Topic: Can someone help identify what happened here?

[achalsey]

I've been having all sorts of issues with this recorder but don't have the money to buy a new one at the moment so am kind of stuck with it.  Good news is it generally works, but last night I noticed a new problem I hadn't seen before.

Halfway through the third band of the evening I checked the levels and noticed two channels were jumping very strangely.  I was running AKG 63s > Naiant Couplings (actives) > Naiant PFA > Tascam 680 (channel 3/4, line in, phantom on).

It seems to my very uneducated guess that the phantom power seems to die at regular intervals.  Kind of turns off and back on.  Does this seem like a 680 issue?  PFAs failing?  After I noticed it I switched the phantom off and on again, didn't do anything.  Unplugged/reconnected the cables, no difference.  I'm pretty sure its the recorder since it happened in both channels at the same time. 

I've been running channel 3/4 with phantom on fairly often and haven't seen this before.  Luckily the mics that had the issue were kind of my "back up" for the evening, so I didn't lose anything important, but it is very frustrating.  I'll have to do some more tests.

https://soundcloud.com/achalsey/sample

http://www.mediafire.com/listen/gervhut7bvmgvh6/sample.wav

[F.O.Bean]

Hmmm, thats very starnge looking man?!?!?! I noticed you said you ran channels 3/4 LINE-IN, Phantom ON. Why did you run LINE-IN with Phantom ON?!?! Is that what people do with their 680s?

Like you said, it goes from fine levels, to BAM, total weirdness. I honestly have no clue other than I do agree with you, and think its a Phantom thing too. Just have no idea WHAT its doing?!?!?!

[achalsey]

Added a mediafire link.  I've never really used it before so hopefully that will work.

http://www.mediafire.com/listen/gervhut7bvmgvh6/sample.wav

[drewloo]

I've had a similar problem happen to me w/ my 680 a couple of times when I tried running mbho 603A's into the 680.  The sound just stopped about every 3 seconds for a fraction of a second.  I talked to the head repair guy at Teac/Tascam (can't remember his name now) and asked him what the max mA phantom the 680 will supply and he gave me some jibber-jabber about how I couldn't/shouldn't expect the 680 to conform to the DIN standard.  I said my mics use around 5mA, not 10mA, but he was so dismissive and condescending that I had a hard time talking with him.  I then asked why Tascam redesigned the circuit board--was it related to phantom power supply?--and he got defensive saying that manufacturers redesign circuit boards all the time.      My gut feeling was that the phantom supply on the 680 is marginal at best and since then I have always run an mp-2 behind my mbho's when using the 680.  Never had the problem w/ my mc930's or vm44 classics, though.

[achalsey]

Huh, interesting.  Thanks for the info.

[drewloo]

You bet.

[achalsey]

Okay, thanks Jon.  Yeah, because of how the issue has affected both channels I assumed it wasn't a problem with the Naiant system, but didn't want to necessarily rule anything out.

[hi and lo]

I think this is exactly the same problem that has been widely reported when the DR-680 overheats. Obviously, it's summertime, but you didn't mention about temperatures. What was the ambient temp, was the unit in direct sunlight, and did you feel that the unit was warm/hot to the touch, particularly in the bottom right corner near the external DC input?

It's definitely not the PFAs.

[achalsey]

Is this that issue?  I was inside and it was night, so room temperature wasn't overly hot, but was pretty warm.  I did not check the machine, but the battery powering it was hotter than I'd ever felt it before.  Also had a V2 in the bag, which can get quite hot.

I'll keep an eye on the temperature for next time.  Running tonight outside, so will test it out some more.  I did buy a cheap portable fan for this exact reason, but haven't put it to use yet.