KIRKE  |  PHONO SYSTEM  |  TWO CHASSIS

The all new Kirke Triode Fet phono amplifier, a serious contender dedicated to the world of analog reproduction

“The Kirke is our new phono preamplifier design, a testament to our dedication to the world of ultimate analog reproduction.The Kirke is stepping on the shoulders of the Talos Series technologies, and blending our new technologies like the TriodeFet to a result which in in our opinion a redefinition on what a great phono preamplifier can and  will bring out of your vinyl collection. A step closer to the absolute ultimate source.”

DESIGNER

The Kirke is using a more refined and evolved circuits from our top of the line phono preamp designs, like the Talos Limited Edition, as well as our Gen2 TriodeFet circuits, developed and used for our top Ianus Series designs.


Presented with a 64-68db gain from the tube stages alone, combined with the dual onboard  customized fully balanced Step Up Transformers,(selection of 12-26db sut) carries  a total gain of 76-94db  is possible, yet with amazingly high signal to noise. There is enough headroom to amplify the signal of any cartridge to it’s full potential and maximum dynamic range.

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The input stage is the most crucial stage for retrieving and preserving information from the cartridge

Input Stage

As in all phono systems, the input stage is the most crucial stage for retrieving and preserving information from the cartridge. We took all steps necessary to provide the best noise cancelling, microphonic free, linear input stage possible.

The input stage in the Kirke is an evolved design originating from our Talos LE versions, and  is a proprietary differential tube stage, using two independent full tube stages per channel in differential mode. The two stages are using two E280F/6j11pe super tubes per channel ,also mounted on our special Vibration Isolation sockets. The two tubes are loaded with a special transformer, (proprietary blend of MU/permalloy core) with fully geometrically and electrically balanced windings.  The differential input stage is fed either directly from the cartridge in differential mode (from floating RCA or XLR inputs), either by our custom SUT transformers which have true balanced output.

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RIAA Stage

As in all of our phono stages, the RIAA filters are implemented around a constant low impedance Double-T LCR filters. These filters are the most transparent and dynamic filters possible. However being very low impedance, it means that you cannot drive them with usual gain stages.

In the Talos LE, we use a newly developed RIAA circuit with custom coils and capacitors, and is finetuned on the fly, using real time date to provide maximum accuracy to the RIAA curve.

The low impedance RIAA filters are driver by a special circuit designed specifically for driving this constant low impedance filter structure – a small SET amplifier. This small amplifier uses the E280F/6j11p-e super tube loaded with a custom step down transformer. It can drive anything down to 50ohm, and it’s output impedance is tuned to work in combination with our LCR filters to provide accurate RIAA correction Equalization.

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Output Stage

Gain Stage

When we launched the Ithaka dac, with the unique TriodeFet stage , we stated that the crown jewel of the Ithaka concept , is the output stage. This is based on our latest generation of our  TriodeFet technology (the specific TF generation  is only used in our top SE amplifier, the QuintEssence). We could not have it any other way for the Kirke.

The output stage is Single Stage-Single Ended  TriodeFet circuit,  an ultra wide-bandwidth , extreme linearity  stage that will not hold back and waste the previous stages transparency and detail /info retrieval  .

Having an output impedance of 1 ohm, the output stage is as potent of a speaker amplifier, as it can deliver 12W if the converter it directly connected to any speaker. Kirke is not a power amp and not supposed to be having speaker driving duties,, however is a sample to it’s output stage potency.

SUT & Cartridge Loading

Our SUT transformers are also wound using fully geometrically/electrically balanced windings, thus outputting a true balanced output, thus fully benefit from our differential tube input stage.

Amplifying the extremely low level signal in differential mode has the advantage of cancelling out common mode noise. Common mode noise is electrical noise picked up anywhere in the signal chain,  from the cartridge body up to the inputs of the phono stage.

The unit comes with no internal loading presets, as this would predefine and limit loading combinations. Loading is thus provided by our loading modules. These are custom built on request, and tailored to a clients cartridge portfolio. Loading modules can be used for both direct and SUT inputs. Loading modules can be any value requested, and users can load any input independently.

All power supplies are located in a matching second chassis, while local capacitor banks in the main chassis provide local decoupling

The Kirke phono system is powered up from a separate full chassis Power supply. The chassis hosts number of independent power sources for the multiple stages of the design. A total of 8 independent high voltage/current and 5 low voltage power sources are implemented in the separate PSU chassis.

Two extremely low noise tube rectified-multi choke -filtered stage PSU per channel are used for the input and LCR stage,using the high current 6AU4GTA damper diodes, and  quad PI filters using low DCR inductors and film capacitors .

The RIAA driver amplifier is being fed by a separate tube rectified PSU, with it’s own double PI filters to provide unmeasurable noise levels.

The output driver/TriodeFet stage is SS rectified and is using high quality chokes and high speed/current capacitors. A total of 11 chokes are used in combination with low ESR capacitors. These provide eight independent ultra low noise power rails for all four X 2 stages.

Extensive local decoupling  is achieved by high quality capacitors in the main chassis.

 

Technical Specifications

SPECIFICATIONS

Tube compliment:

8x E280F  4x 6d22s 1x Gz34 2x Inverted Triodes

Total system gain::

Min 44 Max 60db without SUT
Additional gain using SUT input : +12~26db

Noise floor:

<80db

Maximum Signal to noise ratio:

90db

RIAA accuracy:

+-0.2db

Inputs:

Customizable

Max Output:

10Vrms

Loading Resistance/capacitance:

Unlimited combinations.
(use of external custom built loading modules)

Dimensions:

540 mm W x 530 mm D x 165 mm H

Weight:

130kg total