Pioneer SA-7800 – Two years in the making, worth the wait.

The story of my SA-7800 is one of heartbreak, frustration, and triumph.

I purchased this unit on Craigslist for $200 about two or three years ago.  I picked it up from a self-storage facility in Brooklyn where the owner had set up a tiny electronics repair space.  He apparently owned a radio and television repair shop but had to shut down a few years earlier because no one repairs electronics anymore, they just throw them out.  True enough.

I was excited to take the SA-7800 home and fire it up because I’d never before owned a vintage Pioneer product.  Needless to say, I was immediately disappointed.  It sounded terrible.  Blurry, weak, and bass-less.  Opening it up, I could immediately see why.  At some point there had been a catastrophic failure on the left channel that had resulted in at least 3 resistors going up in smoke, leaving the board with significant char marks.  The previous owner had repaired it by stringing two resistors together and draping them across the backside of the board.  Well, at least it was playing music, which surprised me given how awful it looked inside.  And to make matters worse, it was absolute filthy.  The worst I had ever seen.  Something had to be done.  This amplifier was too beautiful on the outside to simply scrap.

I started by reading every thread I could find on the SA-7800 on AudioKarma and other forums.  I  discovered that this particular failure was not uncommon,  but that the SA-7800 was notoriously difficult to repair because it as a non-switching amplifier.  If a part fails or is installed improperly, it can take out a bunch of other parts with it. 

Undeterred, I started off by using compressed air to clean out as much dust as a I could.  It hardly made a dent in the grim.  I proceeded to remove the various boards and recap them using Nichicon capacitors, which was a fairly easy process.  I also replaced a handful of the transistors with more modern ON Semis.  I had no choice but to leave the strung-together resistors in place, because to give the seller credit, he had found a valid workaround for the charred section of the board.  I put it all back together, and then I made a terrible mistake.

As a final step, I thought it would be a good idea to adjust the bias on both channels.  But I’d forgotten that the single-turn trim pots employed on this amp are prone to failure.  That is exactly what happened when I went to adjust the right channel, which, with a puff of smoke, went from undamaged to destroyed.

I was frustrated to say the least.

I could devote at least 5 pages to describing the various ways I tried to repair that channel, including replacing nearly all of the resistors and transistors (with a few exceptions), but suffice it to say that nothing worked.  Eventually, out of desperation, I went on eBay and bought a new power amp board (this one with no char marks) from an SA-7800 that someone was parting out.  It cost me $75, but I had already sunk too much time and money into this thing to give up.

When the new board arrived, I was anxious to install it.  But first things first.  I started by recapping it, which was easy given that there are only about 4 capacitors on the board.  Then I swapped out the single-turn trim pots for Bourne multi-turn pots.  After reconnecting all the wires, testing for shorts, and setting the bias, I was ready to go.

Oh the joy of hearing that first note.  Forget about the quality of the sound, just hearing this amp play after months of work was incredibly satisfying.  And given that I had it hooked up to my iPhone and a cheap pair of old Infinity speakers, I wasn’t expecting it to sound great anyway.

After letting it play for a few hours and assuring myself that it wasn’t going to blow up or cause a fire, I ventured into the bedroom and hooked it up to my Benchmark Dac2 and KEF LS50s.  All I can say is, wow.  My initial impressions were the exact opposite of what I had heard months earlier when I first fired it up.  I was amazed at how the music seemed to appear before a completely black background, with utter silence between notes.  I was also amazed at the clarity and pace of the amplifier.  It reminded me of Naim amps, which are known for their flow and speed.  This was not the warm. rounded sound that vintage amps are known for, it was something much more modern.  It was intoxicating.

The SA-7800’s specs back this up:  0.009% THD and a 110db signal to noise ratio!  That is significantly lower than many expensive integrated amps out there today.

But my favorite thing about this amp is how great it sounds with all types of music.  I find that some vintage amps sound great with jazz or acoustic music, but can’t handle rock or complex classical music.  No issues here, though.

For some reason, playing Arcade Fire is a challenge that many vintage amps fail.  But through the SA-7800, I played the entire Suburbs album from start to finish and enjoyed every moment of it.  The amp had none of the harshness or fatigue so common when listening to this album on other amps.

Mac Miller’s final album, Circles, also sounds incredible through this amp.  (And if you haven’t heard the album, even if you aren’t a hip hop fan, I highly recommend you check it out.)  His raspy voice sounds eerily real, as if he is standing between your speakers in a haze of smoke and belting it out.

Overall, my advice is simply:  If you have a chance to buy a SA-7800 or one of the higher non-switching Pioneer models from that era, jump at it.  You may never buy another amp again.

Be careful, however, because the lower models, including the SA-6800, do not include the non-switching technology and have significantly higher levels of THD.  I doubt they sound as good as this beast.  Now I need to find an SX-3900, which uses the same technology but has 120 Watts per channel!  Hit me up if you have one for sale for a fair price!