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Old 1st February 2010, 12:00 PM  
Nelson Pass is offline Nelson Pass  United States
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The third annual Burning Amp Festival was held in San Francisco last October, drawing a couple hundred DIY Audio enthusiasts, many from long distances. At previous BAF gatherings I have simply brought a truckload of parts that might appeal to DIYers, but this year an...

Last edited by Variac; 4th February 2010 at 06:39 AM.
4th March 2010
diyAudio Member
Hi, If you look at the old 'barretta' style resistor, you will be in the ball park.
Also, at least if you break one of these incandescents you won't polute the planet with mercury.
An old room heater, the type with a wire coil on a porcelain former could be used if you cut the wire to the right length but it wont glow and look cool like the globes.
Cheers and good luck.
4th March 2010
diyAudio Member
I like the concept with light bulbs, and I considered it "green"...because, you get both an anplifier and a light source. And you don't forget to turn our amp off when not using it because of the light ;-)
4th March 2010
diyAudio Member
Has anyone ever produced a set of instructions for this project? As in 'parts list, do this than do that' level for unskilled people such as myself?

4th March 2010
diyAudio Member
Good point! Plus it also serves as a "ammeter" of sorts. Way easier to see a changing light than the old "lick your finger and hope you don't hear a sizzle" trick.

4th March 2010
audiopip's Avatar
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See here

Lamps Index
4th March 2010
Tea-Bag's Avatar
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@Foolforaradio -
This isn't like a kit instructions set.
I would suggest reading a basic schematics instructions set, or the old navy basic electronics. You'll get it. Then piece it together yourself.
This is one of Nelson's simplist amplifiers ever, meant to teach the basics.
A 1.2.3 Kit would not teach you much.
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4th March 2010
e_fortier's Avatar
diyAudio Member

I have a few NOS Toshiba lateral mosfet model 2SK134 sitting at home, would it be possible to use them as replacement mosfet ? I was made aware that I would need to bias the gate to about 1.5Vdc but how about the bias current going through the drain, what value should I use to get the sweet spot as found but Mr Pass ?

Thanks for your help,

5th March 2010
multi-volti's Avatar
diyAudio Member
I bought a case of those 300 W mogul lamps for an old darkroom enlarger...but they were only frosted and not flashed opal.

Maybe here's another use!

and hey, how about a mega-easy-bake oven to cook with while enjoying music?, and cutting down on the glare at the same time.

I don't like the idea of CFL's...they sound terrible...you self-respecting folks wouldn't use a tantalum coupling cap, so why would you use a 'CFL resistor' with a transfer function that's worse than the non-linear incandescent lamp's...possibly the ultimate in non-linearity, a rectifier followed by a switching circuit! They can put a fair amount of krap back into the power line too... ugh :Oo

I think it's pretty sad how many CFL's I've had fail for punctured film caps...not the lamp itself. I open them up out of habit as I did some e-ballast design work in the early 90's.

An incandescent light bulb is fundamental to the Wein Bridge oscillator. Ugh again...imagine a CFL replacement!

Now here's a thought I wanted to pursue...a CFL with its electronics removed used as a cold cathode VR tube or similarly to a neon lamp...the lamp voltage can be found with a little research...but it is different at 15-40 kHz than at DC-60 Hz range...something about cathode fall potential that goes away above the relaxation freak.

I diverge...gotta go get me some MOSFET.
8th March 2010
diyAudio Member
put an output transformer before loudspeaker may improve the amplifier ?
23rd May 2010
diyAudio Member
I use RED light bulbs, and call mine the "Ampsterdam".............

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