A few questions on this amp design...

Boscoe · 4th May 2011, 07:11 PM

Just wondered if some people could help me out. I want to do this sort of amp design as it isn't too complex but I only have 2SA1492 and 2SC3856 and I don't want to buy any others so would they be compatible? If not could someone suggest something?

Secondly can someone suggest a cheap and easy program to design the PCB for this?

Thanks.

xeclipse · 4th May 2011, 07:42 PM

Its hard to get help without these: schematic? power? speaker impedance?

Boscoe · 4th May 2011, 07:59 PM

Haha sorry forgot to put the link in!

HERE is the link to the design!

Speakers are 8ohm I would like about 100W

Also like to know if I can increase the amount of output devices?

lineup · 4th May 2011, 08:07 PM

yes. that's a good design.
And there are several options of power transistors.
I am sure your transistors will work, too.
And there are instructions how to put it together.

If you like you can order nice PCB boards from ESP Rod Elliott

Boofers · 4th May 2011, 08:54 PM

PCB123 and ExpressPCB are free PCB design programs. Once you design your board you can use these programs to order your boards, and they will manufacture them and ship them to you. Or you can do what I do and just use the program and make your own boards.

Boscoe · 4th May 2011, 09:15 PM

Okay thanks but I want to know for definite whether these transistors will work though.

And yes I would rather order the PCBs from Rod Elliot but I want two pairs of output devices without bodges!

Thanks

lineup · 5th May 2011, 07:04 AM

I searched: 2SC3856 replacement
with google.
MJL4281/MJL1302 should be good replaments.
So, I say you can be sure that you can use those in Rod Elliott project

xeclipse · 5th May 2011, 09:14 AM

As long as you don't exceed the devices' SOA,you are good to go.

chlorofille · 5th May 2011, 09:21 AM

Quote:

Originally Posted by Boscoe

Haha sorry forgot to put the link in!

HERE is the link to the design!

Speakers are 8ohm I would like about 100W

Also like to know if I can increase the amount of output devices?

I used MJL21193/21194 for my P3A and they worked fine. Right now I am rebuilding it with 2SC5200/2SA1943 which have a very low output capacitance(200pF).

With 2 pairs of transistors and +/- 42V, the amp can deliver 100W into 8Ohms. Do not use 4 Ohm speakers with this voltage.

For higher power, look at Rod's P101 mosfet amplifier.

4th May 2011, 07:11 PM	#1
Boscoe diyAudio Member Join Date: Feb 2010 Location: England	A few questions on this amp design... Just wondered if some people could help me out. I want to do this sort of amp design as it isn't too complex but I only have 2SA1492 and 2SC3856 and I don't want to buy any others so would they be compatible? If not could someone suggest something? Secondly can someone suggest a cheap and easy program to design the PCB for this? Thanks. __________________ I thought about it once, but then thought again.

4th May 2011, 07:42 PM	#2
xeclipse diyAudio Member Join Date: May 2010 Location: Where the world's best tea come from:Kericho Kenya	Its hard to get help without these: schematic? power? speaker impedance? __________________ if there are no sparks,it probably doesn't work!

4th May 2011, 07:59 PM	#3
Boscoe diyAudio Member Join Date: Feb 2010 Location: England	Haha sorry forgot to put the link in! HERE is the link to the design! Speakers are 8ohm I would like about 100W Also like to know if I can increase the amount of output devices? __________________ I thought about it once, but then thought again.

4th May 2011, 08:07 PM	#4
lineup diyAudio Member Join Date: Dec 2005 Location: the north	yes. that's a good design. And there are several options of power transistors. I am sure your transistors will work, too. And there are instructions how to put it together. If you like you can order nice PCB boards from ESP Rod Elliott __________________ lineup

4th May 2011, 09:15 PM	#6
Boscoe diyAudio Member Join Date: Feb 2010 Location: England	Okay thanks but I want to know for definite whether these transistors will work though. And yes I would rather order the PCBs from Rod Elliot but I want two pairs of output devices without bodges! Thanks __________________ I thought about it once, but then thought again.


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4th May 2011, 08:54 PM	#5
Boofers diyAudio Member Join Date: Oct 2008 Location: Ontario Blog Entries: 1	PCB123 and ExpressPCB are free PCB design programs. Once you design your board you can use these programs to order your boards, and they will manufacture them and ship them to you. Or you can do what I do and just use the program and make your own boards.

5th May 2011, 07:04 AM	#7
lineup diyAudio Member Join Date: Dec 2005 Location: the north	I searched: 2SC3856 replacement with google. MJL4281/MJL1302 should be good replaments. So, I say you can be sure that you can use those in Rod Elliott project __________________ lineup

5th May 2011, 09:14 AM	#8
xeclipse diyAudio Member Join Date: May 2010 Location: Where the world's best tea come from:Kericho Kenya	As long as you don't exceed the devices' SOA,you are good to go. __________________ if there are no sparks,it probably doesn't work!

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