This is an excellent Harman Kardon A30K, (A300) tube integrated amplifier. The A30K is the kit version of the A300 amplifier.  Some people shy away from kits as they believe a factory built amplifier is assembled with more care than a owner built unit.  I've found that some 50 years after initial construction there is essentially no difference in factory vs. kit.  I've owned and repaired many factory and kit A300/A30K's and find zero differences in them--in addition, the components and circuitry are identical.

Over the past few years, I have restored over 175 HK tube amps and receivers and sold many of them on EBay.  See feedback on my amps and receivers at the end of listing, newer comments on the bottom. To see one of my recently sold A30K's, copy and paste 'Kardon A30K' into the EBay search box, and look for 'sold listings'.

Check my other listings of HK tube amps on eBay.

I had an A300 amp in college in the 1960's and always loved it's sound. I've been restoring HK tube amps and receivers for a few years now as a hobby.  Not any real money in it, but I enjoy making these amps reliable and available to a new generation of tube folks. I've learned all that I can about these amps and have been successful in their restoration. See last picture, that's me in 1965 with my A300.

I never put power to these amps without first replacing the electrolytic and coupling capacitors and diodes.

It is strongly recommended (Google 'recapping radios') that the electrolytic and coupling capacitors be replaced in old tube units. For the A300 there are a total of seven electrolytic capacitor sections in the power supply and a total of eight coupling capacitors to be replaced.  A previous owner had replaced the eight coupling capacitors with new units, I am satisfied that it was done in a workmanlike manner, and I left four of those newish capacitors installed.  I did replace the other four coupling caps with Russian paper-in-oil K40y-9 units, coupled to the output tubes.  All of the power supply electrolytic caps are new, some people say it's OK just to 'reform' the power supply caps. (bring them up very slowly over a couple of days on a variac).  While this is a much simpler and less costly alternative, I'm not convinced that it is as good as replacing dried out caps with new current fresh stock.  The new caps are mounted under the chassis, while retaining the 'can' on the top of the chassis (electrically disconnected) to maintain the aesthetics of the unit.

After restoration I also verified the B+ voltages and critical components are to specification, and replaced other components, mostly resistors, as necessary.  

I also replace the rectifying diodes with more modern units that have fast turnoff/soft recovery, characteristics that provide a little less noise-- makes for a cleaner power supply. No change in the sound of the amp, only just a cleaner power supply.

These restorations do not modify the wonderful 'tube sound'--no real modifications, but rather put back the way the HK engineers designed it, only make the unit safer and more reliable.  See the pictures, shows the before and after of the chassis (bottom cover removed for picture).

In addition to the electrolytic and coupling capacitors, I have tested all the tubes on my B&K 707 tube tester and replaced any that were marginal.  I also have cleaned the tubes, tube sockets, controls and switches (Deoxit D5 contact cleaner for the tube sockets and switches,  F5 Fader Lube for the potentiometers). The output tubes are performance matched RCA 7408's.

I have verified all the operations.  The controls and switches have no noise.  All the inputs are operational.  I have run this unit 8 hours without any issues after the refurbishing.

This unit has an excellent appearance, the faceplate is very nice, has some light marks and scratches, see pics.  The knobs are in very good condition. Faceplate and chassis lettering is essentially sharp and legible.  The chassis is also very nice, does have some small stains, see pics. 

The A300, as a tube unit has a sound unlike solid state units. The Harmon Kardon A Series are referred to as 'Award Series'.  Not sure what the Award was, but these were (and are) highly regarded amplifiers, and have that highly desired 'tube sound'. Interesting that HK is one of the very few hi-fi companies of the 1960's to still be in business.

As a stereo integrated amplifier, there are inputs for lo level (magnetic) phono or tape head, hi level (ceramic) phono, tuner and auxiliary inputs.  The controls are: Source Selector, Loudness (Volume), Bass, Treble, Balance, and Blend.  Switches are provided for power, rumble filter, contour, equalization and stereo reverse.

The major specs are:

IMHF music output power: 15 watts per channel, this was back when power ratings meant something, plenty of power for moderately efficient speakers. I prefer Electrovoice 12TRXB's--a very nice horn type triax speaker. I've heard good reports from buyers using the vintage Klipsch's too.  This amp (as with other vintage tube amps) likes efficient speakers, best to have speaker efficiency of about 90-92 db or greater.

