SW1X Audio Design™ SPA IV Apollo
Performance Level 3/4/5
2A3 DHT Power Amplifier
SPA IV is a 3 gain stage Stereo Power Amplifier without input switch and volume control. Therefore it is ideally paired with our PRE III or PRE IV Line Pre-amplifier.
Available in different versions: Standard, Special and the limited Classic or Signature versions with different power output transformer options (M6, SHiB and UHiB) and all Copper or Copper/Silver windings
SW1X Audio Design™ SPA IV Integrated Amplifier Features:
- Specially Selected and Harmonically Matched Component & Material Quality
- Single Ended, absolutely Zero NFB, Class A, Directly Heated Triode Valve Power Amplifier
- 2 x 6J5/6SN7 Triode driver/input Stage Valves driving the 2 x 2A3 DHT Valves
- 3 Amplification Gain Stage Design
- Point 2 Point Hardwiring Technique for the most consistent production results
- Internally wired exclusively with our SW1X Magnum, Genesis and Opus conductors
- SW1X Audio Design™ Custom Designed (50 Watt) Signal Output Transformers
- Quasi Mono, Directly Heated Double Diode Valve Rectified B+ Power Supply
- Orient grain M6 EI core mains Transformers & Chokes
- Valve rectified Fixed Bias Power Supply
Tube Compliment: 2 x 6J5, 2 x 6SN7, 2 x 2A3, 1 x 5U4GB, 1 x 5Y3
SPA IV is avaiable in 4 Versions with either Satin Silver or Matte Black front Panels
with a following output transformer (OPTs) specifications:
- Standard : SW1X Audio Design™ all Copper wound, orient grain M6 EI Core OPTs
- Special : SW1X Audio Design™ all Copper wound Super HiB DC Core OPTs
- Classic : SW1X Audio Design™ Copper/Silver Windings, Super HiB DC Core OPTs
- Signature : SW1X Audio Design™ Silver/Silver Windings, Super HiB DC Core OPTs
Optional Extras
- Silver wound SW1X Audio Design™ Custom Designed Super HiB or Ultra HiB DC core Signal Output Transformers
- Fully Hardwired Tube Output Stage on the Bakelite Board
- Fine Silver wiring on the Input, Bakelite Board and Output
- AN 2W non-magnetic Niobium resistors on a Hardwired Bakelite Board
- Super HiB double C-Core mains transformers
- Inter-stage signal decoupling capacitors: 1. Copper Foil in Oil or 2. Silver Foil capacitors
- AN 2W silver, non-magnetic, Tantalum resistors
Specifications
Single Ended, Class A, Zero NFB, Output Power (W): 4, which sound at least like 25 Watts and the dynamic delivery feel like 250 W
when paired with with High Sensitivity Speakers (min 96dB/W/1m is recommended)
Input Sensitivity (V): 1
Input Impedance (Ohms): 47K or 100K
Output Impedance (Ohms): 4 & 8
Max Power Consumption (W): 250
Output Noise, Unweighted (mVrms): < 0.5
Dimensions (without tubes and feet): Height (mm) 250 x Width (mm) 440 x Depth (mm) 400
Weight (kg): 35
Note: Due to SW1X Audio Design’s ongoing research and development process, specifications are subject to change without notice
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