Basic functionality of the Voicings on the MP-1 & MP-2

[INRI]

I was wondering: what is the magic of these units for them to have different voicings? How can it go from sounding like a fender clean to cranked marshall? Chat GPT was brainstorming and going all about the DSP being able to change tube bias on the fly etc. But that sounds extreme. Do any of you guys have any idea how this works?


As you may have noticed Im all out fascinated by these units even though Ive never been nearer than 500 miles to one.

[Harley Hexxe]

Hey INRI,

   I can't tell you anything about magic, but I can tell you that the MP-1 does things like this when you manipulate the tube gain levels, and combine that with the way you set your EQ, and maybe add some of the chorus effect in creative ways, you get what some would call a "magic" tone.

  By selecting the voice you want to create from, i.e. S.S. Clean Tube, or Dist Tube, there's a lot of ranges in those voices. It's all about selecting the right voice and tweaking it the way you want to hear it, and that's the key. Use your ears.

   The MP-2 on the other hand does not do the S.S. voices that the MP-1 does since it has no S.S. voice at all. Everything there is all tube voicing. It does every tube voice from crystal clean to gnarly dual rectifier tones and all points in between.

   If I had to sum it up, I would do it like this: These ADA preamps are not modelers, and they don't have DSPs. Instead think of them as extremely versatile amplifier preamps that do what no single amplifier can do.

   That's why they're legends.

[rnolan]

Hey INRI, totally agree with Harley . Simple answer is yes, we've got some idea how it works.
So  technicalities later. Let me say, I did a comparison to a MP-1 (that I'd just bought) with my '73 Marshall 50 (which I'd loved and used for many years). The MP-1 made the Marshall sound like a toy amp (no easy feat?).  While it's not as easy as pressing one button, you can make these preamps sound however you want them.  I think they were chasing a circuit that let you make any amp sound you wanted.

So given most of the tone is initially generated in your fingers, and PUs make a big difference BTW, from an amp perspective, the pre-amp does most of the tone, and tubes do a good job.  While not exclusive, most guitar tube input stages are based around 2 x 12AX7 tubes.  So 4 stages of gain (each is a twin triode).  So what ADA did was take that structure and make it customisable.  So each (most) popular amps have a similar 2 x 12AX7 circuit (i.e. add gain to input), but implemented it different ways.  So what if you could mimic that (by varying the circuit around the tubes) which is what ADA did (and what made the other amps different).  Something to remember for context, amps at the time had only just got master volume and at best had 2 channels which only some let you switch between.  So ADA used digital control circuits to control the analogue tube circuit so you could change and configure what you want.  The best version of that approach is the MP-2 where they created 10 tube "voices" to cover all situations and make new sounds.

So in the tube circuit, ADA made a bunch of things controllable, eq and gain between the 4 triode stages of the tubes (i.e. the voice), other tube control parameters (bias?), all these settings and variables could be changed "on the fly" as they are stored with each (128) program.
Along with volume , master volume, chorus etc.  They also made it stereo (sort of), when the signal hits the chorus (either in or out) the signal is split A & B with B 180deg out of phase (i.e. pseudo stereo). This is also very much part of the magic (for me). 
So more Magic? Well not really, I think they tried (and largely succeeded) in emulating (with real tube circuits) all the other amps of the time. What I loved was I could develop my own tones .

[Harley Hexxe]

Hey INRI,

   Richard nailed it since he has a better understanding of electronics than I do. Even so, I don't need to be an engineer to see when I look in the MP-1, there is a LOT more circuitry than you'll find in any single tube amp, and this is only a preamp! Even with all that, the MP-1 is the simplest of all the preamps ADA made. There are a lot of mods that have been designed for them. I even own a 3TM MP-1 and to be honest, I really don't need much more than the original MP-1. Maybe I'm getting old, but that level of gain in the 3TM isn't really in my wheelhouse. I might roll some different tubes in it to see if I can tame it down a bit, and if that doesn't do it, then I'll probably put it up for sale. It does have a different character than the original MP-1, but it has no clean guitar sounds unless you go S.S.
  Pair any one of these preamps with a good power amp, and you've got a rig that will stand up to anything anyone else has.

   The MP-1 is the reason this Forum started and still exists. And the other ADA preamps and gear are just as good if not better.

[Dante]

People often ask about the rack rigs because they don't understand how that's a guitar amp....I describe it like this; remember stereo systems in the late 70s and early 80s? There was this approach to building a home stereo whereby you could mix/match components (tuner, amplifier, phono player, etc.)

Rack gear is the same philosophy, the Preamp is generating all the tones, the Poweramp is just making things louder, and you have an effects unit (or two, or more) to give you the shimmer. It's a component guitar rig. Use the stuff you like, make your rig.

Where the ADA stuff excelled, as Richard and Harley stated, was that ADA gear is fully programmable. That was unheard of until modelers came around. Well, you don't need a modeler with an ADA, you craft your own tones and just trust you ears.

AS to how they get the 'voices' described, I feel like it's a combination of tube circuitry (sometimes only using one preamp tube) and EQ. I think there are some EQ settings we're not seeing behind the scenes. I'm not technical, this is all presumption on my part (which can be very dangerous )

I've stated for years that Modelers are nothing more than fancy EQ settings to emulate the sound (or voice) of a particular amp

[Harley Hexxe]

Hey Dante,

   That's a pretty good analogy comparing it to integrated stereo systems, I never thought of that, but it's pretty close.
    I usually just break down the basics of a guitar amp like a Fender Twin, or Vox AC 30, or a Marshall Bluesbreaker. All of these are the same thing: a preamp, a power amp, and speakers. You take away any one of these three things and you don't have an amp. As for effects and how they fit into this picture, I like to throw this idea into the picture: Every guitar player knows what stomp box pedals are, because we all started with them, and plugged them into the front of our amps. A lot of those effects do sound better in the front of an amp. Other effects sound much better in between the preamp and power amp.  A rack system lets you put the effects where you want them.

    Here's another question people ask about rack guitar systems: Why would you want a rack type of guitar amp?

  Let me throw out a bit of history of how rack components came into being. In the late 60s and through the 70s into the early 80s, guitar players were using pedals for effects as I mentioned earlier, but many of these things were noisy and some were kind of finicky because they were cheap circuits trying to emulate tricks done in recording studios. Remember the echoplex, or early phase shifters? These are things done with tape decks in the studios. Well, these things evolved into fancy studio processors and sounded so much better than the pedals. Well, now all the high-profile artists got the idea that they wanted to take these studio-grade effects that they used on their records on the road with them when they toured. They bought these high-end processors and had their amps modified to send out line level signals that they could put in these processors, and ran the outputs to separate amps and speakers to duplicate what they did in the studios with the same fidelity. It worked. Stomp boxes got kicked to the curb, and rack processors like Lexicon, Eventide, and a few others were hitting the road and playing arenas around the world. This went on through the early 80s to 1987. That's when Dave Tarnowski saw an opportunity to turn the amplifier industry on its ear, and brought out the MP-1. Now, you could take your preamp signal and insert these processors in between your preamp and power amp, and have all your effects that you want. Plus, he came up with the ideal of making the preamp, which is your basic tone shaper, programmable and allowing you to get any kind of amp tone you wanted from clean to gnarly distorted, and save every single different sound you wanted in a memory chip. Now, you didn't have to be like Joe Perry and take 25 amps with you to every gig. It worked. By the NAMM show of 1988, everyone was making programmable rack preamps. The history speaks for itself.