Description
Specifications
- Common cathode class-A gain stage with no feedback, passive RIAA equalization and cathode follower buffer stage
- 2 x 12AX7 for RIAA correction and 1 x 12AU7 for buffer stage
- Cartridge Compatibility: Moving Magnet
- Input Impedance: 47k ohms
- Output Impedance: 322 ohms
- Gain: 39 dB gain @ 1kHz
- Distortion: <0.05% @1kHz
- Equalization: RIAA +/- 0.5 dB, 40Hz to 30kHz (measured)
- Regulated 12VDC heater power supply elevated to 90V
- Current draw: 24mAmp at 300VDC
- Classic Dale grid resistor
- Reverse-able main Phono amp PCB. Components can be soldered on the same side as the valves OR on the opposite of the valves. This feature enables builder to mount the board with valves outside chassis OR valves being inside of the chassis.
Documentations / Downloads
- Classique Valve 12AX7/12AU7 Phono RIAA schematic
- Integrated Power Supply schematic (linear power supply for HV/B+ and regulated supply for LV)
- Complete schematic (showing phono amp, main supply and heater supply)
- Wiring Diagram UK / Europe / 230VAC
- Wiring Diagram US / 115VAC
- Parts List (Bill of Materials)
- Build Guide
- Mounting plate drawing
- Transformer datasheet
- IEC socket datasheet (Bulgin C14 – PF0001/63)
- Power switch datasheet
The Components
Please note the list below is the complete list for the kit. What you get will depend on the kit ordered.
- 2 x 12AX7 valves and 1 x 12AU7 valve
- 1 x main power transformer – locally made
- 1 x integrated power supply PCB and components (for B+ and heater filament)
- 1 x phono amplifier PCB and components
- 1 x mounting plate (3mm aluminium)
- All screws / nuts / bolts / spacers
- Carling Technologies double pole switch
- RCA input/output terminals
- IEC power socket with with internal fuse slot
The Kit
There is a number of different kits that can be purchased here, depending on your requirements. The simplest kit, Kit A is the PCB and components only, where you will have to purchase everything else.
Please also note that valves (tubes) are NOT included in any of the kits. You will have to source 2 x 12AX7 and 1 x 12AU7. These valves can be purchase from our shop too.
- Kit A = Phono PCB + Components – main phono amplifier PCB and all electronic parts and components (you supply transformers and power supply boards)
- Kit B = Kit A + Integrated Power Supply PCB (includes all electronic parts and components – you supply 2 transformers)
- Kit C = Kit B + 2 transformers
- Kit D = Kit C + mounting plate + wooden enclosure + switches + RCA terminals + IEC power socket + nuts/bolts/stands/washers (this is the complete kit)
Audio Analysis
Graph below shows the measured frequency response tested using 2 x Electro Harmonix 12AX7 and 1 x Electro Harmonix 12AU7:
IMPORTANT NOTES AND DISCLAIMER
This product is sold as a kit, which means that buyer would have to assemble all parts. Printed circuit boards (PCB) are not populated so all parts will have to be soldered onto the PCBs.
It is assumed that buyers would have the knowledge of:
- soldering
- assembling screws/nuts/bolts
- highly skilled and knowledge of high voltage electric circuits and parts
