Small amp sim

[Gus]

Found a 380mw amp circuit in a NS 1982 transistor book.  Changed a few things and simmed it in LT spice

6VDC

Not built as of this posting, looking for a old 12 inch console TV speaker.

C1 adjusts the lows and C5 the highs changed from 220uf and 1000pf

Discuss

[CynicalMan]

Can you please post the .asc file?

[Brymus]

I dont see any schematic or picture.

[Gus]

Brymus

  It is a PNG file. 

http://www.aronnelson.com/gallery/main.php/v/gus/380mw.PNG.html

[maarten]

Gus,
should R6 and C4 not be in series?
Maarten

[Brymus]

Thank you Gus,I can see it now.
That looks super simple,for just under half a watt.
Wonder how it compares sound wise to the 386 type circuits of similar output ?

[Gus]

maarten

This circuit is from a NS book the cap is across the 8 ohm loudspeaker R8.

Yes often you see a series RC across the loudspeaker but it was drawn with only the cap in the NS book.

[Brymus]

I breadboarded it but got no sound,not even a click or pop.
I double checked it,triple,four times.(found two mistakes)
My only difference is using 2N2222A instead of 2n2222 and 100r for R4 and R3 instead of 91r, 6.09V supply.
I am sure its probably me, but if anyone else gets it to work please post.

[John Lyons]

Looks interesting, bump...

I don't think that the "A" designation should have a significant change Bryan.
100R should be fine enough to get sound out...hmmmm...

[CynicalMan]

You have C2 as 0.1F, not 0.1uF. The input impedance looks pretty low, so you might want to increase that above 0.1u.

[PRR]

> should R6 and C4 not be in series?

You are thinking of "better" amplifiers.

This one is so simple and crude that it can be stabilized with just C5 and maybe C4.

> found two mistakes

In my yard, if I find one rock, I know there is another, and another.

What DC voltage at the Q1-C1 junction (the main output before coupling cap)? Better be "between the supply rails". Ideally "half", but actually sensitive to Q3 hFE, so it will vary. At 6V you better have 2V to 4V to have useful output.

Take Q1 Q4 out, Short Q2. This too should give "about half" at Q3 Collector.