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Old 1st February 2010, 12:00 PM  
Nelson Pass is offline Nelson Pass  United States
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Default De-Lite Amplifier

Introduction


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.
 
21st February 2010
JSterritt
diyAudio Member
Thanks one mil for the kick in the pants. I learned more about applied ee in one fun lesson than in all my years of no lessons. Again, thanks.
21st February 2010
nuvistordave
diyAudio Member
Thanks for the article. Although the distortion is low and the amp enjoys a simplicity comparable to SET amps; the problem with transistors is that they look like pentodes to the speaker load. TRIODES ARE UNIQUE in that they have LOW PLATE RESISTANCE; IE the SLOPE of the plate curves DOES NOT FLATTEN OUT.
22nd February 2010
didik wiryawan
diyAudio Member
Hello Mr. Pass,
I am one of thousands of Pass fans !

As usual, your taste of humor is always 'on'.
The D-Lite is really funs and make 'common people' looks stupified-
I don't want to build it , worrying about my electricity bill. :-D
I built F5, it is very good and also built a modified F4 by removing the input stage (JFET) replaced by 6922 SRPP, it sound incredible.

Kindest regards from Jakarta.
didik wiryawan
22nd February 2010
Redhat
diyAudio Member
Pretty cool,

It resembles the circuit example for the basic DE-MOSFET amp in my EE textbook.

One sniveley point though: Shouldn't the schematic symbol for the Dep Mode FET have a solid line for the channel (rather than the dashed one used for Enhancement mode FETs)?

Redhat
23rd February 2010
nuconz
diyAudio Member
no cfls on version 1? not green? extreme disappointment!
24th February 2010
Tea-Bag's Avatar
Tea-Bag
not politcally affiliated
diyAudio Member
Nuconz, the bulb represents a high powered 20 ohm resistor. The bulb dissapates quite a bit of heat. It's running at <100V DC, so not green, but not full blown halogen watts either. Turn it off when not playing, and it won't cost a lot to run.
It's simple to build, and that's the concept here. To learn what all the parts do and enjoy the great sound. If I can build it, about anyone can!
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24th February 2010
Meshuganah
diyAudio Member
Hmmmmm.... How about bridging two of these.
Or even using transformer coupling to the speaker for more power....

Or both even?
24th February 2010
Elvee's Avatar
Elvee
diyAudio Member
Congratulations: this is the essence of simplicity.
May I suggest an improvement?

If the speaker is returned to the positive supply instead of ground, the power supply rejection will be greatly improved.

The speaker will sit at an average +65V above ground, but with a floating load, this shouldnt be a concern.
Cheers,
LV
4th March 2010
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audiopip
diyAudio Member
Dear Mr Pass,

I built your De-Lite but as an environmentally aware individual I have replaced both the lamps with CFL's. Now I have line hum and HF oscillation. Please can you help me?

Yours etc etc
4th March 2010
Redhat
diyAudio Member
I get a kick out of the "green" concept that all incandecent bulbs are evil while other forms of light producing devices are good.

A plain old light bulb is essentially a light emitting (non-linear) resistor. Its not as efficient as a light source as it is as heater, but a watt is a watt no matter how you dissipate it.

The power consumed by an incandescent is transformed into around 20% visible light energy and 80% heat energy (aka infrared light).

A CFL is efficient at converting AC power into light but is it really more green if you have a heater on in your house too?

The CFL has a ballast (with a HF oscillator to make it work) and requires much more resources to produce than does an incandecent. Is it really more green?

The point of the bulbs in the amplifier is not to produce light but to act as a resistive load. The bulb just looks cooler than a power resistor.




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