MOSFET amplifier schematic and PCB needed

dolhastelian · 18th June 2010, 08:07 AM

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 · 18th June 2010, 09:50 AM

try ESP

riktw · 18th June 2010, 09:53 AM

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 · 18th June 2010, 10:25 AM

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 · 18th June 2010, 11:35 AM

Quote:

Originally Posted by AndrewT

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 · 18th June 2010, 11:52 AM

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 · 18th June 2010, 01:39 PM

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

dolhastelian · 18th June 2010, 03:24 PM

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?

zeonrider · 18th June 2010, 04:14 PM

Power amp under development

Regards zeoN_Rider

AndrewT · 18th June 2010, 04:21 PM

the Symasym is not MosFet.

18th June 2010, 08:07 AM	#1
dolhastelian diyAudio Member Join Date: Oct 2009	MOSFET amplifier schematic and PCB needed 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 !

18th June 2010, 04:14 PM	#9
zeonrider diyAudio Member Join Date: Mar 2004 Location: Belgrade RS	Simple & cheap Power amp under development Regards zeoN_Rider

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
N-Channel mosfet amplifier schematic needed	Nexus	Solid State	627	13th December 2011 07:15 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

18th June 2010, 09:50 AM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	try ESP

18th June 2010, 09:53 AM	#3
riktw diyAudio Member Join Date: Sep 2007	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

18th June 2010, 11:52 AM	#6
dolhastelian diyAudio Member Join Date: Oct 2009	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!

18th June 2010, 01:39 PM	#7
juma diyAudio Member Join Date: Nov 2005 Location: Zemun	There are many threads here about SymAsym, a lot of guys built it, and yes, it's a great amp.

18th June 2010, 03:24 PM	#8
dolhastelian diyAudio Member Join Date: Oct 2009	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?

18th June 2010, 04:21 PM	#10
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	the Symasym is not MosFet.