[superjohnny]

I promise when I'm done I'll hang out in the DIY forum for at least two months and answer bone-headed questions... like the one I'm about to ask.

I had some gnarly issues with soldering. I just couldn't figure it out. Luckily we have some kick ass folks around here who set me straight. The 4% silver solder and a wrong size bit on my soldering iron have been replaced and now I'm soldering with the best of 'em. Thank you Dan the audioman, Pars, Pappucho, Ajit, Budgie and Mr. Tangent. [/butt-kissing]

I really don't want to ask this question because I know the answer is staring me in the face, but how exactly does the R1 resistor & D1 LED work?

aww shooot. You just solder them sums-a-bitches together. Is that it? How do you keep from bending the resistor till it breaks? Can someone post a pic so I can see this part?

 

[meat01]

the resistor controls the brightness of the led and makes your battery last longer.

cut most of the leads off of the resistor and use pliers or helping hands to hold the led and the resistor together. A little bit of flux should help also. solder the resistor to the negative end of the LED (the shorter lead or the one that is not red). Put some heat shrink around the resistor.

 

[rickcr42]

Quote:

I promise when I'm done I'll hang out in the DIY forum for at least two months and answer bone-headed questions... like the one I'm about to ask.

damn right you will,I just blocked your access to all other forums here exept for DIY !


KIDDING !

 

[superjohnny]

That makes sense, thank you Meat.

I've been having so much trouble with the soldering and putting this thing together that it was really startying to try my patience. But yesterday I had my first taste of success. I was able to solder in the joints easily, without frustration or even that much work. It just really came together nicely and I'll tell you what, I dreamt of it all night long

A little bit of success goes a long way

 

[rickcr42]

congrats man

nothing better than to have things finally fall into place ,sit back and say "hell yes that was me"

When i began this very frustrating hobby there was no internet available for instant gratification (no friggin' "old" jokes guys .Don't p*ss off the rickmonster this soon after i joined the fray again)

I would go to the local supermarket ,pick up the latest issue of Popular Electronics and attempt to build one of the published projects.

gathering parts was a real pain in the *** due to

1-being fifteen in the 1971 meant I was always broke,geting wasted was expensive

2-parts were EXTREMELY expensive unless you purchased in quantity-no group buys back then (a single LED would run $5-10 !About 20.00 in adjusted loot !)

3-sources were limited,very limited. Radio Shack and Lafayette were about it (anyone here remember Calectro parts ?)

so I would somehow gather the parts at great expense and attempt to get this thing ,whatever it may be, to work as it was designed to work .

Fat friggin' chance . I was a real hack at soldering and for some damn reason i had problems orienting electrolytic capacitors the right way !

You would think that after launching a 4700uf 50 electrolytic for my SWTPC amp into the ceiling (not really but it was dramatic when it turned into a volcano and started oozing electrolyte-after whistlering like a damn bomb first !) that THIS ONE THING i would actually pay attention to.

NOPE !

stubborn is as stubborn does man . I still toss instructions to this day and wonder why crap don't work

It is a "I know everything" kinda state of mind that always leads to trouble

anyway .....

My soldering sucked and there was no place to get help , I had difficulty learning to read schematics-again no where to turn , and even when i could read the bast*rds I did not understand the "why" of it

to this day i consider electricity 'magic" and the people that understand and use it modern day alchemists

But learn eventually i did .

The first time I got something to work i almost fell down !

I thought i was going to explode man !

The pride in myself was so immense that i just had to share with EVERYONE and know what ?

NO ONE CARED DUDE !

's OK though .

I DID

the pride of "i made this" is something no one can take away from you ever and the feeling is a good one

keep plugging away man-it DOES get better



Damn,i gotta stop going off topic with these cheesy posts

RICKMONSTER OUT !

 

[flipzter]

My first Cmoy was DOA and a friendly fellow Hi-Fier fixed it Pro Bono. I kinda lost the "I Did This" feeling, but I've since made another and it worked. Great feeling when you make something and it works.
I called my wife at work and put the headphones to the phone!! (Of course she hung up on me and I had to whine my way back into her good graces. )

But keep at it super! It's a great feeling and there are some great guys here to help when you need it.

