Kaskode One Typical Specifications


Gain MM Mode

46dB


Gaim MC Mode

60dB (1:5 Step-up)

66dB (1:10 Step-up)

72dB (1:20 Step-up)


Channel Balance (Both MM and MC)

<0.2dB


THD+N (MM 3.5mV Input 1KHZ)

<0.05%


RIAA Accuracy

+/- 0.2dB from 20Hz to 40KHz


Frequency Response (-3dB down)

<10Hz and above 175KHz


MM Input Referred Noise (A-weighted)

0.2uV

-132dBu

-88dB SNR relative to 5mV input


MC Input Referred Noise - 1:10 (66dB) Mode (A-weighted)

0.058uV

-142dBu

-72.5dB SNR relative to 250uV input


Rated Output

15V at 0.5% THD+N


MM Input Resistance

47KΩ


Input Capacitance (Selectable)

50pF, 75pF, 100pF, 125PF, 150pF, 175pF, 200pF, 225pF, 250pF, 275pF, 300pF, 325pF, 350pF, 375pF or 425pF


MC Input Resistance for each Step-up Ratio (Selectable)

60dB (1:5):       1910Ω, 1590Ω, 1230Ω, 830Ω, 630Ω, 430Ω, 254Ω, 157Ω or 70Ω
66dB (1:10):     478Ω, 398Ω, 308Ω, 208Ω, 158Ω, 108Ω 64Ω or 39Ω
72dB (1:20):     119Ω, 99Ω, 77Ω, 52Ω, 39Ω, 27Ω or 16Ω


Recommended Load (Output)

10KΩ or greater 


Tubes (Tested and Matched in House)

2x D3A NOS Gold Pin Siemens

6x EC8010 NOS Gold Pin Siemens


Voltage

Available in 115-120VAC or 230-240VAC


Power Consuption

90 Watts


Dimensions (Includes faceplate and feet)

17.5” x 14.25” x 4.5”


Due to the open loop design of this amplifier, actual performance will vary depending on vacuum tube quality. Specifications subject to change

The Circuit


The Kaskode One was designed on the principle of a zero-global feedback or open loop amplifier design. For this type of design, the most important ingredient is vacuum tube performance, which will set the performance of the entire circuit. For this reason, we abandoned standard off the shelf tubes found on most phono preamplifiers and designed our circuit around the NOS West German Telefunken manufactured and Siemens branded D3A. When tridoe strapped, the D3A gives extremely low noise, extremely high gain and excellent linearity. The D3A used in the lower half of an all tube cascode input stage. 

Siemens EC8010 triodes are used in the upper section of the input cascode and throughout the rest of the preamp. In the output stage of the Kaskode One, the EC8010 provides very robust drive capability for consistent sound quality even with long interconnects.

The front panel of the Kaskode One has switches to control the input mode (MM or MC) as well as mute. In MC mode, Lundahl step-up transformer modules can be configured to 3 different gain settings, 1:5 1:10 and 1:20 with dip-switches. These modules can be run as balanced or unbalanced. In balanced, the primary input side of the step-up transformer is isolated from circuit ground. This allows for high noise rejection when using and XLR cable from the cartridge to the phono preamp input. In unbalanced, either the RCA or XLR MC inputs can be used.


Power is sourced from a custom designed low noise and low flux density EI core transformer. Compared to a toroidal transformer, the EI core is extremely forgiving to power quality for consistent sound. Power is sent to dual mono power supplies using precision desecrate high voltage regulators and filament supplies to remove crosstalk. Extensive filtering is used to throughout for extremely clean power.


Premium components are used throughout for the upmost performance, sound quality and longevity.


Features


​The Kaskode One is designed with a time delay start sequence to insure all operating voltages are stabilized and the preamplifier is ready to play audio before the output is active. This removes the chance of any pop and noise during power on and off. The Kaskode One can be turned on and off without any need for power sequencing with other equipment. The “Active” indicator on the front panel shows the status of the power on sequence. The preamp output will be active approximately 60 seconds after power on.

