NAD C375BEE protection circuit activating.

[unacat]

I agree that it may be the amp as it is the only variable in a system that I have had for years. The REL is connected the same way as it was with my Anthem and I doubled checked all of my connections after having the problem. My ohm meter arrives tomorrow and that will provide the only actual information that we have. I would crack the volume every once in awhile, but never near the point of possible speaker damage. I will keep you posted! Thanks always.....Joseph

 

[TLS Guy]

I agree that it may be the amp as it is the only variable in a system that I have had for years. The REL is connected the same way as it was with my Anthem and I doubled checked all of my connections after having the problem. My ohm meter arrives tomorrow and that will provide the only actual information that we have. I would crack the volume every once in awhile, but never near the point of possible speaker damage. I will keep you posted! Thanks always.....Joseph

Correct me if I'm wrong, but you said you had to boost the right channel on the anthem also, which is why you bought the NAD. Is that correct?

 

[PENG]

Correct me if I'm wrong, but you said you had to boost the right channel on the anthem also, which is why you bought the NAD. Is that correct?

He did say:

had to turn the balance on my Anthem way to the right speaker to balance the sound

I am not sure what he meant by "way to the right...". If he has to turn the balance way over = a lot then, yes that would indicate there is something wrong with the quieter speaker. If it is only slightly to the right then it could simply be due to the location of speaker, i.e. room effect.

 

[unacat]

Yes, my posting was completely in error. Particularly after all of the discussion we had regarding the obvious problem with the Totem speaker. My listening position is so close to the speakers that the need to balance to the right could not be due to room acoustics or speaker placement. it is definitely a problem with the speaker. The ohm meter will arrive today and that will provide the information necessary to determine that.

 

[PENG]

Yes, my posting was completely in error. Particularly after all of the discussion we had regarding the obvious problem with the Totem speaker. My listening position is so close to the speakers that the need to balance to the right could not be due to room acoustics or speaker placement. it is definitely a problem with the speaker. The ohm meter will arrive today and that will provide the information necessary to determine that.

Sorry to ask so many questions and that might have confused you to some extent. Now I do have one more silly question, when you tried to balance the left ad right channel, how did you do it, like what source, stereo, mono? If the amp has the mono selection that would be obvious choice, again it sounds silly but I have to ask.

If the speaker is definitely quieter then yes that is a problem and no one would disagree with that, but it still may not be the only problem though much more likely. If the Ohmmeter confirms that speaker is partially shorted, will you then be comfortable to do what I suggested before, that is to hook up the good speaker only and try it at low volume?

 

[markw]

One sure way to isolate to problem to either the speaker otr the amp is to switch the righy and left speaker wires between them to essentially "switch" the speakers. If the problem switches sides, then it's the amp. If the problem stays with the speakers, well then...

 

[TLS Guy]

One sure way to isolate to problem to either the speaker otr the amp is to switch the righy and left speaker wires between them to essentially "switch" the speakers. If the problem switches sides, then it's the amp. If the problem stays with the speakers, well then...

This case is different. There is a high probability that right speaker now has a very low impedance. The impedance is so low there is a good probability it has damaged the right amp channel. Switching that speaker to the left channel stand a good chance of damaging the left channel. It is much safer to measure the DC resistance first, before switching speakers.

 

[markw]

Are you saying this is not an effective method to isolate the problem to either a speaker or the amp? I would dispute that.

 

[TLS Guy]

Are you saying this is not an effective method to isolate the problem to either a speaker or the amp? I would dispute that.

Not at all, but in this unusual case it is unwise.

We know that this speaker was quiet on two different amps. By far and away the most likely cause is shorted VC turns. In this case swapping speakers, puts another amp output stage at risk and would be ill advised.

 

[markw]

If the same speaker showed the same symptoms on two different amps it should have been obvious from the start that the problem is with the speaker, not the amp.

Actually, I would have tried the L/R swap to isolate the problem when the problem first appeared but that's not obvious to all.

 

[PENG]

One sure way to isolate to problem to either the speaker otr the amp is to switch the righy and left speaker wires between them to essentially "switch" the speakers. If the problem switches sides, then it's the amp. If the problem stays with the speakers, well then...

He was concerned about doing more damage to the amp, so I suggested a safer alternative, that is instead of swapping L and R, just use the normal sounding speaker to test each channel of the amp, one channel at a time. That way you can still determine if the amp would hold, when only one channel at a time is used to power the normal sounding speaker. If the amp would hold, then it is probably not damaged and the quieter speaker is. Even for that minimal risk (nothing is risk free), the OP is still concerned about causing further damage to the amp. I don't think that sounds logical and even after he verify the d.c. resistances of each speaker, he will still face the decision to use the supposedly healthy speaker to test the amp, or send the amp back to NAD regardless. It is his amp, so we suggest, and he decides.. If he gets the multimeter today, he will soon have to decide on the next step.

