Krell KST-100 Vintage Solid State Amplifier - 100W

Free Shipping (Contiguous U.S. Only)

General:
The Krell KST-100 is a powerful high current 100Watt Class A/B amplifier. Just like all Krell gear from this era, the build quality and component selection is outstanding. The heatsinks that flank both sides of the amplifier are super robust and the internal power supply look to be well designed.

It offers all you would want in a high fidelity amplifier, balanced XLR and single ended RCA inputs, high quality 5 way binding posts, and the ability to run 2 pairs of speakers at once.

This particular Krell KST-100 is a single owner unit and it has been very well cared for.

In testing it sounded awesome and more powerful than its 100WPC rating suggested. Included will be its original owners manual.

SkyFi Cosmetic Notes:
Very light signs of wear on chassis and rear panel. Looks almost new. Overall great.

SkyFi Technical Notes:
This unit passed all of our bench and long term listening tests but the unit still has all of its original parts. You may want to consider sending the amplifier to Krell for a full overhaul for long term reliability down the road.  

Ownership:
Single Owner

Connections:
XLR, RCA, 5 way binding posts., IEC Power

General Sound:
Smooth, uncolored, undistorted natural and clean

Cosmetic Condition:
8/10 = Very Good. Excellent front faceplate, one minor flaw on chassis side or top. See our detailed rating description here.

Working Condition:
Working perfectly and tested in our lab and listening room.

Included:
Unit, manual, and power cord.

Packing:
Will be packed using our highly developed in-house process and custom packing materials.Reviews:
Click Here

Original MSRP:
$2,500.00

Specs:
Stereo power amplifier
Output power: 100Wpc/8 ohms (20dBW), 200Wpc/4 ohms (20dBW), 400Wpc/2 ohms (20dBW), 800Wpc/1 ohm (20dBW)
Output impedance: 0.125 ohms
Damping factor: 150
THD & IMD: less than 0.1% under all conditions
S/N ratio: 96dB A-weighted
Slew rate: 50V/µs
Input sensitivity: 1.5V for full output
Input impedance: 47k ohms

Dimensions:
Width: 18.0 inches (458 mm)
Height: 6.4–6.5 inches (165 mm), including feet
Depth: 14.8 inches (450 mm), including handles

Weight:
50 lbs.

Approximate Age:
1991

Link to Manual:
Click Here

Recommended Cables:
Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - BALANCED XLR Connectors - Better

Kimber Kable - BALANCED XLR Connectors - Best

Kimber Kable - Speaker Cables - Better

Kimber Summit Series Monocle XL Speaker Cables (PAIR) - Best

Kimber Summit Series BiFocal XL Bi-Wire Speaker Cables (PAIR) - Best If Applicable

Kimber Kable - Power Cords - Better

Kimber Kable - Power Cords - Best

Testing Process:
We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect the PCBs for discoloration from resistors or transistors that may have been running hot. On vintage units we often spot check select capacitors for value and ESR.

If the amplifier passes visual inspection, we move on to a controlled power on sequence using a Sencore safety analyzer to monitor current draw in real time. Once the amplifier is determined to be safe to operate, we connect it to full AC mains for function and power testing. We connect the speaker outputs of the amplifier to a Sencore PA81 Power Analyzer which acts as a dummy load, DC offset monitor, and oscilloscope interface. We start with a low level 1 KHz test signal at the amplifier's input and slowly increase its amplitude while monitoring the output on an oscilloscope for signs of noise, clipping, distortion, or improper channel balance. We continue increasing the signal level until the amplifier reaches clipping.

At this point we take an output power measurement and compare it to the spec sheet of the amplifier to verify proper performance. If the device under test has both balanced and single ended inputs they are both tested at this time.

We finish off the bench evaluation with a 1 KHz square wave check and a 20 Hz to 20 KHz sine sweep to assess the amplifier's frequency response characteristics.

This battery of tests will usually reveal if the amplifier has any issues that need further attention.

Before the device leaves the bench, we perform a listening test with actual music using a variety of preferred test tracks. Our benches are outfitted with familiar monitor speakers which help us identify inconsistencies that will not always show up on our test gear. The main things that we are listening for are hum or noise with no signal present, proper center image, clicks, pops, or any other obvious undesirable audio characteristics.

If the unit passes all of these tests it is moved to our long term testing rig where we simulate real word operating conditions for 6-8 hours minimum. This allows us to monitor the unit for signs of thermal runaway or intermittent issues that only crop up when the unit has fully come up to temperature.