Frequency response--+/- 1 db 15-70,000 cps at normal listening levels.

Output impedance: 8 and 16 ohm

Stereo inputs: low level, 3.0 mv.

Stereo inputs: high level,125 mv. This is suitable input for tuners, CD decks, most smartphones, tablets, etc.

Stereo tape outputs, to feed a tape recorder or second amp.

Now, my lecture.  This is not your son's amplifier.  This is a tube unit, and as such, has voltages inside the chassis that can be lethal, 350+ volts.  Also, it has tubes and a power transformer that gets hot.  Although these are rated for 100% duty cycle (you can listen to them indefinitely), when you are done listening, best to turn it off.

But after listening to a tube amplifier, you may find yourself on Ebay buying up turntables and record changers, collections of vinyl (records), and turning the lights down just so you can watch the soft orange glow of the tube filaments, and talking about bias, tube rolling, and 'gee I need to get another system for the family room'. Can be a slippery slope.

I will email the winning bidder the A300 15 page operator's manual, which includes setup, operation and the wiring schematic.

So, if you are into tubes, or just starting, here is an amplifier that is restored back to the original design specifications.

I have successfully packaged and shipped these amps domestically and to many international locations. I take care in packaging so they are properly protected in shipping.  This is a heavy unit, about 25 pounds shipping weight.

As with essentially all vintage electronics, there is no ongoing guarantee.  If there is an issue, I will work with you, check my feedback.

For international shipping, I ship to all countries covered by the EBay Global Shipping Program.  If your country is not listed, contact me, maybe we can work something out. For International purchases, the high shipping cost precludes a return of this amplifier. I guarantee it was in good working condition as described when shipped, but any damage during shipping is an issue between the purchaser and the shipping operation.  I have not had any issues with International shipping, but believe it's necessary to set this stipulation. 

If there is an issue, I will work with you--check my feedback, I am honest.

Happy Listening!

Harmon Kardon A300 Refurbished Tube Amplifier (#230230883470) Item exceeded expectation, great communication, excellent packing, I'd buy again

Harmon Kardon A30K Refurbished Tube Amplifier (A300) (#230226594587 Great tube amp and he went out of his way to ship it my way!!!!

Harmon Kardon A300 Refurbished Tube Amplifier (#230229344793) I cannot explain how wonderful this amp makes my music sound!!! Fast shipping!!!

Harmon Kardon A300 Recapped Tube Amplifier (#330277726387) Impressive! Packed like a true engineer! The pkg. got me, the amp flew me. Thanks!

Harmon Kardon A300 Recapped tube amplifier, 12AX7's (#230219839832) Great communication, packaging, friendliness, helpfulness. The Best!

Harman Kardon HK A500 Refurbished Tube Amplifier (#230347345804) Shipped fast. Smooth transaction. Ridiculously well packed

Harman Kardon A300 tube amplifier refurbished HK nice (#330388638348) While you guys were sleeping I got a great deal on a true tube amplifier. Thanks

Harman Kardon A30K A300 6V6 tube amplifier refurbished (#230403490711) Here is a very honest good man Thank-you!

Harman Kardon A300 tube amplifier refurbished HK nice (#230414716217) Item as advertised, great communicator, outstanding packaging, A+++

Harman Kardon A300 tube amplifier refurbished HK (230433088703) Amp arrived today, Hooked it up and it works fine, sounds good

Harman Kardon A300 tube amplifier refurbished HK nice+ (#230426845298) First rate all of the way

Harman Kardon A300 tube amplifier refurbished HK (#230433088703) Great service, fast shipping A+++

Harman Kardon A300 tube amplifier refurbished HK sharp (#230437780607)Very nice unit, Top ebayer. Best regards Leif 1791

Harman Kardon HK A50K Refurbished Tube Amplifier, A500 (#330423807461) Very smooth transaction. I highly recommend buying form this seller-excellent!

Harman Kardon A300 tube amplifier refurbished HK nice+ (#330425822207) Very well packed, amp exactly as described. Perfect ebayer. Thanks

Harman Kardon A50K Refurbished Tube Amplifier A500 HK (#230469196743) A really beautiful job of restoration. Highest recommendation.

