For the next part of the tutorial, as promised I will go over the use of preamps and how to get the hottest most agressive sound from your mic pre, basically, make the tubes sing.First thing is first though, lets talk about preamps.
What is a preamps job?
Take the small voltage and condition is for some other form of amplification. Conditioning, meaning, amplifing the voltage by a specified factor determined by the designer and the tubes being used and also filtering out unwanted noise (high and low frequencies that kill headroom and clarity). Another form of conditioning is to add a certain coloration to the signal that is desired for that particular purpose. That is why there are many tube mic pres out there, solid state, tube, different frequency responses, and as a result, some work better for drums, vocals, guitars, bass, or whatever else you can put in fron of a microphone.
What makes a good preamp?
A good preamp is one that utilizes a function of conditioning and coloring the sound. If a preamp just corrected voltages and impedences to where they needed to be, the more expensive pres would not sell becuase you could easily get a behringer (if it doesn't fall apart) and get the same results of the higher priced preamps. Thats wherer you have to watch out for the advertisments, class A tube mic pre. It may very have a class A tube circuit in there, but what exactly is it doing. If it is doing what they would call buffering, it would do nothing more than to send the signal through the tube at a very small level, the preamp circuitry itself is ran by opamps, no transformers, just opamps, bringup up the voltages. They slap a tube in there, give it an unrealistically low voltage underbiased setup and say your pre is tube. Problem is, the tube usually sits in between two op amps, what happens when you try to push the tube to get some saturation? you find that the opamp give out way before the tube will and if you play it like that, well the pre will be toast in a very short time and t would sound like crap.
Whats the solution?
Get a true All tube class A mic preamp. How can you tell its all tube, just take a look at the description, it will usually say something like "has 2 (or 3) 12ax7 tubes", "tube gain stage amplifier" and will usually have a drive/gain control, and an output, be careful however if the input says gain and not drive, becuase in chepaer models gain is simply volume, not tube saturation. If you find a pre that has an input, tube level (tube drive, tube gain, cruch etc) and an output, then its good. The presonus preamps are pure tube preamps, not sure about ART or the higher end behringer, but most preamps over $800 (USD) are all tube or some sort of
SS analog like SSL or grace design.
How do setup mic pre? ¯\(°_o)/¯
When you have your mic setup to whatever you want to record, start of by bringin both input and output gain knobs up until you have reached 0db, slowly, while listening to the sound through the monitors, bring up the input gain while using the output gain to bring down the overal output volume (reverse makeup gain) until you get to the right amount of saturation you wish to have. YTOu want to have the hottest signal possible from your mic going itno the tubes as possible before it starts to clip and the output is used to calibrate the signal going tinto your converters to peak at -6db
What does saturation do?
after a mic, tube saturation adds warmth, it fills space and brings things more up in your face. Not only will it bring up harmonic content and smooth out the highs, it will thicken up the low end. If you are going for emulated gear, its really cool to have the crane song Hedd as its a rackmount device that has triode (preamp), pentode (power amp) and tube saturation on it. If you use impulses you could stick voxengo warmifier after your cabinet simulation (impulses) to simulat pluding int aht mic to a real tube pre.
How much saturation to use?
It all depends, guitars usually see a lot of it in extreme metal, examples I know of are Dimmu Borgir, especially on Puritanical Euphoric Misanthropia, the guitars imo are over saturated but its a great example of how that can make guitars fill in more space, the latest trivium album Shogun has tons of preamp saturation although to me it sounds like post tape saturation is nmore the result and the use of hard limiters on the overall masters helps bring everyhting together, however there may be a bit of tube saturation on the masters becuase they clip like hell. Aother great example is Slipknot, The guitar have been always oversaturated with tubes and especially tape, thats the quickest way to get that sludy slipknot sound without you tone getting muddy. Its also responsible for the pissed off in your face the tone has (that and power tube saturation)
Other than guitars, if you can hear the saturation when that track is solo'd its too much and you want to bring it down. Vocals however, are the ones that you want to hit somewhat hard on more aggresive singing/screaming but jsut enough before saturation on more cleanier parts. Saturate the crap out of the bass, don;t touch a kick too much and saturate away on a snare. I wouldn't touch toms. I heard that on Mercenary's latest album Architech of Lies and distorting toms are just no good IMO
Conclusion
We aren't just talking about clipping, tube preamps will start to become less linear the harder they are pushed and give you more warmth, and that is what it is ultimately about. When tubes start being driven and not even to the point of cliping, the really focus on the low end, and add a fuzzy warm tone that helps everything sound more pleasing to your ears.
So if you are having problems getting your tracks warm, puch your preamp, isn't a good one? no you know how to tell.
EDIT: sorry for the typos I am trying to hurry before I have class, I will fix my errors later. I am actaully trying to build (or design) a simple variable impedance 4 gain stage pure class A tube pre, I have the schematics sitting in from of me, I will have to go over them again and again, however once its done, should be a very simple way to get the purest tube distortion possible. the design is simple enough extremely generic, very similar to the first 4 gains stages of a 5150 and Fireball, which are pretty generic until their tones tacks, but my design is completely stripped down.
