Single channel 601 w/built-in power supply
(With an Altec 15095 output transformer and the new 2T/3T option.)

Here is an example of a single channel unit with self contained power supply.
It is an example of my preferred circuit design as of 2012 / 2013.
The focus of this unit was sound quality more than features, I.E. it has no phantom power.
The enclosure makes more features difficult. On a rack mount version, a phantom power module can be added to the back.

Alps Blue Velvet pots, polystyrene and polypropylene film audio caps, film bypasses on certain electrolytic filter caps, 1% metal film resistors, 2 Tube / 3 Tube option, Altec 15095 output transformer, DC heater power for the tubes, DI input for electric guitars and bass, 20 dB mic pad, XLR balanced output, 1/4" unbal hi-Z output, mic / line switch, master gain on faceplate.
This particular unit costs $950 if I supply everything. The hardwood plywood enclosure with Tolex covering (many styles available) costs $95.

The main controls are the Mic Rec level, the Line Rec level, and the master gain which is the one in the middle with the black dial.

 

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Ampex 600 single channel with UTC A-11, Altec 15095 and remote power supply

The remote power supply lowers the noise level. The 600 series' chassis are too small to use a built in power supply without some noise pickup. When they were in recorders with a 55 dB SNR they were plenty quiet. They are just not quiet enough (for me) for modern recording with a DAW. The DC heater supply and the remote power supply bring the 600 into the 21st century with performance quiet enough for demanding applications.

This customer requested the output on the front:

The remote power supply also makes adding phantom power a neater proposition. There are tricks to get 48V from a typical tube device power supply. I don't believe in these cheesy solutions. I build a proper 48V regulated power supply for the phantom power.