RX-V665 issue or not?

[Joeteck]

I've bought two of these receivers from Audioholics when they were released. One is fine, the other shuts off at higher volumes such as during action scenes. (who wouldn't?) I did a white noise speaker test @ high volume at it keeps turning off at the left channel. These are very old 2 way JBL speakers with a brilliance knob, vintage. 123A-1 woofer. White cone. 3" voice coil. Says 8 Ohms on the speaker. My Grand Father gave them to me 20 years ago. Been using them since I got them. Then suddenly I'm having this issue. So I removed the woofer and checked it with a meter. 4.2 Ohms. So I would assume this is the problem? I tested the right side and its 6 Ohms.

So as a test, I took a high power 6 ohm 50w resister and put it in series of the speaker and the problem went away. I know most of my power will be absorbed into the resistor. However, do I need to abandon these babies? They will surely be missed, and if so, what would you recommend?



Joe

 

[TLS Guy]

I've bought two of these receivers from Audioholics when they were released. One is fine, the other shuts off at higher volumes such as during action scenes. (who wouldn't?) I did a white noise speaker test @ high volume at it keeps turning off at the left channel. These are very old 2 way JBL speakers with a brilliance knob, vintage. 123A-1 woofer. White cone. 3" voice coil. Says 8 Ohms on the speaker. My Grand Father gave them to me 20 years ago. Been using them since I got them. Then suddenly I'm having this issue. So I removed the woofer and checked it with a meter. 4.2 Ohms. So I would assume this is the problem? I tested the right side and its 6 Ohms.

So as a test, I took a high power 6 ohm 50w resister and put it in series of the speaker and the problem went away. I know most of my power will be absorbed into the resistor. However, do I need to abandon these babies? They will surely be missed, and if so, what would you recommend?

View attachment 19922

Joe

You measured the DC resistance of the speaker NOT the impedance. You can not measure impedance with a meter. It has to be measured dynamically with a computer program.

Your speakers are fine. You have a wiring problem or a receiver problem.

 

[Joeteck]

You sure? I removed all speaker wires. All 7 speakers were removed. I only had the JBLs connected. it shut off. I removed the left all worked fine. I removed the right and added the left it shut off. I then added the high power resister and all is working. 4.2 ohms seems too low for the receiver.

 

[TLS Guy]

You sure? I removed all speaker wires. All 7 speakers were removed. I only had the JBLs connected. it shut off. I removed the left all worked fine. I removed the right and added the left it shut off. I then added the high power resister and all is working. 4.2 ohms seems too low for the receiver.

You can not infer impedance form the DC resistance.

However there is one way to decide the issue. Measure the DC resistance of the other driver. They should be the same.

If the DC resistance of the left driver is lower then the right then the left driver has been over driven and has a heated voice coil with shorted turns.

If both drivers measure the same they are fine.

If the left driver is damaged you might well be able to find a recone kit for it still.