AwTAC

Bringing Discrete Console System Design to your Desktop

To get the best picture of what initially inspired us at the Awesome Transistor Amplifier Company and what our goals are, it is necessary to obtain a basic understanding of what is actually happening in a recording console in the first place.

Often enough, over the years, I’ve come across a handful of acutely wise people who have all made similar comments that echo the idea of “I have such and such mic pre, which sounds great, but its still not like the sound I remember from working on that console in the 1970’s, are the new mic pre’s not as good?” or “I bought this vintage mic pre which sounds really good, but its still not the sound I really remember from working on the old board, do you think this needs to be modified?”

Short answer, no, the new stuff is just fine and your old stuff doesn’t need to be modified. Does it sound different? Yes, of course, and (keeping this very basic) here’s why:

You’ve got one piece of a system there. The ladder from a fire truck. Still useful, but if you want to drive around, hook up to water and put out fires, you gotta have the whole affair.

If you have a mic pre with one or two amplifier stages and with one or two transformers, as is commonly found in many, many, many designs out there, you can plug your mic into it, run that to your converter and your recording is microphone, cable, one or two amps, one or two transformers. Sounds good, sure. Nobody in the 1970’s ever made a recording like that, and Im sure in the tape machine world of the ancients you can find lots of guys that wished they could have and maybe one or two that knew their way around the patch bay on a well wired console that actually might have. Most (and most meaning Most) 1970’s guys did this:

Microphone-> Cable-> input transformer-> mic amplifier stage(s) -> output transformer-> EQ amplifier stages -> output transformer-> routing/panner module amplifier stages-> buss amplifiers (in either active of passive bussing schemes)-> input transformer (for passive busses) -> make up / pre fader amplifiers -> line driving amplifier-> output transformer.

That whole mess was often identical for the main left and right outs as well as all the busses. Some consoles had less, some way, way more. Short version is that on such and such console, once you went into the thing, your signal had piles of transformers and amplifiers to navigate and the level of the signal was being amplified, attenuated and buffered throughout the whole system in order to get back out. Going through ALL that stuff is what made the fingerprint sound of such and such console identifiable. Going through just one or two amplifiers is a mere brushstroke in a much larger painting that many people today looking for THAT sound are missing.

Have no misconception, if you dig the sound of old early 1970’s records, you are listening to the sound of highly focused console system design, and a discrete amplifier design is just one element to that, how it all fit together is the real art.

Designing a properly amazing sounding amplifier is not to be under stated and a long list of classic amplifier designs can be created that can and does inspire a lifetime’s worth of study and awe. What is typically left out of most discussions is the true genius of how those amplifiers were made to work together. Designing an amp is one thing, making it feed a stage and having that next amplifier receive it, that is the ballet, and THAT is what made classic consoles desirable and of course none of that is present when a single mic pre is plugged in and sent straight to a converter.

So, after identifying a problem that most folks out there don’t even realize exists, we set out to put a full console channel strip (please do not confuse this with a “recording channel”) into the 500 format so people could get closer to that 1970’s console experience without having to buy a full vintage console. And we are not talking about a mic pre and an EQ nicely packaged in a box. We started this from a full systems design approach and put into our box all the state of the art gain staging that we could fit that would have commonly been encountered in the average discrete transistor recording console design from the early 1970’s.

Take a look at a simplified block diagram of the AwTAC Channel Amplifier where Amplifier stages are represented as Squares, Transformers and Inductors are represented as Trapezoids and Control Elements as Hexagons:

With the High Pass Filter bypassed, a Mic or Line level signal is passing through SIX amplifier stages in series before it gets out of the box. Notably, these amplifiers are not all identical, each is tuned for optimal performance with the signal it receives and the level it needs to operate at. We toiled over making these amplifiers work together as gracefully as possible. It would have been easy to come up with one great amp, slap a bunch together and have a decent sounding box. The AwTAC Channel Amplifier is hundreds of design hours beyond that point. H U N D R E D S .

There is a common thought out there that “less amplifiers the better” and “shorter the signal path the better” and while there are many angles to that discussion, let’s address one: When faced with a not so exciting amp design implemented in a greater system that didn’t have too much passion poured into it, yes of course, less is going to be more. I would rather eat just enough of a mediocre meal to satisfy my hunger and elect to over indulge on the real gourmet meal.

What we discovered designing the Channel Amplifier is that as more amplifier stages were added in series and tweaked for optimal performance next to each other, the unit began to sound more and more Awesome until it commanded a name for itself. You can listen to this in real time with a Channel Amplifier which brings to light a very useful feature for recording:

This is a simplified block diagram of the AwTAC Channel Amplifier with the EQ bypassed:

With the EQ and High Pass Filter bypassed, a mic or line signal is now passing through THREE amplifier stages. With the EQ flat, flip the EQ bypass on and off and listen to how the depth of the soundstage changes when you simply add in or remove those three amplifier stages.

Don’t look at that EQ bypass switch as simply turning the EQ function on or off. A far more sophisticated view of that control is as an amplifier addition/ removal switch. Dialing the EQ flat vs. Bypassing the EQ completely will yield a VERY different sound from the AwTAC Channel Amplifier.

