SW1X PRE III Line Pre-Amplifier

SW1X Audio Design™ PRE III Performance Level 3 Line Pre-Amplifier

 

The PRE III is a near unity gain, zero negative feedback (global or local) design, decoupled with signal output transformer, which not ony increases transparency (not possible with any kind of capacitors) but also lowers the output impedance further close to 10 Ohms. That makes PRE III (as well as the DHT version PRE IV) essentially a power amplifier with line stage output level and volume control, which will enable to drive subsequent power amplifiers to its full potential. In the PRE III pre-amplifier we utilise both EL84 on the output with 5687 as a driver. EL84 is a classic power pentode, which was popular in electric guitar amps and most radios in the 50s and 60s and is known for its articulate character.

In combination with finest materials & component, the sound of the PRE III is transparent, characterised by scale, authority and dynamic bite. It is a great enhancement to any tube power amplifier, driving a sources (DAC or Phono), which has a weaker small signal, indirectly heated tube based output stage.

Available in either double C-core Super HiB transformer version or Pemalloy core version (Special version) and the limited production Signature version on request. The option of a Phono pre-amplifiaction stage will be available in the forthcoming PRE III LPX version.

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SW1X Audio Design™ PRE III Line Pre-amplifier Features:

• Specially selected and harmonically matched component & material quality Performance level 3/4
• Anode follower, zero NFB, signal output transformer de-coupled valve output stage
• Double C-core Super HiB transformer or 80% Nickel Pemalloy core signal ouput transformers
• 1 x double triode 5687 driver, 2 x EL84 triode connected power pentode tube design
• 2 x Mono, 24 Way, discrete resistor Stepped Attenuators made from the Finest Materials and Specially Selected Resistors
• Directly heated Tube rectified CLC (choke filtered) B+ power supply
• For maximum transparency & dynamics, the circuit is hard wired with of a specially selected conductors (single strand or Litz)

 

Tube Compliment:  2 x EL84, 1 x 5687, 1 x 5U4/GZ32

 

Optional Extras:

• Audio Note 2W copper, non- magnetic, tantalum film resistors on plates, cathodes, power supplies
• Audio Note Silver Foil capacitors in inter-stage and ouput stage signal decoupling option
• Circuit is normally wired with specially selected copper but can be ordered with fine silver wiring (including power inlet)
• HiB double C-Core mains transformers and chokes in the power supplies

 

 

Note: Due to SW1X Audio Design’s ongoing research and development process, specifications are subject to change without notice.

Specifications

Dimensions: Height (mm) 150 x Width (mm) 440 x Depth (mm) 400

Weight (kg): 15

Max Power Consumption (W): 80

Output Noise, Unweighted (mVrms): < 0.5

Output Impedance (Ohms): 10

SW1X Audio Design Product Price List

 

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SW1X Audio Design Philosophy