 

[superjohnny]

I hooked up the power-supply and i'm having a bit of an issue. I side-tracked from Tangent's instructions, but not by far. I soldered together the battery clips and attached them to the board. Per his instructions you only temporarily connect them. Whatever, it shouldn't matter. It just means the virtual ground will be -9 +9 instead of +4.5 -4.5.

Anyway when I test with my multimeter it says the -v is about -0v and the +v is about +18v

Any ideas what's going on?

Wish I had my digi-cam, but I loaned it to my dad :/

 

[tangent]

Quote:

how exactly does the R1 resistor & D1 LED work?

An LED has negligible resistance. One of the three forms of Ohm's law is I=V/R: current equals voltage divided by resistance. Anything divided by 0 equals infinity. Resistance of an LED isn't quite zero, but it is damn small. So if you connect an LED directly across a power supply, current is many amperes.

If you go and look at an LED's datasheet, you'll see that they are typically rated between 20 to 50mA. That's 0.02 to 0.05A, and I just showed that without any additional resistance inline with the LED, current is way over 1A. Are you seeing the problem now? The LED burns up. It literally gets hot before it dies.

So, put 10K of resistance inline with it. If V=18, and the drop across the LED is 1.8V, the voltage drop across the resistor is 16.2V. I=V/R, so I=1.62mA. 1 to 2mA is enough current to get good brightness out of an efficient LED, and most LEDs these days are efficient.

Quote:

it turned into a volcano and started oozing electrolyte-after whistlering like a damn bomb

I just turned $20 worth of op-amps into local space heaters the other day by getting the V+ and V- leads backwards. I even let the magic smoke out of a few of them. Doh!!

Quote:

the -v is about -0v and the +v is about +18v

Relative to virtual ground?

That suggests that the voltage divider in the power supply (the two 4.7Ks) isn't doing its job correctly, or something has shorted V- to vground.

 

[Voodoochile]

Quote:

Originally posted by tangent I just turned $20 worth of op-amps into local space heaters the other day by getting the V+ and V- leads backwards. I even let the magic smoke out of a few of them. Doh!!

I did that last fall, but luckily only with one chip. It was ceramic, though.

*POW*

A nice inverted cone-shaped divot in the chip, and the piece went to the ceiling like it was shot from a coil-gun.

Darn good thing my face was not in the way, I'd probably have put an eye out.

 

[00940]

contest of the most stupid mistake ? I spent two hours debugging an amp on which the left channel was out.

Of course it was out.... I was using a mono mini-to-mini, shorting the left channel to ground.

 

[ITZBITZ]

Bonehead mistake: Trying to figure out why left/right are switched. Checked, checked, rechecked.

I was using an old 1/8" to stereo RCA cable that came with my old Sony Discman and it was wired backwards.

Think about it. All those years I was listening to Bohemian Rhapsody with the channels switched. Oh, the humanity of it all...

 

[superjohnny]

Quote:

Originally posted by tangent Relative to virtual ground? That suggests that the voltage divider in the power supply (the two 4.7Ks) isn't doing its job correctly, or something has shorted V- to vground.

By relative to the virtual ground I meant that instead of getting a nice -9/+9 split I'm getting all the juice loaded up on the positive side. Please pardon my ignorant use of the language

(I'm trying)

I was up sooo late checking and re-checking my connections. Thanks very much Tangent, I'll re-check the 4.7k's just as soon as I get home.

I love the bone-headed mistakes. Yea off topic in my thread, but that's ok... I don't mind. The greatest people make the bigest mistakes.

 

[tangent]

Quote:

By relative to the virtual ground I meant...

I wasn't questioning your use of the terms. I was asking if you measured those voltages relative to virtual ground. You said "+v is about +18v", and I want to know what that is measured relative to.

Also, at what point on the board are you making the measurements? Have you tried measuring against other points that should be the same voltage?

 

[superjohnny]

I'm measuring from the signal ground to the hookup wires going to the v+ & v- . I measured both from where the hookup wires go into the top of the board and from the solder joints on the bottom of the board. Both had the same reading.

I don't have the socket & opamp or any of the amplification section installed (except the M jumpers that sit below the R & L in's).

So basically everything above the black box is installed:

I hope you don't mind me stealing and scalping your images. I give you all the credit in the world

 

[tangent]

Measure resistance from V+ to vground and V- to vground.