Warm Audio WA12

The WA12 pre is the first product from a new USA company: Warm Audio.
I invite to all of you to visit their web where you can see specifications and other news about the product: Warm Audio Microphone Pre-Amps

WA12 is based on the original design of legendary Api 312 at a low price. This is a mic or instrument mono channel preamp with external power supply and half rack format, there is an optional accesory to join two units to complete a 19” rack 1U.



Specifications

Gain input 71 db
Gain button uses steps to give fine adjust.
Phantom +48V
Pad -20db
Impedance input selector (600 o 150 ohms)
Polarity invert
All discrete, no chips
Cinemag Trafos for all input and output signal
24 v external power supply
Hi Z frontal input for instrument
Power on button on frontal
Outputs on the back with XLR and ¼” TRS in parallel


When I received the unit WA12 the box remember me another unit I tested: the GAP 73 mic preamp, same external box, same internal protection, plastic bag, very similar at all.


Once unit is open I remember again same impression with Gold Age preamp: same layaout dimmensions, same power supply (Warm Audio recomends to use GAP73 power supply as alternative), similar buttons position. Frontal is orange colour.

From this point it is clear we are in front of another made in china unit, but Warm Audio uses exclusively good japanese and american quality electronic components: Cinemag trafos, and operational amplifier, these are more important pieces, and expensives.
So from the first impression WA12 is an api clone, if we compare both we can say GAP73 is a Neve topology and Warm Audio’s WA12 is an Api design, but from this point both units are totally differents only I feel a similitude comparing both units but this stops when we open the box.

Warm audio has decided to mount american components in China factory. Starting with all made in usa Cinemag transformers (same brand used by Universal Audio on his Solo610, for instance), and the operation amplifier is a clon made themselves by Warm Audio from a 1731 circuit (Api 312 original circuit).

Frontal offers main control, very basic at all:
One gain control
Switches for phanton, polarity, pad, HI Z input, impedance and power on
Jack input for HiZ DI

I agree specially to designer to provide a frontal power on switch. There are lot of units without this frontal button or put on the back!!!, so every time I can see one unit with a power on on the frontal layaout I really agree, it is really comfortable.

On the back side we find all input and output connectors in XLR and jack format. Ouputs are in parallel by one XLR and one ¼” jack, this is good point for the user, you can use both outputs for instance from xlr you can goes to an external processor (one compressor for instance ) and at same time you can connect your audio card by TRS jack and so you can record both signals, processed and clean. This is useful to backguard in some cases where we can use a bad compress signal, or simply to make a mix usign a parallel compression with clean signal. I check TRS output jack have a higher out signal, a couple of dB.


I personally prefer to see this preamp not as an Api clon except a new design inspired on this well known sound but using a personal touch. Even though at this moment I don’t have an Api on my rack to compare in A/B (doesn’t matter, wa12 goes to the classic Api 312 with 1731 operational and actual Api 512c uses a new 2520 circuit totally different at all ), I understand we must to value WA12 what it is and offers and not for this Api’s resemblance.
And as such, Warm Audio unit gives the size without problems.
This is a clean preamp, with low noise, solid, muscular, clear and detailed sound.
Have a good bottom bass, sweet highs, without loudness.
This preamp sound very well and give the size on every situation and instrument we can record.
I am not find the typical presence level of Api preamps, but really it is don’t needed here.

I don’t like one thing about the minimum gain level over 29 dB, a high value for a low gain. This implies in most situations we must to use Pad button, it is not a problem at all, but I think would be better a minimum level lower than actual, maybe 10 or 15 db less. When we put a mic in front a guitar amp or precussions it is necessary to use pad always if not input signal it is very high and we have some distortion and satured signal.
On the other hand we have a fluid gain potentiometer path (it must to cover less gain margin ) and uses steps of about 1/3 db value, so gives us fine adjusts and possibilty to note the value to remember the record situation in the future.

The main new point in front classic Api design is TONE button. This modify the impedance and change over tone. This button allow to adapt preamp impedance to microphone, and also could be used to get different tone on the same microhone signal since everybody knows same microphone offers different sound with different impedance on the preamp input (on this point I invite to check also The Magnetoaudiolabs VariOhm Microphone Impedance Converter ).

