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Such common sense had my head bop in sympathetic agreement. And I too favour the sound—or rather non-sound—of a classic pot on a traditional amp. Resistor-ladder arrays get too coarse, chip-based attenuation seems a bit suspicious. On the other hand my hifi existence has me routinely cross paths with even costly gear that suffers balance issues when listening at low volumes.
The balance control here solved this. It seemed merely logical that it’d lack a center indent because over time that might deviate from true electrical balance. Perfectly continuous is better. Obviously you’ll need to pay attention when first installing the amp and perhaps the assistance of a helper. But then you can sink back into your chair with the assurance that the lead vocals really are locked in dead center.
Checking out the innards revealed Jawil Audio’s focus on ultra-clean board layout, sensible cable routing, quality parts, effective shielding and short signal paths. Hookup wiring which might pick up (or radiate) noise passes through routed-out ‘tunnels’. Or take the passive input stage whose input connectors are soldered directly to the board and bolt to the chassis. Source and volume selectors too sit directly on the minimalist PCB and connect to their fascia controls via extension shafts.
A fat toroid feeds the power supply from its own chamber to isolate the main circuitry from stray radiation. Rectification is via ultra-fast MUR 860 diodes, filtering by low-ESR Elkos. The 32’000uF storage capacitance could have this or that preamp cough in amusement but Jawil deliberately refrain from overkill to shorten capacitive recharge times. Finally there’s a buffered variable output for a subwoofer or such.
The output stage is modular and per request can be configured as pure 40wpc into 4Ω stereo amp or 4 x 20wpc bi-amp scheme. The power devices are four matched op-amps* whose constant-current sources bias them up to ~5 watts in low-distortion class A. Jörn Jansen added that their experiments with feedback showed that the length of its loop had immediate sonic consequences. The shorter the better since the risk of HF and NF distortion grows exponentially. Their response to this observation? A mere 5mm loop on their PCB. The Asgard thus contains a lot of machine-shop labour and brain juice.Power up and plop, Basho’s frog. Jawil frown on redundancies in the signal path, hence a very deliberate choice against any in-rush current relays as Jörn Jansen assured me. Ditto for power-down. The Asgard keeps cruising and fading until the capacitors have fully discharged. Bothersome? Not to me. The Asgard is a fine machine which cleverly straddles the sonic camps of valve and transistor sound – or whatever one might think those are.
" This would make the Asgard into a so-called chip amp though its descriptions refrain from invoking 47lab precedents to seem based on a different circuit than 'gain clones' - Ed.
