MJL4281A/4302A Amplifier or MOSFET's - Page 2

zox2003 · 2nd December 2006, 12:43 AM

I ordered mine yesterday and they were shipped yesterday too.I received them today.

Zox

ReidK · 2nd December 2006, 12:52 AM

Did you order from onsemi.com, or some other way?

I'm obviously not in a big hurry (I can't use them yet anyway), or I'd have bought them from Mouser or Digikey. I'm just puzzled, since the people at onsemi told me this delay was normal. Oh well, beggars can't be whiners.

Reid

bigpanda · 2nd December 2006, 08:46 AM

My situation was even more wried, I received some MJL4281A but never see the MJL4302A. All I got is a order cancellation notice and I tried to reach them but never got any answer. It had been more than 3months already.

AndrewT · 2nd December 2006, 09:01 AM

Hi Zox,

Quote:

Am I will be able to get 150W on 4 ohms with 4 of these devices(+/-42V).

nearly.

1pair will drive 8ohm to about 75W @ 60degree phase angle.

2pair will drive 4ohm to about 140W @ 60degree phase angle.

+-42Vdc is your limiting factor for maximum peak output voltage.

These predictions were checked for continuous operation below 60degC. Music type duty at home would demand much less from the amp (Tc=60degC allows a heatsink of about 50degC which is pretty hot) will not trouble either arrangement.

You will need a stiff power supply that holds up well under load to produce these powers. I suggest 500VA and 4 by 30mF for a stereo amplifier.

zox2003 · 2nd December 2006, 08:50 PM

Anu amplifier schematic recommendation's with these devices?

MEGA-amp · 3rd December 2006, 01:19 AM

Rod Elliotts P3A

FastEddy · 3rd December 2006, 01:30 AM

You might be able to derive a decent schematic from this Wiki kit: http://www.diyaudio.com/wiki/index.p...+the+group+buy ... or ... http://home.ca.inter.net/~lloyd.maclean/Krell/Krell.htm

The diagram above (Rod Elliot's @ http://sound.westhost.com/p3a-f1.gif ) is great ... except that you will have to find suitable complimentary pairs for the first stage of the Darlington out put ...

....

Bob03 · 3rd December 2006, 05:31 AM

This amp is fantastic!

Tim__x · 3rd December 2006, 07:10 AM

Though I'm impressed that he pulled off the CF triplet, that amp has some basic design flaws. Some which save a few cents (shared CCS reference), some which are just plain stupid (the fixed LTP collector resistor).

As I recall, we discussed this designer's work in the past and someone said he designs for "sound" (including intentional distortion), so these may not be mistakes.

I don't think I've ever seen a bias circuit quite like it.

head_spaz · 3rd December 2006, 08:45 AM

Tim_X,
Who's amp are you referring to?
(Wouldn't hurt to be more specific)

3rd December 2006, 08:45 AM	#20
head_spaz diyAudio Member Join Date: Mar 2004 Location: Arkansas	Tim_X, Who's amp are you referring to? (Wouldn't hurt to be more specific) __________________ Writing is good exercize for the texticles!

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2nd December 2006, 12:43 AM	#11
zox2003 diyAudio Member Join Date: Nov 2004 Location: usa	I ordered mine yesterday and they were shipped yesterday too.I received them today. Zox

2nd December 2006, 12:52 AM	#12
ReidK diyAudio Member Join Date: Jan 2006 Location: Los Angeles (a.k.a. Hell on Earth)	Did you order from onsemi.com, or some other way? I'm obviously not in a big hurry (I can't use them yet anyway), or I'd have bought them from Mouser or Digikey. I'm just puzzled, since the people at onsemi told me this delay was normal. Oh well, beggars can't be whiners. Reid

2nd December 2006, 08:46 AM	#13
bigpanda diyAudio Member Join Date: Jun 2004 Location: HKSAR	My situation was even more wried, I received some MJL4281A but never see the MJL4302A. All I got is a order cancellation notice and I tried to reach them but never got any answer. It had been more than 3months already.

2nd December 2006, 08:50 PM	#15
zox2003 diyAudio Member Join Date: Nov 2004 Location: usa	Anu amplifier schematic recommendation's with these devices?

3rd December 2006, 01:19 AM	#16
MEGA-amp diyAudio Member Join Date: Oct 2003 Location: Newington, CT	Rod Elliotts P3A

3rd December 2006, 01:30 AM	#17
FastEddy diyAudio Member Join Date: Jun 2006 Location: North Californie	You might be able to derive a decent schematic from this Wiki kit: http://www.diyaudio.com/wiki/index.p...+the+group+buy ... or ... http://home.ca.inter.net/~lloyd.maclean/Krell/Krell.htm The diagram above (Rod Elliot's @ http://sound.westhost.com/p3a-f1.gif ) is great ... except that you will have to find suitable complimentary pairs for the first stage of the Darlington out put ... ....

3rd December 2006, 07:10 AM	#19
Tim__x diyAudio Member Join Date: Jun 2004 Location: Edmonton area, Alberta	Though I'm impressed that he pulled off the CF triplet, that amp has some basic design flaws. Some which save a few cents (shared CCS reference), some which are just plain stupid (the fixed LTP collector resistor). As I recall, we discussed this designer's work in the past and someone said he designs for "sound" (including intentional distortion), so these may not be mistakes. I don't think I've ever seen a bias circuit quite like it.