dlucy's guide to Harman Kardon Nocturne series 720, 210, 200, 520, 530, 230, 330, 820

[dlucy]

The second era of solid state receivers from Harman Kardon were (what I call) the Nocturne 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 Nocturne era mostly looked different from their predecessors, the Stratophonic receivers, in that the Nocturnes had mostly black faces. They also moved to mostly silicon transistors.

This era is most-easily identified by the mostly-black, all-dark face plates, grey or silver-capped black knobs, and grey or white lettering. Most of these really only show up when they are powered on and the lamps inside start shining.

Model numbers were written-out numbers (e.g. “Seven Twenty”) instead of just numeric digits (e.g. “720”).

There appear to have been three waves of models in the Nocturne era:

• The initial wave included the 720, 210, and 200.
• The second wave only had the 520 and 530.
• The final wave included the 230, the 330 (written out and not numeric digits), and then 820.

Again, these were written-out model numbers, so “Two Thirty” and “Three Thirty”. This distinction becomes important when compared to the next era.

Initial waves of models:

• Harman Kardon Seven Twenty
• Harman Kardon Two Hundred
• Harman Kardon Two Ten

Second wave of models:

• Harman Kardon Five Twenty
• Harman Kardon Five Thirty

Final wave of models:

• Harman Kardon Two Thirty
• Harman Kardon Three Thirty (this is not the HK 330)
• Harman Kardon Eight Twenty

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)

 

[dlucy]

Harman Kardon Seven Twenty

• Nocturne face
• MOSFET front end
• Ultra-wide frequency response
• 80 watts IHF
• 23 watts per channel RMS ?
• Quasi-complementary output (two NPN output transistors per channel)
• Driver stage coupled to the output stage via transformer

It also featured a "center-channel" pre-amp output (summed stereo signal), as well as more flexible I/O provisions. https://audiokarma.org/forums/index.php?threads/harman-kardon-330-variations.396817/#post-5033511

price $359.50

 

[dlucy]

Harman Kardon Two Hundred

• Nocturne face
• FM (no AM) Stereo receiver
• Metal can output transistors with plastic cover on external side of rear panel
• 50 watts IHF
• Quasi-complementary output (two NPN output transistors per channel)
• Driver stage coupled to the output stage via transformer

price $259.50



The HK Two Hundred, Two Ten, and Seven Twenty use transformers between the driver stage and the output stage of the power amp. The output transistors are then direct-coupled to the speakers.

• HK Two Hundred service manual PDF

 

[dlucy]

Harman Kardon Two Ten

• AM-FM stereo receiver
• 1967 nocturne face
• Metal can output transistors with plastic cover on external side of rear panel
• 50 watts IHF, 10Hz to 23KHz, HD less than 1%
• Quasi-complementary output (two NPN output transistors per channel)
• Driver stage coupled to the output stage via transformer

Price between $269.50 and $245 + $21.25 for wood cabinet



The HK Two Hundred, Two Ten, and Seven Twenty use transformers between the driver stage and the output stage of the power amp. The output transistors are then direct-coupled to the speakers.

 

[dlucy]

Harman Kardon Five Twenty

• FM (no AM) stereo receiver
• Same as 530 but left out AM tuner
• 1967 nocturne face
• Metal can TO-3 output transistors with plastic cover on external side of rear panel
• Uses (4) 2N2147 PNP Germanium TO-3 metal can output transistors 
• Had transformers between the driver board and the output transistors
• Used +-21V dual rails on output transistors
• 70 watts IHF, 8Hz to 40KHz, HD less than 0.8%

Price $269 + $25.50 for wood cabinet

Useful links:

• https://www.hifiengine.com/manual_library/harman-kardon/520.shtml

 

[dlucy]

Harman Kardon Five Thirty

• AM-FM stereo receiver (Same as 520 and added MOSFET-based AM tuner)
• 1967 nocturne face
• Metal can TO-3 output transistors with plastic cover on external side of rear panel
• Uses (4) 2N2147 PNP Germanium TO-3 metal can output transistors 
• Had transformers between the driver board and the output transistors
• Used +-21V dual rails on output transistors
• 70 watts IHF, 8Hz to 40KHz, HD less than 0.8%

