MOSFET amplifier schematic and PCB needed

[dolhastelian]

Hello everybody,
I'm quite new to this forum.
I have built some years ago an amplifier that hasn't gave me any listening satisfaction. It was built around TDA 7250 + Darlington transistors(does not work well, the transistors are very hot even without any input signal, or at low level).

I want to replace the power stage with a discrete MOSFET amplifier.

I have a power supply of +/- 35V available (toroidal transformer 500W, bridge, filter capacitors: 2x10000 uF).

I saw a lot of threads on discrete amplifiers.

Could someone suggest me a good amplifier (60-100W) with good performance (very low THD: < 0.001) that was built already by someone and eventually has PCB?

Thanks to all !

 

[AndrewT]

try ESP

 

[riktw]

hello

look at this amp:
60-80W Power Amplifier
you can buy the PCB's on the website, it performs good and dozens of people already made that design.
and with PCB's it easy to build

 

[smartx21]

Another configuration

What about changing the output transistors with a different configuration, without darlingtons?
As stated in the original source, "Q1~Q4 is driver transistor to drive Q5~Q8, a SANKEN transistor. Power supply is 40V, and will give 100W power".
I think you can use your supply without changes.
Just tell us what happened afterwards.
Regards,
Max.

 

[Bill Fuss]

try ESP

I built the P101 a couple yrs ago. It's a very competent amp and easy to scale for any power you wish. 35v rails would be fine.

 

[dolhastelian]

I found Symasym project on the web.

Has anyone built this amp?

Are the specifications real?

I would like to built it. Any comments?

Thank you!

 

[juma]

There are many threads here about SymAsym, a lot of guys built it, and yes, it's a great amp.

 

[dolhastelian]

Thank for the encouragement.

To everybody:
Please reply if you built Symasym.

Can I start to build it without any modifications, only using the information on the project site?

Which version to build? 5_2 or 5_3 ? THD for 5_3 is better, they say, is it?

Is the PCB ok?

 

[stoN_Cold]

Simple & cheap

http://www.diyaudio.com/forums/solid-state/43331-power-amp-under-development.html

Regards zeoN_Rider

 

[AndrewT]

the Symasym is not MosFet.

 

[dolhastelian]

I saw that it is not a MOSFET amplifier but the spec look fine .
Also, it is compatible with my power supply

I still haven't found any MOSFET project to suit my needs.

I am not a beginner in electronics, but have much more experience in digital electronics and embedded design and programming.

Anybody with a reference towards a good MOSFET amplifier?

 

[AndrewT]

It looks to me that you have not bothered to look up either the ESP site, nor the Quasi Thread.
What do you want?
A delivery to the doorstep!

 

[Bone]

Here's one for you AN948 from International Rectifier:
Complete with PCB.

 

[dolhastelian]

Not quite so..

It looks to me that you have not bothered to look up either the ESP site, nor the Quasi Thread.
What do you want?
A delivery to the doorstep!

I have searched for a good amplifier design, including ESP pages, but the PCB is not available for free. I can make the PCB myself, I don't need to buy it. I am looking for a complete project description and information just like the Leach amp, Symasym, etc.

I do not have time to build several amps until I get satisfied with one of them.

That's why I've joined the forum, to have others opinion, to build an amp that others claim that works, which fits my power supply, not to get anything delivered at my doorstep!!

I think i will build the Symasym finally.

Thanks so far for the references!

 

[Federmann]

Here http://www.diyaudio.com/forums/solid-state/168792-300w-amp-irfp240-9240-a.html

 

[smartx21]

I have searched for a good amplifier design, including ESP pages, but the PCB is not available for free. I can make the PCB myself, I don't need to buy it. I am looking for a complete project description and information just like the Leach amp, Symasym, etc.

I do not have time to build several amps until I get satisfied with one of them.

That's why I've joined the forum, to have others opinion, to build an amp that others claim that works, which fits my power supply, not to get anything delivered at my doorstep!!

I think i will build the Symasym finally.

Thanks so far for the references!

I apologize for forum folks behavior. I have been through this fire fight for days with some guys, that can't understand our good intention.
But don't be upset. Most of them are nice ones, and will help you. Guys like apexaudio (Mile), for example.
All you have to do is build your amp and post the results.
For a complete project, with PCB and all you need (except parts and assembling!...), take a look here: Greg's Web Site
I have built the DX Blame ST, that uses -35+35Vdc rail voltages, and sounds superbly. You may also find good advice here: http://www.diyaudio.com/forums/soli...st-pictures-reviews-comments-here-please.html and here: http://www.diyaudio.com/forums/soli...into-blameless-i-am-trying-new-amplifier.html
Have a nice stay in this forum.
All the best,
Max.
(sorry for rough english)

 

[jandr49]

I've just built SymAsym 5.3 as a first amp using only the project page and the original thread. They gave me everything I needed and I had no problems, however I had to modify the PCB pad spacing slightly to fit available components. I'm very pleased with it but can't compare its performance as its the first decent amp I've had.

HTH

Richard

 

[Greg Erskine]

I found Symasym project on the web.

Has anyone built this amp?

Are the specifications real?

I would like to built it. Any comments?

Thank you!

Hi dolhastelian,

The Symasym has been an extremely popular amp here at DIYAudio.

The main thread can be found here:

http://www.diyaudio.com/forums/solid-state/60918-explendid-amplifier-designed-michael-bittner-our-mikeb.html

To find the thousands of other posts about this amp use search.

Select Search (top right hand corner)
Select Advanced search
Type Symasym
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Press [Search now]

regards