Powered OPA amplifier

[Stee]

http://www.eserviceinfo.com/download...%20usa370.html

all stages have a gain... (no current stage)
so this can have a brilliant sound

[Stee]

without output capacitors

[djk]

Thos are not output capacitors, they are the power supply capacitors.

In many of the QSC designs the output/capacitor node is also hooked to the center tap of the power transformer.

[ostripper]

That is a QSC USA400 PA amp, simple 100w PA amp.

It would make a good sub amp as it is not as refined as
a leach or Self amp. Good for simple first project.

[Mooly]

Originally posted by ostripper
That is a QSC USA400 PA amp, simple 100w PA amp.

It would make a good sub amp as it is not as refined as
a leach or Self amp. Good for simple first project.

The "ripple null pot" is a real giveaway as to it's intended use.

[Stee]

http://www.esafono.it/usa3701.pdf
the original source design have a particular Patent
for output capacitors

See version 3

[sakis]

they have everything .....

-solid rock
- class AB+B topology
-wonderfull sziklai ( output configuration provides also some gain )
-average quality
-extremelly simple to make
-low cost
-soft cliping
-much more effective than class AB +- 15% more
-less heatsink requierd
-with good constuction you may drive extremelly low loads

and from latest expirience they can also drive strange loads without problems but quality remains average at all application

lets face it a simple device may produce all the above but with average quality ....

if i ever meet sziklai i will buy him a case of beers

[lineup]

Great Amplifiers, Stee
Keep up the good work.

[Stee]

see the ideal application on phono balanced chain

[Stee]

http://www.esafono.it/allgainstages4.jpg
this version four have little power