Topic: Tascam DR-70D 4-channel audio recorder (Part 6)

[voltronic]

^ ^^ ^^^ Yeah, I have to agree it's probably a much better idea to just return that card and get an approved one, but from a major / authorized dealer so you know for sure their stock is legit.  I was trying to help you with the test procedure, but it's probably going to confirm what we already expect - that it's no good.  No point wasting your time any further.

[Life In Rewind]

Just the rush of living dangerously by using an unapproved card!

hey man, for some of us - that's the only buzz left!!!

[F.O.Bean]

Bean:

I don't know why you're insisting on tempting fate. Use one of the approved cards from Tascam's list!!!

I know, I'm going to definitely go with that 64gb Sandisk Extreme Pro! It is ONLY $20 more But I have used PNY cards for about a year now with flawless results[on BOTH of my 70d's], so I just wanted to stick with what was already working! I'm POSITIVE that if I got another PNY card, but this time from Amazon[since PNY sells the cards directly on Amazon! No chance for a fake!], Id have ZERO problems! But like you guys said, why tempt fate? Even if a new PNY card only fucks up ONCE, that's one too many times for me Might as well use an approved card and be DONE with it, because I do not want to deal with returning ANOTHER PNY card

Thanks for the advice guys, and confirming my beliefs to get that Sandisk Extreme Pro card

P.S.-Sounds like I need a newer generation card reader too! I think that's the issue with Crystal Disk and why it won't even finish the writing tests! I'll probably grab one today or tomorrow, just so I know my cards can read as fast as they can when transferring shows to my PC I'll probably just hit up Wal-Mart or somewhere easy!

[2manyrocks]

This article on cards is worth reading. http://thewirecutter.com/reviews/best-sd-card/

They did a test to see how fast cards will record photos shot in burst mode by recording the shutter and comparing the waveforms.  They are recommending a Samsung pro + (plus) card.  It isn't on the tascam list to my knowledge, but I wonder why a card like that wouldn't work in the 70d?

[F.O.Bean]

This article on cards is worth reading. http://thewirecutter.com/reviews/best-sd-card/

They did a test to see how fast cards will record photos shot in burst mode by recording the shutter and comparing the waveforms.  They are recommending a Samsung pro + (plus) card.  It isn't on the tascam list to my knowledge, but I wonder why a card like that wouldn't work in the 70d?

Maybe the cards trying to writre faster than the stream getting written to it

[voltronic]

This article on cards is worth reading. http://thewirecutter.com/reviews/best-sd-card/

They did a test to see how fast cards will record photos shot in burst mode by recording the shutter and comparing the waveforms.  They are recommending a Samsung pro + (plus) card.  It isn't on the tascam list to my knowledge, but I wonder why a card like that wouldn't work in the 70d?

It very well might work, but Tascam didn't test it so we don't know.  Unless someone is feeling lucky...

Either way, burst photos are writing to a card in a very different way than audio recording.  Manufacturers optimize performance for this kind of data burst writing and that's what the "headline" speed is likely based on.  Multiple continuous streams (as in audio recording) may or may not  be a priority, so the performance could be quite different.

The other thing is that good cameras will have a large and fast buffer for high resolution photos and HD video.  A dedicated audio recorder probably has a smaller buffer, which would make the performance of the card itself even more a factor.  Taking that point further for this recorder, when the card issues started up a few of us suggested that the 70D may have less buffer memory than other 4-channel recorders, and that causes it to only be compatible with a smaller number of cards.  No way to know if that's really happening here unless someone wants to tear down a bunch of recorders and compare the memory chips on a bunch of different recorders.  That is, if it even uses a separate memory chip; it might have buffer memory as part of another chip package.

An interesting point from that article is that they used a USB 3 reader for testing since newer cards can exceed USB 2 speeds.

[morst]

But like I said, I'm PRAYING that my new 64gb PNY keeps working out flawlessly in my old 70d! I'll keep everyone posted!!

Keep praying! And praying, and praying and praying... Until Tascam lists it on the approved list, you'll be needing to pray continuously that this card won't fail soon.

Just the rush of living dangerously by using an unapproved card!

hey man, for some of us - that's the only buzz left!!!

Perhaps you should consider sobriety!? 

[2manyrocks]

This article on cards is worth reading. http://thewirecutter.com/reviews/best-sd-card/

They did a test to see how fast cards will record photos shot in burst mode by recording the shutter and comparing the waveforms.  They are recommending a Samsung pro + (plus) card.  It isn't on the tascam list to my knowledge, but I wonder why a card like that wouldn't work in the 70d?

It very well might work, but Tascam didn't test it so we don't know.  Unless someone is feeling lucky...