Harman Kardon A300 tube amplifier refurbished HK nice (#230471466536) Thanks camaroguy62 you made a 62 year old guy happy. Great sound. Love tubes.

Harman Kardon TA224 tube receiver refurbished HK (#230489993374) Very fine. Leif 1791 (Note: repeat buyer)

Harman Kardon A300 tube amplifier refurbished, HK 7408 (#230486830702) Fast shipping, well packed, excellent sounding amp.

Harman Kardon A50K (A500) Refurbished Tube Amplifier (#230528355151) Best seller ever! Very good follow up and best communication! I give 6 stars!!!

Harman Kardon A300 tube amplifier refurbished 7408, 6V6 (#230575432550) I'm very happy with this purchase. Also, email "Received amp Monday 31st. Sound is fantastic."

Harman Kardon refurbed A30K A300 tube amplifier 7408's (#230586591434) The real deal here, great amp....Excellent thank you!!

Harman Kardon A300 tube amplifier refurbished 7408 nice (#230580499849) Great amp. Thanks so much.

Harman Kardon A500 Refurbished Tube Amplifier, HK (#230582037624) Very nice unit as described... shipped promptly and very well packaged.

Harman Kardon refurbed A224 stereo tube amplifier EL84 (#230587089839) Excellent rugged packaging,quick delivery,honesty and immense care.Thnks fo deal (Note: sent to Russia)

Harman Kardon A500 Refurbished Tube Amplifier 7355's (#230607735073) A Very Helpful, Honest Seller. A Shining Star On eBay. This is someone to trust!

Harman Kardon refurbed A230 stereo tube amplifier EL84 (#330539388127) Outstanding. Vinyl can now be played in perfect mode. Excellent packaging. A++

Harman Kardon refurbed A30K A300 tube amplifier 7408's. (#230607734237) Carefully packed items and fast delivery, a five stars material. (Note: Sent to Thailand)

Harman Kardon refurbed A300 tube amplifier 7408's, 6V6 (#230624946073) This is one incredible sounding amp! Excellent communication, fast shipping!

Harman Kardon A500 Refurbished Tube Amplifier, nice (#230627318471) Excellent communication, shipping, descrption. Amp works great! Thank you!

Harman Kardon refurbed A300 tube amplifier 7408's, 6V6 (#230617937170) Solid seller, professional and stands behind his products. Highly recommend.

Harman Kardon refurbed Lute A220 integrated stereo tube amplifier 6V6/7408's (#230709135428) Well packed, the delivery is fast enough. I recommend the seller. (Note: Sent to Russian Federation, 21 days from shipping to delivery). Also an email "Connect the amplifier, the sound is excellent".

Harman Kardon A300 (A30K) refurbed to orig. integrated tube amplifier 7408 tubes (#330566447577) to be honest this is a six star seller

Harman Kardon A300 refurbed to original, integrated tube amplifier 7408 tubes (#330658656112) Excellent Top notch Ebayer! Very customer focused. Excellent communication!

Harman Kardon A300 refurbed to original, integrated tube amplifier 7408 tubes 28 (#230730395558) Very nice seller. Efficient shipping. Item performs great! A++++++ ^^ (Note: Sent to Hong Kong)

Harman Kardon refurbed A224 integrated stereo tube amplifier EL84/6BQ5 beauty! (#330684623823) What can i say...Camaroguy is simply a true gentleman!!! Can buy eyes closed. (Note: Sent to Cambodia)

Harman Kardon A300 refurbed to orig integrated tube amplifier 7408 tubes beauty! (#230782913856) Very generous with info/details about item. Packaging went "one step beyond." A+

Harman Kardon A500 Integrated Tube Amplifier, Refurbed to orig. specs 25WPC (#330734051861) Absolutely the best amp I've ever owned. Expertly refurbished and shipped.

