The first solid state receivers from Harman Kardon were the Stratophonic series.
This thread is a guide to those models, their specs, and pointers to schematics and restoration threads for each. If you have additional information on any of these models, send me a private message and I'll get your info inserted into the right spot in the top posts.
The Stratophonic units looked a lot like the tube units they replaced and relied heavily on Germanium transistors.
Their was an initial release of Stratophonic receivers and then a second generation, otherwise known as "the B-series", with mildly better specs.
Initial release:
The follow-up release were improved models:
The Harman Kardon Stratophonic receiver series pre-dated the Harman Kardon Nocturne series, the 330/330A/330B series, and the Twin Power series.
First Stratophonic models – SR solid state stereo receivers
Second series – SR “B” solid state stereo receivers
Other Harman Kardon solid state receiver guides:
This thread is a guide to those models, their specs, and pointers to schematics and restoration threads for each. If you have additional information on any of these models, send me a private message and I'll get your info inserted into the right spot in the top posts.
The Stratophonic units looked a lot like the tube units they replaced and relied heavily on Germanium transistors.
Their was an initial release of Stratophonic receivers and then a second generation, otherwise known as "the B-series", with mildly better specs.
Initial release:
- Harmon Kardon SR300 or SR-300
- Harmon Kardon SR400 or SR-400
- Harmon Kardon SR600 or SR-600
- Harmon Kardon SR900 or SR-900
The follow-up release were improved models:
- Harmon Kardon SR300B or SR-300B
- Harmon Kardon SR400B or SR-400B
- Harmon Kardon SR600B or SR-600B
- Harmon Kardon SR900B or SR-900B
The Harman Kardon Stratophonic receiver series pre-dated the Harman Kardon Nocturne series, the 330/330A/330B series, and the Twin Power series.
First Stratophonic models – SR solid state stereo receivers
- The SR300, and it's relatives, SR600, SR 900 were h/k's first attempts at SS receivers, hence the look of a modified tube chassis.
- The SR300 was part of the first series of SS h/k receivers and was $220 in 1964 dollars. It would be $1,606 and change today.
- Descriptions from ads for Stratophonic FM Stereo receivers
- “a complete all-transistor line”
- “According to the HK site SR300B "Stratophonic" was only made in 1964!”
- the first transistor units after the tube era and still built on the old chassis.
- "You should also know that it is the culmination of several years of intensive research in solid-state technology. Your Stratophonic Receiver is LITERALLY born out of space-age development."
Second series – SR “B” solid state stereo receivers
- Descriptions from ads:
- “greatly increased power, far wider bandwidth, flatter frequency response at full power” and drives speakers in two rooms, separately or simultaneously. Germanium output transistors.
- Models are SR-300B, SR-400B, SR-600B, and SR-900B (the ad uses a hyphen but the units themselves omit the hyphen in the model name)
- SR-300B – FM stereo receiver. Same as SR-400B but without AM. 60 watts IHF, power bandwidth 6 Hz to 50 KHz, full-power frequency response 8 Hz to 40 KHz. FM only. $279
- SR-400B – AM FM stereo receiver. Same as SR-300B but adds AM. 60 watts IHF, power bandwidth 6 Hz to 50 KHz, full-power frequency response 8 Hz to 40 KHz. AM and FM. $309
- SR-600B – FM stereo receiver. 80 watts IHF, power bandwidth 6 Hz to 50 KHz, full-power frequency response 8 Hz to 40 KHz, harmonic distortion less than 1%, usable FM sensitivity of 1.95 uV. FM only (no AM). $369
- SR-900B – FM stereo receiver. 100 watts IHF, power bandwidth 3 Hz to 75 KHz, full-power frequency response 5 Hz to 60 KHz, harmonic distortion less than 0.2%, usable FM sensitivity of 1.85 uV. FM only (no AM). $449
Other Harman Kardon solid state receiver guides:
- Stratophonic (SR-300, SR-300B, SR-400, SR-400B, SR-600, SR-600B, SR-900, SR-900B)
- Nocturne (Seven Twenty 720, Two Ten 210, Two Hundred 200, Five Twenty 520, Five Thirty 530, Two Thirty 230, Three Thirty 330, Eight Twenty 820)
- 330 minimalist (330, 330A, 330B, 330C)
- Twin Powered (430, 530, 630, 730, 930)
Last edited:
