HAL SYMFET

[OnAudio]

Hi RSK,

Here it is. Let members comment for a while then you can build.

kind regards,

Harrison.

[OnAudio]

Originally Posted by OnAudio

Here it is.

The statement in the schematic that reads "Replace R37 and R38 with a 2k precision trimmer" should read "Replace R37 and R38 with a 1k precision trimmer".

[OnAudio]

a few more graphs inorder

[dadod]

Originally Posted by OnAudio

a few more graphs inorder

Strange way to do square wave test, only positive swing???

[OnAudio]

Originally Posted by dadod

Strange way to do square wave test, only positive swing???

Hi Dadod,

Not so strange

kind regards,

Harrison.

[OnAudio]

I wonder how much heat the gate protection diodes on these output devices can take ?

[Nico Ras]

Originally Posted by dadod

Strange way to do square wave test, only positive swing???

Is it not? I mentioned it in his previous design.

[Nico Ras]

Originally Posted by OnAudio

I wonder how much heat the gate protection diodes on these output devices can take ?

Why? the device is rated at 150 degrees centigrade, it would be silly if they rated the diodes at any less.

[Nico Ras]

Why use a Vbe multiplier with Lateral Mosfets, that whole arrangement including precision pots can be replaced by a single resistor.

What are the purpose of D9 & D10, the double diode Vdrop will remain the same regardless of the additional noise introduced by the zener.

[dadod]

Originally Posted by OnAudio

Hi Dadod,

Not so strange

kind regards,

Harrison.

OK show us +- swing, or you don't know how to do that?
Use of the bias spreader with laterals is recommended because when trimer loses conntact there is no danger of possible distraction of laterals. Trimer should be connected between base and emitter and bias transistor should not be thermaly bonded with laterals.
dado