Topic: Random spikes and static on SPC4->UA5->JB3 (Optical In). Help.

[tbrown4]

Helping a friend with this issue and we can't figure out where in the chain the problem occurred. Spikes sound like static and are not isolated to one specific channel.

Here is a picture of the wave form.



It is not a consistent problem...just seems to be on a few recordings from this summer. The only common factor we can find is that it was hot/humid and/or raining/wet the nights these recordings were made. He would have been in the pavilion, so the only direct contact with water or beer would be from spillage on or near his gear bag. Could that be the cause? If so, how? And...how can it be avoided in the future.

Just baffled....help.

[drewloo]

Every time I've had something like that it's been a bad cable/loose connection.  The first thing I'd check is your optical cable since they are rather fragile.  Maybe try using a different one next time. 

[JackoRoses]

also if you are using a right angle adapter those have been known to introduce that kind of randomness as well.

[tbrown4]

Every time I've had something like that it's been a bad cable/loose connection.  The first thing I'd check is your optical cable since they are rather fragile.  Maybe try using a different one next time. 

Thats what I thought it could be, the optical cable...but....he hasn't had that issue too often...only a few isolated recordings. I figure when the cable goes bad or is busted....that it's done and you'd see that problem every time after. Some shows he recorded last that same month are pristine.

[tbrown4]

also if you are using a right angle adapter those have been known to introduce that kind of randomness as well.

He does has a permanent right angle on one end of his mic cables, but they aren't adapters.

[JackoRoses]

also if you are using a right angle adapter those have been known to introduce that kind of randomness as well.

He does has a permanent right angle on one end of his mic cables, but they aren't adapters.

sorry I meant an adapter just on the optical cable.

[Chuck]

I have a recording that has that same type of spiking. It was C 481 > V3 > iHP120.
I have never had it again. I suspected it was because I had the iHP-120 resting on the top of the wally world battery I use to power the V3. Since I stopped putting the iHP-120 in that location, I haven't seen that problem again...

[Chilly Brioschi]

Be sure that it's not happening in your transfer to the DAW.
Listen on the headphones on the JB3 and see if the static is on the recording, or if it happened in transfer.
I had a bad Firewire card that caused this... drove me crazy until I realized that the noise kept "moving" within the song.
I listened on the 'phones from the recorder, and viola' no noises!

[terrapinj]

its likely the C4 caps - they are very prone to moisture and humidity and will produce those types of results - Studio Projects (PMI Audio) will tell you to bake the caps at very low heat in your oven for a few minutes, but i had a card cap that had to end up being replaced as the baking would only be a temp solution

as I understand it a bad optical cable can cause drops outs and spikes but it shouldn't cause static

[SmokinJoe]

I second tj's response.  Bad optical cable will cause dropouts/skips, not spikes.  The guy next to me at Mountain Jam had his C4s crap out in the rain... static-ky, then eventually died.  He dried themout under a bare lightbulb that night, and they worked the next day.

[chunga1]

I had the exact same thing happen to me at a show...Only happened one time and only during one bands set....I fixed it with soundforge8..But never had it happen again (so far)..it was a weird static noise but it only happened in the last 20min of the recording of that specific band....It was on the recording and not in the transfer if i remember right..the rig used is in my sig....

tim

[jibooer]

i'm for the opinion of the humidity in the caps only because i've had probs w/ the optical cable before. the sound that was introduced was more of a random ticking....

[Rockinman59]

Thanks guys for all the responses. I'm the new taper with the issue.  I'm thinking at this point that it could have been either the optical cable OR the card caps (only because of the humidity/rain that is the common denominator here) having moisture.   My last 2 shows taped had excellent weather(no humidity to bother the caps) and I also had the optical cable connection to the UA5 out in the open(I turned the UA5 sideways) instead of the cable pressing up against  the inside of my gear bag which could have caused less than a tight connection. Anytime I did have the cable pushed in against the inside of the gearbag, I noticed I couldn't get a signal on the JB3 and when I turned the UA5 around to inspect the connection, the line was disconnected. 

Also, I looked into an optical line with one end as a right angle connector and I'm told they don't make such a thing? I checked with Cablestogo.com and The Guitar Center store.  I need to get another optical line anyway in case I have problems getting a signal.

Thanks again for everyone's advice!  Still learning all this technical stuff but did pretty well in my rookie year.

[JackoRoses]

Thanks guys for all the responses. I'm the new taper with the issue.  I'm thinking at this point that it could have been either the optical cable OR the card caps (only because of the humidity/rain that is the common denominator here) having moisture.   My last 2 shows taped had excellent weather(no humidity to bother the caps) and I also had the optical cable connection to the UA5 out in the open(I turned the UA5 sideways) instead of the cable pressing up against  the inside of my gear bag which could have caused less than a tight connection. Anytime I did have the cable pushed in against the inside of the gearbag, I noticed I couldn't get a signal on the JB3 and when I turned the UA5 around to inspect the connection, the line was disconnected. 

Also, I looked into an optical line with one end as a right angle connector and I'm told they don't make such a thing? I checked with Cablestogo.com and The Guitar Center store.  I need to get another optical line anyway in case I have problems getting a signal.

