Audio Power Labs

The Audio Power Labs exhibit took my breath away, Imagine, a huge, beautiful $175,000 per pair, 200Wpc monoblock tube amplifier using 833C, graphite-plate, radio-frequency transmitter tubes that have a bandwidth of 30MHz and run with 1500V on the plates! These tubes were used in the output stage of BCF-1 radio transmitters. Now imagine that the amplifier's designers are named Squeek Rieker (right) and Peeya Iwagoshi (left), and you know why I had to pinch myself to make sure I wasn't dreaming.

Audio Power Labs buys the 833 Richardson in Texas who imports them from China. Lots go through a matching process that yields 60 pairs, with the rest sold on eBay at cost.

The microprocessor-controlled amplifier has no capacitors in the signal path. It has less than 1% THD at rated output with a frequency response of 15Hz–33kHz ±3dB. The company also sells the 50W 50TNT monoblock for $47,500/pair. It has a frequency response of 15Hz–25Hz, ±3dB with less than 2% THD from its 8 ohm output tap. Unlike the 833TNT, its 572B output tubes are no longer manufactured, so Audio Power Labs has sourced over 700 tubes for their production and warranty work.

Lofty's picture

I heard these amps at the NYC Expona show in May 2011 driving enormous Wharefdale loudspeakers and they were glorious!