Audio Research EC-21 Active 2-Way Tube Crossover - Serviced

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General:
The EC-21 is a 2-way crossover from Audio Research designed to optimize bi-wire configurations.

It sounded great in our testing and features a tube design with matching McIntosh branded JJ 12AX7 tubes installed inside. 

This particular EC-21 was serviced here at SkyFi to work reliably for many more years to come.

From the original Audio Research marketing materials:
The EC-21 is an infinitely variable, fixed frequency and slope, two-way electronic crossover, allowing biamplification of a number of quality loudspeaker systems.

Biamplification greatly improves the dynamic range of an audio system while greatly reducing dynamic distortion. Biamplification is the best approach to increasing system performance and efficiency.

SkyFi Cosmetic Notes:
Light wear is present on all surfaces. The original feet are still in place but have significant wear.

SkyFi Technical Notes:
This crossover was just serviced here at SkyFi. We replaced the majority of the power supply capacitors, along with the timing capacitor for the power-on delay. We also replaced the fuse holder cap and both convenience outlets. Both channels were checked for proper and equal operation.

NOTE - The power-on delay for the bass output features a lengthy time delay by design (approximately 105 seconds) to allow the tube to stabilize after power-on.

After the repairs, we plotted the frequency response and verified the performance against the capacitor kit sheet. The parts that are currently installed in this unit indicate a crossover point of 125 Hz with resistors installed on the output jacks specifically matched to the impedance of many Audio Research power amplifiers. 

For an additional fee we can convert the crossover point to that of your choosing as long as it's an option on the capacitor kit sheet. Please allow up to 2 weeks for us to source the parts, install, and test.

All three tubes are McIntosh branded JJ 12AX7 tubes.

Specs:
Tube 2-way electronic crossover

INTRODUCED
1980

DISTORTION
< .01% total harmonic distortion @ 1.5V RMS output

NOISE & HUM
90 dB below 1.5V RMS output

GAIN
High pass section, fixed, 0 dB. Low pass section rear panel adjustable +9 dB

TUBE COMPLEMENT
QTY (3) 12AX7

DIMENSIONS
19" W x 5 ¼" H x 10 ¼" D

SHIPPING WEIGHT
16 lbs

Brand Background:
Audio Research continues its dedication to unparalleled musical expression and crafting components of the highest quality and lasting value for its customers. Our long-term dedication to service is peerless in this industry (Audio Research, with few exceptions, can repair anything ever produced during its entire history).

We continue to seek out new and exciting ways to make music more real and more enjoyable. More than just a name or a marketing tool, Audio Research has come to represent exceptional performance and long-term value. Experience Audio Research – experience High Definition®.

Ownership:
Second Owner

Connections:
RCA, 2 Power outlets,

General Sound:
Smooth, uncolored, undistorted natural and clean

Cosmetic Condition:
6/10 = Fair. Three to four minor scratches, or one major scratch. See our detailed rating description here.

Working Condition:
Working perfectly and tested in our lab.

Included:
Just the Unit

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