This option is propriety, but with a negative poing, when we push the Tone button general volume increase about 6 dB, what a nuisance! It is necessary to adjust everytime over gain control to check differences between different impedance value choiced, impossible to make A/B comparisons instantaneously.
But the truth is tone changes in an obvious way although subtle(fine) and this feature make this preamp more versatile, because give to us two different sounds but both really good at all.
In the normal mode (no tone pushed ) sound is clean, Look at graphics.

This is original pink noise as itself generated, still not passed thru any process or processor:


Now we can see same pink noise passed thru WA12.

As you can see the frequency response is flat, this point talks about this preamp don’t add any colour to sound spectrum, we can consider totally neutral.

Now we can see what happens with TONE pushed:


We can see there is a little drop on the highs and a little rise on the bass and meddium bass. This modifies the tone offering a more sweet on the highs. Sound becomes more thickset and consistent.
Personally I prefer how it sounds using TONE pushed and I used on this mode in a couple of studio recordings. In any case, it is good to choice the colour on the preamp sound to adapt better to every situation.

Now we will talk about clean/clear level., Wa12 es very very very clean, with a lower distortion level, for me fundamental on any preamp.
First I show image where you can see noise created by my digital audio converters DA and AD ( RME Multiface2):


Now we can see noise on preamp with gain at minimum:

Very low as you can see, we are moving between -105 and -115db, this is a very good value.
I must to explain last values on the top of gain, over 71 dB more, appears typical hiss when we get the end of the gain potentiometer, we can say this is normal on a medium class preamp. In a first level unit we note less noise hiss when we got high gain levels.
This is not a problem in any case, in WA12 until you reach over 55 dB pream is very clean and we don’t need any more, except in specific situations.
I check this point using a dynamic microphone, one ribbon and one LDC without any problem.

Now is turn for distortion levels:

Senoidal 1 kHz and gain at 14db:

For those who are not familiar with this type of graphics, the higher peak is a pure tone we are sending to the preamp circuits. When distortion appears we can see smaller peaks multiples of original signal.
You can see here there is not any signal, except over 2 kHz and 3 kHz (very little) as level is very low in reality this distortion is practically inaudible on ears.

Now we can see same at 5khz:


More or less we get the same answer, a little peak over 10kHz absolutely out of good clean sound.

And the last, now over bass 100hz:


On this point appears some more distortion but in low levels, practically without affecting original sound (-72 dB at 300 Hz).

As you can see we are in fron of a clean preamp, without practially any distortion on the original signal and without any colour in any frequency range, excepts when we push Tone button.
By the way, distortion level with Tone not vary from graphics showed and so I not put any graphic with this mode activated.



Pros and cons

Pros: I consider the following:

Very low level noise
Clean sound, well detailed, neutral but at same time with body and muscle.
Two balanced outputs simultaneously, good idea to get clean and processed recording signal.
TONE button offers two preamps on same box, Modifies sound is fantastic way (for me) and get a sound like a more expensive preamp unit.
Solid and robust construction
Best value price on this range

Cons:

- I miss a high pass filter. Maybe could increase price, but they are very useful on all situations.
- When we push TONE button volume is increased, this point don’t let use a fast A/B test when we are looking for gain levels.
- An Output level control could be fine. I reach limit levels, when you are in high levels units starts to distortion but in sweet level, without an output level control there is no chance to play this option.
- Minimum gain is 29dB. From my point of view too high.
- Also a signal levelindicator (leds or vumeter), helps in more cases

Conclusion

WA12 it’s a medium class preamp but sounds as a high end unit. Difference price value with a high end unit will be justified depending where we use this preamp, obvious, but for those people with a home studio or project studio this is a very good budget, WA12 offers a great money value. For a user looking for quality in low price, WA12 is the option, maybe better in actual market. All circuits made in usa, well construction, and finished.
Talking about sound I personally prefers Warm Audio in front of others, like GAP73.
WA12 plays on same league than Chameleon Labs, GAP73, Focusrite Isa One, Dav electronics and little more, but offers a more competitive price and quality above most of them.
If I was thinking to invest on a preamp, WA12 would be one of the favourites.

Thanks to Marc from Makermid, spanish dealer.

Paco AUDIOANAL
Kadifornia Mastering
KADIFORNIA MASTERING | Estudio especializado en mastering de El Puerto de Santa Mar