 |
  Gain Cell The heart of any audio product is a gain stage. In a preamplifier, for example, the gain stage is needed to amplify a selected audio source such as a CD player, DVD player, tuner, or outboard phono stage. Gain stages can be built with tubes, transistors, integrated circuits or any number of combinations of electronic components that have been used in countless ways over the years people have been enjoying audio and video in their homes. Another example might be a power amplifier where there is also a gain stage. In a CD player or DVD player; yet again there is a gain stage, amplifying the output of the disc. In fact, every audio product from a surround processor to a simple receiver has at least one gain stage built in. Many designs require multiple gain stages. The gain stage is the heart of all audio products. For over 25 years, PS founder Paul McGowan has been working on the perfect gain stage. A stage with Pure Resolution™ and no compromises. Along the way this research has manifested itself in a multitude of high-end audio products, each with an improved version of the ubiquitous gain stage; unfortunately none perfect. The problem with creating the perfect gain stage is the diversity of applications it must fit into. One gain stage might work best on a DVD player, another could work in a preamplifier and yet another design is required for a power amplifier. The perfect gain stage should be capable of being programmed to meet all these requirements in any design.  The perfect gain stage would have little to no distortion under any operating condition. It would have no audible noise, it would be fully balanced from input to output, 100% analog, have exceedingly high common mode rejection, frequency response flat from 1Hz to over 50kHz, handle every input signal from the loudest to the quietest, high input impedance so you can drive it with a tube circuit, and its gain would be adjustable over at least a 100dB range. That’s a pretty tall order. But if you could create such a stage, then you could literally drop it into any audio product and create the perfect piece of equipment.Introducing the perfect gain stage We call it the PS Audio Gain Cell™. The Gain Cell™ is the culmination of Paul’s 25 years of research and work, turned over to PS Engineering to bring the Gain Cell to life in its modular form. The Gain Cell™ is the single most revolutionary advancement in analog audio design since PS Audio was founded in 1973. Not just a gain stage, the Gain Cell represents an entirely new way of thinking about audio amplification. Gain Cells are not based on the traditional gain block that uses varying amounts of feedback to control the gain as is typical in solid state and tube designs. In fact, the Gain Cells are entirely different in their concept and operation and perform almost entirely in the current mode rather than the voltage mode. The PS Audio Gain Cell is a single block of analog gain in a potted module. You can place any size signal into the Gain Cell’s input, from any source (balanced or not), and the Gain Cell will handle that input with near perfection. In fact, you can place up to 10 volts rms into the Gain Cell with no problem whatsoever. For reference, a typical CD or DVD player outputs perhaps 2 volts rms, some Audiophile DAC’s can produce a whopping 5 volts rms, but the Gain Cell won’t care. Once the Gain Cell has received the input, you can adjust the gain of the Cell anywhere from -100dB (essentially no gain) to +30dB instantly; and because the Gain Cell is  100% analog there are no steps in the gain. This means that you can adjust the gain in increments smaller than a thousandth of a dB if you wanted to (a gain step this small is undetectable by the human ear). Further, the performance of the Gain Cell does not vary with gain. Wherever the Gain Cell is set it will perform identically, so from the loudest to the softest gain, the Gain Cell will sound identical.The output of the Gain Cell can drive even the most inefficient of preceding stages with its fully balanced output of up to 5 volts rms and its low output impedance of less than 100 Ohms. How the Gain Cell is used Gain Cells can be used in virtually any piece of audio equipment as an input gain stage, an output gain stage, a volume control, an electronic input isolation transformer, a phono stage, and the list goes on endlessly. In the new GCA amplifier series, Gain Cells are placed in front of the SDAT output stage, set to a fixed gain of 27dB and voila! One of the world’s best sounding power amplifiers is born. Depending on the power of the SDAT™ output stage, we can build any wattage amplifier from the smallest power amp to a whopping 1000 watt amplifier (and beyond) and all with the same Gain Cell as the input.  If you take the same GCA power amplifier and, instead of fixing the gain to produce 27dB, you simply vary that gain with a knob on the front panel or a remote control, you have an integrated amplifier. So revolutionary is this concept, that we have named the integrated a Control Amplifier instead of the classic “integrated amp” title. This is because a traditional integrated amplifier couples a preamplifier and volume control on the input of a power amplifier and places all three in one box. Never before has an integrated amplifier been created with no additional components in the signal path to change the volume up and down. Gain Cells make it possible to build the world’s first true Control Amplifier and we have created an entire series around this concept called the GCC Amplifiers. No longer is the “integrated” a compromised product built for convenience and fewer components. The GCC series is the shortest and simplest audio path ever built. Imagine, separates are now compromised and the integrated is a purer path. Will wonders never cease? No volume control in our preamp! How many preamps do you know of with no volume or balance control inside? We'd wager to say 'none'. But the new GCP series of preamplifier from PS Audio has no volume control inside. The GCP preamplifier is simply a pair of Gain Cells, and a means of selecting which input feeds the Gain Cell. It’s that simple.  Think about it: no volume control! In a typical preamplifier once the input has been selected, the preamp’s internal gain stage amplifies the signal at a constant level. You then need to add a volume control to throw away whatever signal you don’t want. Even the finest volume controls add distortion and sonic grunge to the signal. The GCP series using our Gain Cell is the world’s first preamplifier with no volume control, no balance control and no need to ever throw away any of the signal. The Gain Cell can be controlled over a 130dB range which means that any input from any source, whether it’s a CD player, a DVD player, a phono stage or a tuner can play through the preamp at the very lowest level to the very highest level with no additional circuitry and no degradation. How's it sound? Like nothing you've ever heard before and we mean that literally. The Gain Cell has no sound to it at all. Just Pure Resolution™ with no compression, no loss of dynamics, a beautiful top end and thunderous bass. Whatever is on the recording is preserved and passed on by the Gain Cell with no noise, no distortion, no frequency abberations: nothing. The Gain Cell is about as close to perfect as you can imagine. What’s inside the Gain Cell So revolutionary is the Gain Cell design that we’re not going to publish what’s inside nor do we intend to patent it. Instead, we have chosen to protect the technology by encasing the circuitry in non-conductive epoxy (known as potting), thus keeping our competitors completely in the dark. As typical of PS we'd love to share this news and design secrets with our customers, but considering the lifetime of work required to build such a device we feel strongly that it needs to be protected. What we can tell you is the following: each Gain Cell is built with a  ll surface mount parts on a small 1 inch by 3 inch PCB. Each Gain Cell must be hand tuned before it is encased in the epoxy. After encasement, there are three trimpots used to tweak the Gain Cell's performance on a per-unit basis. These adjustments mean we can set each Gain Cell's performance to within 1/10th of a dB between channels within any particular unit we choose to build.Each Gain Cell is 100% analog. That means there are no digital parts inside the Gain Cell. Each Gain Cell is a fully balanced design from input to output with no coupling capacitors anywhere near the signal. Gain Cells have one of the cleanest, purest audio paths in the world. Gain Cells have impressive performance to say the least:
|
More Articles
Reviews