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Line level on portable recorders
Old 4 weeks ago
  #1
Gear Nut
 

Line level on portable recorders

I'm looking to hack together a better and more portable sound rig for my (amateur) film making. IMHO, the ADC chips in almost all prosumer equipment are now at a good enough quality that preamps are the bottleneck for cheaper sound recorders. So my requirements are basically:

- cheap (this aint my day job)
- high quality preamp
- small and light (often operating as a one man run and gun)
- two channels are adequate

I found the Dantamix Thatmic pre which looks to be small, light and clean. I can even operate it off 5v so can use a low profile usb battery for power. I planned to put one or two of these in a small box with a DC-DC boost and filtering to provide the necessary phantom power.

All good so far, and my plan is to run this into a decent lightweight portable recorder.

BUT

I've since found that almost none do true line level. Even those with separate line inputs are apparently using the same amp. And at the point where you do have true line level bypass, you are into more professional units with a high cost, bigger size and sufficient preamps anyway.

The only candidates I found which have a decently clean line level are the Sony M10 and the Roland R05, both of which are discontinued and don't seem to have an adequate successor.

If there was an SD Mixpre 2 that would probably work and i could ditch the DIY pre, but the 3 is definitely overkill for me.

Any options I've missed?? I could go all in and try to put an ADC module in my box but even then I'm not sure of any small, cheaper units that accept a digital input.
Old 4 weeks ago
  #2
Gear Nut
 

And as a follow up question... I'm assuming the majority of portable recorders with mic/line inputs engage the line input by simply applying a pad to the mic preamp? So just buying a recorder with the quietest preamp and adding an inline attenuator would be essentially a similar thing?

The Tascam dr-40 and dr-100 have a supposedly "pro" line level input via balanced TRS. But I'm presuming they still just pad the mic preamp? Can't find any schematics...
Old 4 weeks ago
  #3
Gear Head
 
Eric D's Avatar
 

The Tascam DR 680 MKII has excellent preamps and true line level inputs .
It has more inputs and tracks than you need (6 analogue inputs, 1 digital input, 8 tracks), but it is portable and very affordable for such a high quality (less than 500 euros) .
Old 4 weeks ago
  #4
Gear Maniac
 

The Mixpre-3, as the OP says, almost does exactly what he wants in one (extremely small) box: the extra channel is hardly overkill and may even come in useful! The price on the mk 1 models, while still around, is pretty good: I'd grab one while you can, or get a used one. It is a real step up sound and function-wise from, say, a decent battery-powered preamp such as the Mixpre-D plugged into an M10 or similar, with much easier operation to boot.

Cheers,

Roland
Old 4 weeks ago
  #5
Gear Nut
 

I could be wrong but I believe the Tascam DR-100 mk3 has true line level inputs. It's small and not too expensive. The preamps are also pretty good.
Old 3 weeks ago
  #6
Lives for gear
I'd like to register a request to any and all multitrack recorder manufacturers (a pretty safe thing to do here since none will be listening or receptive) to produce a 12 track recorder.

The traditional octo-based thinking of theirs means that I'd need to purchase two sync-locked 8 track units and have more inputs than I need, plus the inconvenience of a linking sync cable with the risks that entails. I know there are standalone recorders such as JoeCo, Cymatic, A&H ICE and others...but they don't have the monitoring capabilities of a Sound Devices, Zoom F series, Tascam.

I guess we finally have a Scorpio SD, but that's overkill for someone seeking 12 input channels....
Old 3 weeks ago
  #7
Gear Nut
 

Quote:
Originally Posted by dogmusic View Post
I could be wrong but I believe the Tascam DR-100 mk3 has true line level inputs. It's small and not too expensive. The preamps are also pretty good.
Yes this was on my list. If I could confirm this I might go for it but so far I can only confirm that the Dr-680 bypasses the preamps.

Once I'm in the price range of the dr-100 though it's not a huuuge stretch to the mixpre-3 so I dunno...

I'm going to built the thatmic regardless as I can use it camera mounted and go straight in to the camera (blackmagic pocket 4k) for those times where it's practical.

I might also get a hold of something cheap with decent pres like a sony pcm A10, run the thatmic through it and rent a mixpre-3 to compare. It might be a fool's errand to run a decent pre through a padded average mic pre but at the end of the day real world tests will determine what I'm happy with in terms of portability and sound.

