Discrete amp based on LM38-- family internals?

tiltedhalo · 15th November 2005, 11:45 PM

I just recently built my first gain clone, a single lm3875 then a bridged parallel lm3886's, great sound, overall.... I was woundering if anyone has ever thought about building a discrete amp based on the internals of the chips?? most all of the chip looks like current drive up to the output drivers, and its quasi. I understand a lot of the overall sound quality is due to the close coupleing and common substrate, but you could duplicate most in a discrete design. Any thoughts?

amplifierguru · 16th November 2005, 01:06 AM

Hi tilted halo,

In discrete design we have tools available to us that enable quite simple designs to equal or better such chip amp designs in performance. Bootstrapping for example, with quite large C's to achieve high gain and linearity together. For example -

http://members.dodo.com.au/~gregball/guru_003.htm

There are of course advantages in monolithic design but such can usually be accessed by an op-amp front end with discrete output stage, minimising thermal distortion effects.

Cheers,
Greg

15th November 2005, 11:45 PM	#1
tiltedhalo diyAudio Member Join Date: Sep 2005 Location: Melbourne Florida	Discrete amp based on LM38-- family internals? I just recently built my first gain clone, a single lm3875 then a bridged parallel lm3886's, great sound, overall.... I was woundering if anyone has ever thought about building a discrete amp based on the internals of the chips?? most all of the chip looks like current drive up to the output drivers, and its quasi. I understand a lot of the overall sound quality is due to the close coupleing and common substrate, but you could duplicate most in a discrete design. Any thoughts?

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16th November 2005, 01:06 AM	#2
amplifierguru Account Disabled Join Date: Aug 2004 Location: Earth	Hi tilted halo, In discrete design we have tools available to us that enable quite simple designs to equal or better such chip amp designs in performance. Bootstrapping for example, with quite large C's to achieve high gain and linearity together. For example - http://members.dodo.com.au/~gregball/guru_003.htm There are of course advantages in monolithic design but such can usually be accessed by an op-amp front end with discrete output stage, minimising thermal distortion effects. Cheers, Greg

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