John
The new power amplifier from PS Audio has been in the oven for some time now. Head honcho Paul McGowan explains how it has seen yet further tweaking since its outing at last October’s RMAF. “Finally!” exclaims McGowan, “the BHK Signature 250 is 100% ready to go”.
BHK? Those are the initials of circuit designer Bascom King, he of Constellation Audio, Conrad Johnson and Infinity fame. An engineer for hire, King has been designing amplifiers for fifty years but not wanting to wear his experience on the his sleeve, King’s name appears in full only on the PS Audio amplifier’s back panel. In Las Vegas, McGowan could be heard regularly referring to the BHK Signature 250 as “Bascom King’s Magnum Opus”.
250? This amplifier drives 250wpc into 8 Ohms and 400wpc into 4 Ohms.
Signature? Ya got me there. However, McGowan seems as pleased as punch that his new baby runs flat all the way out to 200kHz!
And the BHK box is a BEAST. Shipping to some territories might not come cheap. The larger of the two transformers runs the MOSFETs, twenty per channel, in a fully balanced configuration. Underneath the centred PCB sits the second, slightly smaller toroidal which juices the input stage above. It’s a no-feedback design isolated by REL caps.
McGowan confesses to previously being leery of valve action because “they wear out and are incredibly microphonic”. It would appear Arnie Nudell – whom McGowan refers to as “The God of Tubes” – managed to bring him around, ultimately voicing the input stage with a pair of Genalex Gold Lion 6922. Rolling in your own is simple enough – unscrew the removable plate on the back panel for full access. McGowan reports the BHK Signature 250 to be incredibly sensitive to tube changes.
There’s no SMD (surface mount) here either – it’s all through-hole. A subcontractor in Kansas City handles the boards. I asked how long each amplifier takes to assemble. “10 hours” was the speedy reply.
The stereo version on display in PS Audio’s suite in the Mirage comes with a retail price of US$7500. The first fifty units will ship in April with full production ramping up in June.
Monoblock versions will also be available. Each will feature the same number of MOSFETs as the stereo version as well as a slightly different input board (with a single tube). Doubling-up like this threatens 300wpc and 500wpc into 8 and 4 Ohms respectively, twice the current delivery and half the output impedance. US$15000/pair.
McGowan says that selling amplifiers is a tougher game than selling DACs but he’s quietly confident that Bascom King’s unit will kick goals. It’d better – his wizardry has been retained for PS Audio’s forthcoming pre-amplifier project.
Further information: PS Audio
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