Thanks for the responses, very helpful.
Old 3 weeks ago
  #8
Gear Nut
 

And for reference, I've had a look at the schmatic for the DR100mkiii. I'm not an electrical engineer but can read the very basics of a schematic and it looks pretty clear that the dr100 mkiii line inputs do pass through the same preamp as the mic inputs. I referenced it with the DR-680 schematic which shows an entirely independent circuit path before the ADC for line level inputs.

The circuit shows that the TRS engages a pad prior to the mic pre. So using a different recorder without line level and an inline attenuator would be, as far as I can tell, physically the same thing.

Last edited by mickdundee63; 3 weeks ago at 11:25 AM.. Reason: Additional information
Old 3 weeks ago
  #9
Gear Maniac
 

Quote:
Originally Posted by mickdundee63 View Post
Once I'm in the price range of the dr-100 though it's not a huuuge stretch to the mixpre-3 so I dunno...

I'm going to built the thatmic regardless as I can use it camera mounted and go straight in to the camera (blackmagic pocket 4k) for those times where it's practical.
If you can stretch to a Mixpre-3, I really think it worth it for your use - esp. as often a one-man-band: one thing to operate only, very small, clear display, great limiters, superb headphone amp, etc. etc.

Cheers,

Roland
Old 3 weeks ago
  #10
Gear Nut
 

Quote:
Originally Posted by mickdundee63 View Post
And for reference, I've had a look at the schmatic for the DR100mkiii. I'm not an electrical engineer but can read the very basics of a schematic and it looks pretty clear that the dr100 mkiii line inputs do pass through the same preamp as the mic inputs. I referenced it with the DR-680 schematic which shows an entirely independent circuit path before the ADC for line level inputs.

The circuit shows that the TRS engages a pad prior to the mic pre. So using a different recorder without line level and an inline attenuator would be, as far as I can tell, physically the same thing.
Where did you find the schematics? Could you post a link?
Old 3 weeks ago
  #11
Lives for gear
 
jimjazzdad's Avatar
Quote:
Originally Posted by dogmusic View Post
Where did you find the schematics? Could you post a link?
I have never seen Tascam schematics for the DR series; I suspect he meant the block diagrams that are in the owner's manual...
Old 3 weeks ago
  #12
Gear Nut
 

Yes, sorry the above is correct, I was looking at block diagrams from the service manuals. There are no values but you can see the signal paths and, for example, the tell tale pad configuration of resistors. I found the service manuals with block diagrams at ektrotanya.com.

More support for the mixpre-3! All roads lead to one path... It really is a great price (probably thanks to Fostex stepping in to their territory) and I could use it as a mobile usb interface as well. I have an apollo twin but sometimes a smaller box with mobile power is so convenient for testing new locations and gear.
Old 3 weeks ago
  #13
Gear Nut
 

Quote:
Originally Posted by jimjazzdad View Post
I have never seen Tascam schematics for the DR series; I suspect he meant the block diagrams that are in the owner's manual...
Okay, thanks. I had seen the block diagrams for the 680 in its manual but there are none in the dr100mk3's manual. But I was able to download at the ektrotanya site.

Sorry about the misinformation. Since on the DR100mk3 you cannot record line-in through the XLR inputs, only through the TRS 1/4" inputs, I assumed they were separate circuits.
Old 3 weeks ago
  #14
My DR70D uses the mic preamp circuits as the line inputs as do most of these devices. The gain is set low and pads are engaged. It's not any different than a low cost analog mixer.
Old 3 weeks ago
  #15
Gear Nut
 

Quote:
Originally Posted by Jim Williams View Post
My DR70D uses the mic preamp circuits as the line inputs as do most of these devices. The gain is set low and pads are engaged. It's not any different than a low cost analog mixer.
Thanks Jim. Do you have any advice on the real world consequences of using the line in with an external pre for field recording? I ask because I've used the DR60D previously and have access to it. I think it's pretty much the same machine in a different form factor?

I found it's preamps pretty decent but as an amateur without a sound guy riding the levels I've sometimes had to boost in post pretty significantly. I wonder if using a clean high gain external pre with something like the dr60d/dr70d or similar would have much of a positive effect on the noisefloor.
Old 3 weeks ago
  #16
Lives for gear
Generalizing here.... when using any recorder which has an external body more than 50% of which is made of plastic (which is many-to-most, these days...) the mic preamp gain is pretty clean for the first 60-90% of its rotary travel.

The hiss and other noise (zipper, hum etc) usually comes in during that last bit of (logarithmic) rotary pot travel....which also holds the majority of the usable gain, especially if you're using a lowish output condensor mic, and especially so for a dynamic or non-active ribbon !

