Technical

The First Sound Linestage uses a pure Class A triode circuit with no negative feedback. Tube regulation is employed in the power supply with massive power supply storage. There is only one triode tube per channel in the signal path. This ensures the highest level of signal purity possible in an active circuit. The results are unmatched sonic performance along with very high reliability. The circuit uses a minimalist and direct approach reflecting our company philosophy.

Frequency Response: 5 Hertz to 250K Hertz, +0, -3db
Input Impedance: 150 Kilo Ohms
Output Impedance: 1200 Ohms
Absolute Phase: Inverting
Total Harmonic Distortion: less than 0.4% at 2V
Noise: Better than 91 db below 2V
Maximum gain: Greater than 15 db at 1 kilohertz
Tube Complement: 2 6DJ8 or comparable, 2 OA2
Maximum input: 6 Volts RMS.
Inputs: Six line-level inputs
Outputs: Two main outputs, one tape output
Dimensions: Main chassis: 18″ W x 14″ D x 5.5″ H
Power Supply: 8″ W x 13″ D x 5.5″ H
Shipping Weight: Paramount Statement: 159 lbs., Paramount: 81 lbs., Presence Deluxe 4.0: 78 lbs., Presence Deluxe: 57 lbs.

The External Power Supply
The First Sound Linestage uses a power supply the is separated from the main chassis and audio circuity. It is connected via a custom made umbilical cord. The sonic performance is greatly enhanced using this configuration. A power transformer emits different kinds of spurious radiation and by its nature vibrates. These two elements negatively affect the music signal when placed close to the audio circuit and its components resulting in a degradation in the performance. Removing the power transformer away from the main chassis prevents this from occurring. Though implementing an external power supply is expensive, it nevertheless ensures the purity of the signal from spurious radiation and vibration from the power supply.

The ON/OFF Switch
The on/off switch of the First Sound LInestage is an electromagnetic circuit breaker. It functions as a regular on/off switch and replaces the regular a.c. fuse. The electromagnetic circuit breaker provides a solid contact for the a.c. to go through. The a.c. in a standard fuse goes through a very thin wire. The connections in the electromagnetic circuit breaker are direct soldered. This ensures full contact in the electrical junction.

Current Rating of the Bridge Rectifiers
The current requirements of the First sound Lines stage is relatively small at less than 1 amp. The current rating of the bridge rectifier used is 15 amps. Such overkill is not by accident but by design. Aside from having great safety margins in using overly large current ratings, this again ensures the unimpeded flow of electrons to their destination, resulting in a power supply that is quick, instantaneous and responsive to the needs of the music. The bridge rectifiers are made from discrete parts using Hexfred diodes. This translates into a focused, effortless and natural performance with clear and defined presentation at the musical extremes.

Power Supply Storage
The First Sound power supply is unparalleled in the industry. The power supply uses large 2.0″ x 4.125″ computer grade electrolytic capacitors as storage. These provide for vast amounts of power reserves. The total capacitance used in the Presence Deluxe MKIII-SI is at least 230,000 mfd. The total capacitance can go up to 578,000 mfd and higher depending on the model. The extremely large power storage used ensure enormous amount of power is readily available instantaneously. No delay or lag in the power delivery. This provides stability and filtering in the power supply.
The result of the massive power supply is excellent and unexcelled sonic attributes. The lowering of the noise floor, the creation of a soundstage that is stable, spacious, free of grain, smear, electronic haze and more. The transients extends to the highest high and the lowest low with blazing speed and recovery. Bells and cymbals are recreated with such realism that you can almost see the thickness of the instrument and smell the brass. Bass plunges to the very bottom depths with such speed, authority and weight while retaining the very subtle nuances, giving such texture and delineation to the bass notes you never have thought you would be able to experience.
The music is allowed to present itself with all of its intricacies and purity.

Advanced Power Filtering
There are multiple layers of power filtering employed in the First Sound. Featuring the very complex MPDA (multi-phase differential array) 30 element surface mount filter network and proprietary component filters that isolate electrical noise. Each component on its own greatly reduces electrical noise. The synergy of these two components working together far exceeds the sum of its parts.

The Custom-Made Umbilical Cord
The umbilical cord uses the advanced Power Supply Delivery System (PSDS). Four large 12 gauge high purity OFC copper wires with advanced geometry are used with mil-spec high current Amphenol connectors. Close to over 500 painstaking steps are needed to craft this unique umbilical cord. These same robust wires are used from the external power supply all the way to the main circuit board. The combination of all these elements allows for the unimpeded and direct flow of power to the audio circuit.

The Main Chassis
The main chassis is made out of .06 inch thick cold rolled steel. It is plated with copper as per MIL-C-14550B Class 2 specification. The combination of steel and copper provides the best shielding against spurious radiation in the environment. This shielding allows the audio circuitry to perform to its maximum potential and not subjected to any degeneration from the external spurious radiation. Copper plating has the added benefit of lowering the resonant frequency of the steel chassis to a level that is harmonics with the musical signal.

