Topic: TASCAM DR-680 portable 8-track #6

[Chuck]

I will be testing one in my DR-680 tonight.

[yltfan]

I will be testing one in my DR-680 tonight.

Look forward to hearing the results, Mr. Guinea Pig!

[Chuck]

I have no reason to doubt that they will work. Lexar is an established name in SDHC cards. The cards I got were delivered in professional packaging. I have already checked the storage volume of the cards and they are all the proper size.

I'll report back if I have any troubles with them.

[Chuck]

I have no reason to doubt that they will work. Lexar is an established name in SDHC cards. The cards I got were delivered in professional packaging. I have already checked the storage volume of the cards and they are all the proper size.

I'll report back if I have any troubles with them.

Update:

Those Lexar SDHC cards work fine.
I used one in my DR-680 last night, recording 6 channels each for four bands over the course of 6 hours. No problems.
I also put on in my Lumix camera and took 200 pictures and it work great in that application as well.

[Gutbucket]

Error log-

Had the 'fluctuation' problem arise weekend before last-  the cyclic gain 'pumping' which begins with a fast momentary level bump, followed maybe 15 to 30 seconds later by a level dip and smaller bump every few seconds across all channels until the recording is stopped.  This is the typical manifestation of the suspected over-heat field problem, perhaps facilitated by providing only the minimum 9V from an external battery (that’s never been confirmed, and is only my personal suspicion).

It happened for 2 sets out of about 12 recorded over the weekend at a 4 day Americana festival, specifically day 2 of my 3 days of taping. Two late-afternoon/early-evening sets affected both approximately one hour & 15 minutes into the recording.  I did not realize it at the time and only discovered it on playback.  Deck was either simply stopped or powered down for a while between each set.  Whether I just stopped or powered down before, between and after these two sets I can't recall.  I can probably tell by looking at the time stamps on the files and checking if there was a file recorded during the intervening soundcheck.  The final two sets of that day were not affected, nor were the two sets recorded the final day.

Temperature was warm but not hot, sunny shorts and T-shirt weather.  Gorgeous day.  Recorder was in its tight-fitting Tascam protective case, placed in a moderately large soft-sided cooler bag along with DVD batteries, wiring, a couple PFAs and a second rig consisting of a DR-2d, plug-in-power preamp and external lithium battery, none of which run hot.  DR-680 was the only primary source of heat inside the bag. Lid was unzipped but closed loosely and I threw a t-shirt over it to keep the sun from shining directly on the bag. 

Phantom power was on for all 6 channels- Microtech Gefells in 4 channels, Naiant PFAs powering DPA 4061s in the other 2.

I did reach in at some point over the weekend (probably that afternoon) and notice that the underside of the deck was hotter than normal.  Looks like I’ll need to provide additional ventilation next time.  One new data point on this phenomenon- the cyclic dip rapidly moves across all channels in something akin to a wave.  I noticed this because these are surround recordings and on playback the manifestation of the distortion sort of wraped around the room.

Unfortunately affected something like the last 15 minutes of Sam Bush Band and Del McCoury Band (or as Del says Bill Monroe used to pronounced it- “Dale McCurry”)

[Gutbucket]

So the post above was mostly an informational heads up to other users, with an known work-around ( keep it cool)..

On my active problems list, I’m still hoping someone might have insight on a way to do this-

Anyone try transfering files back onto an SD card from a computer for multichannel replay on the DR-680?

I've tried copying the compete directory structure from a card to the computer and back without otherwise editing anything, including the MUSIC and UTILITY folders and the dr-680.sys and dr-680.tak files in the root directory, but the machine doesn't recognize the files.  If I then select the folder containg the wav files and execute a REBUILD operation the machine will recognize and play the files, but only sequentially as individual tracks, not simultaneously as mutichannel files which is what I'm looking for it to do.

bump.

[fsulloway]

Error log-

Had the 'fluctuation' problem arise weekend before last-  the cyclic gain 'pumping' which begins with a fast momentary level bump, followed maybe 15 to 30 seconds later by a level dip and smaller bump every few seconds across all channels until the recording is stopped.  This is the typically reported manifestation of the suspected over-heat field problem, perhaps facilitated by providing only the minimum 9V from an external battery (that’s never been confirmed, and is only my personal suspicion).
Unfortunately affected something like the last 15 minutes of Sam Bush Band and Del McCoury Band (or as Del says Bill Monroe used to pronounced it- “Dale McCurry”)

were you running 9v or 12v?

[Gutbucket]

9V

Not to rehash the whole thing again, but the consensus is that this problem is heat-realted, not 9V related. 

My lingering thought is that a higher volatage supply such as 12VDC might postpone onset though not prevent the manifestation.  I simply want to manage the issue in a practical way to prevent it's occurance when likely and wonder if a bit more voltage might reduce current demands and make a difference.  It may not make any difference, or it may make it better or worse.  It's nothing more than speculation.