Thanks again for everyone's advice!  Still learning all this technical stuff but did pretty well in my rookie year.

soundprofessionals had a right angle optical cable for sale at one time.
I'm not sure if they still do or not.
Good luck in tracking down your issue it can be a bit frustrating at times.

[willndmb]

welcome tom

[Rockinman59]

Thanks Will.  It was good meeting you at Hartford.  I've been on TS since March when I bought this gear, just had some unexplained static but I think I know what's causing it.

[Rockinman59]

Thanks guys for all the responses. I'm the new taper with the issue.  I'm thinking at this point that it could have been either the optical cable OR the card caps (only because of the humidity/rain that is the common denominator here) having moisture.   My last 2 shows taped had excellent weather(no humidity to bother the caps) and I also had the optical cable connection to the UA5 out in the open(I turned the UA5 sideways) instead of the cable pressing up against  the inside of my gear bag which could have caused less than a tight connection. Anytime I did have the cable pushed in against the inside of the gearbag, I noticed I couldn't get a signal on the JB3 and when I turned the UA5 around to inspect the connection, the line was disconnected. 

Also, I looked into an optical line with one end as a right angle connector and I'm told they don't make such a thing? I checked with Cablestogo.com and The Guitar Center store.  I need to get another optical line anyway in case I have problems getting a signal.

Thanks again for everyone's advice!  Still learning all this technical stuff but did pretty well in my rookie year.

soundprofessionals had a right angle optical cable for sale at one time.
I'm not sure if they still do or not.
Good luck in tracking down your issue it can be a bit frustrating at times.

Thanks for the info.  I did find a bunch of optical cables and some with right angles at this link:

http://www.soundprofessionals.com/cgi-bin/gold/category/220/audio


I just have to get the right one that has a right angle end that matches up with the output of the UA5.

[Rockinman59]

Every time I've had something like that it's been a bad cable/loose connection.  The first thing I'd check is your optical cable since they are rather fragile.  Maybe try using a different one next time. 

Well, I just taped last night and listened to the wav file after transferring the show to my hard drive and it has the worst spikes I have ever seen.  I just got through taping a month ago 2 shows that came out perfect after having the spike problem a month before that.  I had the same set up with the optical cable not being pressed up against the inside of my gear bag for last night's recording and yet I got worse spikes than ever before, it covers the entire wav file and the audio even cuts out at times.  If the caps were the issue, it would have happened a month ago when it was very hot and humid outside and yet those recording had no spikes at all.   I have to try another optical cable.  The connection to the UA5 optical out seems very weak and it does not take much for it to come out. I really hope it's something that simple.

[Rockinman59]

Every time I've had something like that it's been a bad cable/loose connection.  The first thing I'd check is your optical cable since they are rather fragile.  Maybe try using a different one next time. 

Well, I just taped last night and listened to the wav file after transferring the show to my hard drive and it has the worst spikes I have ever seen.  I just got through taping a month ago 2 shows that came out perfect after having the spike problem a month before that.  I had the same set up with the optical cable not being pressed up against the inside of my gear bag for last night's recording and yet I got worse spikes than ever before, it covers the entire wav file and the audio even cuts out at times.  If the caps were the issue, it would have happened a month ago when it was very hot and humid outside and yet those recording had no spikes at all.   I have to try another optical cable.  The connection to the UA5 optical out seems very weak and it does not take much for it to come out. I really hope it's something that simple.

UPDATE:   I notice the optical cable fits and snaps in snug on the UA5 if I plug it into "Optical In" but it doesn't snap in tight on Optical Out, could this be causing the issue if it's not making the proper connection inside the Optical Out?

Thanks for any help

Tom

[Rockinman59]

i'm for the opinion of the humidity in the caps only because i've had probs w/ the optical cable before. the sound that was introduced was more of a random ticking....

Thanks to you and Smokin Joe as well.  This appears to be the issue, the caps get moisture.  I called Studio Projects who informed me that is very easy for moisture to affect the caps and produce static.  He suggested putting the mics in a sealed bag with silica gel packs, another taper here suggested it in another thread.  At first, it was impossible to find any, but my wife works in a lab and has lots of them, duh why didn't I think of that first?  Now I know why I couldn't duplicate the problem when testing all the equipment at home, the caps dried out again.  Will use those silica gels from now on and we'll see if the problem is solved.

Thanks everyone here for their input and help!

 Tom G

[RobertNC]

Yeah I had what I think is the same problem with my ADKs this summer. 

Outdoor show, light rain on and off.  Mics were under an umbrella, but it was really humid.  Rolled for about 2.5 hours no problems.  Then all of a sudden there is static and general weirdness in both channels for about 10 minutes of runtime, then it goes away again.  My theory is that the humidity was not the the real problem, but rather some heavy clouds moved in and the temp dropped pretty fast and some moisture condensed in the mics, but that is just a guess.

I was running mic in, so there was only one set of cables involved.  Did a visual and found no problems.  Set everything up and really gave it all a workout pulling and twisting cables and could not make it happen again.  And besides, it would be a pretty big coincidence for a two cable rig to have problems start in both channels at the same time, and problems in both channels go away about the same time.

Pretty sure what I had was a moisture problem not a cable problem, so it does happen.