Marantz Model 7C Vintage Tube Preamplifier - Amazing Condition

Description

Marantz Model 7C Vintage Tube Preamplifier - Amazing Condition
SkyFi Audio - Curators of Vintage Audio Gear
SkyFi Audio is a small startup business specializing in the purchase, reconditioning, and reselling of high end audio equipment. We only buy equipment that we admire and are passionate about. No mid-fi, no gimmicks, no junk.
Each piece of equipment is cosmetically restored and fully tested in our well-equipped lab by an engineer with 30+ years of experience in the HiFi world. If it does not meet or exceed the original manufactures specifications, it will not be sold. We are very selective about the equipment we purchase, focusing on mostly analog, high-build quality, American, and European built units.
Through our sister company, which is an authorized dealer for McIntosh, Audio Research, Sonus Faber, ClearAudio, Project, and Sony ES, we have access to OEM parts, service, and support.
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This very desirable and collectible 7C was owned by our client for 48 years and was well cared for.
A clean 7C is really hard to find these days and that's just what we have here. An unmodified, unmolested, excellent working preamp from the best Marantz era.
(The "C" in the model name stands for the wood cabinet)
Best of all it comes equipped with a brand new set of NOS (NEW OLD STOCK) Japanese made vintage Raytheon tubes. That's right, at some point Raytheon chose to source their tubes from Japan.
He smartly kept up with the maintenance on this preamp so it required very little work from us. We just tested and cleaned the controls and every single tube to ensure the next owner has a great experience. It was last serviced about 12 months ago.
Cosmetically it's very clean with only the slightest imperfections on the faceplate. The metal top does have a few light scratches, but overall this is the cleanest 7C we've had.
Condition on the cabinet really stands out. We gave it a light polish and the grain really popped and now looks amazing. The cabinet is nearly perfect with no scratches or imperfections.
Additional (cool) note: we installed a missing bottom shock mount and located correct new replacement screws for the bottom panel as shown in our listing photos.
From The Absolute Sound by Robert Harley "TAS Legacy: Marantz Model 7 Preamplifier:
"The Model 7 was a breakthrough in preamplifier design at its introduction in 1958. Largely engineered by Saul Marantz, the Model 7 offered dual phono inputs, two tuner inputs, and in a stroke of prescience, a “TV” input. In 1958. The front panel featured an array of four knobs on each side flanking four toggle switches. The right-side knobs provided independent bass and treble adjustment for each channel. The left-side knobs allowed source selection, volume, balance, and stereo/mono modes. The center toggle switches were tape monitor, a three-position phono equalization switch (78, Columbia, RIAA), and high- and low-pass filters. Minimalism in preamplifier design had clearly not yet taken hold.
The model number was not on the front panel, just the inscription “Marantz Stereo Console,” with the word “Stereo” in fancy script. The front-panel layout was created by Mr. Marantz, who had a background in drafting, graphic arts, and industrial design.
The circuit was based on three 12AX7s per channel. The phonostage was particularly innovative in its three-stage circuit, which was soon dubbed “the Marantz circuit.” Phono gain was 64.5dB (22.5dB line). The frequency response was 20Hz–20kHz +/- 0.5dB. Noise was -80dB with a 10mV phono input. The unit weighed 20 pounds.
In production for more than 12 years, the Model 7 was the most popular preamplifier of its time, with sales of more than 130,000 units—a staggering number considering its price of 5 (11 in 2016 dollars). Throughout its 12-year run, the Model 7 remained essentially the same as the prototype, with only minor production updates over the years. The Model 7C simply signified that the chassis was mounted in a wooden case."
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 uséd 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.
Item
Included
Original Box
Not Included
Manual
Yes Included
Remote
Not Applicable
Cables
Yes - Power Only
Physical Condition
7 / 10
Working Condition
10 / 10
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PURCHASING GUIDELINES:
1)
This item will be professionally packaged and insured for safe transit to your home unless you opt for local pickup from our shop. All local pickup items are only wrapped in industrial strength clear stretch wrap if the original manufacturer packaging is unavailable.
Local pickup is available in Glen Rock, NJ, just a half hour drive from Midtown Manhattan, with convenient parking near our building.
If we don’t have the original manufacture’s packaging, we use heavy duty double-ply corrugated boxes with custom made to your item SealedAir Instapak expanding foam custom inserts. In many cases this has proven to be better than the original packaging!
We also use high quality fiber reinforced tape to seal our packages. Lightweight items will be bubble wrapped and shipped in a high-quality box.
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