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Author Topic: External battery causing noise on recording??  (Read 4308 times)

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colinw

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External battery causing noise on recording??
« on: July 29, 2014, 02:03:48 PM »
I taped a Tweedy show over the weekend and was surprised to hear a weird noise on the files when I was processing them.

At regular intervals throughout the show I hear a small bit of digital interference or something. It almost sounds like you're listening to vinyl and there is dirt on it and every revolution you hear "noise".

Here is a sample of Hummingbirg. Turn the volume up and you can hear it clearly.

http://yourlisten.com/maritimetapers/jeff-tweedy-2014-07-26-hummingbird-weird-digital-noise

I was running CA14 cards > Naiant tinybox (mid setting) > tascam dr2d. I was also powering the DR2d with an external battery bank.

I ran tests just now and everything is fine running the tinybox at the three different levels of gain. The "chirping" or noise comes in when I plug in the battery pack, so I am guessing it is the cause.

anyone ever heard of this or experienced it??

I have used this exact setup for many shows and never heard the noise when using the battery pack before. It was fully charged before I started recording. I used the same cables and exact gear and setup as before with no previous issues.

Any ideas? maybe a bad cable?

colinw

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Re: External battery causing noise on recording??
« Reply #1 on: July 30, 2014, 08:57:31 AM »
thanks for the reply Jon. I will give it a shot and see what happens.

THe interference is only present with the battery pack attached. Without the pack attached, changing the gain on the TB or the tascam doesn't cause any issues.

I will test again tonight with the battery pack attached and adjust the gain on the TB and the recorder to see if that makes a difference. I will also try a different battery cable as well.

I am hoping I can figure this out, as I am loving having the long battery life of the external battery. The dr-2d is a hog on regualr batteries and I was getting tons of life from the external source.

runonce

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Re: External battery causing noise on recording??
« Reply #2 on: July 30, 2014, 09:15:58 AM »
Does the position of the battery make a difference?

I seem to remember getting weird noises from my JB3 when it sat on top of my DVD battery (which wasnt even being used on the JB3.)

Offline anr

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Re: External battery causing noise on recording??
« Reply #3 on: July 30, 2014, 03:06:06 PM »
Many Lithium-Ion battery packs have a noise filter to reduce this but it would only be regarded as critical in, say, Military use, where the oppo can triangulate your position a lob mortars at you.  I've been to a few music venues that seem like that. 




Offline dnsacks

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Re: External battery causing noise on recording??
« Reply #4 on: July 30, 2014, 03:18:35 PM »
colin - give us more details on the batteries you're using -- Jon's point re a "switching" battery is questioning whether your external battery is simply a bank of cells attached together in series (i.e. 3x 1.5v alkaline batteries producing 4.5 volts) or is using electronics to change the voltage output by the cells (a "switching" battery) -- your post also indicated you only use the external battery to power the dr2d -- I saw another post indicating noise on the dr2d when using an external battery to power a second device simultaneously (and that the issue was resolved when the second device was removed from the dr2d

colinw

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Re: External battery causing noise on recording??
« Reply #5 on: July 30, 2014, 06:21:18 PM »
OK, I tried some more tests. I can confirm that when I turn on the battery pack, I am hearing the interference noise.

Without the battery, I can adjust the gain on the Tinybox (low, med, high) with no issues, and adjust the gain on the Tascam dr-2d with no issues. I can plug the battery pack into the tascam with no issue, but as soon as I hit the power/on button on the battery pack the interference starts. I tried different cables from the battery to the recorder, and the interference remains. I coiled the CA cables, and even tried my pair of CA14 omnis, interference still there. I moved the battery, tinybox and recorder close together and farther apart, all still had the interference. It only goes away when the battery is turned off.

I am only feeding the Tascam recorder with the battery pack, nothing else.

