TUBE COMPLEMENT: (3)
| 1 | Dual Triode 9-pin base 5687WB [JAN Military NOS] | INPUT / DRIVER STAGE |
| 2 | Triode 4 PIN-base Full Music TJ mesh plate premium gold 300B | OUTPUT STAGE |
CIRCUIT DESCRIPTION
All stages operate in pure class "A1" single ended and contain automatic self-biasing circuitry. We have maintained our Topaz tradition in the use of exceptionally large value Solen polypropylene coupling capacitors. This together with our custom built HAMMOND output transformer has endowed this amplifier with very extended low and high frequency response. Each of the two output triodes are individually self-biased, with only the plates tied together in a quasi parallel configuration, which is nearly equivalent to having one high powered triode. Our 12 pound output transformer provides 18 Watts RMS per mono-block with solid bass and absolute stability into all low impedance loads. The output windings can be toggled via two high current switches to allow selection of impedance for 2, 4, 8 or 12 Ohms. WE EMPLOY NO FEEDBACK of any kind due to the low distortion ultra-linear amplification stages employed in this design.
POWER SUPPLIES
- Toroidal power transformer voltage input can be selected for 115V/230V 50-60 Hz operation via an internal toggle switch. Three output windings provide full-wave rectification using spike & noise suppression circuitry.
- Separate DC power supplies provide total isolation between the INPUT and OUTPUT stages. These consist of a triple Π [pi] filter for the 460 Volt output rail and a double Π [pi] filter for the 400 Volt input & driver rail. The use of RC filter networks with very large electrolytic capacitors and wire wound power resistors provide an unparalleled ripple reduction and low noise operation.
- Rectified and filtered DC provide the power for the input tube filament of the 1st and 2nd stage. The other two 300B output tube filaments each have their dedicated regulated DC floating power supply that eliminates the normally found hum adjusting potentiometer. This provides a very low noise floor that allow all subtle nuances in the music to be heard.
MECHANICAL CONSTRUCTION
- Extremely rugged (14 gauge) all welded steel chassis further reduces any possibility of vibration induced signal aberrations.
- Highly polished brass handles allow for easy handling and accentuates the chassis styling.
- Gold plated brass holder with 3M rubber feet inserts accentuates the styling and allows proper air flow for the vents under the chassis
- Very high quality paint / primer coat and baked on finish enhance the artistry.
- A deep lavender color accentuates the satin black finish of the output transformer and toroid cover.
- A cast aluminum box is used to cover the power Toroid transformer to strengthen an already appealing look.
CIRCUIT BOARDS
The components are mounted on a Printed Circuit board [PCB] which is made from FR4 glass epoxy with double sided copper traces and plated through holes. Both sides have a protective green solder mask. A silkscreen is printed in white showing the component layout and parts value. This PCB was designed manually in house. It has enlarged power and signal line traces to attain the best analog integrity that automatic routing circuit programs cannot attain. Our Printed Circuit Board program allows for an infinite varieties of traces and component layouts that can be developed into our own custom library parts. We have created a library of custom component layouts that are specifically suited to develop our Analog circuits. Wiring to the PCB is attached via screw down crimp terminals to allow for ease of repair should the need ever occur where the board would need to be removed. We have reduced the signal path length to less than 6" on the PCB board. The final assembly of parts to the PCB is done by hand soldering of all components, which is superior to automated flow-soldering techniques, by allowing more solder on each and every joint.
AUTO-SEQUENCING
A time-delay relay provides extended tube life and proper power sequencing for stabilized circuitry on power up. The filament voltage is turned on for 45 seconds before applying the DC voltage power, after which the ready (green) LED comes on.
POWER SWITCH
Applies power to the automatic power up sequencing circuit.
OUTPUT IMPEDANCE MATCHING
- Toggle Switches enable setting for 2, 4, 8 & 12 Ohms
- matching numbers indicate which impedance is selected
FREQUENCY RESPONSE
- + 0 / - 1 dB > 11 Hz to 28 kHz
- + 0 / - 3 dB > 6 Hz to 43 kHz
INPUT IMPEDANCE
| LOW | 55 Kohms | GAIN | 20db | > 1.28 VRMS for full output |
|---|---|---|---|---|
| NORMAL | 50 Kohms | GAIN | 25db | > 0.6 VRMS for full output |
| HIGH | 200 Kohms | GAIN | 30db | > 0.38 VRMS for full output |
- ABSOLUTE PHASE:
- non-inverting (can be set to Invert at Factory)
- POWER OUTPUT:
- 18 Watts RMS per Channel
- ENERGY STORAGE:
- 300 JOULES
- Universal Voltage Select:
- 115/230 Volts 50/60 Hz
- POWER CONSUMPTION:
- 185 Watts per mono-block
- WEIGHT (NET):
- 2 x 33 lbs. (30 kg)
- WEIGHT (SHIPPING):
- 2 x 38 lbs. (35 kg)
- DIMENSIONS:
- 9.5" W x 16" L x 8.5" H
- LIMITED WARRANTY:
- Tubes: 1 year
- Components: 5 years parts & labour