A clean highish output external mic preamp (ideally with a pad included) allows you to run any mic/line input at 0 on the recorder....which means its noise contribution will be effectively of the same order. It doesn't take the recorder's on-board mic-pre out of circuit, but its contribution will typically be truly negligible.

If for any reason your external preamp fails to supply the necessary mic gain, just 'top up the gas tank' by cracking open the onboard pre a fraction, to make up the deficit ! In this way everything upstream of the A-D converter is working within its sweet spot.

This may be technically 'hairy', as a description...but in practice this is how it works in most cases.

As mentioned in the opening line, you can pretty much ignore this when using a Nagra digital recorder containing the Roman numeral 'V' in its designation, and also for any Sound Devices recorder similarly bearing the numeral '7'
Old 3 weeks ago
  #17
THD+noise is mostly determined by the converters used inside. Don't expect much beyond -100 dbu. Noise is dominated by the conversion at line or low gain settings. Analog noise dominates at the high gain settings.

Unless you use a device with a digital input, no outside boxes can overcome the innards on these budget devices. Like Dirty Harry says: "A man's got to know his limitations".
Old 3 weeks ago
  #18
Gear Head
Quote:
Originally Posted by mickdundee63 View Post
More support for the mixpre-3! All roads lead to one path...
Read here please:
http://taperssection.com/index.php?t...009#msg2316009
Old 3 weeks ago
  #19
Quote:
Originally Posted by mickdundee63 View Post
I'm looking to hack together a better and more portable sound rig for my (amateur) film making.
When Zoom announced a few years ago the Zoom F8 that was a massive massive MASSIVE LEAP FORWARD for indie filmmakers when it comes to sound. Not just the sound quality either, but the feature set as well is massively better than anything else we'd ever seen before at that price point.

Since then Zoom has released more recorders in their F Series: F4, F8n, F6.

And Sound Devices has responded to the new very high level of competition from the low end by bringing out their first (and recently, 2nd Generation) generation of MixPre recorders.


If you're an indie/amateur filmmaker then you should look no further than a Zoom F series or a Sound Devices MixPre series.

Nothing else at this price point makes sense! (only reason to look elsewhere is if you're serious about this, or a working professional, and wish to spend more such as: Sound Devices 833, Zaxcom Nova, Aaton Cantar Mini, Sonosax SX-R4+, etc.... or if you're utterly totally broke, then get a Tascam DR60D, but I'd suggest spending the little bit more for a secondhand Zoom F4 instead)
Old 3 weeks ago
  #20
Quote:
Originally Posted by studer58 View Post
I'd like to register a request to any and all multitrack recorder manufacturers (a pretty safe thing to do here since none will be listening or receptive) to produce a 12 track recorder.

The traditional octo-based thinking of theirs means that I'd need to purchase two sync-locked 8 track units and have more inputs than I need, plus the inconvenience of a linking sync cable with the risks that entails. I know there are standalone recorders such as JoeCo, Cymatic, A&H ICE and others...but they don't have the monitoring capabilities of a Sound Devices, Zoom F series, Tascam.

I guess we finally have a Scorpio SD, but that's overkill for someone seeking 12 input channels....
Good news, no need to go overkill with a Scorpio!

Recently Sound Devices announced their 888

The Sound Devices 888 is a 16-Channel / 20-Track Multitrack Field Recorder
Old 3 weeks ago
  #21
Gear Nut
 

I actually have an old microtrack ii lying around which I had given up on but forgot it actually has spdif in. If I could build some cheap small pres around an ina217 for example and add a quality adc that would be a fun option to DIY. But the latter part of the equation is missing. The only module I can find is from Beiss but it's a fairly large footprint I'm going for compact!

Similarly, that's why I would go for the Mixpre-3 over the fostex f4. I've no doubt that the latter would be more than adequate for my needs but it's just that little bit bigger for a one man operation which I am on occasion.

Some really interesting information from folks much smarter than me! If i do some tests I'll report back. Unfortunately Dantimax seems to be a bit caught up with orders so need to reassess if I can get that piece of the puzzle. A decent preamp that small is also hard to find!
Old 3 weeks ago
  #22
Lives for gear
Quote:
Originally Posted by IronFilm View Post
Good news, no need to go overkill with a Scorpio!

Recently Sound Devices announced their 888

The Sound Devices 888 is a 16-Channel / 20-Track Multitrack Field Recorder
Only if you're using Dante...otherwise 8 analog mic ins plus 4 (?) unbalanced line ins

Ideally I'd like 12 analog balanced mic/line ins....sorry, should have explained that in my original gripe outline !
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