Topic: Sound Devices MixPre-3 and 6, Part 5

[zorba]

How does it work with the musician plugin? Do the frontal knob control the gain?

[Gordon]

The three channel knobs on my MixPre-3 does not have the same angle when set to 0 dB.
Non of them are pointing at 12 and no one is at the same angle as the others. All of them are a few different minutes early of 12.

Anyone else have noticed this or did I just have bad luck?

That is to be expected when running mic in and using knobs for gain. With line in 12 should be 0db.

[rippleish20]

I don't entirely understand the question nor answer. Can you explain more Gordon?

The three channel knobs on my MixPre-3 does not have the same angle when set to 0 dB.
Non of them are pointing at 12 and no one is at the same angle as the others. All of them are a few different minutes early of 12.

Anyone else have noticed this or did I just have bad luck?

That is to be expected when running mic in and using knobs for gain. With line in 12 should be 0db.

[Gordon]

with line in the knobs sitting straight up at 12 o'clock is 0db.  I assumed that's what he was referring to.  mic in 0db would be all the way to the left I think.  now that I re-read his post it sounds like he is line in but they are off a hair. 

[justme]

What I meant was that they do not have the same physical position although they are set to the same numerical value.
They all have a slightly different position at any given value except at lowest or highest.

They are off a hair.
Which means I can not look at them and trust their physical relationship to each other. And is forced to nudge them to get the true numerical relationship.

It’s annoying and I believe they should not be that way.

[rippleish20]

Mine also vary by a bit

What I meant was that they do not have the same physical position although they are set to the same numerical value.
They all have a slightly different position at any given value except at lowest or highest.

They are off a hair.
Which means I can not look at them and trust their physical relationship to each other. And is forced to nudge them to get the true numerical relationship.

It’s annoying and I believe they should not be that way.

[spyder9]

^^^  My question:  First stage is the "Gain" in the Advanced Menu option (which affects the ISO tracks loudness)  and 2nd stage is the Knobs (which affect the Mix loudness)?  Does that sound correct?

Yes

Thank you so much for the above tip!  I ran 4 mics last night, so I could compare:  Nakamichi CM-1000 vs DPA 4011TL.  Understanding these two Gain stages really improved my decision making on the fly.  I can now run Microphone and external Preamp comps with confidence.  Making the MixPre-6 a very useful tool.  That said, it's now found a permanent home in my rig collection.   

[borjam]

This is why I have previously suggested that there is actually no analog gain control but that setting levels is always post ADC.

They say it quite clear. The maximum analog gain is 75 dB. And indeed, with the gain control set to "advanced" you have access to the
analog preamplifier gain.

If you apply gain with the fader then you are applying digital gain. And you can achieve a maximum of 96 dB from microphone to recording.

"The maximum analog gain is 75 dB. And indeed, with the gain control set to "advanced" you have access to the analog preamplifier gain"

From my reading this is largely correct, or at least its the impression I've gotten.  This is why I sued advanced mode.

"If you apply gain with the fader then you are applying digital gain"

I think this is true in advanced mode but not in custom...

Sorry, my phrase was poorly written. If you use the basic gain mode the faders apply both analog and digital gain. I wanted to say “you are applying digital gain as well”.

i imagine that the first 76 dB will be analog, and moving the fader further will add digital gain.

Also, note that the unit has 32 bit A/D converters. Sound Devices don’t mention why, but I imagine that they wanted to reduce quantization noise for low level signals. Or maybe part of the 75 dB of analog gain are actually digital? Anyway as long as the noise specs are maintained it should be harmless.

I guess my conclusion that the pre-amp is a probably a digitally controlled, analog preamplifier. In other words, the knob are digital controls. In custom mode, the "fader" knobs also control the pre up to the maximum pre gain and then the purely digital gain kicks in?

Yes, that’s how I think it is. And of course the preamplifier is digitally controlled. But I’m still curious about the 32 bit A/D.

By the way, I saw the internal photos in the FCC filing. Indeed the converter is 32bit (I don’t remember the part number) and the electrolytic caps are high end ones (Nichicon).

[Chuck]

Somehow I lost all my Int Presets. Anyone know what could cause that? This will be a problem, as I tend to format the SD card for each new recording. I do load presets into the SETTINGS folder on the SD card from a computer, but if I didn't do that I'd have to quickly rebuild a preset in the field if the Int presets are erased.

[rigpimp]

Somehow I lost all my Int Presets. Anyone know what could cause that? This will be a problem, as I tend to format the SD card for each new recording. I do load presets into the SETTINGS folder on the SD card from a computer, but if I didn't do that I'd have to quickly rebuild a preset in the field if the Int presets are erased.

Saving the presets to the card is the problem . I had that happen early on and quickly learned to save them to the machine instead.  Any time you completely format the card you'll lose the presets.

[zorba]

What happens when the mixpre 6 switch from external to internal power? The recording continue without interruptions?

[Chuck]

OK, So I set up my presets again by: Save to Int 1, Save to Int 2 etc...
I formatted the SD card and the only presets are those that I saved via Int. No presets in the SETTINGS folder on the SD card now.

Is there any way those Int presets can be erased and screw me now? By removing the battery sled for too long? I will carry a backup SD card now, that has presets loaded, just in case.

One more thing... Has anyone found a protector for the touch screen?  That could be useful.


Impressions after recording 10 sets. I really love this thing.
I recorded some shows with just 2 mics, some with 2 mics and SBD and some with 4 mics. All great sounding with no stress set-up. I find it mostly intuitive and I trust it. My small complaint is the On/Off switch is in a spot that's hard to switch with my big fingers.

[Chuck]

What happens when the mixpre 6 switch from external to internal power? The recording continue without interruptions?

Yes, seamlessly.

[Gordon]

Has anyone found a protector for the touch screen?  That could be useful.

When I bought mine from SOS he had one on it.  Maybe he can chime in with what he used.

[checht]

Impressions after recording 10 sets. I really love this thing.
I recorded some shows with just 2 mics, some with 2 mics and SBD and some with 4 mics. All great sounding with no stress set-up. I find it mostly intuitive and I trust it. My small complaint is the On/Off switch is in a spot that's hard to switch with my big fingers.

Agree completely with all of this, except I have a 3 so ran 2 mics and mono SBD. Kinda wishing I had gone for the 6. With a USB C cable plugged in, it's hard to switch power. Not a fatal flaw.

I think the  MP-3 signal path is the most flattering to my Schoeps of anything I've ever run.