 

[unacat]

Hi folks. Received my multimeter but the instructions are written for someone familiar with this type of instrument, which I am not. There are black and red leads and on the face of the meter are three inputs the left reads 10ADC, the center COM and the right V (omega symbol) mA. i so know that the omega is the symbol for ohm, so I am guessing that is my choice which (to me) means black to common and red to the right (omega). The rotary selector has several selections, but one (green) has the omega / ohm symbol and five selections: 2M / 220k / 20k / 2k / 200.
there is then a red segment and a white segment and (still green) 10A / 200m / 20m / 2m / 200u. Forgiving my ignorance, how do I proceed? May I take the reading with the speaker leads connected, or must they be disconnected. I thank you for your patience as well as for your continued interest in assisting me in discovering the source of my dilemma. And yes, on both amps the balance had to be turned almost to 3 o'clock to achieve a balanced sound. Thank you....Joseph

 

[PENG]

The rotary selector has several selections, but one (green) has the omega / ohm symbol and five selections: 2M / 220k / 20k / 2k / 200.

Set it to 200, that means in the range it will measure resistance of up to 200 ohms. It will give you the best accuracy for the few ohms you are measuring. 2K means 2,000 ohm and 2M means 2,000,000 (2 millions) ohms.

there is then a red segment and a white segment and (still green) 10A / 200m / 20m / 2m / 200u.

Don't get close to those, leave them alone, they are for d.c. current measurements and not suitable for beginners.

May I take the reading with the speaker leads connected, or must they be disconnected.

Disconnect the speaker leads from the speakers, remove jumpers, but you already did because you were by-wiring before right? Then do the following:

1) Set the meter to the 200 ohm range.
2) Plug the black lead into the COM and red lead into the VΩmA terminals of the meter.
3) Short the leads together and you should see the meter display read 0 ohm. This step is just to verify the battery in the meter is good and is reading correctly.
4) Put the leads onto the woofer's terminals, black to black and red to red, though it really does not matter for resistance measurements.
5) Take the reading after the display stabilizes, it will vary for a split second as it will be charging up the capacitor of the crossover circuit.

And yes, on both amps the balance had to be turned almost to 3 o'clock to achieve a balanced sound. Thank you....Joseph

That is almost a certain sign of trouble.

 

[PENG]

Just to be sure, is this Excel XL830L Digital 3 1/2 LCD Display Multimeter Voltmeter Ammeter Ohmmeter AC DC Volt Ohm Tester Meter - - Amazon.com the one you bought?

 

[unacat]

Yes, PENG that is the meter. I plugged the leads in and touched the leads together but the reading just keeps jumping about erratically to different numbers, iy does not rest on just any one value.

 

[TLS Guy]

Yes, PENG that is the meter. I plugged the leads in and touched the leads together but the reading just keeps jumping about erratically to different numbers, iy does not rest on just any one value.

If the meter is set up exactly as Peng described and you have the prongs firmly together, it should read zero. If not is is defective.

Unfortunately there is a lot of Far Eastern Junk out there that never works.

A while back at Eagan I had to sort out my daughter's tail light problem, so I bought a meter at Home Depot. It did what yours is doing. The staff admitted when I returned that everyone sold had been returned. I had to drop $50 to get a meter that would work in the store.

So go to Home Depot, or Radio Shack, and get a meter that you know works in the store. Send the one you have back.

 

[unacat]

Thanks TLS Guy. I will pick one up @ Home Depot and see that it is operating properly prior to purchase.

 

[PENG]

Thanks TLS Guy. I will pick one up @ Home Depot and see that it is operating properly prior to purchase.

This time please try to get one with some recognized safety approval marking on it, such as UL in the US.

 

[unacat]

Will do. I didn't realize that purchasing an inexpensive meter would prove to be a mistake. I paid $7.95 for it with free shipping so it is probably not worth the price of packaging and shipping to return it. Again, I appreciate you folks sticking with me while I fumble and at the same time learn something.

 

[TLS Guy]

Will do. I didn't realize that purchasing an inexpensive meter would prove to be a mistake. I paid $7.95 for it with free shipping so it is probably not worth the price of packaging and shipping to return it. Again, I appreciate you folks sticking with me while I fumble and at the same time learn something.

Cheap Chinese junk is generally a mistake on any day. The waste of resources really annoys me.