Dual Mono Construction
The main chassis uses a true dual mono construction in all the First Sound models. All controls and components are repeated for both the Left and the Right channels. Separating the components for the left and right channels decreases the possibility of the crosstalk between channels. Crosstalk can lead to poor focus, instability of the presentation, smear of imaging, grain and inability to have clear delineation of the different instruments and their location in the soundstage. Minimizing crosstalk or having great channel separation is one of the key aspects of a great sonic performances. The importance of a dual mono construction cannot be overstated. Dual mono construction is effectively the best way to minimize crosstalk. This is the reason all First Sound models employ dual mono construction.

Separate Tube Mounting Platforms
In adherence to the true dual mono construction philosophy, the First Sound employs separate left and right mounting platforms. These are made from the same material as the chassis and also plated with copper. These platforms are shaped in an L figure with one of the planes held vertically to provide for further shielding from the other channel. It houses the separate circuit boards in its underside (for further shielding) and attenuators and selector switches, along with the computer grade electrolytic capacitors.

Short Signal Path
Four long brass rods are apparent when looking inside the First Sound. These rods extend the controls for the volume and selector switches located at the back of the unit. Keeping the switches at the back allows for a very short signal path. This philosophy extends to the traces on the circuit boards as well. A short signal path the lessens the possibility of sonic degradation while maintain the integrity of the signal.

The Use of Damping Materials
The use of damping materials is employed on all the First Sound models. Circular damping materials along with other vibration absorption devices help tune the overall performance. Vibrations or resonant frequency play a significant role in the sonic signature of a chassis. Extensive listening tests were conducted to determine the level of damping needed to produce an overall balance in the chassis. The chassis is tuned to be in harmony with the overall presentation.

High Grade RCA Connectors
Gold plated solid body rca connectors provide performance levels that fit the parameters of excellence of First Sound. The solid body construction ensures that there is no gap or breach in the flow of electrons. The gold plating provides for superior contact and resistance to oxidation. These high quality gold rca’s are chosen for their sonic performance. Giving the perfect balance.

The Use of High End Wire
First Sound uses custom wire from high end wire manufacturers. High purity ofc copper is exclusively employed in the signal path. An array of various wire sizes are used in the signal path. Specific wires are used particularly only for that portion of the circuit. Additionally the art of blending various wire sizes is used to provide the utmost performance.

Air Dielectric Wire Array
Wire dielectric is a quandary for wire manufacturers. The balancing the need to have a dielectric and its adverse effects to the performance. A wide range of dielectric materials are used from teflon, polypropylene to silk and other exotic materials. The aim is to minimize the effect of the dielectric on the signal. However, each material presents its own inherent sonic signature. First Sound uses air dielectric on its audio signal path. Practically speaking, no dielectric. This approach is the best way to eliminate the effects of the dielectric. The result is greater purity of the signal itself.

Extensive Grounding Network
The complex grounding topology used in all the models of the First Sound the linestage is derived from the First Sound Passive Unit. This particular grounding technique is unique in the electronics industry. It can only be found in First Sound products. Such extensive topology provides for quieter backdrop that allows the music to unfold in its entirety. It further establishes the quick and controlled bass response along with the full bodied expression of the high frequency. The importance of proper grounding cannot be emphasized enough. There is a delicate balance in the relationship between the positive and negative legs of the signal. The experience gained from the grounding network of the First Sound Passive has been used to allow the First Sound linestage to excel in all aspects of the musical performance.

Attenuator
The First Sound linestage uses an array of discrete resistors on a switch to set the volume level. This is called an attenuator. These hand made attenuators are superior to any volume potentiometer (commonly known as a pot) with regards to the manner of providing attenuation. The resistance in a pot is done through having a film of carbon spread over a plastic film. The thickness of the carbon would vary from one end to the other thus providing the means of attenuation. An attenuator on the other hand has discrete resistors with specific values to set the attenuation level. The performance of a specific resistor is infinitely better than having carbon on a plastic film. The switch used in the attenuator of all the models of First Sound is the same switch used to select the inputs. This switch is a massive with a current carrying capacity of 25 amps! The very high rating ensures the uninterrupted low loss delivery of the signal in the full frequency spectrum. Premium quality metal film resistors are used and for the LTV92 attenuator, the unparalleled naked Vishay thin foil resistors are used. The attenuator is painstakingly crafted where each end of the resistor is looped once through the solder lug then crimped. After which it is soldered. The extra step of looping the resistor leads through the solder lug ensures mechanical reliability and optimum contact between the surfaces. The careful process of hand crafting each attenuator results in a presentation that is clear, focused and natural. The lack of grain and smearing, the rounding of the edges and loss of the inherent subtlety of the musical instruments are some of the obvious aspects achieved when using an attenuator.

Caddock and naked Vishay resistors
These premium brand name resistors are at the top of their field. Using metal film foils as the resistive element provides for an unparalleled performance. Due to their excellence, these are the only resistors employed in the main circuit. Using anything less would result in a sharp decrease in sonic performance.

Non-magnetic Hardware
These are used throughout the unit particularly in critical areas such as in close proximity to the audio signal. All used in other instances to balanced out the resonances of the chassis.

Upgrade Options
All First Sound Linestage models are upgradable. From the Presence (circa winter 1992) to the models last year, each unit can continually add on options that raise the level of performance all the way up to the top level of performance. This provides a gradual and convenient path for attaining a desired level of performance without having to have to sell current unit at hand. This further gives an opportunity to see the difference between each level of the options/performance, giving an added dimension in developing ones high end system.