Marantz 7T Solid State Vintage Preamplifier - Serviced w/ Reproduction Cabinet

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General:
The Marantz Model 7 and Marantz Model 7T are among the most iconic preamplifiers of the 1960s, celebrated for their exceptional sound quality, intuitive usability, and timeless design.

This particular unit is the solid-state 7T variant, featuring what were considered cutting-edge transistor technologies of its era. It is also fitted with a beautifully crafted reproduction wood case, which remains in excellent condition. The Model 7T is also a bit more affordable than its vacuum tube brother the Model 7.

Notable features include dual phono inputs and six rear-panel AC convenience outlets, ideal for powering low-current audio components such as a turntable or cassette deck.

This 7T has recently been serviced, and during testing it performed beautifully. The preamp sounds excellent, and all functions operate as intended. It will be shipped with care so it arrives safely at its new home.

SkyFi Cosmetic Notes:
The cabinet included with this unit appears to be a reproduction, likely made in the 1970s. The cabinet and the unit itself are both in excellent condition.

SkyFi Technical Notes:
This 7T was serviced in house here at SkyFi. It needed a bit of routine maintenance which included the replacement of a handful of known to fail capacitors, internal and external cleaning, and the replacement of some components in the low filter circuit. The unit has been returned to functional condition, all controls and features passed testing in our lab after the service was completed.

Ownership:
Second Owner

Connections:
RCA, Captive power cord, Ground Screw Down Terminal,

General Sound:
Smooth, uncolored, undistorted natural and clean

Cosmetic Condition:
8/10 = Very Good. Excellent front faceplate, one minor flaw on chassis side or top. 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:
Frequency Response: 20Hz to 20kHz (±1 dB)
Total Harmonic Distortion (THD): <0.05% at 1V RMS output
Intermodulation Distortion (IMD): <0.15% at 10V RMS output
Gain: 64.5dB (MM Phono), 22.5dB (Line)
Signal-to-Noise Ratio: 100dB below high-level input
Input Impedance: 47kΩ (Phono), 1MΩ (High Level)

Dimensions:
14-3/8 x 5-3/8 x 8-1/2 inches (approx)

Weight:
9 lbs.

Approximate Age:
1966

Link to Manual:
Click Here

Recommended Cables:
Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - Phono Interconnects

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 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 1 KHz 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 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.

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.