Price $299 + $25.50 for wood cabinet

Useful links:

• https://www.hifiengine.com/manual_library/harman-kardon/530.shtml

 

[dlucy]

Harman Kardon Two Thirty

• Identical to the 230A other than cosmetics
• Switched designs from
  • transformer-isolated quasi-complementary Germanium TO-3 PNP outputs with dual power rails with direct-coupled output, to
  • quasi-complementary Silicon TO-220 NPN outputs with single power rail with capacitor-coupled output
• still discrete AM and FM, no ICs
• Has MAG and CER phono inputs (is this still RIAA?)
• 10 watts per channel from quasi-complementary 2SC931 Silicon NPN TO-220 output transistor
• Has separate AM and FM tuning panels (but they share the tuning knob) “Newly designed dial illumination shows AM or FM dial scale independently for maximum visibility. Entire top section of receiver turns black when receiver is switched to phono mode of operation.”
• “Illuminated pushbutton ON/OFF switch glows in red to indicate that receiver is on. continuously variable balance control lets you adjust stereo balance to suit acoustic requirements of your room. Permits you to sit far to one side of your room and still maintain perfect stereo.
• Does NOT have pre-out / main-in jacks

There were lots of problems with the output transistors and some of this is detailed at the end of the service manual. We also have an AK’er from HK talking about the 230 and 230A https://audiokarma.org/forums/index...eceiver-distortion.362843/page-2#post-5130180

“The 230 series was never produced in Plainview. They were all produced in Japan. The 230 and 230A produced by Roland, and the 230E produced by Shin Shirasuna.”

One of the important notes he shares is “The original output devices are 2SC931. They are mounted to the inside rear panel and wires to them lead to the driver board which is edge-mounted nearer to the front of the unit. Almost any NPN silicon TO-220 output device intended for audio output service can replace the 2SC931. It's not critical.”

About 230 and mentions of 230A https://audiokarma.org/forums/index.php?threads/harmon-kardon-two-thirty-230-project.209159/

 

[dlucy]

Harman Kardon Three Thirty (this is written out as letters, not numeric digits. The "330" is a different receiver.)



The preamp and power amp circuit design of the Three Thirty Nocturne is repeated in the 330A and again in the 330B. All three are a quasi-complementary, cap-coupled design. The output transistors are driven by a single stage of drivers. The Three Thirty and the 330A/300B preamp + power amp circuits are very close copies of each other.

The Three Thirty Nocturne has no pre-out and main-in rear panel jacks, so the preamp outputs go directly to the main amp internally.

The Three Thirty Nocturne has its TO-66 package output transistors mounted on the outside of the rear panel. The entire rear panel is the effective heatsink for these output transistors.

The 330A and 330B use plastic TO-220 devices for output transistors and they are mounted inside the chassis on a multi-piece heatsink. That heatsink is then physically interfaced with the metal rear panel and the metal chassis which all the unit’s boards mount to.

The Three Thirty Nocturne has one set of varistors (double diode) physically mounted to the rear panel to self-adjust based on temperature. The 330A and 330B have the same one set of varistors mounted to the internal heatsink. The Three Thirty Nocturne has a second set of varistors, these sprouting up from the PCB itself.

UPDATE: I've purchased an original HK Three Thirty (not 330) service manual, done a simple scan, and the resulting PDF is linked below in the "Useful Links" section.

The power supply in the Three Thirty Nocturne produces a single rail of 45 VDC from a two-diode full-wave rectifier circuit. The main power supply in the 330A and 330B produce 51 VDC from a four-diode full-wave bridge rectifier circuit.

• AM-FM stereo receiver
• In the Nocturne or black-faced design
• Ultra-wide frequency response
• MOSFET FM frontend
• Automatic FM mono/stereo switching
• Stereo indicator lamp
• Signal strength meter
• Loudness contour switch
• 20 watts per channel RMS
• Harmonic distortion less than 0.8%
• Frequency response 7 Hz to 50 KHz

Price $199.95 + $21.95 walnut case





Useful links:

• Adjusting the pre-driver/driver in the HK Three Thirty (not the 330) @markuus3889
• Harman Kardon Three Thirty (not 330) service manual by @dlucy

 

[dlucy]

