbs so not hard to move around.

 

[pwcopy]

OK. i have a buddy who will let me test it at his place. I'll take it over in the next few days and get back to yous guyz. Thanks!