Either way, burst photos are writing to a card in a very different way than audio recording.  Manufacturers optimize performance for this kind of data burst writing and that's what the "headline" speed is likely based on.  Multiple continuous streams (as in audio recording) may or may not  be a priority, so the performance could be quite different.

The other thing is that good cameras will have a large and fast buffer for high resolution photos and HD video.  A dedicated audio recorder probably has a smaller buffer, which would make the performance of the card itself even more a factor.  Taking that point further for this recorder, when the card issues started up a few of us suggested that the 70D may have less buffer memory than other 4-channel recorders, and that causes it to only be compatible with a smaller number of cards.  No way to know if that's really happening here unless someone wants to tear down a bunch of recorders and compare the memory chips on a bunch of different recorders.  That is, if it even uses a separate memory chip; it might have buffer memory as part of another chip package.

An interesting point from that article is that they used a USB 3 reader for testing since newer cards can exceed USB 2 speeds.

^I didn't see it mentioned in the Wirecutter link, but another review of the Samsung Pro Plus card mentioned "large block transfers" as an evaluation criteria, but didn't explain what that is.   There has to be a common technical reason why some cards made it on the approved list but other cards didn't.   It's a puzzlement to me why a card may be fine for recording 4k video, but may not work in the 70d?   If we understood what that reason is, then perhaps we could intelligently choose from a wider ranger of cards for the 70d than the approved list without resorting to rolling the dice.     

[voltronic]

On sale for $200 after coupon right now:

http://taperssection.com/index.php?topic=177134.0

[aaronji]

SD card speed ratings are based on continuous write speeds.  Most cards should be able to do audio, even 4-channel 24/96, with absolutely no problem.  I would also point out that if the card reader plays a prominent role in the benchmarking of cards, then those results (and tests) are meaningless...

[voltronic]

SD card speed ratings are based on continuous write speeds.  Most cards should be able to do audio, even 4-channel 24/96, with absolutely no problem.  I would also point out that if the card reader plays a prominent role in the benchmarking of cards, then those results (and tests) are meaningless...

The card reader should only be a factor if it's a bottleneck - that is, its maximum transfer rate is slower than the card can go.  The same goes for the bus it's plugged into (USB 2.0 vs. 3.0).

Clarification to the bold statement above:

Speed Ratings are based on the maximum burst data read/write rate, which would come into play mainly in photo applications like the test 2manyrocks linked.  That is going to be the max read speed; the write speed will be much slower.
Speed Class is a minimum continuous data rate, and is usually close to the card's write speed.  So this means for audio (and video) recording, the Class is much more relevant than the Rated Speed.  You may have meant that anyway, but people use these terms interchangeably sometimes and don't realize they're different things.

http://kb.sandisk.com/app/answers/detail/a_id/1996/~/difference-between-speed-class,-uhs-speed-class,-and-speed-ratings
https://www.sdcard.org/developers/overview/speed_class/

Now the question is: why should some Class UHS-I or UHS-3 cards not work for audio, when on paper they should be able to handle the data rate easily?  Specific models in a series work; others do not.  Clearly, there's more going on here than the factors we're discussing, but relatively little info out there testing cards in audio recorders.  All of the tests you see are for photo and video.  As it stands right now, we have to rely on manufacturer recommended media lists - that's your only safe bet.

[aaronji]

^ I meant whatever metric is listed on the card.  "Speed Class designates minimum writing performance to record video. The Speed Classes defined by the SD Association are Class 2, 4, 6 and 10.", per sdcard.org.  Those.  There is really no question as to why some cards don't work for audio in the DR70D, which is that there is a design flaw n the recorder.  These cards seem to work fine for audio in most any other recorder.

As for the reader, a couple of people posted that they noticed decreased performance with some, which suggests that they are slower than the card (or other reader)...

 

[mfrench]

I'm probably going to answer my own question while asking it,.....

I know that the unit requires 1 amp of power, or 5 watts.  Is this sufficient to run at full compliment of phantom power, full usage?
Or would I be better off running at the 2 amp battery pack output?
FWIW, I'm running the USB Power Bank battery.

I ask, because the new USB cable fits better to the 1 amp output on the battery.

[voltronic]

Here's how I understand it: The 1 vs. 2 amp outputs on a battery means that's the current that output can supply, but only if that current is demanded.  Something attached to the higher amperage output has to be "asking" for that much current for you to get an actual 2A electrical flow.  For instance, recent phones will pull 2A to charge off of that output.

For the 70D, I don't think there's any harm in connecting it to a 2A battery output, but probably no benefit either.  I only ever use the 1A output on my battery, even when phantom powering 4 mics.

[mfrench]

Thanks.
I've always used the 2 amp output, even in transferring cassettes to digi-realm.  But, as I said, ergonomically, the fit to the battery is better to the 1amp output; less bends.
thanks, Volt.