Harman Kardon Eight Twenty

• FM (no AM) stereo receiver
• TOTL
• In the Nocturne or black-faced design
• Ultra-wide frequency response
• MOSFET FM frontend
• Four gang tuning capacitor
• ICs and crystal filter in IF
• Between-station quieting (FM mute)
• Automatic FM mono/stereo switching
• Stereo indicator lamp
• Signal strength meter
• Loudness contour switch
• Center Output jack on rear panel
• Does NOT have pre-out / main-in jacks
• 40 watts per channel RMS
• Harmonic distortion less than 0.5% at full output across 20 Hz to 20 KHz
• Frequency response 5 Hz to 60 KHz

Price $299.95 + $25.50 walnut case

Useful links:

• https://escapements.wordpress.com/2013/01/01/harman-kardon-nocturne-eight-twenty/
• http://audioklassiks.de/db/html/seite04.eight.twenty.htm

 

[Moving Ahead]

Looks like you've cornered the market.
Never seen this series where I'm from, so thanks for the info, which is well done to you.

 

[roger2]

Impressive organizational skills to post all of that in 31 minutes

 

[59volvo]

how do they sound compared to the numerical series - 330, 430, 730 and the 330c etc?

 

[mark_m]

how do they sound compared to the numerical series - 330, 430, 730 and the 330c etc?

I have a Three Thirty and also a 330A that I recapped and gave to one of my sons. I felt the Three Thirty, which was unrestored, had stronger transients, even 'though I'd upped the caps in the 330A. The Three Thirty did have some graininess in the highs but if I remember right it might have just been dirty pots. I'm about to restore the Three Thirty so I'll compare them again when I'm done. Maybe I'll have made the Three Thirty worse, will find out Been a decade or more since I listened to it but I remember favoring it over the 330A at the time.

p.s. I would not consider that a particularly meaningful preference, just what I remember from some time ago.

 

[dlucy]

how do they sound compared to the numerical series - 330, 430, 730 and the 330c etc?

Different.

some of these Nocturne units use transformers between the driver stage and the output stage. Others do not. That will change the way they sound, compared to one another.

some of these Nocturne units are capacitor coupled (big audio cap between final output transistor and the speaker) and all of the 330c 430 630 730 930 units are direct coupled (no output cap). Cap-coupled designs tend to get comments like “warm” or “tube like” while direct-coupled units usually get “neutral” or “less warm”.

 

[knifeswitch]

The Three Thirty Nocturne has no pre-out and main-in rear panel jacks, so the preamp outputs go directly to the main amp internally.

First off Thankyou very much for all of this! Strangely the Three Thirty Nocturne I just received today does indeed have pre/main jacks. Sounds pretty damn fine I might add.

 

[dlucy]

First off Thankyou very much for all of this! Strangely the Three Thirty Nocturne I just received today does indeed have pre/main jacks. Sounds pretty damn fine I might add.

VERY interesting! Will you send me photos or post here?

 

[knifeswitch]

VERY interesting! Will you send me photos or post here?

I love a mystery! I just ordered a hard copy SM last night.

 

[dlucy]

I love a mystery! I just ordered a hard copy SM last night.

There have definitely been different "runs" of early HK solid state gear, so I guess this shouldn't surprise me. Most of those differences have been internal, though. Will you post photos of the insides, the top side and bottom side of the "guts"?

I've scanned and linked the HK nocturne series Three Thirty above (in that unit's Interesting Links section). I don't see any indication of pre-out and main-in wiring in that schematic. You may well find other differences. If so, please summarize those here for others.

 

[knifeswitch]

Currently there is a Fender Hotrod with it’s guts spilled all over my bench. The moment that things out of here, I plan on spending some family time with this unit and will report back here.

 

[zenith2134]

These units are really golden-age solid state; They have that smooth sound that many people are after. Interstage transformers and capacitor coupling will do that.

I have heard a 330, 430, and 720 (IIRC). They are a pleasure to work on since they're all discrete save for the MPX.

Shin Shirasuna also built the later lines, such as the HK385i, and PM-660 series. Very nice build quality. They were known as the brand •Silver• overseas, as you likely know. I have a cache of NOS Hitachi metal outputs for the 330,430 if anyone needs any.