New Amp: Hex-Fet or LM 3875

Higo · 30th June 2003, 02:19 PM

Hello guys,
I`m wanna build my first amp. The choices are:
1- Amp based in LM3875 CI or something similar
2- AN 948 (HEX-FET 60W/4ohm Amplifier or a modifcated version Almost final AN948 mosfet amp)

The intention is use the amp with this Preamp : http://www.normankoren.com/Audio/Spi....html#NewPhono (the purist version) that presently I`m building...

Which do you recommend? LM version or Mosfet?. Any advice will be apreciated.
Thanks a lot
Marcelo.

Higo · 2nd July 2003, 01:21 PM

Any advice....

li_gangyi · 2nd July 2003, 01:44 PM

I would go with the lm3875...seems to be simpler than the hexfet designs...and they are pretty good sounding as far as I can tell...

nobody special · 2nd July 2003, 04:55 PM

I vote lm3875 too.

daatkins · 2nd July 2003, 06:52 PM

For a first amp, a Gain Clone type device would be ideal: easy construction, plenty of advice (and opinions) from other builders and very easy construction.

Try other, more complicated, designs when your GC is to your satisfaction!

Nice one,
David.

millwood · 2nd July 2003, 07:23 PM

why not try both? I am looking also at a p3a or Nelson's Mosfet citation 12 (essentially the same as an948).

Does anyone realize that Motorolla also has a 100w/200w highperformance amp in their application notes?

Higo · 2nd July 2003, 08:29 PM

Thanks for your answers guys.
Well, the idea is bi amp. First I wanna build a Mosfet Amp for mid/high frecuency. The LM3875 amp for woofer???

...I don`t know
Marcelo

Higo · 2nd July 2003, 08:45 PM

Quote:

Originally posted by millwood

Does anyone realize that Motorolla also has a 100w/200w highperformance amp in their application notes?

Where? I can not find the Ap in the motorola web site
Thanks.
Marcelo

millwood · 2nd July 2003, 09:36 PM

it is available from On Semi, the ex-Motorola semi conductor business, titled "100 and 200 watt high fidelity audio amplifier utilizing a wideband-low feedback design". It uses the 3281/1302 twin.

http://www.onsemi.com/pub/Collateral/AN1308-D.PDF

enjoy.

30th June 2003, 02:19 PM	#1
Higo diyAudio Member Join Date: Feb 2002 Location: Argentina	New Amp: Hex-Fet or LM 3875 Hello guys, I`m wanna build my first amp. The choices are: 1- Amp based in LM3875 CI or something similar 2- AN 948 (HEX-FET 60W/4ohm Amplifier or a modifcated version Almost final AN948 mosfet amp) The intention is use the amp with this Preamp : http://www.normankoren.com/Audio/Spi....html#NewPhono (the purist version) that presently I`m building... Which do you recommend? LM version or Mosfet?. Any advice will be apreciated. Thanks a lot Marcelo. __________________ There is no emotion; there is peace.There is no ignorance; there is knowledge.There is no passion; there is serenity.There is no death; there is the Force.

2nd July 2003, 01:21 PM	#2
Higo diyAudio Member Join Date: Feb 2002 Location: Argentina	Any advice.... __________________ There is no emotion; there is peace.There is no ignorance; there is knowledge.There is no passion; there is serenity.There is no death; there is the Force.

2nd July 2003, 01:44 PM	#3
li_gangyi diyAudio Member Join Date: Jun 2003 Location: Woodlands Circle	I would go with the lm3875...seems to be simpler than the hexfet designs...and they are pretty good sounding as far as I can tell... __________________ Kids in the back seat cause accidents...Accidents in the back seat cause kids...

2nd July 2003, 04:55 PM	#4
nobody special diyAudio Member Join Date: Oct 2002 Location: USA	I vote lm3875 too. __________________ Nobody

2nd July 2003, 08:29 PM	#7
Higo diyAudio Member Join Date: Feb 2002 Location: Argentina	Thanks for your answers guys. Well, the idea is bi amp. First I wanna build a Mosfet Amp for mid/high frecuency. The LM3875 amp for woofer??? ...I don`t know Marcelo __________________ There is no emotion; there is peace.There is no ignorance; there is knowledge.There is no passion; there is serenity.There is no death; there is the Force.


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2nd July 2003, 06:52 PM	#5
daatkins diyAudio Member Join Date: Aug 2001 Location: Bath, UK	For a first amp, a Gain Clone type device would be ideal: easy construction, plenty of advice (and opinions) from other builders and very easy construction. Try other, more complicated, designs when your GC is to your satisfaction! Nice one, David.

2nd July 2003, 07:23 PM	#6
millwood Account Disabled Join Date: Apr 2003 Location: US	why not try both? I am looking also at a p3a or Nelson's Mosfet citation 12 (essentially the same as an948). Does anyone realize that Motorolla also has a 100w/200w highperformance amp in their application notes?

2nd July 2003, 09:36 PM	#9
millwood Account Disabled Join Date: Apr 2003 Location: US	it is available from On Semi, the ex-Motorola semi conductor business, titled "100 and 200 watt high fidelity audio amplifier utilizing a wideband-low feedback design". It uses the 3281/1302 twin. http://www.onsemi.com/pub/Collateral/AN1308-D.PDF enjoy.

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