Slide show
Tubes
To isolate the high DC voltage from the tubes and the low DC voltage of the transistors, a capacitor is required. There are other ways of doing it but we would rather not go there… So the choice of part is important and we use this highly expensive copper foil part. Not only for sonics but for reliability.
Magnetics
This is the K-70’s main output board and is truly a labour of love to produce. Thin tracks have been replaced by flat, wide conductors with extra low inductance. The opposite side of the board contains an identical pattern, essentially creating a “Litz” configuration for better conduction. Each 140uM layer of copper is gold plated and traditional silk screening and solder masking is omitted for sonic reasons. As in the rest of the amplifier, our special “four nines” alloyed solder is used with every wire being polished and surgically cleaned before soldering. When this delicate hand soldering, performed on each side of the board is complete, a thorough cleaning and testing process begins.
The most sensitive signal paths are hard wired with our Japanese speciality silver wires and finally all metallic surfaces are sealed with a high performance nanno seal to enhance reliability and inhibit surface deterioration.
While the board actually contains very few parts by comparison, the whole critical assembly takes days to complete. It is built solely in the pursuit of reliability and sound quality.
The board houses the finest selection of parts many of which cost many times that of what others use. Such extreme attention to detail as seen in the whole fabrication of the K-70’s output board is made worthy by the purity of the circuitry it holds.
outpun PCB
This is the K-70’s main output board and is truly a labour of love to produce. Thin tracks have been replaced by flat, wide conductors with extra low inductance. The opposite side of the board contains an identical pattern, essentially creating a “Litz” configuration for better conduction. Each 140uM layer of copper is gold plated and traditional silk screening and solder masking is omitted for sonic reasons. As in the rest of the amplifier, our special “four nines” alloyed solder is used with every wire being polished and surgically cleaned before soldering. When this delicate hand soldering, performed on each side of the board is complete, a thorough cleaning and testing process begins.
The most sensitive signal paths are hard wired with our Japanese speciality silver wires and finally all metallic surfaces are sealed with a high performance nanno seal to enhance reliability and inhibit surface deterioration.
While the board actually contains very few parts by comparison, the whole critical assembly takes days to complete. It is built solely in the pursuit of reliability and sound quality.
The board houses the finest selection of parts many of which cost many times that of what others use. Such extreme attention to detail as seen in the whole fabrication of the K-70’s output board is made worthy by the purity of the circuitry it holds.
Capacitors
To isolate the high DC voltage from the tubes and the low DC voltage of the transistors, a capacitor is required. There are other ways of doing it but we would rather not go there… So the choice of part is important and we use this highly expensive copper foil part. Not only for sonics but for reliability.
Binding posts
The tube section is absolutely simple – as it should be. Of course hand wired with the same silver and attention to detail. Only the highest quality ceramic tube bases will do!
Negative feedback? Local feedback? Cathode followers? Nah! Lineararity and low output impedance come naturally to this circuitry.
Tube section
The tube section is absolutely simple – as it should be. Of course hand wired with the same silver and attention to detail. Only the highest quality ceramic tube bases will do!
Negative feedback? Local feedback? Cathode followers? Nah! Lineararity and low output impedance come naturally to this circuitry.
DC cable
Fitted with sturdy military grade connectors the DC cable may be ordered to custom length. Power amplifiers with separate DC power supplies are rare and in such systems it is possible that the quality of the DC cable has notable audible effect. In the K-70, the cable carries no audio signal related components and therefore possible cable interaction issue are neatly side-stepped. The only remaining criteria being that the cable is safe with the currents and voltages to be passed through it.
Transistors
Each channel uses thirty two power transistors, each rated to 150W giving a total capacity of almost 10KW for the system! These devices are designed for exclusive use in linear amplifier design but are not custom to us. The total array of devices are configured to give an astonishingly low output impedance of some 0.07 ohms across the audio bandwidth – without the use of negative feedback. Actual power dissipation of each part is restricted to about 10W. This, with the generous heatsinking ensures the part's silicon “chips” is operated at a reasonable temperature with minimal thermal cycling to aid both sound quality and part longevity.
Speaker cable
We have adopted these beautifully Japanese made Teflon tube sockets. The tubes fit in snugly making excellent electrical contact while the Teflon not only provides perfect insulation but also helps to dampen vibration that might otherwise enter into the sensitive tubes thru their pins.
Socket
We have adopted these beautifully Japanese made Teflon tube sockets. The tubes fit in snugly making excellent electrical contact while the Teflon not only provides perfect insulation but also helps to dampen vibration that might otherwise enter into the sensitive tubes thru their pins.