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Gear / Technical Help => Recording Gear => Topic started by: down2earthlandscaper on September 04, 2018, 03:06:23 AM

Title: Mixpre 6 Question
Post by: down2earthlandscaper on September 04, 2018, 03:06:23 AM
I've never encountered this issue yet with the Mixpre 6.

All is normal on channels 1/2 (Nak 700's P48 mod) and 3/4 (dpa4022's)

Channel 5/6 (Aux "Line In" on Mixpre 6) was AKGck63 > Naiant Tinybox > Line In on Mixpre 6 .

Gain was set to medium on Tinybox and 6db for channels 5/6 on Mixpre 6.

To the best of my knowledge limiters were Off.

So channel 5/6 is where the issue occurs.

Why is the wave form chopped off abruptly and no peaks above -6db on channel 5/6 ?  The levels did seem a little hot but nothing too crazy, however I did kick them down to 3db after the 3rd song.

Does anyone no why this would appear to be brick walled?
Title: Re: Mixpre 6 Question
Post by: Craig T on September 04, 2018, 08:58:33 AM
I'd start looking here:

Gain was set to medium on Tinybox

I brickwalled a few recordings with my TB set to medium gain in not so loud situations.
Title: Re: Mixpre 6 Question
Post by: dallman on September 04, 2018, 11:31:25 AM
I'd start looking here:

Gain was set to medium on Tinybox

I brickwalled a few recordings with my TB set to medium gain in not so loud situations.
I'd tend to agree. I have used the TB on low and had the gain higher on my 5/6 Mixpre6 settings.
Title: Re: Mixpre 6 Question
Post by: down2earthlandscaper on September 04, 2018, 02:18:48 PM
I'd start looking here:

Gain was set to medium on Tinybox

I brickwalled a few recordings with my TB set to medium gain in not so loud situations.
I'd tend to agree. I have used the TB on low and had the gain higher on my 5/6 Mixpre6 settings.

The Tinybox setting does make sense as the culprit.
. I’m curious however. Why does it cut off at exactly -6db?
Title: Re: Mixpre 6 Question
Post by: goodcooker on September 04, 2018, 02:33:43 PM

I agree on the Tinybox being the culprit. I used MED on a show that I didn't think was that loud and my DR60d showed good levels but the recording was toast. I used low every time other than that and it was perfect.
Title: Re: Mixpre 6 Question
Post by: dallman on September 04, 2018, 04:30:54 PM
I'd start looking here:

Gain was set to medium on Tinybox

I brickwalled a few recordings with my TB set to medium gain in not so loud situations.
I'd tend to agree. I have used the TB on low and had the gain higher on my 5/6 Mixpre6 settings.

The Tinybox setting does make sense as the culprit.
. I’m curious however. Why does it cut off at exactly -6db?
I honestly do not know the answer to that question but if I had to guess, I'd say that when the deck (any deck for that matter) is recording a brick-walled preamp's sound, it seems the preamp goes into some sort of distorted sound loop characterized by a bunch of distorted noise and that noise has a range that peaks at "X". I cannot say what determines "X" though and it is probably different on different preamps. It "feels like" some sort of "feedback loop". Quotes being used because I am unscientifically talking out of the side of my uninformed mouth on what is more based on "feeling" than "fact".  ;D :help: ;D
Title: Re: Mixpre 6 Question
Post by: Walstib62 on September 04, 2018, 09:58:14 PM
It looks like the limiter may have been on. What do the suspect channels sound like if played in solo? If they sound reasonably OK-not distorted-then the limiter was likely on. If they sound distorted, then the signal is likely clipped. Tinybox mid-gain is +18 dB, which should be fine if in fact the LINE was selected for the input.
When I use my tinybox I almost always use mid gain and never have clipping problems, but I  set the input to LINE IN and low gain, as my dr-680  dr-70 both have HI/LOW gain settings.

 
Title: Re: Mixpre 6 Question
Post by: Craig T on September 05, 2018, 08:42:47 AM
Tinybox mid-gain is +18 dB, which should be fine if in fact the LINE was selected for the input.
When I use my tinybox I almost always use mid gain and never have clipping problems, but I  set the input to LINE IN and low gain, as my dr-680  dr-70 both have HI/LOW gain settings.

You're playing with fire.  The recorder's input isn't being overloaded, the TB pre is, so it's sending a brickwalled signal to the recorder.  I think the lack of headroom becomes more an issue when the battery ages and weakens.  I ran at mid gain for awhile before getting burned back-to-back.  Ran the TB at low gain without issues for awhile longer, then the battery croaked.
Title: Re: Mixpre 6 Question
Post by: Walstib62 on September 05, 2018, 01:05:30 PM
Tinybox mid-gain is +18 dB, which should be fine if in fact the LINE was selected for the input.
When I use my tinybox I almost always use mid gain and never have clipping problems, but I  set the input to LINE IN and low gain, as my dr-680  dr-70 both have HI/LOW gain settings.

You're playing with fire.  The recorder's input isn't being overloaded, the TB pre is, so it's sending a brickwalled signal to the recorder.  I think the lack of headroom becomes more an issue when the battery ages and weakens.  I ran at mid gain for awhile before getting burned back-to-back.  Ran the TB at low gain without issues for awhile longer, then the battery croaked.

Interesting. My tinybox is custom.  I specified an impedance balanced output instead of the internal battery. I use only external power, so I never have low battery issues. Certainly low battery would have a large effect on the gain structure of the tinybox. The DC rail voltage being low would compromise the performance of the Op-amps greatly. So yes, if the internal battery is not at full charge, as the DC rail voltage drops, the Tinybox performance will also diminish.

 
Title: Re: Mixpre 6 Question
Post by: willndmb on September 06, 2018, 12:35:31 PM
I have recorded a ton of stuff with akg > tb at medium and never had an issue
If you brickwalled the pre the source was loudddddd as hell imo
Title: Re: Mixpre 6 Question
Post by: down2earthlandscaper on September 09, 2018, 05:24:08 AM
Thanks for all the info. I suspect that limiters may have been on although I cannot verify that, as I upgraded the firmware before discovering the issue.
I did record Mule a few days ago with 5/6 gain at 0db and tiny box at medium and my levels didn't get anywhere near a danger zone (and this was a loud show).