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. =)
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. =)
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.
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.
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.
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
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
Coming along. I have the transformers than Jan Didden
came up with for a Nemesis version.
There are several variations in the works.
I think it's a great idea. You just have to figure out how much current you want to pull and how many heaters that would be at your chosen Vcc.
It seems to resemble the sound I heard at BAF.
It seems more dynamic to me than an F3 - but still rich sounding.
I hope that helps. Keep in mind, my reference test speaker is an Onkyo full range (a $3.00 speaker). Just a single channel so far.
I have a bit of hum to troubleshoot.
I am going to try some panasonic resistors out as well. I don't think these speaker resistors are ideal.
It seems more dynamic to me than an F3 - but still rich sounding.
I hope that helps. Keep in mind, my reference test speaker is an Onkyo full range (a $3.00 speaker). Just a single channel so far.
I have a bit of hum to troubleshoot.
I am going to try some panasonic resistors out as well. I don't think these speaker resistors are ideal.
Sorry about the pix, I just switched to linux on my home pc, and cannot figure out how to shrink them down to a prefered 200k.
I am using an old hafler DH-200 40-0-40 IE tranny ~ 370va (using just one side) with 4 15k 63v United Chemicon caps from Steve at Apex Jr. (cheap) The 2 10W 2ohm resistors paralleled run about 60c in the PS. I switched to two 3W panasonics for the source resistors, and they run about 70c. I can see why Nelson used some power resistors on the chassis for this. I dont know what wattage or type.
The D-Fet runs about 35c.
I bypassed the output 15k cap with an Elna Silimic 100uf 100v.
Most of the hum disappeared when I moved the clip leads around a bit more. I suspect some is coming from that tranny. It's certainly doing some mechanical humming with this workout.
It has not lit on fire, yet.
I am using an old hafler DH-200 40-0-40 IE tranny ~ 370va (using just one side) with 4 15k 63v United Chemicon caps from Steve at Apex Jr. (cheap) The 2 10W 2ohm resistors paralleled run about 60c in the PS. I switched to two 3W panasonics for the source resistors, and they run about 70c. I can see why Nelson used some power resistors on the chassis for this. I dont know what wattage or type.
The D-Fet runs about 35c.
I bypassed the output 15k cap with an Elna Silimic 100uf 100v.
Most of the hum disappeared when I moved the clip leads around a bit more. I suspect some is coming from that tranny. It's certainly doing some mechanical humming with this workout.
It has not lit on fire, yet.