{"product_id":"marantz-model-7-vintage-tube-preamplifier-skyfi-restored","title":"Marantz Model 7 Vintage Tube Preamplifier - SkyFi Restored","description":"\u003cp\u003e\u003cb\u003eGeneral:\u003c\/b\u003e\u003cbr\u003eThe Model 7 is an extremely desirable and collectible vintage tube preamp, and the flagship in the vintage Marantz lineup. Not to be confused with the similar looking and less desirable solid state version.\u003cbr\u003e\u003cbr\u003eEven better this particular Model 7 was restored in-house here for long term reliability and performance.\u003c\/p\u003e\n\u003cp\u003eThis preamp is a great match to the Model 8 tube amplifier and Model 10B tuner. Both are extremely well regarded.\u003cbr\u003e\u003cbr\u003eLooking super sharp in its champagne finish and sporting all the original knobs and switches.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFrom The Absolute Sound by Robert Harley \"TAS Legacy: Marantz Model 7 Preamplifier:\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003e\"The Model 7 was a breakthrough in preamplifier design at its introduction in 1958.\u003cbr\u003eLargely 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.\u003c\/p\u003e\n\u003cp\u003eThe 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.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eThe 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.\u003cbr\u003e\u003cbr\u003eThe 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.\u003cbr\u003eThe circuit was based on three 12AX7s per channel.\u003c\/p\u003e\n\u003cp\u003eThe 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.\u003cbr\u003e\u003cbr\u003eIn 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 ($3,640+ in 2024 dollars).\u003c\/p\u003e\n\u003cp\u003eThroughout 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.\"\u003cbr\u003e\u003cbr\u003e\u003cb\u003eSkyFi Cosmetic Notes:\u003c\/b\u003e\u003cbr\u003eLight wear is present on the faceplate and knobs. All metal surfaces show wear as well. One of the convenience outlets on the rear panel is damaged. The four \"top hat\" front panel switch caps are not original. We've also added aftermarket shorting plugs on the Mic and Tape Head rear inputs.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eSkyFi Technical Notes:\u003c\/b\u003e\u003cbr\u003eThis Marantz 7 underwent an extensive in-house restoration which included a full rebuild of the power supply and main preamp boards. We also installed a new Alps volume control.\u003c\/p\u003e\n\u003cp\u003eThe components necessary for RIAA equalization were replaced with precision parts for better adherence to the RIAA standard.\u003c\/p\u003e\n\u003cp\u003eIn addition to the work above, we also performed some routine maintenance which included a full cleaning of all of the controls, a modification to the rear panel jack grounding, new suspension components, and a fresh pilot lamp.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eTube Notes:\u003c\/strong\u003e\u003cbr\u003eThis preamp is loaded with a set of strong, vintage, period correct Telefunken smooth plate 12AX7 tubes.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eOwnership:\u003c\/b\u003e\u003cbr\u003eSecond Owner\u003cbr\u003e\u003cbr\u003e\u003cb\u003eConnections:\u003c\/b\u003e\u003cbr\u003eRCA, Power Outlets, Ground\u003cbr\u003e\u003cbr\u003e\u003cb\u003eGeneral Sound:\u003c\/b\u003e\u003cbr\u003eBig beautiful musical sound with little fatigue.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eCosmetic Condition:\u003c\/b\u003e\u003cbr\u003e8\/10 = Very Good. Excellent front faceplate, one minor flaw on chassis side or top. See our detailed rating description \u003ca href=\"https:\/\/skyfiaudio.com\/pages\/our-rating-scale\" target=\"_blank\"\u003ehere\u003c\/a\u003e.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eWorking Condition:\u003c\/b\u003e\u003cbr\u003eWorking perfectly and tested in our lab and listening room.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eIncluded:\u003c\/b\u003e\u003cbr\u003eJust the unit and power cord.