Topic: DAT transfer equipment 2024

[bonghitwillie]

fostex 5d is the best dat machine ever made. easy to take the cover off and clean the drum head if necessary. play that into a tascam da-3000. play everything into the da-3000.

[DSatz]

One thing that I wonder about in all this is pre-emphasis. All the Sony portable DAT recorders, like the PCM-F1-type recorders before them, recorded with a prescribed 10 dB shelving treble boost with inflection points at 3.183 kHz and 10.610 kHz (50 and 15 μsec "time constants"). This helped overcome the noise of early A/D converters. The recording on tape, and the S/P-DIF data stream coming out of the digital output on playback, had a flag bit set, which indicated that any playback equipment needed to correct this pre-emphasis by rolling off the treble according to the inverse of the same curve.

But this flag bit has no counterpart in a .wav file, the practice has faded out as converters have improved over the decades, and with that, awareness of the issue has faded as well. If you transfer a pre-emphasized recording to a .wav file, you need to be clearly aware that it's been treble-boosted by some 10 dB in the top 2-3 octaves, and deal with it accordingly. You could burn audio CDs from that data and set the pre-emphasis flag in the process; any proper CD player should see that flag and engage its de-emphasis circuit to give you back the original sound. (They do not all do so equally well.) Or there are programs that can remove the pre-emphasis from a .wav file, a process which should give you most if not all of the originally intended noise reduction effect; that's how I prefer to handle my old PCM-F1 and DAT recordings; it's closer to being foolproof.

But if you (or someone else in the future who may not know that this issue even exists) simply play(s) back pre-emphasized wave audio data without de-emphasis, it will be bright/harsh sounding relative to the original signal. I was surprised to read this thread without seeing any reference at all to this issue. It needs to be handled judiciously.

[GLouie]

Gee, Dsatz, you ask for people to know what they are doing!
I'll also note that my experience is that DAT preemphasis was abandoned fairly early, but not all decks have the playback deemphasis even available (like SV3700-3800). As Dsatz notes, the DAT digital output will have the preemphasis. At least Sonys will light up an indicator to tell you, but the decks I've seen only do the deemphasis on the analog outputs.

Computer CD drives have a similar problem, some don't recognize the emphasis bit at all so analog and digital outputs still have the preemphasis.

[robgronotte]

If you played the DAT back in the same type deck it was recorded on would it not correct for that while playing? Or does it only correct to the analog output and not the digital?

What program do you use to remove the pre-emphasis?

[goodcooker]

10 dB shelving treble boost with inflection points at 3.183 kHz and 10.610 kHz

But if you (or someone else in the future who may not know that this issue even exists) simply play(s) back pre-emphasized wave audio data without de-emphasis, it will be bright/harsh sounding relative to the original signal. I was surprised to read this thread without seeing any reference at all to this issue. It needs to be handled judiciously.

Seems like a 10 dB treble boost would be very bright sounding. I've transferred 100s of tapes recorded on Sony portables and never run into this "issue". Not once. Maybe the deck I'm using is doing the lifting same as all the other folks who don't have any issues.

[grawk]

10 dB shelving treble boost with inflection points at 3.183 kHz and 10.610 kHz

But if you (or someone else in the future who may not know that this issue even exists) simply play(s) back pre-emphasized wave audio data without de-emphasis, it will be bright/harsh sounding relative to the original signal. I was surprised to read this thread without seeing any reference at all to this issue. It needs to be handled judiciously.

Seems like a 10 dB treble boost would be very bright sounding. I've transferred 100s of tapes recorded on Sony portables and never run into this "issue". Not once. Maybe the deck I'm using is doing the lifting same as all the other folks who don't have any issues.

I've also never run across a dat with pre-emphasis encoded on it.  I'd really only expect it to be at all likely from recordings from the 80s.

[GLouie]

Only the first few years of DATs even had emphasis. At least the first Sony PCM2500s had it as a switchable option during recording, with an indicator in playback. Later Sony models did not seem to offer it for recording, but kept the playback indicator showing the deemphasis filter was in use on analog output when the bit was set.

I got burned a few times before figuring out our early portable DAT, a Teac DA-P20 (AKA Casio DA-7), used emphasis and never mentioned it. Playback on a Sony would show that, but none of our Panasonics (SV3700-3800) would. I can't remember now, but it's possible the Panasonics didn't even have deemphasis, even on analog.

Here's a pic of the CD/DAT curve. If you search, I've seen a tabular chart version, too. You should be able to estimate it with a DAW, or there is probably a plug-in. I think this graph is from the Red Book.

[Melanie]

Glad I waited until the early '90s to get a DAT deck. Bob

[goodcooker]

there is probably a plug-in

Waves Q10 (the plug in) has a preset for this and other types of corrective EQ curves for various needs.

[H₂O]

I see the sound devices 702 can record at 32khz (the good old DAT long play setting). Are there other recorders (preferably with Sd card) with coax input that can handle that? I have a bunch of dat tapes in 32khz…

Over the years oflooking into this questions I only found two portable recorders that support 32Khz input:
- Creative Labs  Nomad JukeBox 3 (built in hard drive) - what I used  10+  years ago
- Sound Devices 7xx series - I would look into now


Other wise  look into a  sound card  solution

[rowjimmy]

I see the sound devices 702 can record at 32khz (the good old DAT long play setting). Are there other recorders (preferably with Sd card) with coax input that can handle that? I have a bunch of dat tapes in 32khz…

Over the years oflooking into this questions I only found two portable recorders that support 32Khz input:
- Creative Labs  Nomad JukeBox 3 (built in hard drive) - what I used  10+  years ago
- Sound Devices 7xx series - I would look into now


Other wise  look into a  sound card  solution

Dug up my Nomad not too long ago and it still boots up.
Sadly, I've no way to transfer audio from it.

[robgronotte]

I see the sound devices 702 can record at 32khz (the good old DAT long play setting). Are there other recorders (preferably with Sd card) with coax input that can handle that? I have a bunch of dat tapes in 32khz…

Over the years oflooking into this questions I only found two portable recorders that support 32Khz input:
- Creative Labs  Nomad JukeBox 3 (built in hard drive) - what I used  10+  years ago
- Sound Devices 7xx series - I would look into now


Other wise  look into a  sound card  solution

I just found a description of the SD-702, and it says "PCM audio at 16 or 24 bits with sampling rates between 32 kHz and 192"

But DAT long play mode is 12 bits. Are you certain that it can handle the format?

[Scooter123]

I just transfer those DATs via analog.  I doubt anyone could audibly tell the difference. 

[robgronotte]

I just transfer those DATs via analog.  I doubt anyone could audibly tell the difference.

Probably not, but digital copying would be easier and probably less likely to have transfer issues.