Pin 1 Problems

[escapemcp]

I have been getting a bit too much noise for my liking on my system, especially on my newly purchased powered monitor (not BFM ). After reading some of the internet to increase my knowledge on the subject (including the Rane library stuff), I am still slightly puzzled.

I did find that on some of my store bought leads (they were purchased early on, before I got onto Bill's crossover soldering lesson), that pin 1 was connected to the connector's shield. Reading Rane's notes suggested that this was bad, so I spent last night ripping my system apart and checking that I had no pin 1 to shield connections. Upon plugging everything back into the system, I still had quite a bit of noise.

This noise is only really evident when I have the volumes cranked WAAY higher than what is required to get max output from the speaker. If I turn it down so that max output from my mixer creates max (undistorted) output at the speaker, the noise is much less (obviously) but still there.

Reading those Rane notes, it mentions that I should be disconnecting pin 1 here.

So can anyone please enlighten me how I should wire my XLRs? I always assumed that pin 1 should always be connected to the shield, but after much reading, I am still not sure.

Can anyone help please? I realize that this is a basic question, but it is one I cannot seem to find a definite answer to (which probably means that there isn't one!)

Thanks,

Aidan

[Hackomatic]

Is the noise of the hum variety or more of a white noise sort?

[escapemcp]

Is the noise of the hum variety or more of a white noise sort?

Um... it's more like electrical noise... the type of noise that you get out of a crappy laptop soundcard - do you understand what I mean by this?

[escapemcp]

I've been wondering if I need to upgrade my interconnects to the Neutrik EMC ones....



But at £15 per interconnect (male & female ends), it's going to get rather expensive rather fast!

[Hackomatic]

Yep . . That's what I was attempting to describe as white noise sound, though technically it is not.

Reading Rane's notes suggested that this was bad, so I spent last night ripping my system apart and checking that I had no pin 1 to shield connections.

Do you mean you disconnected the shield wire from pin 1 entirely, or you disconnected a secondary jumper wire that went from pin 1 to the connector body?

[Hackomatic]

Hmm . . I just can't see the need to spend that kind of money on those connectors to fix the problem . . unless you are doing gigs in and around high power transmitters, chances are it is not outside interference. I'll assume you do not get the noise out of the monitors when the cables are disconnected? Even when you turn their gains all the way up?
If you run the output of your system to some other source (besides your new speakers) do you hear the noise at all?

[escapemcp]

Yep . . That's what I was attempting to describe as white noise sound, though technically it is not.

Reading Rane's notes suggested that this was bad, so I spent last night ripping my system apart and checking that I had no pin 1 to shield connections.

Do you mean you disconnected the shield wire from pin 1 entirely, or you disconnected a secondary jumper wire that went from pin 1 to the connector body?

I disconnected a little bit of wire that jumped pin 1 to the plug's chassis (the locking tab thing)

[escapemcp]

Hmm . . I just can't see the need to spend that kind of money on those connectors to fix the problem . . unless you are doing gigs in and around high power transmitters, chances are it is not outside interference. I'll assume you do not get the noise out of the monitors when the cables are disconnected? Even when you turn their gains all the way up?
If you run the output of your system to some other source (besides your new speakers) do you hear the noise at all?

The noise is deffo coming from the leads... the speaker plugged in by itself is fine... no noise.
I have plugged it into an alternative source and I get a small amount of noise, but nothing like when connected to the rack. Do you think it may just be the cumulative noise of all the equipment I have hooked up (DEQ, DCX and amp). My DEQ/DCX are connected via AES/EBU and removing that connection lowers the noise somewhat (which makes me think it is just the noise floor of the equipment I am hearing due to the high gain I have on the speaker).
It seems that each extra bit of equipment I have in the chain increases the noise, but to me each unit is adding far too much noise. Hence why I was wondering if I should be disconnecting pin 1 completely at the downstream end of the wire (as is recommended in certain places). I was mainly just wanting to check if this is needed or not (as I have seen it mentioned on the web to get rid of ground loop problems).

[Bill Fitzmaurice]

Hence why I was wondering if I should be disconnecting pin 1 completely at the downstream end of the wire

There's only one way to know for sure. But you wouldn't necessarily disconnect pin 1, you'd just disconnect pin 1 from the body lug and see how that works first.

[Bruce Weldy]

Do you think it may just be the cumulative noise of all the equipment I have hooked up (DEQ, DCX and amp).

That or one device that is causing it. Recheck your setting on each device and make sure that the EQ looks right. Try putting a low pass on the highs or just rolling some off.

