McIntosh C38 Solid State Preamplifier, Full Featured w/Phono Stage

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Hailing from the 1990's this full featured preamp featuring a timeless McIntosh design and was recently refreshed by our professional technical staff.  

Loaded with features including phono inputs and balanced outputs for the best possible connection to your amp. 

The C38 is also capable of remote control which is included with your purchase.

SkyFi Service and Cosmetic Notes:
• Front faceplate glass sourced new from McIntosh and replaced.
• Light scratching on end caps as shown in our photos.

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 - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - Phono Interconnects - Better

Kimber Kable - Flagship Tonearm Interconnects - Best

Kimber Kable - BALANCED XLR Connectors - Better

Kimber Kable - BALANCED XLR Connectors - Best

Kimber Kable - Power Cords - Better

Kimber Kable - Power Cords - Best

More from McIntosh:
There are eight pairs of high level inputs to accommodate all the traditional program sources as well as the most recent new sources. A pair of low level inputs is also provided that will accept signals from a moving magnet phono cartridge in a record player. Digital Logic integrated circuits drive Electromagnetic Switches on all inputs and operating functions for the most reliable and distortion free switching available.

Separate RECORD and LISTEN circuits allow recording from one source while listening to another. A continuously variable Active Loudness Control allows loudness compensation to be selected for any setting of the volume control. The Loudness Control circuit elements are removed from the circuit path when the control is in the flat or fully counterclockwise position.

Bass and Treble tone controls provide 12dB of boost or cut. At the center "Flat Response" or detent position of the tone controls, all tone control circuit elements are removed from the signal path.

Two Signal Processor loops are provided. One is for Listen signals and one is for Record signals. Power supply voltage regulator circuits maintain stable operation even though the AC power line may vary. Double shielding of the power transformer completely isolates it from the audio circuits. This eliminates the need for a clumsy outboard power transformer used by some less sophisticated designs.
Front panel pushbuttons control two switched outputs as well as two pairs of speakers when an optional SCR3 switching relay is added.

The Mcintosh C38 "Classic Glass" front panel has all control, switch and pushbutton nomenclature illuminated. 

For full specifications please see the linked manual below:
McIntosh C38 Owner's Manual

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.