General:The C26 is a great vintage preamp from McIntosh and an excellent foundation to your system. Would pair up well with the MR78 tuner and MC240 amplifier we also have listed.Standout features include dual phono inputs for the avid turntable enthusiast, and dual tape loops. In addition, it has standard outlets at back for powering other equipment making it quite versatile.In testing, this preamp sounded wonderful and all of the controls are nice and quiet. This particular unit also has the benefit of a light service in house where we replaced some critical parts. It will be packed with care so it arrives safely to its new owner. SkyFi Cosmetic Notes:This unit has some minor cosmetic blemishes on the faceplate and top surfaces. The RCA jacks also show some pitting. Overall the condition is good.SkyFi Technical Notes:This unit arrived in functional condition but it needed some basic service which we completed in house. We replaced (3) electrolytic capacitors, cleaned all of the controls, and detailed the faceplate and knobs.The integrated power/volume controls from this era tend to develop tracking error over time. On this unit, the Left channel is louder than the right at the earliest position of the control. If you have very sensitive speakers we recommend pairing this C26 with a vintage McIntosh amplifier with adjustable level controls to balance out. The remainder of the control tracks quite well.Brand Background:McIntosh Laboratory is an American manufacturer of handcrafted high-end audio equipment based in Binghamton, New York. The company was founded in 1949 by Frank McIntosh. The company designs and produces audio amplifiers, stereo tuners and other consumer electronics products.Ownership:Single OwnerConnections:RCA, Power Jacks, Power CordGeneral Sound:Smooth, uncolored, undistorted natural and cleanCosmetic Condition:7/10 = Good. One or two minor scratches. Well Maintained. 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.Specs:Frequency response: 20 Hz to 20 kHzTotal harmonic distortion: 0.1%Gain: 62 dB (MM), 20 dB (line)Input sensitivity: 2mV (MM), 250mV (line)Signal to noise ratio: 74 dB (MM), 85 dB (line)Output: 250mV (line), 2.5V (Pre out)Dimensions:16" x 5.4" x 13" (406.4 x 138.1 x 330mm)Weight:31 lbs.Approximate Age:1970Link to Manual:Click HereRecommended Cables:Kimber Kable - RCA Interconnects - BetterKimber Kable - RCA Interconnects - BestKimber Kable - Phono InterconnectsTesting 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. When we first power on a preamplifier we connect its RCA output to a Sencore PA81 Power Analyzer which simulates real world loading conditions and gives us an oscilloscope interface.The first order of business is checking that the volume control works smoothly throughout its entire range with acceptable channel balance. This is accomplished by feeding a 1 KHz sine wave into one of the preamp’s line level inputs while monitoring the preamp’s output on an oscilloscope.We then switch to a 1 KHz square wave to test the tone controls, loudness function, and filters where applicable. During this step we are watching for equal alteration of the test signal by both channels. This also helps us identify dirty controls that will need treatment.Once the basic line stage functions are verified, we test each input individually. This is especially important for devices that use relays to select their sources. If the preamp is equipped with a phono stage we test that as well. We use an inverse RIAA filter which allows us to feed a reference test signal into the phono input with the proper RIAA equalization and level. A square wave or sine sweep is used to verify that the device’s phono stage is faithfully reproducing the RIAA curve. If the preamp under test has balanced inputs and/or outputs these are tested as well.We finish up our bench testing with a listening test with our bench amplifier and reference speakers. During this test we check for hum or hiss that may not have shown up in earlier testing. We also check that all of the tone controls and filters perform as expected.If the preamplifier has remote control functions these are also tested. Preamps with tube circuits or complicated power supply topologies are connected at our long term test rig for extended stress testing under real world conditions.
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