\u003cbr\u003e\u003cbr\u003e\u003cb\u003ePacking:\u003c\/b\u003e\u003cbr\u003eWill be packed using our highly developed in-house process and custom packing materials.\u003ciframe width=\"1280\" height=\"720\" src=\"https:\/\/www.youtube.com\/embed\/wuWesEecAbE?\u0026amp;autoplay=1\u0026amp;mute=1\" title=\"This Is How We Pack Sensitive Electronics at SkyFi Audio, Less Than 0.2% Shipping Damage\"\u003e\u003c\/iframe\u003e\u003cb\u003eSpecs:\u003c\/b\u003e\u003cbr\u003eTubes:\u003cbr\u003e6 x ECC83\/12AX7 Type\u003cbr\u003e\u003cbr\u003eGain - Phono and Tope-head\u003cbr\u003e64-1\/2 dB\u003cbr\u003e\u003cbr\u003eMicrophone\u003cbr\u003e62 dB\u003cbr\u003e\u003cbr\u003eHigh level\u003cbr\u003e22-1\/2 dB\u003cbr\u003e\u003cbr\u003eAt Recording Outout\u003cbr\u003ePhono and Tape-head\u003cbr\u003e42 dB\u003cbr\u003e\u003cbr\u003eMicrophone\u003cbr\u003e40 dB\u003cbr\u003e\u003cbr\u003eHigh-level\u003cbr\u003eUnity (0 dB)\u003cbr\u003e\u003cbr\u003eFrequency Response \u003cbr\u003eWithin 1\/2 dB from 20 CPS to 20 KC.\u003cbr\u003e\u003cbr\u003eIM Distortion - Typical measurements\u003cbr\u003e10 volts equ. peak RMS, 0.1%.\u003cbr\u003e2 volts equ. peak RMS. 0.01%\u003cbr\u003e\u003cbr\u003eTotal Noise:\u003cbr\u003eIn 20 CPS to 20 KC audio range, 80 dB below 10mv phono input with RIAA curve. Hum is far below thermal noise.\u003cbr\u003e\u003cbr\u003eThe Marantz Company, 25-14 Broadway, Long Island City 6, N.Y.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eDimensions:\u003c\/b\u003e\u003cbr\u003e14-3\/4\" W. × 5-3\/8\" H. x 8⅓\" D. Ponel: 15-3\/8\" W. × 5-3\/4\" H.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eWeight:\u003c\/b\u003e\u003cbr\u003e16 lbs.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eApproximate Age:\u003c\/b\u003e\u003cbr\u003e1967\u003cbr\u003e\u003cbr\u003e\u003cb\u003eLink to Manual:\u003c\/b\u003e\u003cbr\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0003\/3275\/9084\/files\/Marantz-Model-7-Instruction-Manual.pdf?v=1679586265\" target=\"_blank\"\u003eClick Here\u003c\/a\u003e\u003cbr\u003e\u003cbr\u003e\u003cb\u003eRecommended Cables:\u003c\/b\u003e\u003cbr\u003e\u003ca href=\"https:\/\/skyfiaudio.com\/products\/kimber-kable-hero-interconnects-pair-rca-ultraplate-or-wbt-connectors-new\" rel=\"noopener\" target=\"_blank\"\u003eKimber Kable - RCA Interconnects\u003c\/a\u003e - Better\u003cbr\u003e\u003cbr\u003e\u003ca href=\"https:\/\/skyfiaudio.com\/products\/kimber-kable-silver-streak-interconnects-pair-rca-ultraplate-or-wbt-connectors\" rel=\"noopener\" target=\"_blank\"\u003eKimber Kable - RCA Interconnects\u003c\/a\u003e - Best\u003cbr\u003e\u003cbr\u003e\u003ca title=\"Kimber Kable - TAK-CU - New Speciality Series Tonearm Cable, New - SkyFi Audio\" href=\"https:\/\/skyfiaudio.com\/products\/kimber-kable-tak-cu-phono-cable-with-wbt-connectors\" rel=\"noopener\" target=\"_blank\"\u003eKimber Kable - Phono Interconnects\u003c\/a\u003e\u003cbr\u003e\u003cbr\u003e\u003cb\u003eTesting Process:\u003c\/b\u003e\u003cbr\u003eWe 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. \u003cbr\u003e\u003cbr\u003eWhen 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.\u003cbr\u003e\u003cbr\u003eThe 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 1 KHz sine wave into one of the preamp’s line level inputs while monitoring the preamp’s output on an oscilloscope.\u003cbr\u003e\u003cbr\u003eWe then switch to a 1 KHz 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.\u003cbr\u003e\u003cbr\u003eOnce 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.\u003cbr\u003e\u003cbr\u003eWe 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.\u003cbr\u003e\u003cbr\u003eIf 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.\u003c\/p\u003e","brand":"Marantz","offers":[{"title":"Default Title","offer_id":46862332625150,"sku":"106309","price":0.0,"currency_code":"AUD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0003\/3275\/9084\/files\/marantz-model-7-vintage-tube-preamplifier-skyfi-restored-545.jpg?v=1770310034","url":"https:\/\/skyfiaudio.com\/en-au\/products\/marantz-model-7-vintage-tube-preamplifier-skyfi-restored","provider":"SkyFi Audio","version":"1.0","type":"link"}