Steady hands..... (SMT based amp)

[leok]

Bruce,

Oh, now I see. I thought it was a TI part, but no .. as you point out, it's Tripath.

Leo

[sfogg]

Had a chance to wind the coils last night... this is the completed amp.

The two unpopulated capacitors are input coupling caps. You have a

choice of using through hole or SMT for the input caps and I went with

SMT for them. The kit is supplied with both caps as well as a couple of

different resistors to allow the user to set the gain of the amp as the

desire.

Shawn

[Daddy Dee]

I'm still trying to grasp the small scale of this little guy.

Thanks for photographing it with the dime in the pic.

[sfogg]

"

I'm still trying to grasp the small scale of this little guy. "

It is tiny! I was expecting it to be small but it still shocked me how

tiny it is. Could have been made even smaller but then reflow would

likely be the only way to build it.

It could have been made even smaller if the coils went on both sides of

the board but that would have made mounting the chip for heatsinking

much more difficult.

Shawn

[Erik Mandaville]

Shawn:

A little off topic, but I'm interested in what kind of lens is on the digital camera you're using. I'm still pretty much stuck in the days of manual 'analog' photography, and have no idea about this stuff. I want to get a good digital camera, preferably an SLR type (if they're still referred to as SLRs in the digital world), and don't know what to look for in terms of how many popsicles or mega-popsicles it should have.

Also: It is not possible that this amplifier will sound any good. 1) it's too small. Music signals are very discriminating about the size of the components they swim through. 2) It's physically far too light. Good amplifiers have to weigh at least 75 pounds in order to sound good (it's one of the ways we are able to confirm that we have purchased true hi-fidelity equipment) 3) I see electrolytic capacitors on the board, and they don't appear to be made by Cerafine or Blackgate. 4) And Shawn: I hate to have to tell you this, but the dime isn't going to do anything here. It's not even connected to the circuit. My feeling is that it may have been included with the kit as a last-ditch effort toward maybe a little RFI suppression, but I don't see that it's connected to the circuit ground in anyway. 5) if the DC power supply you'll be using to bench test it incorporates solid state rectification.........well........that's too terrible to even think about, even on Halloween weekend!

Erik

[sfogg]

Erik,

That picture is with an older Nikon CoolPix 950. It is more along the

lines of a PHD camera (push here dummy) then a 'real' camera.

"I'm still pretty much stuck in the days of manual 'analog'

photography, and have no idea about this stuff. I want to get

a good digital camera, preferably an SLR type (if they're still

referred to as SLRs in the digital world),"

Yup, there are still digital SLRs. My main digital is a Nikon SLR that

I bought on closeout (D1H) and it is a great camera. I retired my F5

after getting the D1H.

What SLR do you have now?

" and don't know what to look for in terms of how many popsicles or mega-popsicles it should have.""

The mega-popsicles is really only one aspect of digital. The D1H I have

is fairly low megapopsicles compared against even some $300 PHD

digitals but there is little doubt which camera will take better

quality pictures.

"1) it's too small. Music signals are very discriminating about the size of the components they swim through. 2) "

I have read that. Something about if the wavelength is longer then the

size of the component trying to output it it won't be able to and will

really just reproduce a lot of higher frequency waves, that have

wavelengths that fit in the amp. I think 41hz is working on an Amp7

that will address this... it is 45' long... they are attempting to make

it a 1/2 wave amplifier.

"2) It's physically far too light. Good amplifiers have to weigh

at least 75 pounds in order to sound good (it's one of the ways we are

able to confirm that we have purchased true hi-fidelity equipment)"

Ahh... but the amp isn't in an enclosure yet! This is why some have 1"

thick faceplates and so on.... makes the scale read higher and therefor

makes the sound better. I am taking the cheaper route though... just

put it in an enclosure and since the module is so small there is plenty

of room for a brick in the chassis. Not a 'VPI Magic Brick'... just a

brick.... it will add weight to the bottom end of the music.

"4) And Shawn: I hate to have to tell you this, but the dime

isn't going to do anything here. It's not even connected to the

circuit. "

READ MY LIPS........... heatsink!

