Possible grounding issues?

[mosshorn]

Hum is still going, but I did notice that when I twisted the plug in the RCA jacks, it caused more/less hum. I think I'm going to run to Radioshack, pick up some new jacks, and see if that resolves anything.

[mosshorn]

Ok so just got back and installed some new jacks (things are so tiny it's almost funny compared to the stock ones)


Same hum. Well, now to try that again. It sounds almost like an electrical static, which is why I started at the tubes. It goes in pulses kind of. Should I maybe resolder the capacitors? I just can't figure out what it may be :/


Thanks again all,
Brian

[Paul Joppa]

>>...when I twisted the plug in the RCA jacks, it caused more/less hum

That makes me thing there may be a bad ground inside the interconnect, or the plug's outer shell is not tight enough to make a solid contact with the jack.

>> ...It sounds almost like an electrical static, which is why I started at the tubes.

That could be an iffy solder joint in the signal path somewhere, or an external radio wave such as a current carrying switch - even refrigerators have been known to cause this symptom

>> ...It goes in pulses kind of.

And of course that makes me think of cell phones, flourescent lights, dimmers, and battery-operated motorized devices ...

Sorry to have so many vague possibilities, it's just kind of the nature of sleuthing out hum and noise problems. Frustrating unless you're an amateur detective.

[mosshorn]

>>...when I twisted the plug in the RCA jacks, it caused more/less hum

That makes me thing there may be a bad ground inside the interconnect, or the plug's outer shell is not tight enough to make a solid contact with the jack.

>> ...It sounds almost like an electrical static, which is why I started at the tubes.

That could be an iffy solder joint in the signal path somewhere, or an external radio wave such as a current carrying switch - even refrigerators have been known to cause this symptom

>> ...It goes in pulses kind of.

And of course that makes me think of cell phones, flourescent lights, dimmers, and battery-operated motorized devices ...

Sorry to have so many vague possibilities, it's just kind of the nature of sleuthing out hum and noise problems. Frustrating unless you're an amateur detective.

Detective indeed. I tried resoldering a cap that had a nasty connection since I originally did it (14u if I remember correctly), and reflowed 15u and one of the power connectors, also one of the transformer terminals (terminal 2 to be precise). Strangely enough, it made the static sound worse. Odd.

I DID notice something though. I'm connecting the Crack to my Audioengine D1 via optical. BUT it is powered via USB! So whenever I move the mouse, I can hear a little bit of whirr from the mouse moving. Weird eh? I thought about my DAC being the problem, but it did the exact same thing with a previous DAC as well.

I also turned off all my lights, the router, AND the modem, and still nothing :/ Worth a shot though! Thank you so much for the help so far

[Grainger49]

Jumping back, did you short the inputs as 2wo suggests in the last post on the first page?  Shorting the inputs will tell you if the crackle is in the crack or elsewhere.

What source(s) is/are you using?  It could be within the source.  Have you eliminated the source as the problem?

[BNAL]

I had a crazy problem with interference that was driving me crazy.My Crack is connected to a modded Squeezebox2. I have the SB2 connected to a wireless Ethernet adapter so that I can avoid any RF interference.  When I would power on the crack with my SB2 off I would hear a crackling sound every once in while. It was driving me nuts because everything sounded great. When I would turn the SB2 on the crackling would be much worse. I tried the Crack with my sons setup and it was dead quiet. So I knew that he Crack was good. Come to find out that the Ethernet adapter was to close to the Crack and SB2. Once I moved it away the Crack and SB2 were dead quiet.

It just goes to show that there are outside influences that can cause problems with the overall sound.

[Grainger49]

Brad, that is exactly why I asked the questions above your post. 

[mosshorn]

I tried a jumper going from one channel to ground, but will try both tomorrow. Doing just one, the crackle was just as bad as before.

I'm using Crack>Audioengine D1>Computer. I'm also going to bring the Crack into another room to see if the problem is isolated.

[Grainger49]

You should try the Crack with an analog source, TT, Tape, FM etc. to rule out digital problems.

[mosshorn]

Just tried it from my turntable, and now I'm really confused. One channel is playing in my headphones thru the amp (left channel), and I can hear some (maybe the other channel) being played out my turntable? It's low but definitely there. I'm pretty much a layman in that area, so I don't even know. Anywho, there was still a noise with the TT plugged in. A tracking buzz, kind of like the record spinning.

[Grainger49]

The stylus in the groove can be microphonic.  And it might not be.  That is without any amplification on it can make sound.  Some TT setups don't do this.  Is this what you mean?  

So now with your TT you are missing a channel, right?  Is the crackle there?  You mention a "tracking buzz" can you describe this?  That sounds like a buzz caused by a grounding issue that is not that uncommon with first time TT setups.  Often it is a loose or missing grounding wire.

To help the helpers you need to continue to answer the questions that are asked.

[mosshorn]

I put my ear up to it, and I'm thinking it is microphonics. I guess I've never heard it before since I always have my headphones on, not to mention I found it weird that is the audible song, just very quiet.


With my TT playing, I can't hear a single pop or crackle, even on quiet passages. If I raise the arm up, about 2 seconds later it starts that tracking buzz, a "tickatickatickaticka" that sounds like the motor perhaps?


Thank you so much for your help by the way, I can't explain how much I appreciate it.

[Grainger49]

I put my ear up to it, and I'm thinking it is microphonics. I guess I've never heard it before since I always have my headphones on, not to mention I found it weird that is the audible song, just very quiet.

That makes sense.  I can't hear it across the room but with one ear piece not working the dead ear should hear it.

With my TT playing, I can't hear a single pop or crackle, even on quiet passages. If I raise the arm up, about 2 seconds later it starts that tracking buzz, a "tickatickatickaticka" that sounds like the motor perhaps?

That says the pop/crackle is not the Crack, per se.  It is either the source or an interaction between the Crack and the source as a number of posters have suggested.

The buzz is as I mentioned in reply #25 "caused by a grounding issue that is not that uncommon with first time TT setups."

But to find the source of the problems you need to answer all the questions asked.  What we have now is that the sound from the TT is microphonic.  The pop/crackle is not happening in the TT setup.

Another question that comes up is the "tickatickatickaticka" noise.  Does it go away if the table is turned off?  How about if you invert the AC plug for the TT?  That is, take it out, rotate it 180 degrees and put it back in the socket.  Ground loop problems can be minimized this way.

[mosshorn]

When I turned the TT off, it stopped that noise. I'll try inverting the plug when I get home in a few hours, in class right now (love 1 o clock classes this semester)

[Grainger49]

This also says that the Crack is not the problem.  It is a problem, but the Crack is innocent.  It could be the table/ground/motor.  There are a number of problems. 

We should get one problem fixed at a time rather than jumping around.