Kaskode One Phono Preamplifier

MM + MC Class-A Phono Stage

Passive RIAA EQ, Ultra-low noise, Open loop

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

Kaskode One

Moving Magnet Only

$4,899.99

Moving Coil Module

Add-On

$599.99

For MM + MC, order both the Kaskode One and Moving Coil Module.

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All Tube Signal Path...

​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).

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 flexibility.

 

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 triode strapped, the D3A gives extremely low noise, extremely high gain, and excellent linearity. The D3A is 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.
 

No longer worry about compatibility when upgrading your cartridge....

 

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 a 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 discrete high voltage regulators and filament supplies to remove crosstalk. Extensive filtering is used throughout for extremely clean power.

 

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

The Circuit​

"The Kaskode really embodies what I think of when the word analog is brought up."               

                 

                   -Jeff Dorgay

TONEAudio / AnalogAholic

Kaskode One Typical Specifications

Gain MM Mode

46dB

 

Gain MC Mode (with MC Module Installed)

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 Consumption

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 Kaskode One is designed with a time-delay start sequence to ensure 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.

On board Moving Coil support...

The Lundahl MC step-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 in this module.

 

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.

 

Features​

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.

 
 
 
 

Kaskode One Features​


 

  • SHIPS WITH NOS SIEMENS D3A AND EC8010 GOLD PIN TUBES

  • IN HOUSE MATCHING OF TUBES ACROSS GM, MU, 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 NOISE

  • GROUND LIFT SWITCH FOR FLEXIBILITY WHEN INTEGRATING WITH AN AUDIO SYSTEM

  • SORBOTHANE® FEET FOR VIBRATION ISOLATION

Kaskode One PDF Documents

MC Configuration Tool

Related Technical Articles

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