Sonic Frontiers SFL-2 - All TUBE Dual-Chassis Preamp

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Gorgeous dual-chassis all tube preamp from Sonic Frontiers. Made in Canada. Sounding wonderful with typical tube warmth and resolution. 

Plus you know it's something special when it's Stereophile Class A Rated *AND* featured on the fantastic vintage HiFi website The Vintage Knob!!

"Last but not least, and most important, crucial even, the volume attenuator is a 46-position fixed resistance array - only the best so the SFL-2 could be that good."

Built like a tank and designed for quiet operation mostly due to the power supply being housed on a completely separate chassis.

Features a great compliment of XLR and RCA inputs/outputs.

Just cleaned and serviced by our technical staff.

Tube Notes:
All tubes tested with our modern and professional vacuum tube tester, the Amplitrex AT-1000. Check out the Amplitrex in action via our YouTube channel.

4 x RAM 6DJ8
4 x Amperex 

Sonic Frontiers SFL-2 Preamplifier Manual

Specifications:

Vacuum-tube line preamplifier with fully differential, all-balanced circuitry, outboard power supply, and remote control of all functions with 0.5dB steps of volume and balance.

Inputs:
• Two line-level balanced (XLR)
• Four line-level single-ended (RCA)

Outputs:
• Two balanced (XLR)
• Two single-ended (RCA)
• "HeadRoom" processed headphone output
• Buffered tape loop

Common Mode Rejection Ratio (CMRR):
• Better than 60 dB

THD:
• <0.01 %

Dimensions:
• Preamp: 19" W by 4.5" H by 14.25" D
• Power Supply: 9" W by 4" H by 13" D

Weight: 33 lbs

Price: $3295 (1997)
When adjusted for inflation = $5300

The SkyFi Testing Process for Preamplifiers:

We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage. Special attention is paid to the power supply which is the most common source of failure for preamps. We then power up the unit and run a simple 1k sine wave while monitoring the low voltage output on an oscilloscope for signs of distortion or noise to get a baseline.

At this point we will lubricate and clean all switches and potentiometers (that are not sealed) with a high quality contact cleaner, and then re-test all functions for any signs of noise or scratching.

Final testing involves putting actual music through the preamplifier We have learned over time that some issues are only noticeable to a trained ear while listening to a familiar source material. Our test bench has reference vintage KEF speakers that we are super familiar with which will quickly reveal any discrepancies. Some preamps will then move into the listening room where they will be tested with our in-house reference system.

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.