Harman Kardon A224 Stereo Tube Amplifier
Archived listing from the original vintage-amplifier.com. Prices, seller details and purchase links have been removed; this page is a reference record, and nothing here is for sale. About this archive.
Harman Kardon refurbished tube type A224 integrated amplifier, serial number 2904939. The A224 is one of the nicest EL84 tube amps of that era (about 1959). This amp appearance is excellent, the faceplate looks great, I see very minor mars and scratches, one ding on the lower LH corner, see pic. , the knobs are excellent, all the lettering is legible and distinct–see the pictures. The cover has been repainted, and looks very nice. Now, when the cover is removed, you will see that this has a copper flashed chassis, and generally is impossible to clean, so best to keep it covered. The amp size is compact, about the size of a turntable, see pic.,
The A224, as a tube unit has a sound unlike solid state units. 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, Mode, Loudness (Volume), Bass, Treble (with power switch), Balance, and Blend. Switches are provided for rumble filter, contour, and speaker selection.
It is strongly recommended (Google ‘recapping radios’) that the electrolytic and paper or molded (original disc mica type are OK) coupling capacitors be replaced in old tube units. 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 a good as replacing dried out caps with new current fresh stock.
See the last two pictures, ‘before’ and ‘after’ recapping. After restoration I also verified the B+ voltages and critical components are to specification. This restoration does 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.
About this model
Wikipedia dates the A224 to 1959 and describes it as a 24-watt stereo amplifier that Harman Kardon advertised as "the largest selling stereo amplifier and tuner in America". The seller of this example, serial number 2904939, calls it one of the nicest EL84 amplifiers of its era, and the listing gives a full picture of the controls: source selector, mode, loudness, bass, treble, balance and a blend control, with switches for rumble filter, contour and speakers.
The restoration notes are a good model. All electrolytic and paper coupling capacitors were replaced (original mica capacitors were left alone), B+ voltages were checked against specification, and before-and-after photographs were taken. The seller also notes the copper-flashed chassis, which tarnishes and is very hard to clean.
| Maker | Harman Kardon, USA |
|---|---|
| Model | A224 stereo integrated amplifier |
| Year | 1959 |
| Rated output | 24 W total (Wikipedia) |
| Output tubes | EL84 (listing) |
| Inputs | Magnetic and ceramic phono, tuner, auxiliary (listing) |
Questions collectors ask
How powerful is the Harman Kardon A224?
Wikipedia describes it as a 24-watt stereo amplifier, introduced in 1959.
What does the blend control on the A224 do?
It mixes some of each channel into the other, narrowing the stereo image. It was a common feature on early stereo amplifiers, when many recordings had exaggerated left-right separation.
Sources: Wikipedia: Harman Kardon; Wikipedia: EL84.
