Grace M101 Microphone Preamp Review

[ocinn]

Great measured performance, but I was never a fan of these in the studio. IMO the whole point of using external mic preamps for modern DAW-based music tracking is to achieve a "sound" that you can't get with your standard interface mic-pres, or that plugins fail to sound as good/fit your desired workflow. Ex: drive them to taste to get a "color" on your tracking, and to play with the impedance matching between them and a given microphone.

Ultra-clean, ultra low noise, mic preamps are great for classical recordings, field recordings, cinema/video/foley recordings, but I (personally) would likely never reach for something like this over a Neve 1073/Chandler TG2/API 512/M72/M76/UA 610/Tube Tech MP2A, etc, etc (or any of their clones) for tracking music where the color and workflow that those can add is a very desired trait.

Now, of course, those would measure horribly compared to this, but the great thing about music production/recording/mixing/mastering is that objective performance is completely irrelevant if you are able to achieve the sound you want. It is art, not science, and there are no rules to art. That's why those preamps are legendary and found in like every recording studio.

This doesn't apply to the playback system/signal chain, which, of course, should always be as objectively optimized as reasonably possible.

I suppose this would be perfect if you were using VST plugin preamp emulations on all of your recorded tracks, to give a super clean baseline, but that isn't my preference.

 

[SHB]

I say "to tape" because I started on tape, but don't work on tape that much anymore.

It’s way too expensive.

 

[Ricardus]

It’s way too expensive.

It is. I have 2 rolls of 2-inch hanging around the house. But I have a friend who collects vintage analog gear and we have a few working machines. 24tk and 16tk.

 

[SuicideSquid]

What are you recording? A typical session for me includes taking 8-12 channels of drums to tape, bass guitar, scratch guitar, and scratch vocals (guide track). 16 mic preamps are a must in that scenario.

Personally, I don't do "live off the floor" recording, I record most instruments separately. One channel for vocals, 3-4 channels for micing acoustic instruments like guitar, flute, violin, cello, I DI my electric guitars and bass and use modellers rather than reamping. The only time I ever need 8+ pres is live drum recording, and even that I'm phasing out - I added a good quality electric kit to my studio, and my drummer and I take a hybrid approach - he plays the electric kick, toms, and snare, and we record real cymbals and hi-hat, which only requires four channels (two overheads, cymbal mic, hi hat mic).

I've got one really good four-channel preamp (Focusrite ISA428mkII with the ADAT board) and an interface with four totally decent preamps (Focusrite Clarett 4Pre) and that does me for absolutely everything these days.

 

[Casper]

I record live chamber music concerts and the stereo version (m201mk2) looks like a good deal, even at nearly $2k. It is less expensive than the comparable Millennia HV-3C, and it has two balanced outputs per channel. Those dual outputs are important because you can simultaneously feed your main recording rig and a backup field recorder. Low noise and distortion are very important for this type of recording because you have to give your self plenty of headroom because you don't always get a rehearsal to set levels and the music can be very dynamic.

 

[Robin L]

I record live chamber music concerts and the stereo version (m201mk2) looks like a good deal, even at nearly $2k. It is less expensive than the comparable Millennia HV-3C, and it has two balanced outputs per channel. Those dual outputs are important because you can simultaneously feed your main recording rig and a backup field recorder. Low noise and distortion are very important for this type of recording because you have to give your self plenty of headroom because you don't always get a rehearsal to set levels and the music can be very dynamic.

So you can only imagine the requirements for recording Orchestra and/or Chorus. I did a fair amount of that sort of recording with a Mackie mini-board. Yes, the noise floor was audible, at least between the notes. Used a starved-tube hybrid design in addition, I think the tubes provided a touch of peak compression. Also was involved with orchestra sessions that used Millennia gear, definitely cleaner at the lowest dynamic levels.

 

[Rja4000]

Those dual outputs are important because you can simultaneously feed your main recording rig and a backup field recorder.

Well, an Y cable does the same, doesn't it ?

 

[SuicideSquid]

Well, an Y cable does the same, doesn't it ?

Y-cables can cause issues with pro audio gear, particularly with longer cable runs, you may end up with impedance mismatches or signal loss. May not work at all if you need phantom power (though that's unlikely for a line out from a preamp to an audio interface).

 

[Rja4000]

Y-cables can cause issues with pro audio gear, particularly with longer cable runs, you may end up with impedance mismatches or signal loss.

Well, for short range line level inputs, that should still probably work OK.

May not work at all if you need phantom power (though that's unlikely for a line out from a preamp to an audio interface).

Unlikely ?
Oh yes. Very very unlikely, actually !

 

[SuicideSquid]

Well, for short range line level inputs, that should still probably work OK.

Unlikely ?
Oh yes. Very very unlikely, actually

Sure but if you're making field recordings at different venues you may not always be able to keep yourself to a short run. Point is there are certain situations where multiple balanced outputs can be useful.

