Preamp Gain Minimum 6db on Line Level -

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Preamp Gain Minimum 6db on Line Level -

Postby mike@purrezaudio » Fri Apr 08, 2016 21:33

I have a Hapi with 2 A/D cards - one is Rev E and one is Rev F. While trying to record line level from a Tascam RA1000 - the input is in overload above 0dB (clipping). The Line Level preamp gain will not go below +6db.
I have tried controlling gains in the DAW, remotely and stand alone with the Hapi not connected using the front control knob. It appears to be a firmer issue on Hapi.
I want to be able to record analog in at 4XDSD and this is making it impossible (without clipping or lowering the inout and causing SQ to go down).
Does anyone know of a fix? THANKS!
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Re: Preamp Gain Minimum 6db on Line Level -

Postby mpdonahue » Fri Apr 08, 2016 23:25

mike@purrezaudio wrote:I have a Hapi with 2 A/D cards - one is Rev E and one is Rev F. While trying to record line level from a Tascam RA1000 - the input is in overload above 0dB (clipping). The Line Level preamp gain will not go below +6db.
I have tried controlling gains in the DAW, remotely and stand alone with the Hapi not connected using the front control knob. It appears to be a firmer issue on Hapi.
I want to be able to record analog in at 4XDSD and this is making it impossible (without clipping or lowering the inout and causing SQ to go down).
Does anyone know of a fix? THANKS!

The Max line input level on a Horus is +24 dBu. I suspect that you have the DV-RA1000 set to the +24 dBu level as well. Turn down the Tascam and you will be fine. You can adjust the output level of the DV-RA1000. If Memory serves, changing the Reference level changes the sensitivity of both the inputs and outputs together.
Just to play the devils advocate, wouldn't it make more sense to transfer the file off the DV-RA1000 and use the DSDConvert application?
You can't get more resolution than you already have. I suspect that the re-modulator in DSDConvert will give you a better transfer....
As always, YMMV.
All the best,
-mark
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Mark Donahue
Soundmirror, Inc.
Boston, MA
mark@soundmirror.com
www.soundmirror.com
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Re: Preamp Gain Minimum 6db on Line Level -

Postby mike@purrezaudio » Sat Apr 09, 2016 23:36

Mark -

Thanks for the reply... OK so this is very weird. I decided to verify the RA1000's output level. I checked the RA1000 - measuring it with the an Audio Precision.. The output with 0db Cd playing measured +19.45dB.
I hooked up a Oppo Blu_Ray player - It measures +12dB. I then hooked up the Ap to the Hapi - and now I can get the Preamp Gain to stay at 0dB - before you could lower the slider and then it would jump up to +6dB.
Using the Ap into the Hapi set to +24db and the pre set to 0db on the Hapi - the meters on a record session now say -0dB.. Which is what I would expect. So over a one day period with the Hapi left on, and the computer shut off. The Hapi appears to be working as expected. But yesterday - resetting everything on power down and reboot made no difference. Even the Hapi stand alone with the PC off - I could not get the pre to go to 0dB using the front panel knob.
Very frustrating - anyone have this experience or know what might cause this kind of behavior?
FYI - I was just testing the new A/D card and running 16 channels for an hour before a new upcoming gig, and the RA1000 was just handy to use for this.
What I would really like to figure out is how to record 16 channels of 4x DSD with providing 48Khz 24bit files to the customer after the gig within an hour strike down time. The Hepts SRC with 16 channels of 1 hour of 4X DSD took over 2 hrs to output the files. Anyone know of a faster way? THANKS!
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Re: Preamp Gain Minimum 6db on Line Level -

Postby mike@purrezaudio » Sat Apr 09, 2016 23:52

FYI -
OK - Now I see what is causing it - which appears to be a SOFTWARE BUG.
I previously opened a session at 48Khz and everything was fine. I now have a 4xDSD session open and the preamp will not go below +6dB.
Which means I can't record a DSD session the same as a PCM session with the preamps behaving this way - unless you keep below +24dB (+18dB max) using other gear or changing settings on the external gear.
I will post a request to on the bug reporting form page.
Thx.
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Re: Preamp Gain Minimum 6db on Line Level -

Postby HarriettTitus » Thu Mar 16, 2017 14:51

mike@purrezaudio wrote:FYI -
OK - Now I see what is causing it - which appears to be a SOFTWARE BUG.
I previously opened a session at 48Khz and everything was fine. I now have a 4xDSD session open and the preamp will not go below +6dB.
Which means I can't record a DSD session the same as a PCM session with the preamps behaving this way - unless you keep below +24dB (+18dB max) using other gear or changing settings on the external gear.
I will post a request to on the bug reporting form page.
Thx.

Thank you. Very useful:)
Technologies are my biggest passion. It is the source of cool emotions for. I always like to knoe something new in this field:)
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Re: Preamp Gain Minimum 6db on Line Level -

Postby Guillaume Defer » Mon Apr 24, 2017 11:33

Hi,

A/D +6dB gain in DSD mode was implemented for benefit from the +3.1 dB SACD headroom :
http://www.merging.com/uploads/assets/I ... df#page=54
This feature was required by many customers working for SACD support.

The possibility to disable automatic DSD A/D +6dB gain has been reported in the Merging database for future features.

Best regards,
Guillaume Defer
 
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