The known preventive measure to is to better ventilate the deck, and to stop recording and preferably power down between sets to let the deck cool and to stop the problem and reset things if it does happen.

Mine has been fed nothing but a steady diet of 9VDC DVD-battery power backed up with the internal AA's since birth.  I think I used the AC supply once.  The AA's in the deck were dead by that afternoon but I didn't get a chance to change them out.  I checked to make sure and after that was simply careful to make sure I did not need to hot-swap DVD batteries during a set.

[fsulloway]

I wasn't trying to start that whole thing up again, just curious. I'll be running in some warm/hot weather soon enough so hopefully there won't be any issues.

[Gutbucket]

A few all day warm weather festival tips-

Keep it cool with shade and good ventilation (had it shaded, was lacking in optimal ventilation).
Stop and start a new recording at the end of each set. 
Power off between sets instead of simply stoping recording and switching off phantom.
Keep an eye on it during warm mid-day sets over an hour long.  If you notice the cyclic fluctuation happening (or hear it though headphones if your monitor while recording) stop the machine and restart the recording, provide increased ventilation and maybe fan the machine with forced air for the remainder of the set.

[bdasilva]

I recorded this weekend and ran into the same problem... i took the unit out of the case... in the corner on the bottom it was very hot  I turned it over and set my iced drink over the spot... we.re talking Phoenix Arizona... maybe a non wet coldpack for in the bag...

[Gutbucket]

Yeah I was considering something like that.  Unfortunately the humidity here in FL makes anything cold turn rapidly wet with condensation, and would only work for a while, but might be a good short-duration strategy out there in the dry desert.  A couple of those first-aid cold compress packs that chill down once you crush them may be a good idea to keep in the bag to remedy the problem once it happens I guess.

I'm thinking that adding a large passive heat-sink might be the best solution if it works.  I might grab a piece of 1/4" aluminum plate out of the scrap bin at work, shear it to basically the same dimensions of the recorder and place it directly underneath.  I should probably loose the form fitting case, or at least open up the bottom of it around the power supply board hot zone area, but I like the protection it provides.  Maybe I can fit the aluminum plate inside the case. 

Anyone know of any sort of thermal transfer conformal pad, or even some sort of gel which won't make a total mess of things like traditional thermal paste?  Might not be necessary for sufficient heat transfer to the large surface area aluminum plate, but woudn't hurt.  Thinking something like a metalized foam pad or sponge thing might exist out there somewhere.

Thinking out loud though my fingers here..

[lukpac]

Has anyone from Tascam confirmed that that amount of heat (and the issues associated with it) is normal?

[Chuck]

I looked into then abandoned the gel type laptop heat sinks. I now have a 12v fan I pulled from an old computer. I put velco on it and the bottom right of the recorder. It works, but it does make noise. I haven't been in a situation yet that it was too noisy. But, I've only ever used it three times.

Actually all this talk about that problem has got me re-thinking what to do this summer. If anyone comes up with a good solution, I'd love to hear it.

[Gutbucket]

Question for those of you who've felt up the 680's hot bottom , how localized was the heat in the bottom right corner?  Hot there and considerably cooler across other sections of the bottom of the machine?

After some searching there are conformal heat transfer pads (usually soft silicone/ceramic compounds, sometimes called T-pads) designed to fill air gaps in the interface between a heat producing component and a metal heat sink which appear to be much cleaner than thermal grease.   I can't tell if they remain intact or melt and make a mess once applied and are for one-time application only, apparently some are designed to melt in place during the first heat cycle which would not be good.  Many of them seem to have peal-and-stick adhesive on one side so they could adhere to the aluminum plate and hopefully the other side would conform to the contours of the bottom of the DR-680 but only stick to it very lightly, or just conform and not stick at all.  If so, something like that might work.

I'd guess PC builders on this board may be familiar with that stuff.

Checking out the 3M offerings..

Hmm, they also have Heat Spreading Materials, basically copper or copper and aluminum based confromal tapes with thermal adhesive and a black or copper colored top surface.  That could do the job on it's own, eliminating the need for the aluminum plate heat sink, simply adhering to the bottom of the recorder itself and spreading heat across a larger area of the bottom surface more evenly.  May stick permanently and become a permanent mod to the machine.

http://solutions.3m.com/wps/portal/3M/en_US/Electronics_NA/Electronics/Products/Product_Catalog/~?N=7234426&rt=c3

3M™ Heat Spreading Materials are designed to provide excellent in plane heat spreading for quick heat dissipation on a preferential heat transfer path between heat generating components and designated cooling devices such as heat sinks, fans, heat pipes and metal frames.

Our heat spreading tapes provide robust mechanical strength with good long term stability at higher temperatures, making them ideal for applications such as spreading heat from hot spots on backlights, batteries or PC boards.

Might have to open the case and take a look.  Maybe the answer is a conformal T-pad on the inside plus the heat dissapating tape on the outside of the case.  I'd really like to find a simple passive solution which lets me rest easy in these situations and doesn't require a fan.