Harman Kardon A500 Integrated Tube Amplifier, Refurbed to orig specs 25WPC beaut (#330742827034) A+++++++++++++++++++++++++++++

Harman Kardon A300 refurbed to orig., integrated tube amplifier 7408/6V6 beauty! (#330724342234)  SUPER item, GREAT SELLER TO DEAL WITH -now just have to set this baby up! Thanks

Harman Kardon A300 refurbed to orig., integrated tube amplifier 7408/6V6 nice! (#330808089199) promt delivery, great communication,great packaging, amplifier works great

Harman Kardon refurbed A230 15WPC integrated stereo tube amplifier, EL84/6BQ5 (#230878310062) the best, most helpful seller on eBay, couldn't be more happy

Harman Kardon A300 refurbed to orig., integrated tube amplifier 7408/6V6 outputs (#230902106920) Great Ebay Seller! Outstanding communication and support. A+++

Harman Kardon A300 refurbed to orig., integrated tube amplifier, K40Y-9 PIO caps (#330852079075) the very best!! highly recommended!! thank you sir!!

Harman Kardon A30K (A300) refurbed integrated tube amplifier, K40Y-9 PIO caps (#330877006072) Great guy and excellent working unit. Everything he said it was. A+++Seller

Harman Kardon A50K Integrated Tube Amplifier, Refurbed to orig. specs 25WPC A500 (#330874769968) Great service, fast shipping A+++    NOTE: Shipped to Estonia

Harman Kardon refurbed A220 integrated stereo tube amplifier 6V6 outputs (#230934331966) Great sounding stereo! Well packed, fast shipping++++++++++++++++++

Harman Kardon A30K (A300) integrated tube amplifier, refurbed to orig., nice (#230942903430) Packaged very well and fast shipping, pleasure to do business with

Harman Kardon A300 integrated tube amplifier, refurbed to original, nice unit (#330896129005) I have never received anything that was packed this good. Excellent Seller!!!

Harman Kardon A300 refurbed integrated tube amplifier, K40Y-9 PIO caps, nice amp (#330901386193) Packed very good,sounds great and works like a champ, my first tube amp.TY

Harman Kardon refurbed A224 integrated stereo tube amplifier EL84/6BQ5 beauty (#330901581618) Very good communication, helpful and honest seller. Recommended.

Harman Kardon A300 refurbed integrated tube amplifier, nice amp. (#230980302576) A+++++ everything was as described phenomenal customer service

Harman Kardon refurbed A230, 15WPC, EL84/6BQ5 integrated stereo tube amplifier (#230991580545)  Thank you. Perfect. Fast. Great communication.

Harman Kardon A30K (A300) refurbed integrated tube amplifier, 7408 (6V6), nice (#231013537159) Amp is great! Just as described, very good communication, Recommended!

Harman Kardon A500 integrated tube amplifier, refurbed to original 25 WPC, nice! (#231103795100) Extremely Satisfied Exactly as described. Bought before AAAA++++ Ebay Seller

Refurbed Harman Kardon A230 stereo integrated tube amplifier, 6BQ5/EL84, 15WPC (#231101498741) Perfect package, quick shipping, accurate description, excelent communication++

Harman Kardon A300 integrated tube amplifier, refurbed to orig., K40-9 PIO caps (#231113685092)  A+. The packaging, communication and of course the A300... just awesome. A+A+A+

Harman Kardon A30K (A300) integrated tube amplifier, refurbed, K40-9 PIO caps (#231123278867) Amazing amp! Packaged well, sent out in a timely way! A great seller!!!!!!

Harman Kardon A300 integrated tube amplifier, refurbed to orig., K40-9 PIO caps (#231127557692)  A+++++ excellent communications & great shipping/pkging. Great restore on unit!

Harman Kardon A300 integrated tube amplifier, refurbed to orig., K40-9 PIO caps (#231117161141) The great seller! Very responsible! Excellent packing!!! Extremely recommended! Note: Sent to the Russian Federation.

Harman Kardon A300 refurbed integrated tube amplifier, K40-9 PIO caps, beauty! (#231129361216) Couldn't have been a better experiance.

Harman Kardon refurbed tube A10 amp & FA10 receiver pair for stereo, 6BQ5 / EL84 (#231150623416) Unbelievable detail,care,support!! Best seller on eBay...best on the planet!!!!!

Harman Kardon A224 integrated stereo tube amplifier, refurbed nice vintage amp (#231159509912) 6 stars if I could! Could not be happier - I love, love love this amp!

