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nbcd 9th February 2009 12:13 PM

good amp project needed
Hy all ,

My intention is to build my own amplifier that would be rated between 200 and 300W. I also want to be able to connect it directly to a laptop or computer sound card without additional preamplifiers.
If any of you has a project that is functional and really hyfi that worths building, please let me know.

Kind regards ,


nbcd 9th February 2009 06:31 PM

Did someone built thid amp?

What is your opinion.

Thank you.

nbcd 9th February 2009 06:49 PM


ostripper 9th February 2009 07:24 PM


What is your opinion.
It looks like it would work, but at low power.. it must be
one of Nico's early ones..

Bc556 /Bd 140's are low voltage devices and best suited for
baby amps (50W). I really dont see where it could do 300W???

To add current mirrors/CCS and approach a more standard
"blameless" topology makes for a more reliable , foolproof design
with not much added complexity...better devices would assure
that there would be no fire:hot: as well. 2SC1845(LPT),
MJE340-50 or 2sa1381-2Sc3503 (VAS) would make
for a real high voltage, properly derated project.

Look in my :

Built some of them , simulated all of them,, amps from Quasi,
Jagodic,leach , mine (frugalamp), DX.. all sorted by
type and power output. Happy reading.

AndrewT 9th February 2009 08:07 PM

try some of the Quasi amps. There's about four in the series and at least two can do the power you think you require.
You have not specified the speaker impedance nor the speaker sensitivity. It's hard to give advice based on the sparse info you have supplied.

nbcd 9th February 2009 08:21 PM

AndrewT , ostripper

Thank you for your replies.

I will use 300W speakers 4 ohm that are produced here in Romania. I do not know much about them. All i know that they are very heavy monsters with a big magnet.

The fact i am asking you for a good amp is because i have experience only in digital hardware. My experience in analog is minimal. I still could use my skills to build my own PCB-s in Altium Designer as i do with my embedded boards.

Why i am telling you all this because it will help me a lot to have a project that has a list of components with all the features (power , resistance , package of the transistors etc..). I found a lot of projects that have only a electric schematic , and that is not enough for me.

please give me a link if you have available.

Thank you once again.


andrewlebon 11th February 2009 12:17 AM

power amplifier
hi nbcd
greetings making a good amplifier is rare try dx tubo easy to
assemble cheap no regrets made one with 9 output pairs tested in
2 ohm load did not give up go for it use st make output transistors
no fakes less than 2$ a pair practically tried amplifier bye

thanking you
andrew lebon

bigpanda 11th February 2009 05:32 AM

Hi nbcd,

Still snooping around for curcuits with your fingers crossed?

nbcd 16th February 2009 06:56 AM

hello andrew ,
Do you have some schematics?

Best regards ,


ravslanka 16th February 2009 07:06 AM

Re: schematic

Originally posted by nbcd
hello andrew ,
Do you have some schematics?

Best regards ,


go for one of quasis nmos series

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