 

[sergeauckland]

Sure but if you're making field recordings at different venues you may not always be able to keep yourself to a short run. Point is there are certain situations where multiple balanced outputs can be useful.

In broadcast use, Y cables were hardly ever used as if the input of one destination goes faulty and presents an undesirable impedance or short circuit, it will affect the other destination, thus taking them both out. The 'correct' way is to use a Distribution Amplifier that has separate buffered outputs. Hopefully, this device's balanced outputs are separately buffered and not just paralleled.

S.

 

[srkbear]

Nice review of a different sort of product @amirm. Fortunately I invested in Shure’s SM7db mic that has an integrated preamp, which spared me having to buy a Cloudlifter. For an extra $90 bucks I saved myself a lot of hassle, and the SM7db also comes with its own high pass filter and presence boost as well. Sounds terrific.

 

[IamJF]

I
I'm not sure there actually is a norm.
Personally I do 20Hz-20kHz, but that's an arbitrary choice.
Most vendors give 150 ohm dBu(A) figures.

Here is a short analysis of various brands' specs for EIN.

View attachment 505486

(Note that there may be more details in the manuals: I just had a look at the specs sheets)

The noise of an 150Ohm resistor is 0,23uVrms (20-22kHz) and 0,18uVrms A weighted. So the noise of the resistor alone would be -132,7dBu(A).
To define the noise of the preamp a shorted input as 2nd value would be helpful. Or a more realistic resistor, like 50-70R.

 

[Rja4000]

The noise of an 150Ohm resistor is 0,23uVrms (20-22kHz) and 0,18uVrms A weighted. So the noise of the resistor alone would be -132,7dBu(A).
To define the noise of the preamp a shorted input as 2nd value would be helpful. Or a more realistic resistor, like 50-70R.

150 ohm is widely used and that's corresponding to an average dynamic microphone.

Personally, I'm now publishing the preamp noise too, with the resistor effect removed.
See in the bottom right here.

I suggest you read the methodology I propose here:

How to measure EIN (Equivalent Input Noise) of an interface's Mic preamp

For audio interfaces with Mic preamp, low level / high gain noise is a key performance parameter. I therefore always measure EIN when reviewing an interface. But what is EIN, and how do we measure it ? I thought it was worth adding a proposed methodology that everybody could use. Of course...

www.audiosciencereview.com

 

[IamJF]

150 ohm is widely used and that's corresponding to an average dynamic microphone.

Widely used doesn't mean it makes sense to define the input noise of the PREAMP. dB(A) is also widely used to measure environmental noise and sound pressure levels ...

Some impedance of mics lying around:
_________DC______1kHz
SM57:__17,5R___329R (transformer)
B58A:___26,3R___257R
M201:__230R___238R
V7:_____310R___316R
v.beat:__310R___313R
D6:_____262R___30R (filtering internal)
D112:___217R___231R

The last condenser mics I built for a company had 2x 27R and a coil at the output,

I prefer my methodology - set to 60,0dB gain, input impedance to your liking (for me 0R or 51R) and then read the noise in dBu on your Audio Precision. Add 60dB. But I also did my noise measurements with an RME UFX during my diploma thesis - works really well, digicheck is a great help for that btw and basically all you need.

The impedance of real dynamic mics already influences the preamp noise significant and while that's still extremely low in real live it doesn't make sense to mimic that when you want to know what the preamp is able to deliver.


Back to topic - when you have a great interface these clean preamps are not bringing too much to the table. A channel RME 12Mic or XTC costs about € 200-300,- including conversion. The newer RME preamps sound really good, measure great and are stable with digital recall.

But this seem to be a very solid unit, very well built (no 50/60Hz problems, big coil at the input, great internal layout and useful functions) and will probably outlive us middle aged engineers ... so it definitely has it's usecase.

 

[AnalogSteph]

* Rane (Mr. Bohn) explained already in 2001 (or earlier) that EIN should be given unweighted. Unfortunately while he donated all the excellent Rane Audio Reference to the AES, see

Pro Audio Reference: PAR - AES

Pro Audio Reference Concepts, terminology, standards, history, and assorted surprises What is the PAR? The Pro Audio Reference attempts to explain all the various terms commonly used by engineers in the pro audio field. (Scroll down for the full history.) You can either search for a term in the...

aes.org

EIN is just a link in there to the (old) Rane website - which no longer includes that one as Rane has changed their product line completely. Currently you can still find it here:

Audio Specifications

To understand specifications, you must understand the tests. This note describes audio tests used to characterize audio performance with conditions.

web.archive.org

This one?

Audio Specifications

To understand specifications, you must understand the tests. This note describes audio tests used to characterize audio performance with conditions.

www.ranecommercial.com

 

[MC_RME]

Perfect find!

 

[Mr. Swordfish]

Add me to the list of readers who want to see mic preamp measurements, not just line level. Thanks.