RCA cables gone bad?

[Funkenrong]

My setup is Castle floor speakers (2) connected to a NAD C270 power amp, (sometimes not always from a NAD preamp same era), and a DAC connected to a PC running AP-Linux 5.0. I control with MPDroid on an Android phone.

The interconnects are all copper -- a Qunex pair of cables is the oldest at about 10 yrs

I noticed that the right channel faded within an hour so that the balance was poor

I sent the power amp to an able tech 2 years ago who sent it back reporting no issues

The issue has been intermittent since then

Two weeks ago, fade on right again.

I sent my tech a text

He says: try swapping out the RCA cables

He said on one occasion a bad cable was his problem

I tried it and it seemed to work

the right channel got its strength back

is this crazy

How is this possible

 

[kchap]

It's not crazy, replace the cables. Do not spend a lot of money; the advantages of expensive cables are dubious. Also it is a process of elimination. You cannot rule out a faulty connector on your DAC or amps. Replace the cables and see if things improve over the next few days and weeks.

 

[Killingbeans]

Oxidation, a cold solder joint failing after having been functioning by pure luck for years, mechanical stress. That's my guesses.

 

[DVDdoug]

It can happen with a "high resistance" connection when a contact is corroded or bent or when a wire comes unsoldered, but usually wiggling the cable or connection will make it better or worse and it should be easy to diagnose. ...It is unusual that the sound didn't occasionally cut-out completely on one side.

Sometimes when you have a marginal connection cranking-up the volume will temporarily "bring it back" (if you are increasing the signal through the bad connection).

It could also be a bad connection somewhere else and moving things around may have fixed it. Intermittent problems are often caused by bad cables/connectors and it could be a bad connection inside the amp or preamp or inside the speaker, etc.

 

[Funkenrong]

The tech is frustrated that I say there is still a problem. He had it for 3 weeks, played it, checked it, everything was great. Fantastic amp, he says. No work done, no charge.

A reason I never thought of the RCA interconnects over the past 3 years is that they are $$

I have 2 pairs of inputs to the NAD C270: either straight power input to RCA females (must be controlled from preamp or speakers will blow) --or-- input via 2nd RCA females with a 1/2 inch sized pot. The pot is the only volume control on the C270. When I get fading level on the right side, I can plug the male RCAs to the 2nd RCA females with pot. THEN, weird, the unused no-pot channel will restore itself & I can go back to it.

Like Doug mentions, for a time I could crank the right side up by using balance and then its level would stay up for an hour maybe.

 

[DanielT]

Can you record your problems and send the film to the tech/repairman?

Check here, Mr. Repairman, what you waffle about, that it works, check here you see for yourself that it does not work ... or what tone you now want to use towards your repairman.

Maybe not the smartest thing to say to the repairman that he waffles considering any continued service.

 

[Funkenrong]

Can you record your problems and send the film to the tech/repairman?

Check here, Mr. Repairman, what you waffle about, that it works, check here you see for yourself that it does not work ... or what tone you now want to use towards your repairman.

Maybe not the smartest thing to say to the repairman that he waffles considering any continued service.

My tone is wrong somehow. The repair tech is my hero.

 

[DanielT]

I was just kidding, a fictitious example of what you could say.I do not know what you said or your tone.

Record a video and send to your tech and he will see what is wrong. That way, there will (hopefully) be no misunderstandings between you in the communication.If you can document the error with Nad on film that is.

Can't you and your tech meet IRL and go through it with your NAD?

Or based on tips and advice in this thread maybe you can solve it yourself?

Edit:
Your repairman did not charge anything, if I got it all right, but otherwise they usually charge per hour. Then it is, as usual, the question of when it is not worth paying for repairs and service on a, 20 years ?, old amplifier. This, of course, is up to you to decide for yourself.

 

[Holmz]

I bet a cheap set off RCAs would be nice to swap into the chain.

 

[JRS]

From my own experience = twice. On one occasion seemed to happen out of the blue, the other involved moving equipment. Not having any experience first time it happened, it never ever occurred to me that an RCA cable could malfunction--with trauma maybe like dragging an amp by a connector, but otherwise never. Sherlock Holmes said: After eliminating the impossible, whatever remains, however improbable must be the truth. And so finally after all my clever experiments left me still puzzled, I swapped out cables and viola. Second time took less time, but I should have known effing better. And I no longer use junk--good stuff costs 20 bucks on the net, and is well worth it IMO.

