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"The transistors are on the bottom sandwiched between board and bottom plate which acts as the heat sink. The main amplifier is all hand wired. If you pull the bottom cover off, it only goes back on one way. There is a silver dot facing front for orientation. I shipped the amp with stock new production Russian tubes - Tung Sol-branded 6SN7s and EH 300Bs.  
"The power supply consists of two circuit boards with two power transformers. The regulator board has two tube sockets to run the 6X4 rectifier tubes, dual voltage regulators and a driver tube heater regulator. The other board is the power oscillator which is the 18-watt wide bandwidth transistor amp with a surface mount 40.000Hz oscillator board. When you install the rectifier tubes be sure the piggy-back board is pushed down. If the shipping box gets dropped on its head it's possible to have this board come off its pin connectors.

"I'm sure you have better tubes to roll in. Jac at Emission Labs is sitting on some NOS AVVT PX4s that may be the holy grail. I'm sure he would lend you some for your review [upper right]." Had Craig forgotten his own memo about delivering the amp with KR PX4s? A quick reminder was in order that it wasn't my job to procure specific tubes he wished the amp reviewed with. That reissued the memo. Next day I had a prompt and courteous email from KR's US importer Dr. Bradley W. Smith to confirm dispatch of a pair from Ann Arbor Michigan.

Considering that the BA carries a $4.000 sticker, what kind of innards do direct competitors counter with? Here we see my fully optioned out $4.000 US-built Woo Audio Model 5.

Here is my $3.295 US-built ModWright LS100 linestage with headphone output and 5AR4-powered 6SN7s in a very dressy enclosure with remote control (signature perforated cover with company logo not shown). There's also the option of adding a phono module or USB/coax DAC module via user-fittable board and terminal slot on the rear panel.

Here is Emillé Audio's €3.000 Ara from South Korea which to the headphone amp concept adds a quad-paralleled 16-bit/44.1kHz TDA1543 NOS DAC with PCM 2906 USB receiver and CS8416 S/PDIF receiver. There's also a credit card remote for volume and mute, 22wpc speaker power from 4 x 6922 driving 4 x 7591A pentodes in push/pull; and a fully integrated very handsome tube cover.

Disregarding Eddie Current's deliberate retro styling, it's fair to say that Woo, ModWright and Emillé are internally neater.

My Supratek Cabernet Dual preamp [above] of course had been the Ph.D of internal messiness compared to the BA's lesser efforts. Apparently this hadn't impinged on the Aussie's sterling performance. Still, it's fair to also report on the state beneath the sheets when components in a particular category place themselves near the top of the price heap.