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Vintage Dynaco ST 150 Stereo Power Amp - $225 (Alamo Heights)
condition:
good
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This is Dynaco’s legendary, top-of-the-line and most powerful power amp of its’ time: mid-1970’s. Designed to be used in two amp configurations - 75 watts in stereo or 150 watts mono - this model is designed to accept installation of 2 blue power meters, like a McIntosh amp, once the upper face-plate cover is removed. Or it can be used as is.
Note: This particular amp is clean and its metal cabinet and wood veneer sides are all in great condition, but it has some issues. The plastic power switch end is broken off but can still be moved. All parts are complete but it needs to be tested by a qualified audio repair tech. Selling ‘as is’. 250.00 OBO
There are kits available that not only restore the Dynaco to its original specs but enhance it with replacement capacitors and transistors to surpass it’s original specs and make it run better overall. One good one is here: www.updatemydynaco.com/Stereo150.html
Info From Hi-Fi Engine…
The Dynaco Stereo ST-150 is a high-end two-channel power amplifier employing all silicon semiconductors. They include 24 transistors, 2 zener diodes, 16 diodes, and 2 thermal sensors. The output circuitry is of the full complementary symmetry design. The entire amplifier, except for an input network, is direct coupled.
The design of a very fine power amplifier implies the necessity of several protection techniques for the amplifier, and the speaker load. In addition to the AC line fuse, four separate B+ fuses are supplied.
It's measured distortion levels approach the threshold of much laboratory test equipment, not only at the commonly specified full power ratings, but more importantly at very low power outputs as well.
This is the result of circuit techniques which eliminate any discernible crossover notch at low levels, and contributes to the Stereo 150's freedom from listening fatigue.
It's accurate, uncoloured sonics have been achieved on a wide variety of loudspeaker loads, including electrostatics and multiple drivers with complex crossovers.
Electronic volt-amp limiting ensures safe operation of the output transistors, and a thermal sensor mounted directly on each output stage reduces the input if high temperature occurs.
An unusually large radiating area for the heat fins, which are coupled to an aluminium back panel, form a highly efficient heat sink. Speaker fuses protect the load.
The Stereo 150 has been designed as two independent 75 watts (at 8 ohms) amplifying channels with a common power supply having a high degree of inherent regulation.
In addition, where higher powers or higher volt-amp capabilities are required for lower load impedances, easy internal restrapping permits monophonic operation for 150 watts output (at 8 ohms).
An accessory kit is planned at additional cost for two output meters and meter switching, which includes alternative inserts for the front panel.
Specifications
Power output: 75 watts per channel into 8Ω (stereo)
Frequency response: 20Hz to 20kHz
Total harmonic distortion: 0.25%
Damping factor: 50
Input sensitivity: 1V
Signal to noise ratio: 95dB
Speaker load impedance: 4Ω to 16Ω
Semiconductors: 24 x transistors, 2 x zener diodes, 16 x diodes, 2 x thermal sensors
Dimensions: 14.5 x 13.75 x 7 inches
Weight: 29lbs