The battery is a lithium ion 5v output, 6000mah battery pack. The cable is a USB on the battery pack end to a B tip on the recorder end. I charge the battery pack with a regular mini-usb DC charger. It is not switchable to different outputs, and it is not just a bank of cells. I assume inside is a single li-ion cell, which is all wrapped in a plastic enclosure.

I used this exact setup, and also with phantom powered Busman bsc1s instead of the small CAs, and it worked fine at least 10 shows worth.
The first show this noise appeared was at Tweedy.

Is this just a crappy battery which is no good after a few uses? It seems to still hold a charge fine and power the device, the only difference is that this noise has been introduced. I am not too clear on if this is something that happens with external batteries, or if I need a better quality battery to prevent it happening again.

As I stated, I am a huge fan of the extended life (up to 12 hours), instead of the palty 3 hours I get from regular batteries.

Any more ideas?

colinw

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Re: External battery causing noise on recording??
« Reply #6 on: July 30, 2014, 06:37:36 PM »
Also, the interference is only present when the recorder is actively recording a file. When I have it on standby (record light flashing) the interference is not there. When I pause an active recording, the interference stops.
I got similar results using line in, mic in, and even the internals on the tascam. All the same deal, as soon as I hit record and start recording with a solid red light the chirping is back. When I pause, no chirping.
I tried multiple different SD cards with the same results.

I also tried an external battery pack (4 AA cells, with a USB output), and the pack seems to power the tascam but the chirping is still there just like when I used the li-ion pack.

This leads me to believe that is is not the battery pack, cables, tinybox, sd card, mics which is causing the issue and it is something with the way the tascam is reacting when fed external power. What is so mysterious is that this worked fine for a bunch of shows.

What could have changed to have this noise all of a sudden? (and yes, I did go back and listen to my recordings and the interference is not there!)

Offline Gutbucket

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Re: External battery causing noise on recording??
« Reply #7 on: August 01, 2014, 10:04:54 AM »
As I stated, I am a huge fan of the extended life (up to 12 hours), instead of the palty 3 hours I get from regular batteries.

Have you ever updated the firmware?  3 hrs with internal batteries sounds like the original firmware runtimes.  Any version after the second release about doubled that.

I occassionally still use a small Energizer brand LiION external battery designed for netbooks which is about the same size as the recorder.  I'm sure it uses a switching mode power supply as it has multiple hard-wired ports offering various output voltages in addition to the 5V USB port I'm using to power the DR2d.  That external battery will run it all weekend.  Never had any weird noises using it that way, but ever since the first frimware update I only used the external battery for a few multi-day festivals.  5-6 hrs on two AAs is perfectly adequate for single concerts for my usage.
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

colinw

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Re: External battery causing noise on recording??
« Reply #8 on: August 01, 2014, 10:27:41 AM »
As I stated, I am a huge fan of the extended life (up to 12 hours), instead of the palty 3 hours I get from regular batteries.

Have you ever updated the firmware?  3 hrs with internal batteries sounds like the original firmware runtimes.  Any version after the second release about doubled that.

I occassionally still use a small Energizer brand LiION external battery designed for netbooks which is about the same size as the recorder.  I'm sure it uses a switching mode power supply as it has multiple hard-wired ports offering various output voltages in addition to the 5V USB port I'm using to power the DR2d.  That external battery will run it all weekend.  Never had any weird noises using it that way, but ever since the first frimware update I only used the external battery for a few multi-day festivals.  5-6 hrs on two AAs is perfectly adequate for single concerts for my usage.

thanks Gutbucket. I had updated the firmware when I first got the dr-2d and I think I am at the most recent level. I will check and update again to make sure. Perhaps it is the brand or type of battery I am using. If I could get 6 hours that would suit me fine as well. Are you getting the 5-6 hours recording 4 channel, or just 2?

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Re: External battery causing noise on recording??
« Reply #9 on: August 01, 2014, 10:43:57 AM »
I get ~6hrs with Maha Imedion LSD AAs.  Dual_Line 4-channel mode, plug-in power off, 24/48.
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

 

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