QUASI Amplifier for Beginners

[apexaudio]

Quasi complementary amplifier based on old Dynacord. For begginers Class B without adjust.
PCB with corect is in post #294

 

[apexaudio]

I use this circuit many times in the past for quick build 100-500w amp with parts which I already have, work every time, low cost and even begginer can do it as first amp ever. With two 2N3055 on +/-30V DC you can have 60W amp.
Regards

 

[qsa]

I use this circuit many times in the past for quick build 100-500w amp with parts which I already have, work every time, low cost and even begginer can do it as first amp ever. With two 2N3055 on +/-30V DC you can have 60W amp.
Regards

Is it cost effective quick build by yourself ?

,... because in our country to buy commercial similar amp from China is cheaper than semiconductor parts in our country for quick build

 

[apexaudio]

Is it cost effective quick build by yourself ?

,... because in our country to buy commercial similar amp from China is cheaper than semiconductor parts in our country for quick build

I agree DIY isn't cost effective hoby, fishing is much better

 

[apexaudio]

On the other hand any diyer have some old case, transformer, heatsink... only two new pcbs is needed for build functional amp, and have fun.
Regards

 

[apexaudio]

I agree DIY isn't cost effective hoby, fishing is much better

Fisherman told me fishing isn't cost effective hoby, better buy fish

 

[apexaudio]

PSU from http://www.diyaudio.com/forums/solid-state/162081-dc-servo-mosfet-amplifier-4.html with protect and clip also can be used for this amp.

 

[FLT]

scaled down version?

I use this circuit many times in the past for quick build 100-500w amp with parts which I already have, work every time, low cost and even begginer can do it as first amp ever. With two 2N3055 on +/-30V DC you can have 60W amp.
Regards

Hi,

nice circuit. What about two 2N3773? 120W?

Frank

 

[apexaudio]

Hi,

nice circuit. What about two 2N3773? 120W?

Frank

For single pair 2N3773 use +/-40V DC rail voltage.

 

[jaycee]

I have to honestly say that I dont think "beginners" should be building powerful amps. I also don't see why theres no adjust - a resistor, a trim pot and a transistor dont exactly add a lot of complexity to the circuit.

 

[apexaudio]

I have to honestly say that I dont think "beginners" should be building powerful amps. I also don't see why theres no adjust - a resistor, a trim pot and a transistor dont exactly add a lot of complexity to the circuit.

Beginners who want to build powerful amp for party... can start with this amplifier with single pair and add more outputs later, and they don't want adjust bias, just connect power supply and play.

 

[apexaudio]

MJE340, MJE350, MJE15030 and MJ15031 must have TO220 heatsinks.

 

[jaycee]

Beginners who want an amp for a party are normally trying to do it cheaper than buying one - which they won't manage. With a total of 130V DC present, they can do a lot of damage.

 

[vedmitraa]

Thank you mr. apex for the circuit and P.C.B. design , as i have a good stock of 2n37773 transistors with me.I am a professional Audio and stage light hirer and I am using 2n3773 Amplifiers made as per the 325 watts circuit published in electronics Australia long time ago with modification of using 10 pairs per channel and 70-0-70 volt dc. Will you be kind enough to send this ciruits slew rate and distortion levels . please send any modification also if there is any.as i plan to modify my 10 stereo amplifiers which are made as per cosmic amplifier Circuits with 4pairs 2n3055 each channel. I personally rely much on metal casing transistors. with lots of regard vedmitra Sharma from city of Tajmahal.

 

[bobodioulasso]

Some baxendall diode wouldn't cost much.

 

[apexaudio]

Beginners who want an amp for a party are normally trying to do it cheaper than buying one - which they won't manage. With a total of 130V DC present, they can do a lot of damage.

With suggested PSU and protect circuit or triac DC protection, and fuses on amp pcb, they can't do any damage.

 

[apexaudio]

Thank you mr. apex for the circuit and P.C.B. design , as i have a good stock of 2n37773 transistors with me.I am a professional Audio and stage light hirer and I am using 2n3773 Amplifiers made as per the 325 watts circuit published in electronics Australia long time ago with modification of using 10 pairs per channel and 70-0-70 volt dc. Will you be kind enough to send this ciruits slew rate and distortion levels . please send any modification also if there is any.as i plan to modify my 10 stereo amplifiers which are made as per cosmic amplifier Circuits with 4pairs 2n3055 each channel. I personally rely much on metal casing transistors. with lots of regard vedmitra Sharma from city of Tajmahal.

I have not slew rate and distortion levels, I use this Dynacord clone long time ago, and there's no any modification for this circuit, but this simple circuit give you great chance to build or fast repare any old amp. This is retro design.

 

[apexaudio]

Some baxendall diode wouldn't cost much.

1N4148 can stabilised bias if are montage on heatsink, and connect with trimpot in series for adjust bias.

 

[bobodioulasso]

I meant a diode in the 15031 emmitor to compensate dissymetry.

 

[apexaudio]

I meant a diode in the 15031 emmitor to compensate dissymetry.

That will increase crosover distortion