Plugged the PA1X into the PA today. Hum that I haven't noticed on previous outings was evident.
After playing around with all the cables, the issue seems to be related to the Mains cable, even when the Korg is not powered, which puxzzles me.
Quick fixes welcomed....
My thoughts centre on the following....
1. Replace cable
2. Replace cable with a screened version that I have been reading about, anywhere from 30-50 english pounds.
3. Use a DI box? I keep looking at these but am never really sure about their benefits.
4. Buy a PA3X
Of these, the one I am most interested to hear the opinions of others is that of the screened cable.
Hi Chris,
I'd opt for the direct box as a final solution "has solved all for me anyway".
As a test, I'd try lifting the mains ground of the PA1X just to see if the hum is coming from a ground loop.
I don't intend that lifting the ground is a permanent solution, just a test to prove, or disprove my ground loop theory.
In the event that lifting the ground stops the hum, the direct box is the best solution.
Just my .02
Cheers, Hanon
I used to play Korg instruments, then I took an arrow to the knee.
I did try a couple of things, one being an "audio interface" seemed to be designed originally to work to reduce hum from the power supplies of laptops. This worked, but not as well as Active DI boxes. I have now acquired two of them, as when the keyboard is running through the mixer and PA, I have got into the habit of running the PA1X in stereo.
The other reason for the purchase of two rather than a single stereo box, which would have been cheaper, was so that if another instrument cause problems, I could easily run the Korg in Mono and have the second box closer to the source of hum.
1. The AC Power cable (120 Vac, 60 Hz)
2. The Speaker Cables
3. Some line level cables, like between mixer and power amp
4. Instrument Cable
1. AC Power cables are usually not shielded and here in the US we like three (3) Prong type cables.
2. Speakers Cables should not be shielded, and are usually of higher gage wire to properly transfer the power from the Amp to the speaker. Shielding can cause freq loss effects in this application.
3. Line level cables should always be shielded.
4. Instrument cables should be shielded.
All cables should be as short as possible.
Cables with different functions should not be ran (layed) together. Never coil up Instrument cables and lay them over the power cable. Try and have them cross only once at a right angle.
Thicker wire is normally better in most applications.
Star-Quad (two twisted pair and shielded) are the best.
If signals are balanced, it always best to run balanced cable (3 connections) you get better signal to noise ratio. (PS. Balance AC Power is cool too!)
I make my own cables, as they are better quality and usually cheaper in cost.
The less adapters you use the better off you are.
DI's are for impedance balancing. (ie guitars at +10Kohm to mics at 300 ohm.) But some people like to use them on keyboards.
Don't use RF cable for audio applications.
All things being equal (and they never are) high end cables do sound better, you just can't here it.
If you shake a cable and it makes noise, you need new/better cable.
Never coil cable in tight loops, let the natural bend be you guide.
Power all equipment from the same outlet. (avoid groud loops)
Last edited by JPWC on Mon Aug 08, 2011 3:08 pm, edited 1 time in total.
Higher gauge is not better in all applications. In instrument cables for instance, it's entirely unnecessary to have thick gauge cables because they operate in a high resistance environment, so the lower resistance from the thicker cable is actually entirely irrelevant to the application. Some companies feed terribly on this misconception. The only thing to be careful about it that SOME thinner cables have higher capacitance, which can cause some high frequency roll off. But then we're really talking VERY crappy cables, quite long, and unbuffered signal like a passive electric guitar.
Some of the best instrument-level cables are actually really thin, or at least the conductor part is.
EDIT:
To clarify, I assume with "higher gauge" you actually meant "thicker cable", even though a higher gauge number actually means a thinner cable? Just checking, 'cause I've never heard someone say that thinner cables are normally better in all applications.
Guys, it seems you have good knowledge of the subject, so can you give us some brand names of cables that you'd recommend for various applications? Or even tips on making up your own cables. Thanks.
@JWPC
Thicker conductor, more copper, is NOT better in the case of instrument cables. In fact, the benefit that you get from a thicker conductor (slightly lower resistance), is entirely irrelevant to the application because instrument cables (guitar, mic or line level) operate in a high resistance environment anyway. The myth that thicker cables are better is carried over from the world of speaker cables which carry amplified signal in a low resistance environment, i.e. from the amp to the speaker. There, the resistance of the cable has a real effect, especially in very long cables.
The property that you SHOULD perhaps be marginally concerned about for instrument cables is capacitance. This has more to do with the shielding material used than with the amount of copper in the conductor. Basically, an instrument cable acts as a capacitor, which means loss of high frequency, especially with very long cables and a very low signal (such as a passive electric guitar).
Which brings me to Giner's question;
I use Klotz AC110 for my (unbalanced) instrument cables. They have some of the lowest capacitance available at somewhat decent prices. The cable is really rugged as well. It's not extremely flexible because the shielding is relatively thick and tough, so if you'd want to use it for a very mobile application I'd check it out first. The actual conductor is very thin.
The Canare mentioned above is supposedly also quite good. It was somewhat hard to get over here so I went with the Klotz.
For my mic- and balanced cables I use Tasker C300. I really love that cable, it's very strong and still flexible. Picked it mainly because I had some prefab Taskers that I really liked.
My plugs are all Neutriks, I find them really rugged and they work well for me. Your mileage may vary, I believe the term is.
Don't go crazy on audiophile nonsense though. There are many misconceptions about cables that companies like Monster Cable like to prey on. More expensive is not always better, thicker is not always better. And at some point, a cable is just as good as it gets for the application.
