Nelson Pass; Thanks, and a quick question please!

mg16 · 6th December 2001, 12:50 AM

Just wanted to let you know that your excellent sounding DIY projects are greatly appreciated here. I have been using your Bride of Zen preamp for several years, and it's made a major improvement in my sound system.
Will try to build your Zen amps for my Klipsch Lascalas soon.
Thanks for making these available to the DIY community.

Quick question regarding the original Bride of Zen preamp:

Is there anything to be gained sonically by increasing the power supply voltage to say, 120 vdc regulated, and doubling the 40 ma. bias current through the IRF mosfets? If the mosfets were then biased at 40 volts,(80 volts dropped across drain resistor R104), would the higher voltage swing,(headroom),ability be worthwhile?
I read in your Zen article in AA, that these IRF devices operate better when operated at higher current levels.
Naturally, heatsinks on the mosfets, and higher power resistors/higher voltage caps,& a bigger transformer would be needed.
Thanks Again!
mg16

Nelson Pass · 6th December 2001, 06:09 PM

You can lower the distortion a bit with this,
and it does open up the sound somewhat, but
you'll have to think in terms of higher wattage
resistor off the Drain and maybe some more heat
sinking on the transistor, not to mention
capacitor ratings and a new power supply.

Perhaps you should simply consider an active current
source in parallel with the Drain resistor, or even
making a miniature version of the Zen amp, but with
the 510's or 610's.

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6th December 2001, 12:50 AM	#1
mg16 diyAudio Member Join Date: Nov 2001 Location: western pa	Just wanted to let you know that your excellent sounding DIY projects are greatly appreciated here. I have been using your Bride of Zen preamp for several years, and it's made a major improvement in my sound system. Will try to build your Zen amps for my Klipsch Lascalas soon. Thanks for making these available to the DIY community. Quick question regarding the original Bride of Zen preamp: Is there anything to be gained sonically by increasing the power supply voltage to say, 120 vdc regulated, and doubling the 40 ma. bias current through the IRF mosfets? If the mosfets were then biased at 40 volts,(80 volts dropped across drain resistor R104), would the higher voltage swing,(headroom),ability be worthwhile? I read in your Zen article in AA, that these IRF devices operate better when operated at higher current levels. Naturally, heatsinks on the mosfets, and higher power resistors/higher voltage caps,& a bigger transformer would be needed. Thanks Again! mg16

6th December 2001, 06:09 PM	#2
Nelson Pass The one and only Join Date: Mar 2001	You can lower the distortion a bit with this, and it does open up the sound somewhat, but you'll have to think in terms of higher wattage resistor off the Drain and maybe some more heat sinking on the transistor, not to mention capacitor ratings and a new power supply. Perhaps you should simply consider an active current source in parallel with the Drain resistor, or even making a miniature version of the Zen amp, but with the 510's or 610's.