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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: sokiN on May 30, 2011, 03:34:34 PM

Title: MixPre problem?
Post by: sokiN on May 30, 2011, 03:34:34 PM

Hello everyone.
It seems that something is wrong with my MixPre. I'm running it on internal power and in comparison with a Rode NT4 and an edirol HR09  (the phantom power for the Nt4 is provided by the MixPre). I have noticed that after running this setup for an amount of time, there's a big difference in the amplification of the two channels (channel 2 is much less amplified). Has anyone noticed something similar on their MixPre?

 I've checked and I'm sure that the problem is on the MixPre and not the recorder. Can anyone also tell me if it's a good practice to use the 9volt battery on the rode NT4 for phantom power? I suppose the batteries on the MixPre will last longer so I'll postpone the situation described, but I'm worried I will introduce additional noise to my recordings.

Thanks

Title: Re: MixPre problem?
Post by: Beedy on June 02, 2011, 03:47:06 AM

I had a faulty cable in terms of a similar problem. If its possible check this with another cable.

Title: Re: MixPre problem?
Post by: sokiN on June 02, 2011, 11:03:42 AM

thanks Beedy but the cable is ok.

 It seems that the problem appears as the batteries of the MixPre go off. I'm the second user of the MixPre and when phantom is on (using both channels) I only get about an hour without this problem. Could anyone suggest a better way of powering (externally) the MixPre? A not very expensive way is preffered...  :)

Title: Re: MixPre problem?
Post by: jbell on June 02, 2011, 11:09:41 AM

you could use a DVD battery or a Tekkeon and have Ted make you a cable.  I run my SD MP-2 of DVD batteries and 2 will get you ridiculously long run times. 

Title: Re: MixPre problem?
Post by: sokiN on June 02, 2011, 11:31:53 AM

thanks jmbell. Could you suggest any specific model for the batteries?
 Apart from that does anyone know what kind of cable is that? I'd preffer making one cause I'm in Europe and I suppose getting it from the U.S. will be a little expensive.

Title: Re: MixPre problem?
Post by: jbell on June 02, 2011, 12:36:29 PM

Not sure about european vendors, but someone is selling some DVD batteries in the Yard Sale.  I'm not sure about making the cable, but it would either be a barrel connector or 4 Pin Hirose on the Mixpre side I'm not sure about the tip the DVD battery would need.

Title: Re: MixPre problem?
Post by: sokiN on June 02, 2011, 02:58:28 PM

thanks.
If I remember correctly it's 4 Pin Hirose on the Mixpre. I suppose I'll buy the dvd battery and work things out.
Has anyone ever noticed similar behaviour on their MixPre or other pre-amps?

Title: Re: MixPre problem?
Post by: mepaca on June 02, 2011, 03:19:31 PM

My mixpre goes for about 6 hours with 48 volt phantom power on using 2 energizer lithium AA batteries.

Title: Re: MixPre problem?
Post by: sokiN on June 02, 2011, 03:33:31 PM

I suppose this means I have to check what's wrong with mine...

Title: Re: MixPre problem?
Post by: Teen Age Riot on June 03, 2011, 12:06:16 PM

Did you contact Sound Devices? Their customer service is great, from what I hear.
I have an MP-2 which as you probably know is quite similar to your preamp. It has never behaved like that.

Title: Re: MixPre problem?
Post by: sokiN on June 04, 2011, 04:33:25 PM

I haven't contacted them yet, but I will. I'm just a little busy these days.
So far I've mostly used my MixPre with a Rode NTG3 for some short films and I hadn't realised the problem that arises in the second channel.

Title: Re: MixPre problem?
Post by: goodcooker on June 08, 2011, 02:59:30 PM

I had a MP2 for a while and the levels would drop as the AA batteries drained but not at different levels on the two channels. I agree on trying an alternative power source or trying a different type of battery before seeking out repairs.

Title: Re: MixPre problem?
Post by: SmokinJoe on June 09, 2011, 05:12:58 PM

Some basic troubleshooting ideas...

You can run the NT4 off a battery just fine.  A friend of mine does it that way all the time.  Try it with the battery in the NT4, set it up at home and let it run a while.  Does it actually post pone the issue as you suspect?

Also, once the problem starts, what happens when you switch Left and Right cables running into the preamp?  If the problem moves, that implies something with mic/cable before the pre.  If the problem still stays in the same channel, it's preamp > recorder.

Title: Re: MixPre problem?
Post by: sokiN on June 09, 2011, 05:54:18 PM

I've tried running the NT4 off a battery and it does postpone the problem. I can't tell the difference either, but I should mention that I haven't run any proper listening tests.

I've switched cables and the problem stays in the same channel so it's not a cable issue. Im also pretty sure it's not the recorder since I can hear the difference between the two channells when I'm monitoring using the MixPre's Headphone output.

During the weekend I'll buy some new batteries both for the NT4 and the MixPre and we'll see how much recording time I can get with no issues.

Thank you all for the responses-suggestions