Hum generated by CD Player

[Cabdiver]

I have a CAL DX1 CD player that generates a humming sound which comes through the speakers. The hum gets louder as I turn up the volume. This hum occurs even with the CD player unplugged, hooked up to the amplifier with RCA interconnects. If I unplug the left channel, the hum is only heard in the right speaker, and vice versa. I've tried different cables and different amps with the same result. Running a ground wire from the ground post on the amp to the CD player chassis made no difference. I took out the main circuit board and touched up a couple of suspicious solder joints, but that also made no difference. I'm a new hobbyist with a soldering iron and a good supply of ignorance. Any help would be greatly appreciated.

 

[onplane]

I have a CAL DX1 CD player that generates a humming sound which comes through the speakers. The hum gets louder as I turn up the volume. This hum occurs even with the CD player unplugged, hooked up to the amplifier with RCA interconnects. If I unplug the left channel, the hum is only heard in the right speaker, and vice versa. I've tried different cables and different amps with the same result. Running a ground wire from the ground post on the amp to the CD player chassis made no difference. I took out the main circuit board and touched up a couple of suspicious solder joints, but that also made no difference. I'm a new hobbyist with a soldering iron and a good supply of ignorance. Any help would be greatly appreciated.

Can you borrow a CD player from friend or family to see whether the problem is with your cd player or your house wiring?

Regards,
Jerry

 

[Cabdiver]

I pulled an NAD cd player from my office system and plugged it into my test station where the DX 1 has been humming along. Silent - no hum. Good idea, though, and thanks for thinking this through with me. Randy

 

[bimasta]

I have a DX-1. Haven't used it in years. It was fraught with problems. Fix one, and discover another. I'm sure they can all be solved in time, but I just switched to a different player.

Since your hum is cable-independent and a ground-wire doesn't help, it might be a leaky cap. It's a pretty simple board, might be easy to find and fix. Good luck.

 

[Cabdiver]

Yes, I've had trouble with this puppy before, but sounds so nice when it's working. I'm not sure, but I think this is a 60 cycle/s hum. Can that come from a leaky or open capacitor? If so, I guess I'll have to start recapping.... Thanks, Randy

 

[onplane]

Yes, I've had trouble with this puppy before, but sounds so nice when it's working. I'm not sure, but I think this is a 60 cycle/s hum. Can that come from a leaky or open capacitor? If so, I guess I'll have to start recapping.... Thanks, Randy

Randy, caps in the power supply will cause ripple as they age. This ripple usually sounds like 120Hz on full wave rectifiers. On half wave rectifiers, you'd hear 60Hz.

Problem is ac hum is all around us. Make certain all ground connections in the CD player are sound. Reason I'd not be too concerned with the power supply caps is you said the hum occurs even with the CD player unplugged. Thus the hum is NOT coming from the CD player's power supply.

Hope this help...
Jerry

 

[Cabdiver]

Thanks, Jerry. I plugged some headphones into my laptop and found a tone generator to compare the pitch with my hum. Best I can tell it's 120 Hz.

 

[Cabdiver]

I walked away from the DX1 for a bit and then came back to it. I repositioned a few caps that were in physical contact with each other, though I have no idea if that matters. I also noted that the input jacks are flimsily mounted, placing stress on the solder joints. Under magnification I could see a small crack, so I remelted the solder of the input jack connections. I didn't think any of this would help, but when I turned it on and tried it, the hum was gone and it sounds great. Not sure if either of these actions helped or if the resident poltergeist just moved on to my Dynaco ST 70 (another story.) Thank you again for your help and insights!

 

[sqlsavior]

Congratulations, and welcome to AK!

 

[guiller]

I walked away from the DX1 for a bit and then came back to it. I repositioned a few caps that were in physical contact with each other, though I have no idea if that matters. I also noted that the input jacks are flimsily mounted, placing stress on the solder joints. Under magnification I could see a small crack, so I remelted the solder of the input jack connections. I didn't think any of this would help, but when I turned it on and tried it, the hum was gone and it sounds great. Not sure if either of these actions helped or if the resident poltergeist just moved on to my Dynaco ST 70 (another story.) Thank you again for your help and insights!

Nice ending! It may have been a cold solder joint.

 

[NAD80]

Nice Fix!. Welcome to AK.

 

[niles300z]

Interesting. I'll try that with mine.
She hums too but I don't think it does with the power off. Maybe caps in my situation.
I'll let you guys know if I have any luck. Great player, but I see why they revised the drive or replaced it for a fewer moving parts model in the DX-2 geesh.

 

[Cabdiver]

I'm still listening to my DX-1. It stopped reading discs a short while back, but a general cleaning and very careful cleaning of the lens brought it back to consciousness. Good luck with yours and let us know what you find.

 

[bazzle592]

My beloved DX-1 picked up a hum that I've been trying to track down for weeks - can confirm the RCA jacks are the culprit. The solder joints looked flawless, but I fully extracted the jacks, gave them a polish with some brasso because why not, and soldered them back in and it sounds great again. Thanks!

 

[Cabdiver]

You're very welcome. May your DX-1 sing for many years to come.

 

[CassetteBoy]

I had the same hum symptom on my JVC XL-V311 and it also turned out to be a loose soldered connection of the RCA plug assembly to the PCB (the common ground to be exact). Quiet as a mouse now! Thanks for the tips, all.