Topic: JB3 hd noise = audible on recording? + preventing shutdown!

[bmr]

I bought a few refurbed JB3s a few months back, and sent one to a buddy in australia. He ran CSCs > SP bbox > JB3 for his first JB3 show last night, but had two major problems which are driving him nuts...and since I sold him the JB3, I feel I have a bit of a moral obligation to help him get to the bottom of this for him. Hopefully wiser heads here can help...

1) When familiarizing himself with it, and taping his stereo at home with his rig, he was able to cleanly hear the JB3's hard drive spin up on the resulting wav file upon playback. His mics were far enough away for it to where it wasn't being picked up by them; it had to be generated internally, he said. He then went 1/8" > 1/8" from the stereo's headphone out > JB3 line in, recorded for a while, and not once did he hear the sound. He sent me a sound clip from the show he recorded last night, where it's definitely audible, and is definitely the hard drive's noise.

Is it a common thing to be able to hear the hd spin on a recording? And why would it only do it with the mics > bbox and not the 1/8" line signal? I run optical into the JB3, so I haven't experienced this...but I also haven't heard my hard drive ON my recordings, either...any idea what's going on here? Anything he could do to lose the noise?

---

2) He was "1000% sure" that he button-locked the JB3 during his recording, yet it continually shut down on him while recording. He selected "continuous" on the "Record Settings" screen, though I told him I'm pretty sure that refers to the length of the wave file and doesn't have to do with power. He kept it in a large jacket pocket, which he said wasn't hot...and after the FIFTH time it shut down on him, he held it in his hand and hit the scroll wheel every minute or two to manually keep it active.

Is there anything he needs to be doing other than set the button lock? I button-lock my JB3, but I also (in Settings > Edit Profile) set "sleep timer" and "idle timer" to "off" since I'm not exactly sure where/when those take effect.

I'm just really worried I may have shipped him a lemon...when he returns home this evening, he's going to run his rig again and record, to see if he notices if it shuts off at a specific time or something like that.

Any ideas?

[hexyjones]

What kind of noise is it...? Can you describe...?

[bmr]

What kind of noise is it...? Can you describe...?

Turn on your JB3, and put your ear next to the bottom of the unit...that spinning up sound is what's on the recording.

[hexyjones]

What kind of noise is it...? Can you describe...?

Turn on your JB3, and put your ear next to the bottom of the unit...that spinning up sound is what's on the recording.

Hmm...I wonder if this problem is similar to "cable handling" thumping noise that can sometimes occur with unbalanced lines or shoddy connections...

[Sanjay]

the pocket may not be hot, but it still can shut down, i have had this happen one too many times for my liking.  As for the HD noise it either has to be his battery box picking up the noise from the HD (is that even possible?) or his mics are too close, because if it records through line-in correctly from the stereo with no noise it shouldnt be a nomad problem.

[Swampy]

Ya, I think in the past some people have talked about HD noise on analog ins on the JB3... I not sure why it happens, but Id be interested to find out too.

[hexyjones]

I might add...one of my JB3s is incredibly sensitive to heat...so not all units are the same...

I wonder if all jb3s ship with the same hard drive?...maybe some have shit drives in them?

[hhf32]

What you have is normal for a JB3.  I've written about this a few times.  You get some bleed into the analog circuits from the hard drive activity - as I recall it alternates at 5 sec/10sec intervals.  If your source signal is high enough, it is not audible.  If your source is low and you need to crank the volume or boost with software, it becomes audible.

This, along with the pre-amp self noise and quality, is why some people elect to use external pre/a>d boxes.

What are you plugging into the JB3 and what recording settings are you using (mic-in / line-in and gain settings)?

You reported "noisy recordings" - let's hear one.

This sounds kind of what your experiencing. I remember reading this awhile back, do an advanced search and there's alot on the subject.

[hexyjones]

What you have is normal for a JB3.  I've written about this a few times.  You get some bleed into the analog circuits from the hard drive activity - as I recall it alternates at 5 sec/10sec intervals.  If your source signal is high enough, it is not audible.  If your source is low and you need to crank the volume or boost with software, it becomes audible.

