McIntosh C11 Vintage All Tube Preamplifier From ABKCO Music & Records - The Rolling Stones And More!

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General:
This is no ordinary C11 vintage tube McIntosh preamp.

This C11 comes to you from ABKCO Music & Records, home to The Rolling Stones, Chubby Checker, Sam Cooke, and many more! 

Check out our photos to see ABKCO owner & founder Mr. Allen Klein alongside the BEATLES, with McIntosh gear prominently featured in his office and recording studios.

Born in Newark, NJ, Mr. Klein was an American businessman whose aggressive negotiation tactics fundamentlly changed industry standards for compensating recording artists. Mr. Klein also increased profits for his musician clients by negotiating new record company contracts.

He first scored monetary and contractual gains for Buddy Knox and Jimmy Bowen, one-hit rockabillies of the late 1950's, then parlayed his early successes into a position managing Sam Cooke.

He went on to manage The Beatles and the Rolling Stones simultaneously(!!!), along with many other artists, becoming one of the most powerful individuals in the music industry during his era. (Above three paragraphs courtesy of Wikipedia with some editing)

The C11 is as capable and feature rich as the venerable C22, but earlier in development.

It's also a bit less complicated in design and execution.

Cosmetically it has a very cool vintage feel and will look at home in most vintage or mid-century decor.

Controls are just what you need too - with an input selector, volume, balance, and tone adjustments for both left and right channels.

Best of all it features a set of vintage Telefunken tubes, which are coveted in the audiophile world.

Cosmetic Notes:
- Bottom metal extrusion shows wear.
- Silkscreen lettering is worn in multiple places.
- Misc. light blemishes throughout consistent with age (60+ years).

Tube Notes:
- All tubes are vintage long smooth plate Telefunken ECC83.

Service Notes:
- This C11 was serviced by Bristol Electronics in March of 2023.
- One multi-section electrolytic capacitor replaced.
- Selenium rectifiers swapped for silicon.
- Select out of spec parts replaced as needed.

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 Owner

Connections:
All RCA inputs and outputs, captive power cord. 6-convenience outlets.

General Sound:
Big beautiful musical sound with little fatigue.

Cosmetic 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:
Just the unit and power cord.

Packing:
Will be packed using our highly developed in-house process and custom packing materials.Specs:
Please see last picture

Weight:
15 lbs.

Approximate Age:
1962

Link to Manual:
Click Here

Recommended Cables:

Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - Phono Interconnects - Better

Kimber Kable - Flagship Phono Interconnects - 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 PCB’s 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.