Since the AU222 is such a special amplifier I decided to dedicate a special page to it.

The combination of elegant simplicity and intrinsic quality makes it one of the most ideal Sansui models for upgrading and modifying.

One owner gave me the freedom to go ‘all the way’.

Not only have I replaced all electrolytic capacitors and transistors, I have also left-right matched all new transistors and capacitors to achieve exactly matched left-right dynamic behaviour of the resulting amplifier circuit.

Only very few left; original ‘new old stock’ Sanken 2SC1111, without a doubt the finest power transistor possible for this model. (and for the 555A/505 for that matter!)

There is a lot of debate about which capacitors are the best for a given application. I have so far achieved the best results with Vishay, Panasonic and Kemet/Rifa. More than once I have been asked to investigate amplifiers that, according to the owner, “don’t sound ‘right’ anymore”, often described as ‘harsh/agressive’, not the ‘sweet’ sound they had hoped for. I have so far always found ‘fine gold’ and other ‘audio’ capacitors in these amplifiers, including the notoriously agressive sounding red Wima capacitors.
Without any exeption, owners let me know that their amplifiers/receivers sound beautiful and ‘sweet’ again, once I have replaced all these ‘audio grade’ capacitors with the forementioned brands and types of capacitors.

This particular AU222 is ‘minimalised’, which results in losing all functionality exept on/off, volume control and source select. The original tone/line amplifier is modified to become a unity gain (emitter follower) buffer amplifier that sits between the volume control and the power amplifier. All tone and filter circuitry, including the balance control, is completely removed from the signal path.

Replaced all the original RCA input connectors for gold plated ones. These particular ones are relatively expensive, but of a very high quality.

They fit snugly in place, less that one mm to spare. A thick copper wire serves as the main signal ground plane. The AU222, like the 555, has a peculiar input circuitry, where all inputs, including the line inputs, pass through the phono preamplifier! For the aux inputs the signal is first reduced tenfold, than amplified again. The RIAA correction circuit of the phono preamp is set to neutral. With modern high level signal sources such as D/A converters and CD players, this can result in driving the phono preamp into distortion, which cannot be corrected with the volume control! When I minimalise an amplifier like this, I connect the Phono 1 input directly to the actual phono preamp input and re-wire the source selector switch to select at line level, thus making all the other inputs, including Phono 2 and Tape Head, line level and routing them directly to the volume control instead of through the phono preamp first. A revelation soundwise and for modern applications a much more usable amplifier.

Also fitted new red/black 4 mm speaker terminals. Both the RCA as well as the speaker terminals are fitted in the original hard pertinax boards of the amplifier. I carefully remove the original connectors from these boards and enlarge the holes to allow for the new connectors to be fitted.

Of course it is wise to fit a 3-wire mains cable and properly connect the metal case of the amplifier to ground, thus allowing it to work as a proper shielding for ‘new’ sources of RF interference, such as WiFi, DAB, 4/5G, GSM, Bluetooth etc. This does make an audible difference!
The endresult is an incredably homogenous, musical and ‘sweet’ yet transparant and still impactful sounding AU222.