F5 power amplifier

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digits

digits

Member
Joined 2011
Hehe, I am part of a development team working on LED lighting useing Cree LEDs. If you think LED lighting is the same as the beatifull point source glow of incandecents you are plain wrong. It is not so much colour reproduction that annoys me but the directivity of the LED, our current diffuser is a 3 part jobby and does an OK job at getting some light on the walls, but at the cost of efficiency.

What I don't like about the CREE module you linked, is that it is not a simple retrofit, i.e. it has to be installed, for most people without the skills, at conciderable cost. I don't see it as something that you can hang on the shelf next to CFL's and expect to sell any where near as many as the nasty CFL bulbs.
 
L

labjr

Member
Joined 2003
digits said:
Hehe, I am part of a development team working on LED lighting useing Cree LEDs. If you think LED lighting is the same as the beatifull point source glow of incandecents you are plain wrong. It is not so much colour reproduction that annoys me but the directivity of the LED, our current diffuser is a 3 part jobby and does an OK job at getting some light on the walls, but at the cost of efficiency.

What I don't like about the CREE module you linked, is that it is not a simple retrofit, i.e. it has to be installed, for most people without the skills, at conciderable cost. I don't see it as something that you can hang on the shelf next to CFL's and expect to sell any where near as many as the nasty CFL bulbs.
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What I don't like about LED lighting is the cost. Some of the bulbs are like $30 or more. Nobody wants to spend that kind of money when we can get 4 incandescent bulbs for 87 cents. And the manufacturers make exaggerated claims.
 
h_a

h_a

Member
Joined 2006
I love that forum, even a Cree man around here :cool:

If you think LED lighting is the same as the beatifull point source glow of incandecents you are plain wrong.
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Don't worry I have that module and I really like it. Honestly I expected pretty worse directivity, but it works like a charm for me. I certainly did not expect point source lighting or wanted it in the first place.

i.e. it has to be installed
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Well, I perfectly agree. Things are going to change and bulb replacements might require new lamps.

Any case, I simply build a wooden structure around it (in the best DIY sense) and have a truly beautiful lamp for less money than anything I could buy with this amount.

Hannes

PS: Oh and don't worry I already took care of the module's thermal managment as well (neats a heatsink).
 
alazira

alazira

Member
Joined 2007
h_a said:
Sure, for me it's the same. Fortunately prices are going down with increasing volume.

But things can't stay as they are with a single light bulb drawing more power than a fully featured tv-set, IMHO.

Hannes
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Hi,
The freemarket idealists over here would prefer that consumers make the decision. If a product is indeed better and more cost efficient, then people will buy it without legislation. Government social engineering is rarely a good thing, or at least not without consequences. If some had their way they would outlaw plasma TV's, Ferrari's (that get 10mpg), french fries, and having more than two children, not to mention class-A amps.
 
alazira

alazira

Member
Joined 2007
digits said:
Or God forbid, make plants illegal, wait, they allready did that. Lol, a war on plants! :spin:

I agree fully with your views on social engineering an the like, and once you wake up to it, it is very hard to watch TV etc. afterwards.
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Aren't plants used for "carbon offsets" (for the sins of fast cars, class-A amps, etc) since they metabolize CO2? Oh, wait, you are referring to certain illegal plants ;). Here in Las Vegas they have banned new plantings of Olive and Mulberry. As a funny aside, a TV crew did a report on a public school that had these offensive plants as part of their landscape. Governments make the laws, but don't always feel the need to follow them:rolleyes:
 
V

vtr

Member
Joined 2010
back to f5

just finished my f5 with help of hannes transistor kit-thanks alot

and pcb from daniel

built as monoblocks with 300VA 2*30V trafo and lundahl choke as LC filter-(gives 25V of DC with 20mV ripple with 24000uF)


and i´m impressed, didn´t expect it to be that good!

thanks mr pass for this design, the 6moons review hits the point, perfect description

and on my altec 604-no turn on off bumps, silent, sensitive enough for me

my old transistor reference class A LFA from elector has to leave....
:p
 
Dzius

Dzius

Member
Joined 2010
There was such question somewhere already, but it still makes me courious. Is there any explanation why on "F5 Distortion Spectrum @1 Watt @ 1kHz" (Fig8 in Operation and Service manual) the 4-th harmonic distortion is missing ? Original answers by Nelson was like that he had forgotten about it. But being more serious what part of cirquit canceled it ? The same phenomena do shows in "The Amazing FET Circlotron" by Michael Rothacher since amplifier is similar. Further more I couldn't find such distortion spectrum of F3/Zen v9.
 
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Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
vtr said:
but i can find the red wire and see the blue one but not where the blue ends-its like in tv which one to cut???? :D
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green wire is routed to pcb (end below RCA input) ;

both gnds for RCA and speaker binding post are connected there

2_5.jpg







remember old saying ....... gnd reference is just state of mind ....... :rofl:
 
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