Harman Kardon A300 refurbed integrated tube amplifier very nice! (#331115102141) Great transaction. Packaging and followup assistance was beyond expectation.

Harman Kardon A300 refurbed integrated tube amplifier, Russian K40-9 PIO caps (#231166554536) Arrived promptly, very well packed. I already am enjoying the sound! 

Harman Kardon A500 integrated tube amplifier, refurbed to original 25 WPC, nice+ (#331362987112) Best ebay seller ever!!! This guy goes above and beyond and does quality work.

Harman Kardon A500 integrated tube amplifier, refurbed to original 25 WPC (#331395070215) Item exactly as described, fast shipping, one of ebay's finest sellers!!

Harman Kardon A300 refurbed integrated tube amplifier K40-9 PIO caps nice amp! (#231410935476)  The A300 is wonderful. I will cherish and enjoy it for many, many years to come

Harman Kardon refurbed tube mono FA10 receiver , 6BQ5 / EL84, nice unit (#231409222152)  excellent seller, A+++++++++++, really cares, sounds like very nice person

Harman Kardon A300 refurbed integrated tube amplifier K40-9 PIO caps nice amp! (#231431267758) A+++ Transaction, great communication

Refurbed Harman Kardon A230 stereo integrated tube amplifier, 6BQ5/EL84 15WPC (#231452884122) Best seller on ebay. Thank you again!

Harman Kardon A50K (A500) integrated tube amplifier, refurbed, nicest A50K ever? (#331485031949) Excellent and reliable seller! Thanks for your notes and fast shipping! A+++++++

Refurbed Harman Kardon A230 stereo integrated tube amp, amplifier, EL84 15WPC (#231508063897) excellent all the way!!! Careful professional packing, Thanks for all your effort

Refurbed Harman Kardon A230 stereo integrated tube amplifier, 6BQ5/EL84 15WPC (#231684860285) Arrived quickly as described. Excellent seller A++

Harman Kardon A230 refurbed stereo integrated tube amplifier, 6BQ5/EL84 15WPC (#331675385537) exactly as described thank you

Harman Kardon A500 integrated tube amplifier, refurbed to original, 25 WPC (#231733594704) One of many amps I've purchased from Camaroguy. Top notch! Extremely fortunate!

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Harman Kardon A500 integrated tube amplifier, refurbed to original, 25 WPC nice! (#331727584123) Very nice transaction. Good communication, fast shipping and great description.

Harman Kardon refurbed A230 stereo integrated tube amplifier, 6BQ5/EL84 15WPC (#331749889193) Great seller! Item was as described and shipped immediately, packaged well.

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Harman Kardon A224 refurbed stereo integrated tube amplifier, EL84/12AX7 12WPC (#331761566635) Prompt, packed well,very friendly. Thanks D M Clark

Harman Kardon A300 integrated tube amplifier, refurbed to original, nice, 15 WPC (#231824022460) Excellent item and transaction. Thank you!!!

Harman Kardon A224 refurbed stereo integrated tube amplifier, 12WPC, EL84/12AX7 (#331781059630) I REALLY think camaroguy62 is better than 5 stars! HK = labor of love for him.

Harman Kardon A500 integrated tube amplifier, refurbed to original, 25 WPC (#231831027613) great seller.thanks 

Harman Kardon A500 integrated tube amplifier, refurbed, 25 WPC, beautiful! (#231865864633)  Awesome man perfect communication great packaging fast shipping best seller here 

Harman Kardon A50K A500 integrated tube amplifier, refurbed, 25 WPC, beautiful! (#331790711087) Fantastic item as described. quick to arrive and info included as directed. THQ Note: Sent to England.

Harman Kardon A300 integrated tube amplifier, refurbed to original, 15 WPC, nice (#231878915940) most honest, knowledgable & trustworthy amp salesman in USA. Buy with Confidence

Harman Kardon A224 refurbed stereo integrated tube amplifier, 12WPC, EL84/12AX7 (#331834352822) Great ebayerHarman Kardon A300 (XAM, Mark IV) refurbed integrated tube amplifier, nice 15WPC (#331850722092) Great unit! Sounds fantastic and is exactly as described. Highly recommended