McIntosh C28 All Analog Vintage Preamp - Clean

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The C28 is the best McIntosh selling preamp in our shop.  It's easy to service, has a low noise floor, great vintage looks, and every feature we would want. The individual left and right tone controls are a nice plus.  

Cosmetically it's very clean - the glass is perfect except for a missing red dot and the paintwork and stenciling are super nice.  Chassis is super clean with no signs of rust or corrosion.

This has been fully tested in our our lab where it performed well. 

Previously Serviced Note:
Our investigation at the bench revealed that this C28 was serviced in the past. Several electrolytic caps on the main board and power supply were replaced. 3 of the power supply caps were tacked on to an existing multi-section can. This is not the method that we normally use here at SkyFi, but in our detailed testing the repair was confirmed that the unit is functioning as intended. We cleaned the controls and cleaned the unit.

SkyFi Cosmetic Note:
There is a small black burn-in mark on the red mode selector filter.

C28 Standout Features:

• Use 3 Tape Machines
2 with their own electronics and 1 tape playback deck with complete easy front panel switching

• Built-In Headphone Amplifier
Listen to your favorite music --- privately

• Main and Remote Loudspeaker Switching
Turn the main speakers on or off without affecting the remote speakers and vice versa (operates with accessory relay)

• New Low Noise Phono Input
Listen to your records with a new quietness

• Individual Channel Phono Level Controls
Match levels from different phono cartridges without degrading signal to noise ratio

• Individual Channel Output Level Controls
Perfect balance from your stereo always

• Individual Channel Tone Control Switches
Complete, repeatable flexibility

• New Compensation Control
One position for loudness compensation, one position is flat and a third position that adds presence compensation!

Click below to add our recommended matching cables from Kimber Kable, all brand new as SkyFi is an official Kimber dealer.

Kimber Kable - RCA Interconnects

Kimber Kable - RCA Interconnects (Next Step Up) 

Please see the following PDF's for full technical specifications:

Click here for a PDF copy of the McIntosh C28 Sales Brochure

Click here for a PDF copy of the McIntosh C28 Owner's Manual

Click here for a PDF copy of the McIntosh C28 "If You're in a Hurry" Guide

The SkyFi Testing Process for Preamplifiers:

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 1KHz 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 1KHz 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.