Jade

The Jade has been upgraded with the analog circuit and power supply taken from the Pearl. In addition a new selector circuit board mounts to the back of the input RCA connectors and now uses relay switching for all functions. Front panel selector and tape monitor switch, now control the relays, which handle the routing of the signal. Previous coax wiring running from the rear to the front selector & monitor switch has been eliminated, reducing the length of the signal path while eliminating much wiring and labor cost. This also enhances the life expectancy and reliability.

As a consequence the Pearl name has been discontinued and the new product will retain the name of the Jade. The new unit will sport the 24K gold plated knobs previously used on the Pearl. The Jade's former black nickel knobs will still be available while supplies last at a no cost option

This line amp uses a grounded grid configuration which is isolated by a cathode follower stage before and after it. All three stages are non-inverting thereby maintaining absolute phase. The grounded grid configuration is known for its extremely wide bandwidth and high speed! Each channel cathode follower is provided with two RCA output jacks to accommodate bi-wiring or bi-amping. All stages are DC coupled and only one capacitor is used in the output stage for DC blocking. No feedback is used and mirror image circuitry is implemented using a separate circuit board for the audio section.

Power Supply

A unique design for the power supply was implemented in order to eliminate all ripple and noise.

The power supply is built on a separate terminal board, and uses passive shunt regulation of the 200 volt DC supply.

A dual π (pi) filter, consisting of two large chokes, a large electrolytic reservoir capacitor, several polypropylene capacitors and an array of high power (30 W) zener diodes are used to shunt the current while stabilizing the DC voltage level, providing exceptional power for the analog circuitry.

This filter is designed using only passive components that allow the speed of the power supply to keep up with the analog circuitry. DC for the filaments is supplied using a solid state 3 terminal regulator for hum free operation.

We have avoided using active feedback in order to maintain the speed of the power supply in relation to the extremely fast analog circuitry. Stability is ensured by the use of a large electrolytic reservoir capacitor and speed is enhanced by using a large (30µf) polypropylene film capacitor as a final filter stage located directly on the analog terminal circuit board. The Jade 200 volt DC power supply completely eliminates all noise and ripple to below what our test instruments can detect. An AC power line filter is also used to prevent unwanted noise and hash from entering into the unit.

Parts

We use precision quality parts throughout. 

We import our stepped ELMA volume controls from Denmark - they use 0.1% precision metal film surface mount resistors that are second best in life expectancy only to the Shallco military switches used in the Opal.

Since perfection is our goal, we don't think parts should impart a signature sound but rather allow the sound to flow through unaltered. The type of parts used therefore must have a synergistic relationship to the circuit in which they are placed. It is this relationship of which type of part to use where, that ranks our products apart from the crowd!

Mechanical Construction

• Machined aluminum plates (1/4 in. & 1/8 in. thick) bolted to square post are used to construct the preamp chassis. This provides excellent shielding from external radio frequency fields.
• Hard gold plated solid machined brass knobs for smooth operation of switches.
• The stepped Volume control has gold plated contacts with surface mounted 0.1% precision metal film resistors. (channel balance within +/- 0.05 dB)
• Selector & Balance controls use precision Shallco with silver alloy contacts.
• Noiseless TOROIDAL power transformer and NKK rugged quality toggle switches
• Non magnetic stainless steel and brass hardware is used throughout.
• Automotive high gloss paint finish.

Circuit Boards

Hand crafted printed circuit boards using precision double turret terminal posts

Our fixed terminal hand crafted printed circuit boards are a new technology used in construction and is a first in the industry. Again Wyetech Labs is at the forefront and is always looking for ways to improve reliability and construction.

Most of the components are mounted on double turret terminal post. The octal tube sockets are also hard wired to these fixed terminals which in turn are soldered to the printed circuit board. This makes the tube sockets easily replaceable should the need ever arise. Chips and relays are mounted in sockets which are soldered to the board.

The double sided printed circuit board [ PCB ] has been manufactured with the same high standards as that found in the Sapphire amplifier. It has full solder masking on both sides of it's premium glass epoxy board with white silk screening that identifies parts and there placement for fast efficient hand soldering and assembly. These boards are held elevated from the surrounding metal chassis to avoid any capacitive coupling between components.

We also use WECO screw terminal connectors to fasten wires to the PC board to facilitate easier replacement of parts for future reparability and long service life. This technique will result in much faster trouble shooting and repair in the event of a failure and thereby reduce the labor and cost of any necessary repair.

High quality Teflon coated silver plated OFHC copper wiring is used where appropriate to make connections to and from each board and silver solder is used throughout.

Automatic Power Sequencing and Muting

To allow circuit stabilization and quite operation a 45 second automatic muting is activated during power up. Muting is accomplished using a 2-pole relay that shorts the preamp outputs. When disengaged the muting circuit is not in the signal path.

Selectable Gain Control

Overall amplifier gain is controled by a toggle switch for each channel. Gain can be switched between:

• HIGH 13 dB (4.4x), and
• LOW 5.5 dB (1.85x)

To change the gain settings, you must remove the top cover. The analog board on the left contains the left and right channel switches to select high or low gain.