"5) if the DC power supply you'll be using to bench test it

incorporates solid state rectification.........well........that's too

terrible to even think about, even on Halloween weekend!"

The idea is to give nightmares..............

I could try batteries.... though I have seen some measurements

elsewhere the suggest battery power is actually a pretty noisy supply

when it starts to get loaded. How about running it off banks of

glass capacitors? If it is good enough for the Navy Sonar systems it

might be acceptable for a home stereo? $5000 worth of capacitors for a

$25 amp sounds about right for the lunatic fringe out there....

.... NO.... I've got it.... SOLAR power! Nothing is more pure then sunlight right?

Shawn

[fini]

Audio with a flare!

[sfogg]

More power during flares too!

Shawn

[Marvel]

Perhaps the dime was added just to increase the cost of the amp. []

[sfogg]

Could be... the dime is 1/250th of the cost of the amp......

Shawn

[Erik Mandaville]

Shawn:

"READ MY LIPS........... heatsink!"

Well, I didn't even think of that. I guess a coin would work well for heatsinking, and it certainly reflects a well-thought-out design strategy. I think it would be better if the company sent it pre-drilled, but I'm sure careful use of a center punch will make quick work of it. I think the idea of solar power is pretty cool, too. True story: My dad's rig/s of transmitters and receivers are entirely solar powered. Actually, he uses the panels to charge large batteries. It makes for kind of an interesting setup, but sort of complex IMO. He really does it for 'conceptual' reasons, though, not for the sake of convenience or practicality. Batteries are kind of a hassle, though. I had played around with battery powered bias and filament supplies on the Moondogs, but it seemed to cause more problems than it solved. They're really weren't any problems to begin with; I just wanted to try it for the sake of trying it. Same with PWK's 'minibox.'

You asked about my trusty old Nikon. It's an FM2 that I got when I was in grad in school primarily for photographing artwork. I set up a little studio in our apartment in upstate New York (Rochester), which consisted of a long roll of seamless dove-grey paper pulled over a table, a soft-box for Tungsten lighting, and a tripod and cable release. Kodak makes an excellent (but expensive) film balanced for Tungsten light, but a tripod and cable release were needed because of very slow shutter speeds -- 1 second+. What was nice was that this film required common E-6 (I think I have that right) processing, so it was possible to get the slides back quickly. When I used Kadachrome, the film had to be sent to Kodak for processing -- a secret, no doubt!

It's really sort of interesting how pervasive digital technology has become, and even more curious how closely digital reproduction of music and photographic images parallel one another. Over the past years, I have read countless times how digitally-derived or processed music, as sophisticated as it is in a technical sense, is still not able to match the accuracy and/or realism obtained by a tiny needle scraping its way through a groove. If that's really the case, it seems the gap between the two is now becoming increasingly narrow.

Thanks for the info. on digital SLRs,

Erik

[sfogg]

Erik,

One advantage of sticking with a Nikon SLR if you go digital is your

lenses (and flash) should work. Nikon is one of the few that

didn't change lens mounts when they went to autofocus or digital. If

they are totally manual lenses you won't get all the advanced metering

options and obviously not auto focus but they would still be useable.

Some of the really old lenses with the aperature linkage being external

to the lens (what the original F used among others) may not work

properly on the newer bodies.

Keep in mind on a Nikon digital SLR the lens effect size increases by a

factor of 1.5x. IOW a 50mm on a film SLR will act like a 75mm on a

digital SLR. This is due to the size of the digital sensor being

smaller on the digitals compared against the size of film.

Shawn

[Erik Mandaville]

Shawn:

"One advantage of sticking with a Nikon SLR if you go digital is your lenses (and flash) should work. Nikon is one of the few that didn't change lens mounts when they went to autofocus or digital. If they are totally manual lenses you won't get all the advanced metering options and obviously not auto focus but they would still be useable. Some of the really old lenses with the aperature linkage being external to the lens (what the original F used among others) may not work properly on the newer bodies."

Is that right!? The fact that I have very high quality lenses was the main reason I haven't gone further into digital photog (as the the guys and gals at RIT used to say). If I can still make use of my lenses, that would be really great! These are totally manual lenses, so I would just need to look into it. What a great camera the 'F' was/is.

Erik