This, along with the pre-amp self noise and quality, is why some people elect to use external pre/a>d boxes.

What are you plugging into the JB3 and what recording settings are you using (mic-in / line-in and gain settings)?

You reported "noisy recordings" - let's hear one.

This sounds kind of what your experiencing. I remember reading this awhile back, do an advanced search and there's alot on the subject.

I follow that...but I've never heard it...I just stealthed a show in a theatre. Used a stereo mic...line in..used all 12db of gain. The recording only came out at like 10%...I had to add like 20 something db of gain. On the final boosted version, between songs I can hear the line in noise...almost like analog tape...just a bit higher freqency. But I havent heard anyting that sounds like drive movement.

Thats why I wondered if these things all had the same drives....? Maybe some arent as well sheilded?

[Humbug]

Apologies if anyones read similar from me before...I've made somwehere around 100 stealth recordings now with two different Nomads. Always kept in jacket pocket, sometimes taken out while recording to give them some air.

Nomad #1 (new April '03) has been reliable 95% of the time, shutting down only under extreme conditions (lots of heat, people bumping into me). One time I was almost knocked over by a bouncer pulling out someone who had fainted, and that was the exact same moment it shut down. Running 1.20.06. Seems to run hotter than #2.

Nomad #2 (refurb) arrived a month ago and has been used around 10 times, but not under extreme conditions. 100% reliable so far. Running 1.40.06.

The testing continues, and I'm not changing this little box for anything right now...neither am I taking them both apart to see what hard drive is in there, I'd never get it back together!

[The Kilted Taper]

I will agree with some of the others on the shutdown issue, that is is probably heat created. The pocket may not be hot, but these units generate a good amount of heat and need to be able to "breath".  If at all possible, attach a belt clip to the back so it can be worn and get air. I have one of those pleather cases that has a clip on the back that I attach to my belt while stealthing. I'll cover it up with my unzipped hoody and just lift up the hoody occasionaly to let it breath. No problems yet (knock on wood  )

[hexyjones]

I will agree with some of the others on the shutdown issue, that is is probably heat created. The pocket may not be hot, but these units generate a good amount of heat and need to be able to "breath".  If at all possible, attach a belt clip to the back so it can be worn and get air. I have one of those pleather cases that has a clip on the back that I attach to my belt while stealthing. I'll cover it up with my unzipped hoody and just lift up the hoody occasionaly to let it breath. No problems yet (knock on wood  )

Well with mine it's a "Start Up" Issue...if it's a warm day and I let the deck get even a tiny bit warm before I turn it on...it wont start...I really have never had it shut down...once it locked up. Once the power blew at a show and it took a few minutes before it would start up...but as long as it's cool...no problem. Glad fall/winter is here...well not so glad since I got second nomad that seems to work a little better...

[Karl]

I can address the issue of the noise that you are hearing--yes, it is noise created by the hard drive spinning.  I ran into lots of problems with it at first, because I had to tape for about a year with just mics>bb>jb3.  I taped a lot of classical type material, with a wide range of dynamics, so in the quiet sections you would hear that nasty hum from the HD spinning.  It's nothing that a good preamp and/or external a/d could take care of.

What I noticed was that about every 18 seconds (recording at 44.1k) you would hear the HD hum.  The reason you hear it is this--there are multiple clocks etc running on the jb3, and they all create what's called RF interference--basically radio waves.  When the hard drive spins, it creates a frequency that mixes with other frequencies to equal frequencies that are in our audible hearing range.  Because the innards of the jb3 are not that well shielded, they easily pick up those frequencies, and it gets recorded as audio.

What I ended up doing to save those recordings was to identify the frequency of the hum (I think it was just above 8kHz) and deleted just that frequency.  Though, that should prob only be done with wave editors that work in 32 bit (float) format, and even there you may notice some artifacts.

If you primarily tape music that is loud (and constantly loud) then you can get away with using mics>bb>jb3, because the music will cover up that humming noise.

[Karl]

jk, check your pm's

[Brian Skalinder]

jk, check your pm's

Am curious to see the response to JKL's question posted publicly, if you're willing.