 

[Doodski]

From my own experience = twice. On one occasion seemed to happen out of the blue, the other involved moving equipment. Not having any experience first time it happened, it never ever occurred to me that an RCA cable could malfunction--with trauma maybe like dragging an amp by a connector, but otherwise never. Sherlock Holmes said: After eliminating the impossible, whatever remains, however improbable must be the truth. And so finally after all my clever experiments left me still puzzled, I swapped out cables and viola. Second time took less time, but I should have known effing better. And I no longer use junk--good stuff costs 20 bucks on the net, and is well worth it IMO.

I've seen many bad RCA cables and other bad cables too. I once worked part-time for a engineer in his electronics metrology lab. He got me to service his hundreds of various test cables to ensure the integrity of each of them was good. Cables go bad and it should be expected.

 

[DanielT]

General cleaning amplifier. Remove oxide. What others in the thread have been talking about.Also applies to preamplifiers and integrated amplifiers. Use electronics spray and spray on potentiometers and switches. Where you can spray. Clean inputs and outputs.Test the inputs and outputs you have the opportunity to test. Switch and try.

Exclude step by step where the fault may lie. You have the signal to your NAD via cables. No fault in the signal source or RCA cables (as others have been in the thread, replace RCA cables)? Then you have the signal out from your NAD to the speakers. Check, for example, that there is no gap in your banana connectors, the speaker cables. Then check the speakers so there is nothing wrong with them.

Okay now you have basically done what you can do (I can have miss something, you others may add what it can be in that case). You have done what you can as happy (not right now but you will be happy if you solves the problem) amateur who is not a repairman. The next step requires a little more knowledge in troubleshooting. If you do not have that knowledge and the error remains so, well then it will be to turn to your / a repairman. It can be anything, faults on relays, bad solder joint and so on. But if it is not something you can investigate yourself then, to the repairman. If you think it's worth it? Will your repairman ever charge you?

Regarding electronic spray and when you can and cannot, should use it, there are different views. Electronics spray dries quickly on its own

I use canned compressed air to blow away dust.There are those who say do not use compressed air in a can, you can blow shit into relays. I haven't had any problems with that.

Here is a video about using electronics spray, albeit on an integrated amplifier and volume control, but you understand how it works when it comes to removing oxide (can be good to know if you have an amplifier with crackling volume control):

Troubleshooting - NAD C270 Owner's Manual [Page 7]

NAD C270 Manual Online: Troubleshooting. Cause • Power AC lead unplugged or power not switched on • Input Select switch not set to active input • Input Level Control turned down • Balance control not centred • Speaker not properly connected or damaged • Input lead disconnected or...

www.manualslib.com

 

[Holmz]

From my own experience = twice. On one occasion seemed to happen out of the blue, the other involved moving equipment. Not having any experience first time it happened, it never ever occurred to me that an RCA cable could malfunction--with trauma maybe like dragging an amp by a connector, but otherwise never. Sherlock Holmes said: After eliminating the impossible, …

I put in a new amplifier which required longer RCAs and also some longer speaker cables.
Made the speaker cables out of lampshade wire until I get the better stuff in.

The RCAs were Mogami and Neutrik Profi ends... and I soldered them up.

Then one channel did not work… Speaker, new amp, speaker wires RCAs?
I swapped LHS and RHS RCAs into the amp and the problem jumped channels… So the speaker and speaker cables were OK.

I knew it was a bad solder joint in the RCAs, so I swapped them at the Pre-Amp and Amp… And the sound stayed on the bad channel… Hence my handmade RCAs were OK.

Then I plugged the iPhone into the preamp and all was good. So I knew it was likely the old CD player.
I swapped the RCAs from the CD player to the Preamp and the problem went away… So it was the store bought RCAs were the bad component.
It was the last thing I suspected was the problem, and it took about 20 minutes to work it out.

But it is just a process of elimnation using substitution and using iPhone and earbuds rto listen in mid stream is usually helpful… using the $10 RCA to 1/8” (3.2 mm) male and female adapters.