For your consideration ...
This is an LM3386 stereo power amplifier built into a Dynaco Stereo 80 (ST80) chassis.
I mostly design and build tube amps, and occasionally solid state amps, but I heard
so much about this chip that I decided to give it a try. A project I put off for over
The modules all came from China so I didn't have the bother of making PC boards.
Needed some mods though. The power amps each needed a Boucherot Cell (Zobel) which
is placed under the board. I also added output inductors along with the damping resistors.
These changes will improve the amp stability with a wide variety of loads.
Very nice sweet sound. I was not disappointed and I wish I could keep it around.
I listen to B&W speakers on my Stasis amp, and this amp performs favorably to that.
Some things I like better, such as the more defined mid-bass. Amp gives a good sense of
"air" that I like.
The heatsink is large, and will afford continuous high level audio listening while maintaining
the SOA (Safe Operating Area). No skimping here.
I added speaker protection in case a chip should fail. Although they are "self protecting",
there is no sense is risking your speakers in the event of a catastrophic failure, which
of course would destroy the self protecting feature anyway.
The toroidal power transformer is a 320VA unit, therefore power reserve is not an issue.
I replaced the original junk speaker connectors with some heavier duty units, and upgraded
the sorry input jacks to some nice nickel plated pieces. I left the original power switch, AC
cord and fuse holder intact, but replaced the pilot lamp with something more reliable and
quieter. The chassis top is in near perfect condition. The chrome part of the chassis is lightly
pitted, just like most of these vintage pieces. Not too bad though as you can see in the pictures.
I retained the original Dynaco serial number sticker, and placed it on the power transformer.
All power measurements were at my residual of .03%.
42W at 8 ohms.
55W at 6 ohms.
65W at 4 ohms.
Noise below my residual.
The nature of this beast is such that for speakers of 8 and 6 ohms where often the speaker
impedance dips, rises and is irregular, this amp will rise to the task. For 4 ohm speakers, like
my B&W's, the amp never strained in my 15x15 foot room. Monitoring the output, the room
was easily filled with sound without approaching clipping. The heatsink gets slightly warm.
So we're looking at good stability.
You get the amp safely packed, and a circuit diagram.
NOTE: This amplifier is for sale locally and on other services, so I reserve the
right to cancel and bids or offers.