This of course provides for incredible options when it comes to the dimension of the soundstage that a stereo pair of Channel Amps can make on an additive level when it comes to stacking your tracks in a mix. Tracks recorded with the EQ In vs. Out will sit in different places naturally in the mix. Couple this with the Forward / Back control with the EQ in, you’ve now got three different acoustic “depths” that your tracked material will naturally sit in a mix before you’ve done anything to it. Dimension. Expert level experiments could be as easy as tracking all your drum mics with the EQ in Back. All your vocals EQ in Forward. All your guitars EQ Bypassed. Then go back and make a recording of the same sources all with one setting, say, EQ in Back. Now just bring the faders up and see how the tracks sit with each other and compare the two experiments. One should come across with a slightly different sense of depth in the stereo field than the other.

This is the true power of working with the Awesome Channel Amplifier.

Thoughts on the EQ

Sitting down to design the EQ, there were two basic design requirements on the table:

1. Curves should be as wide as possible.

2. EQ should sound good with all bands on 10, boost or cut.

It is my experience, with many Equalizers, that when you get the boost up past +3 or +5 db, things start to get nasty and unpleasant, and usually pretty quickly after that. A band could have 100 dB of boost, but if it starts to get unusable at +6db its not so relevant what its maximum range is.

The bands on the Channel Amp’s EQ boost and cut around 12 dB each. All knobs sound good on ten. Try it, you’ll be surprised. The added benefit of putting only 12 dB of *usable* boost and cut is that all of a sudden, the turn of that knob has extended resolution to dial in on a precise amount of boost or cut.

The shape of the cut on each band is not an inverse of the shape of the boost. Make sure to exercise those pots all the way in both directions to get an idea of what each side of that center mark has to offer, in detail.

The center points printed on the front panel don’t give the suggestion that the bands overlap, but the Q on the curves is so wide that the heads and tails of each band’s curve definitely overlap. A pair of AwTAC Channel Amps EQ’ing the same source in series is a powerful experience.

Our stringent component selection has provided for a high shelf that is extended and smooth, without getting hard or shrill, even at maximum boost. A low shelf with a deep, deep bass that never gets woofy and a mid band that is never nasally nor will make your eyebrows raise in wince.

Our midband was tuned by ear, not math equation, the fastest way to get an idea of how the midband is stepped is to put the mid pot on maximum boost or cut and then step through the selection of the Mid Frequency Select switch from top to bottom and you’ll see where the center frequencies fall.

As you step through the midband you’ll notice 1K and 3K are duplicated with a higher Q position for when you need a little more control for sources like vocals or guitars. In testing, these points were continually useful in both a wide and narrower bell, so we included both for versatility. A good critical listening to the sweep of this EQ will set up the user with the familiarity required to really get the most out of the feature set of this EQ.

The Authority of Fingerprint

For years, as I grew as a musician, than as a recording engineer which then led to designing circuits, the one thing that I always struggled with was understanding why my favorite old early 70’s recordings that shaped and changed my life sound the way they do. I still passionately struggle with this, but have come to terms with one distinct part of it:

Limited choice led directly to the Authority of the Fingerprint that any given record would have, and how those records could be shaped in a mix were absolutely what studios built their mystique around at the birth of discrete console design. Sit ten mix engineers down on a console that has a state variable EQ and it is very likely that you can have ten records that really sound nothing like each other at all and really, from where I listen, don’t sound like anything at all. When you can infinitely sweep a frequency and its Q simultaneously, sure, you can remove every offending frequency on all the tracks and of course when this occurs any interesting personality usually goes out the door with it. If there is a sound to “modern” recordings, thats it. What happened in the 80’s? State variable EQ’s on inline mixing consoles, thats what.

Now take those ten engineers and sit them in front of a console with only 14 EQ points to chose from, like we are offering, and while you can wind up with ten different records, they are all going to be doing the same thing. Each guy had the same 14 points to solve problems with and as a result, the ten records have a distinctive shape born of limitation. This. Is. Classic. Rock.

It is this limitation that made Empires out of the first wave of studios with custom consoles in the late 60’s and early 70’s. If you wanted THAT sound, you had to go to THAT studio. Of course back then, having 14 points on an EQ was like having the world open up in front of you but looking back on the aftermath of the state variable’s impact on music recording, it was the limitation of choice that kept things focused, made things easy (you can not toil over what *exactly* to cut for hours when there is only one or two bands near your problem frequency that help) and in the end, allowed for a certain type of Interesting to build a foundation.

Looking at things in that light, when presented with the choice of what type of EQ to design for our console, it was instantly obvious which direction to go in. When you make a record with AwTAC Channel Amplifiers, its not going to sound like anything else.

There is a certain delight in the exclusivity of that thought. You can be part of this.

We didn’t set out to design a great Mic Pre. We didn’t set out to design a great EQ. We set out to design a great Recording Console, and this is the first piece, the heart of the system: the Awesome Transistor Amplifier Company Channel Amplifier. We are proudly looking forward to the future, offering more modules to completely round out the system and bringing the full functionality of a early 1970’s discrete transistor console to your desktop. Yes, this is happening. Check it.