Classic Valve Design
The Borealis series preamplifiers were created for clients who wanted a superior quality preamplifier and control centre with the flexibility of tube rolling.

A balanced gain stage design that has switch selectable gain tube choices for 6SL7 and 6SN7 to keep those tubes at their highest performance level. The output buffer tubes may be swapped with any 7AC, 7S or 8ET basing power pentode EXCEPT the Borealis-H models, which have their output buffer biased very hot and are limited to pentodes with 25W or greater anode dissipation.

Also featured is an all tube regulated power supply, phase inversion select, balance, volume and a standard four channel selector for one XLR balanced and three RCA unbalanced inputs. One set of XLR balanced plus two sets of RCA unbalanced outputs allow the driving of a second amplifier (for bi-amping) or subwoofer without the need for a Y-splitter cable or connector. Balanced inputs and outputs are true transformer balanced and not a dual-single-ended design like some other manufacters use to cut costs.

The models using the 300B as a gain stage obtain most of their gain and sonics from the 300B tube, rather than the 6SL/6SN7.

The 300B model filaments are powered with DC constant current and have a protection circuit built-in should one of the current stages fail or if the 300B is removed when the unit is powered (they are DC coupled to the buffer tube).

An ECC88 based Parks Audio phono stage may be added to any model for extra.

We cannot ship these to Europe or RoHS compliant countries (lead based solder joints).


Models Available


Borealis / Borealis-H: Basic preamp and control centre. $1,500 USD. These are production units.

Borealis-H: High bias preamp and control centre. $1,500 USD. Not for use with 6G6-G or 6V6 output buffer! These are production units.

Borealis-PH / Borealis-HPH: Includes Parks Audio phono stage for MM cartridges. $2,200 USD. Custom built only.

Borealis-300: $2,500 USD. Comes with Electro-Harmonix gold grid 300B. Custom built only.

Borealis-300PH: Includes Parks Audio phono stage for MM cartridges. $2,800 USD. Custom built only.

Add an Extra Balanced Input: base price + $100 USD
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