The Lundahl MC setup-up module is an optional plug in for those who run Moving Coil type cartridges. It has been designed so that the user can later upgrade their Kaskode One by plugging this module in.


With the Lundahl MC step-up module installed, the following gain and input cartridge loading options are available:

60dB (1:5):          1910Ω, 1590Ω, 1230Ω, 830Ω, 630Ω, 430Ω, 254Ω, 157Ω or 70Ω
66dB (1:10):        478Ω, 398Ω, 308Ω, 208Ω, 158Ω, 108Ω 64Ω or 39Ω
72dB (1:20):        119Ω, 99Ω, 77Ω, 52Ω, 39Ω, 27Ω or 16Ω


The user can also enable or disable a 20Hz subsonic filter to remove inaudible noise like record warp which would otherwise consume amplifier power and reduce headroom.


Construction


An aluminum chassis with stainless steel hardware houses the circuitry for superior shielding to minimize magnetic coupling from external sources. Inside the chassis, the power supply is isolated from the sensitive amplifying stages with an extra thick cold rolled steel baffle. The ferromagnetic baffle keeps any magnetic noise and interference out of the signal path.


The chassis design allows the Kaskode One to achieve superior noise performance without the added cost, complexity, and space requirements of typical two chassis phono preamps. Top and bottom venting  keeps the Kaskode One running cool for long tube life while Sorbothane isolation feet reduce mechanical vibrations.


The circuit is built on extra thick FR4 PCBs for high reliability and lowest noise. All connectors are mounted on the rear panel of the unit and hand wired to the PCB for long life.


The Kaskode One is extremely flexible offering both Moving Magnet (MM) and optional Moving Coil (MC) support in a single unit. MM mode gives 46dB of gain whereas MC mode has user configurable step-up transformers with either 60dB, 66dB or 72dB of gain. For MC mode, each step-up ratio has a wide range of input resistances for properly loading your MC cartridge. All cartridge loading options are controlled by dip-switches for easy selection and maximum felxability.

Additional Options


  • Moving Coil Module is available to convert MM only to​ MM + MC

The Kaskode One was designed for one purpose; to get the absolute best sound and performance from your phono cartridge. 

The Class-A all tube signal path utilizes the finest NOS special quality (SQ) tubes, creating one of the lowest noise fully integrated tube phono stages available. ​Fully passive RIAA equalization is implemented with hand matched components for not only extremely tight RIAA accuracy, but also matched performance between channels. Tight RIAA accuracy combined with a wide bandwidth open loop design provides superior transient response allowing you to hear deeper into your favorite records. ​All tubes are matched in house at their operating conditions across 4 key parameters; gm, u, Rp, and Ia (transconductance, gain plate resistance and current).



Related Technical Articles

Kaskode One Tube Phono Preamplifier




Redefining High Fidelity Audio Reproduction!

​​​​​   Kaskode One Features


  • Ships with NOS Siemens D3A and EC8010 gold pin Tubes
    • In house matching of tubes across gm, u, Rp, & IA
  • MC MODULE CAN BE INSTALLED BY THE USER AS AN UPGRADE
    • High performance Lundahl MC transformers
    • supports 1:5 1:10 and 1:20 step-up ratios
    • SUPPORTS BALANCED AND UNBALANCED CONNECTIONS
    • XLR AND RCA INPUTs FOR MOVING COIL MODE
  • Mute switch to easily quiet playback
  • Dual Mono regulated power and filament supplies
  • Selectable subsonic filter to remove warp and rumble below 20hz
  • Time delay output active circuit for pop free startup and shutdown
  • custom designed low flux density EI transformer
  • Extra thick FR4 printed circuit boards​
  • aluminium chassis with steel divider for lowest nosie
  • Ground lift switch for fexibility when intergrating with an audio system
  • sorbothane feet for vibration isolation

MM + MC Class-A Phono Stage

Passive RIAA EQ, Ultra-low noise, Open loop 

Handcrafted in Chicago IL USA

Kaskode One PDF Documents