Marantz Model 7 Vintage Tube Preamp - Bone Stock Collectors Piece - MINT

Free Shipping on *ALL* Electronics (Excluding Speakers, Contiguous 48 US States Only)

This preamp looks like it just left the factory. The wood case is the cleanest we've ever seen. Internally its unmolested and factory original!

Working as it should, though if you're going to use it full time, it should probably undergo a restoration listed below for long term reliability.

A collector might want the unit in its current form, while an audiophile might want it restored. Please inquire if you'd like a price for the additional work.

Needless to say this is a legendary preamp and well worth the price.

Bone Stock tested and working well in its current state, but a preservative restoration is recommended for long term reliability as mentioned above.

All tubes are Telefunken 12AX7 / 8CC83. Some of the tubes have faded text and one is marked Fisher, but they're ALL West Germany made with identical internal construction.

Check out our YouTube video from a different Marantz 7 we had previously listed for sale for more details:

The Marantz 7 is well regarded even in stock form, but the original units tend to develop volume control consistency issues due to aging carbon tracks.

The power supplies also employ Selenium rectifiers which drag down the power supply voltage values as they age.

SkyFi's preservative restoration targets these two primary areas of interest.

We start by completely rebuilding the power B+ and Filament power supplies with silicon rectifiers and modern electrolytic capacitors. This ensures years of stable operation without fear of catastrophic failure, or the slow development of hum as the original capacitors age.

The volume control is replaced with a precision Alps control to resolve uneven channel tracking throughout the volume control range.

Finally, we replace the axial electrolytic capacitors in the signal path, and test the remaining signal path caps for leakage.

If they test good they are left in place to preserve the original sonic signature of the preamp. We also offer the option to install signal path caps of your choice during the restoration for an additional fee.

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 $385 ($3211 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."

Marantz Model 7 Instruction Manual

The SkyFi Testing Process for Preamplifiers (All):

We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage. Special attention is paid to the power supply which is the most common source of failure for preamps. We then power up the unit and run a simple 1k sine wave while monitoring the low voltage output on an oscilloscope for signs of distortion or noise to get a baseline.

At this point we will lubricate and clean all switches and potentiometers (that are not sealed) with a high quality contact cleaner, and then re-test all functions for any signs of noise or scratching.

Final testing involves putting actual music through the preamplifier We have learned over time that some issues are only noticeable to a trained ear while listening to a familiar source material. Our test bench has reference vintage KEF speakers that we are super familiar with which will quickly reveal any discrepancies. Some preamps will then move into the listening room where they will be tested with our in-house reference system.

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.