I am new here...hi! I came upon this forum researching issues with the DR-70D recorder. I recently purchased one and am having trouble. I bought it based on my great experience for 4 or 5 years with my DR-05 and the great reviews I saw on Amazon and Sweetwater. Wish I found this thread before I bought it.
I am using mine to record 4 channels out of my mixer when my music duo performs. The first time out with it, I got a file write error during our 3rd set...and it was lost. I got a replacement memory card, same one as the original which was a PNY P-SDX128U395-GE (128 GB high speed class 10 card) and got the same problem when I let it sit and record over night. I use this very same memory card in my Canon HD video recorder with no problems (knock on wood).
Based on the discussion here, I have ordered a card from the approved list from Tascam. Since I see that others have used the PNY card that I tried, I'm not holding out too much hope. We'll see. The card on its way to me is a SansDisk Extreme Pro 128 GB Class 10 card (SDSDXPA-128G-G46).
I wanted to add to this thread what my experience has been. I will report back my experience with the SansDisk card.
If this recorder doesn't pan out, I'll be getting a Zoom H6 to replace it. It will do what I want, though the form factor isn't ideal for me. I will make it work if I have to.
My setup is I am recording 4 channels to mono files at 16bit/44.1kHz. I am using line level inputs using TRS cables. I am feeding it line level signals coming from the direct outs on my mixer for each channel. I am powering via USB and have batteries installed. I am running the latest version of firmware available from Tascam's website. I also formatted the card (the option that takes longer...not the "quick format").
Welcome to TS! About your questions with the DR-70D:
Yes, it's picky with cards. Much hay has been made about that here, and we've never received a definitive answer from Tascam as to why, and probably never will. Long story short, some of us have had good luck with cards not on the recommended media list, while others do not. Cards that
are on the list should be OK.
About the "formatting procedure", I think capnhook was referring to what I and a few others did to straighten out cards that got their filesystem borked in the 70D. This involves mounting the card in your PC and using the official SD Association Formatter and running a FULL (Over Write) format.
Here's a link to it as well as some other flash memory utilities.
Beyond that, it sounds like you were doing the right thing and using the Erase / Full Format, but if the card is simply not compatible, it may not matter. Hopefully you have better results with the SanDisk. FWIW, I don't know if anyone here has successfully used a 128GB PNY with the 70D, but I seem to remember a couple people did have good luck with the 64GB size.
There's a link in my signature to an FAQ for the 70D, and among other things there is an SD Card survey you might be interested in.
Last point - I would encourage you to stick with the 70D if possible vs. the H6. Having used both, I think it's a much better unit overall, especially the quality of the built-in preamps.