The Alesis MMT-8 has a one transistor power amp in single ended class A

It is a midi recorder.


Here is the schematic:
https://elektrotanya.com/cgi-bin/download2.cgi?dk=j9pj4enqr46fdf51ag1rtrlxlizeypwe3j9c9tzi8bwnqqtp&fid=120827&file=alesis_mmt8_rev.2_schematic.pdf


Strange isn't it?
One of the best sounding amplifiers even seen or heard by mankind used to drive the metronome speaker?


No wander how huge the sound is from just a tiny speaker.


In fact it is 2 transistors in parallel and no other component. Class A operation (electrons flowing all the time).


Transistors are 2N4401 GE.


Hmm.


All possibly needed is biasing with a suitable resistor from collector or Vb to base so that transistor current is flowing all the time while music to be amplified is fed to base. Ie class A operation ie electrons flowing all the time.


Here is the datasheet:
https://www.onsemi.com/pub/Collateral/2N4401-D.PDF


(At your risk)
Take all safety voltage, current precautions.
Protect your hearing.
How would it sound driving high Z headphones or headphones in general?
Sound presure level should be kept low in order to avoid hearing irreversible damage.