Simplest possible

[Mr. Triatic]

anybody have a schematic over the simplest-ever-fairly-good sounding amplifier with discrete BJT:s, preferrably NPN-types??
in the range of 5-30 W will do.

[peranders]

If you are after low power amp with fair audio quality, why don't you check some intergrated amp? Cheap, few parts, protected, Ok performance, small etc.

National, Apex (not so cheap), Thomson, Texas, has chips.

[Mr. Triatic]

well.. a friend of mine, a non-technical one, is eager to build his own amplifier, so he wanted me to help him to do so, therefore i want this simple amplifierschematic that i can explain to him in not-too-technical terms, an IC-amp would be too much for him... 8-)

[mgoedeke]

They don't get much simpler (or cheaper) than IC amps. A LM1875T Gainclone suits even my own budget which takes planet10's frugalphilia to new ... uhm ... lows (concerning price)?

Slap together the IC, some components (9 last time i checked), a heatsink (do a quick google search on gainclone) and a powersuppply (which costs the most anyways) for an amp that could be used for computer speakers and more (will scale from a miserly couple of watts to a little over 20W for the LM1875, but more powerful ICs are available). You could even buy a cheap kit using these ICs.

I am sure this link has been given by many, but it is a good guide to amplifier basics http://sound.westhost.com/amp-basics.htm. He has a couple of rudimentary schematics though I wouldn't be able to recommend parts.

Martin

[dhengkoel]

Originally posted by Mr. Triatic
... with discrete BJT:s, preferrably NPN-types??
in the range of 5-30 W will do.

Try following link:
ESP Project: http://www.sound.westhost.com/project36.htm
JLH Project: http://www.gmweb.btinternet.co.uk/

Regards:
ragil.hastomo

[planet10]

Originally posted by mgoedeke
They don't get much simpler (or cheaper) than IC amps. A LM1875T Gainclone suits even my own budget which takes planet10's frugalphilia to new ... uhm ... lows (concerning price)?

I don't know... i continue to work on making the cost of my hifi less & less. Turntable is going next (anyone need a Linn?)[/QUOTE]

Slap together the IC, some components (9 last time i checked), a heatsink (do a quick google search on gainclone) and a powersuppply

You won't get much simpler. Amp Chip DIY forum for gain klone info. And the low budget kit version. $12 CAD (<8 USD!)* per channel. Then the power supply. If you find it necessary the PS can be repurposed later. * a couple sample chips from Nat Semi and a little rummaging in the parts bins and you could get away with even less (ignoring your time)

dave

[pinkmouse]

A completed one for your perusal using a lm3875, (note the heatsink is only for testing, it would be too small for a working amp!)

If I can build one, anyone can!

[traderbam]

Mr Triatic,
I'd say the simplest all-npn discrete amp would be a single-ended output class A. Will get rather hot - is this a limitation? But it will easily give you power within the range you stated and will sound sweet as a nut. 5 transistors in the signal path and 3 current sources. I don't have a schematic capture program or a scanner or I'd post it. But if you want it I'll try to sort something out.
Another way is to use an output transformer (like in a valve design). Getting hold of a suitable transformer may be tricky.