Pass "DeLite" Amp from BAF

[Pano]

I like this idea a lot! Mostly because it uses light bulbs. A bright idea.
I also saw and and heard Hiraga's little 1 mosfet "Nemesis" amp back in the 80s (transformer output). Sounded very good, but no light bulbs!

What's the status of this project?

I know my way around light bulbs - or "lamps" as we call them in the biz - because my father was a theater lighting designer and so was I. Used to have quite a collection of lamps of many wattages.

Since it seems that the lamp sets the current, and Nelson likes a healthy dose of current, there might be some fun choices in the world of theater or industrial lamps. Or maybe even some of the old carbon filament lamps. =)

[Zen Mod]

someone already sez that - good looking alternative is to use adequate tube , heating filament instead of bulb , and aditionall power resistors , to adjust/complement filament resistance as load .....

but be sure to not use good tube , with life in it .......

[Jacques Merde]

Originally Posted by Zen Mod

someone already sez that - good looking alternative is to use adequate tube , heating filament instead of bulb , and aditionall power resistors , to adjust/complement filament resistance as load .....

but be sure to not use good tube , with life in it .......

The old ballast tubes were designed for exactly this purpose.

[Bas Horneman]

How about a cascoded ccs with the same mosfet as load? I thought that the bulb was just a quick and dirty solution to test the concept?

[revintage]

Hey guys,
Is there really any bigger difference using lightbulbs or resistors in this case. Positive for bulbs is they don´t need heatsinks. Maybe they also have some stabilizing effect here.

The depletion FET itself sets its bias(think tubes) with the IXYS at zerobias as shown by NP at the blackboard just above 1A. With the theoretic schematic shown by NP the amp will have the same Zout as the bulb/resistor ie maybe 20 ohms. With two parallelled IXYS things will look better with over 2A bias and maybe 10 ohms out.

I trust you have something nice up your sleeve to complete this amp, Nelson.

[tiefbassuebertr]

Originally Posted by Zen Mod

someone already sez that - good looking alternative is to use adequate tube , heating filament instead of bulb , and aditionall power resistors , to adjust/complement filament resistance as load .....

but be sure to not use good tube , with life in it .......

Very similarity to my proposal with 6C33C at post #52 here on page 6
But for that I still see no statement. Please note, I mean faulty devices, where the heating filament is still useful

[tiefbassuebertr]

Originally Posted by Michi124

Where to find those beautiful light bulb sockets Nelson uses on this amp?
The ones on the photos linked by Steve seem to be the same...

I already checked german online stores, the nicest ones I found are those:

I try to open this weblink, but I haven't success. Please do perform a URL garbling (e. g. underscore instead than dot). Now this forum don't perform the change to the headline of the respective URL

[Pano]

Well lamps are not quite like resistors. The resistance of the filament goes up as voltage goes up. So they are somewhat self regulating.

I don't know if this is important to the circuit, tho...

[Zen Mod]

Originally Posted by tiefbassuebertr

Very similarity to my proposal with 6C33C at post #52 here on page 6
But for that I still see no statement. Please note, I mean faulty devices, where the heating filament is still useful

[Tea-Bag]

Can someone tell me what wattage resistor I should use for the 1 ohm source resistor? The pic looks like a 15-25 watter. I wonder if it needs to be non-inductive. I am trying to throw a channel of this together maybe this weekend. Snow is promised, but it was nearly 70 degrees today....