I doubt seriously that a cable is the issue. That said, if you are using those cheap Chinese pieces of crap - no telling. They are the only cables I've seen that connect the shield to the case.

Go buy two Neutrik XLRs and build your own cable - pin to pin, then see if that fixes it. If not, it's in the gear.

[Hackomatic]

Do you think it may just be the cumulative noise of all the equipment I have hooked up (DEQ, DCX and amp). My DEQ/DCX are connected via AES/EBU and removing that connection lowers the noise somewhat (which makes me think it is just the noise floor of the equipment I am hearing due to the high gain I have on the speaker).
It seems that each extra bit of equipment I have in the chain increases the noise, but to me each unit is adding far too much noise.

Adding to what Bill and Bruce have said and something you may already know but I'll throw it out there . . the way of achieving the best signal to noise ratio with multiple pieces of series connected gear is to run the outputs of the first piece of gear as high as possible, turn the input on the second piece of gear down to get in the correct level range of the processor's function, and repeat for each piece of series connected equipment. Set the output of the final piece of gear to achieve the desired overall level (which in your case would be your powered speakers). Doing it reverse of that just magnifies the preceding gear's quiescent noise as the audio chain progresses..

[escapemcp]

Adding to what Bill and Bruce have said and something you may already know but I'll throw it out there . . the way of achieving the best signal to noise ratio with multiple pieces of series connected gear is to run the outputs of the first piece of gear as high as possible, turn the input on the second piece of gear down to get in the correct level range of the processor's function, and repeat for each piece of series connected equipment. Set the output of the final piece of gear to achieve the desired overall level (which in your case would be your powered speakers). Doing it reverse of that just magnifies the preceding gear's quiescent noise as the audio chain progresses..

Yes, I tried that method late last night by running a sine wave from my CDJs, I'd then push my mixer as high as it would go (with everything downstream turned down low, but enough to hear it). You hear the point at which the sine wave distorts, so I'd then back the signal off a slight amount and then move onto the next piece of gear and repeat. I didn't actually finish this troubleshooting because my bed was calling, but I will try tonight.

I am also going to make a very short cable with pin 1 disconnected, so that I don't have to keep un-soldering and re-soldering cables to work out where the problem may lay. I can just insert my test cable onto the end of the bit of cable I want to verify and hey-presto - instant pin 1 disconnection.

Thanks for all the help guys. I will report back in the interests of completeness and general forum good manners

[escapemcp]

That said, if you are using those cheap Chinese pieces of crap - no telling. They are the only cables I've seen that connect the shield to the case.

Yup... they're the one's I had. 3 stereo patch leads all with pin 1 connected to the plug's shield. To be fair though, they were a Christmas present from my parents, so they didn't really know what they were buying. I've cut the connection to the plug's shield (and re-soldered a few, just to be sure). I'm measuring just under 1Ω now for the whole cable length... is that ok, or is the (what I consider) high resistance due to the measuring proddy on the multimeter not getting enough contact?

Go buy two Neutrik XLRs and build your own cable - pin to pin, then see if that fixes it. If not, it's in the gear.

First you moan at my Berry amps... now you are having a go at my Ching-Won XRL connectors. I wonder how long until you'll be telling me my LAB1A drivers are total flaps.

[Bruce Weldy]

First you moan at my Berry amps...

You've got the wrong Br___. Brent was gigging you on the amps. About the only thing I've ever encountered with the yellow triangle that's been worth a crap is the amps.....and I even had one of those lay down on me during a show. (wasn't mine - I don't own any .... just used some of their stuff here and there).

Life is too short to try and save a buck or two here and there. I figure that every brand will break at some point - I'm paying more to make sure those points are few and far between. That's why I build my own cables, even though sometimes there are deals where I can buy them for less than the materials to make 'em.

[CoronaOperator]

Yes, I tried that method late last night by running a sine wave from my CDJs, I'd then push my mixer as high as it would go (with everything downstream turned down low, but enough to hear it). You hear the point at which the sine wave distorts, so I'd then back the signal off a slight amount and then move onto the next piece of gear and repeat. I didn't actually finish this troubleshooting because my bed was calling, but I will try tonight.

If you have a spare piezo tweeter laying around, connect that to your amp. Run a 400hz sine wave through your CDJ's recorded at 0 dBfs. The piezo tweeter will scream when the 400 hz sine wave begins to clip. This method will get you within a half dB of an oscilloscope.