Jaycee, if it's not then it's pretty damn close - Thank you.
The only differences I can see are the choices of VBE multiplier and Driver transistors.
The only differences I can see are the choices of VBE multiplier and Driver transistors.
So, in a bi-amp system, which amp needs to be of the higher quality.
Bass or Mid/Tweeter.
My crossover frequencies are at 400 Hz and 3.8KHz.
Bass or Mid/Tweeter.
My crossover frequencies are at 400 Hz and 3.8KHz.
The alternative driver transistors are actually mentioned in the article, so that's probably it. He also mentions that pretty much anything can be used as the VBE device, so I wouldn't be surprised if that's a BD139 that's been used.
I agree, its the David White design. It's a strange way of using lateral mosfets, whose main advantage is that they don't need temperature compensation in the classic and very good, Hitachi circuit.
I was just reading the August 2001 Electronics World, where DW modified the Hitachi design to use vertical mosfets. Unfortunately he put a current source in the VAS stage current mirror
I was just reading the August 2001 Electronics World, where DW modified the Hitachi design to use vertical mosfets. Unfortunately he put a current source in the VAS stage current mirror
You could also concider one of the Quad 405 mods listed here
http://www.keith-snook.info/amplifier-hifi-schematics/QUAD 405 schematic evolution.pdf
on Keith Snooks excellent web site
the Mod3 and 4 offer the lowest componant count, as the output stage is unbiased there are no thermal issues
Stuart
http://www.keith-snook.info/amplifier-hifi-schematics/QUAD 405 schematic evolution.pdf
on Keith Snooks excellent web site
the Mod3 and 4 offer the lowest componant count, as the output stage is unbiased there are no thermal issues
Stuart
I listened to the Quad 404s with B&W DM2s many years ago and I wasn't impressed.
Now the Aleph4 I've got seriously outshines them in every way with my DM683s.
Now the Aleph4 I've got seriously outshines them in every way with my DM683s.
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