Vintage Marantz 7 Preamplifier
This customer came in with a functioning 1959 Marantz 7 Preamplifier. He was told by his friends that "the Marantz 7 would perform well only if major components are upgraded, such as capacitors, resistors and attenuators".
We performed a bench test on the unit and found very few components which needed to be replaced (4 resistors, and 2 capacitors). We also performed the following test:
L/R Balance check
Amplifier noise and hum check
Line output distortion check
RCA and Tube sockets, integrity and oxidation check
Power capacitor leakage check
Phono stage noise and distortion check
The unit was bench tested again to ensure all factory specifications were met.
We advised the customer not to proceed with the optional "exotic" upgrades, which in our opinion were unnecessary. He welcomed and accepted our advice.
Total Cost of Upgrade: $ 80 dollars including parts
Turnaround Time: 2 hours, repaired on spot.