Not all SD cards are equal. The Portastudio DP series, like a lot of small market devices, can be a little picky about which SD cards work and do not work with it (just be glad you aren’t trying to find a SD card for your Blackmagic movie camera) There are a number of different make and models of SD cards out there. Only some will work with the DP series of Portastudios without problem. SD cards tend to be designed to dump or read a lot of data at once (not both at the same time). The Portastudios, on the other hand, need to be able to read a moderate amount of data (up to 4.6 megabytes a second) while writing a moderate amount of data (up to 1.2 megabytes a second). Not all cards can handle this, even if they are rated, say, to write 10 megabytes a second. The only way we can see if a card works is via empirical testing. Tascam has a list of cards that work with the DP-32SD but the list only lists some models readily available in Japan. SanDisk is the most popular brand; it’s low cost but has high performance (other users have used Lexar or other brands without problem, but SanDisk has been the most widely used). Based on the experience of users here, the only SanDisk brand which will always work without issue is the Extreme Pro line of cards. In particular, there are no reported issues using a number of generations of 32gb (and no bigger) SanDisk Extreme Pro cards; people have recorded entire albums on 2016 or the more recent 2018 vintage of these cards without issue. So, get the latest 32gb SanDisk Extreme Pro card. Other brands, of course, will also work, but we know the SanDisk works. Read the rest of this post to understand my reasoning behind this choice for a DP Portastudio card. (And, no, I have no relationship to SanDisk except as a customer who hasn’t had issues with their cards) Use a 32 gigabyte card The first thing to remember is this: Do not attempt to use a 64gb, 128gb, or 256gb card with a DP-24SD/DP-32SD. The highest capacity which will work is 32gb, because anything bigger than 32gb uses a technology called SDXC which the DP line of Portastudios do not support. Yes, I know, Tascam does list a single 64gb card as being compatible with the DP-32SD, but both MJK and myself are convinced, based on our own testing with 64gb cards, that this is a typo. Card speeds: Theory and practice In theory a class 6 (or class 10) card is fast enough to record and play back 32 tracks of 24-bit 48 khz digital audio (4.6 megabytes second; class 6 can handle 6 mb/second and class 10 can handle 10 mb/second). In practice, SD speed ratings are designed for digital cameras, where we are not reading and writing at the same time, so a card rated to be able to write 10 megabytes a second (or read 45 megabytes or even 100 megabytes a second) may not work reading 3.5 megabytes a second while writing 1.2 megabytes a second (i.e. eight tracks at 24-bit 48khz while playing 24 24-bit 48khz tracks) at the same time. This in mind, the only way we can know if a given card works is via empirical testing. That’s undoubtedly how Tascam makes their compatibility chart: They put a card in; record 24 tracks, then try to recording eight more tracks while playing back 24 tracks, followed by playing back all 32 tracks at once. People usually buy SanDisk While Lexar, Samsung, and others make SD cards, most people buy SanDisk cards (since they tend to be cheaper with the same speed ratings), so that brand is what has been empirically tested the most by users here (but some users have had good results with Lexar, probably better results than with SanDisk). Understanding SanDisk’s line of cards SanDisk makes several tiers of SD cards. In ascending order of price and quality: Standard (blue cards), Ultra (silver cards), Ultra Plus (also silver), Extreme (gold), Extreme Plus (also gold), Extreme Pro (Black with gold letters), and finally the very expensive Extreme Pro UHS-II cards. SanDisk also makes white high endurance cards designed for dashcams and other security cameras, where there are more temperature extremes and write cycles than other use cases; I have not tested these, since SanDisk only announced a U3 high endurance card this year, and that card has not been released yet. Use the SanDisk Extreme Pro In our experience, and in the Tascam compatibility matrix, anything below Extreme Pro sometimes has problems. Extreme can (and in my case, has) worked if the capacity is higher, but MJK had an issue using an Extreme card in his DP-32. I have never had an issue with a older 2016 vintage SanDisk Extreme Pro U3 95 megabyte/second card, and I have recorded most of an entire album on it. I will frequently record four tracks at a time while playing up to 28 tracks at a time (four tracks: A stereo synthesizer and its reverb). In addition, I have just run a 30-second stress test with the current SDSDXXG-032G-### card (the one I link to at the top of this posting) and had no issues. I, over three passes, recorded 24 tracks of 30 second silence. I then went back and recorded another 8 tracks of 30 second silence while playing back the 24 tracks of silence. The DP-32SD did not report any read or write errors when running this test, which gives me confidence this card can handle a complex song without problem. This is a card I bought from B&H. Tascam has also never seen an issue with a SanDisk Extreme Pro card, so if going the SanDisk route, I suggest using an Extreme Pro or better. Considering that 32gb Extreme Pro cards are only $14 right now, and are big enough for an entire album (115 minutes if using all 32 tracks at once, more if making songs using fewer tracks — keep in mind that one needs some free space for Audio Depot exports), I don’t see any point in taking chances with more inexpensive cards. Likewise, I don’t see the point of getting the $60 UHS-II Extreme Pro card, since one is paying four times more when the more inexpensive $14 Extreme Pro card works fine. Be careful of counterfeits Another thing to keep in mind is to buy from a reputable dealer. There are a lot of sellers on eBay and what not who will sell a counterfeit card which will not work. This is why I usually post B&H links; while Amazon directly sells the current 32gb SanDisk Extreme Pro card (the counterfeit issues on Amazon usually come from third party sellers), the chance of getting a counterfeit when buying direct from B&H are next to nil. I will not buy a card from eBay, even though I could get the Extreme Pro for $12 instead of $14 there; there’s too much danger of getting a counterfeit card. Why 32gb may be going away in a few years When SanDisk updated their Extreme Pro line to have 170mb/second read (instead of 95 megabyte/second read) speed, they did not update the 32gb SDHC card. This indicates that SanDisk is no longer expending R&D on the 32gb capacity cards, which is probably the first sign of them phasing out and no longer making these cards. This is why I recommend getting four or five cards right now, while it’s still possible to get them brand new at a great price from a reputable dealer. (This is just speculation; maybe they froze this card simply because they don’t want to break compatibility, and consider 32GB a line where legacy compatibility is more important than trying to squeeze more speed out of the card) Indeed, reviews of the only 2gb pre-SDHC card B&H still sells indicate the quality of these older cards is going downhill (one guy ordered six and got two bad apples); SDHC cards will eventually decrease in quality as everything except Portastudios moves up to SDXC.