buffer question...did i get this right?

[pinkjimiphoton]

i tried diy layout creator for the first time today, and after a couple revisions trying to get it as compact as i think i can realistically, ended up with this:



it's a basic buffer i found on beavis's most excellent site...i know the cut at e7 is unnecessary, it was from an earlier revision, i forgot to remove it...ooops...

did i get this thing right? i THINK  i got it.... this is the schem i tried to layout:



if i didn't mess it up, i hope to add it to a couple projects that i think may need buffering...as always, thanks in advance!!!
peace,
jimi

[tempus]

You need to double check it, because it looks like about 75% of it is wired wrong.

Just for example, if I'm reading it right, you have R1 and R@ both connected to B+ and neither of them to ground.

[trjones1]

Looks good to me.

[pinkjimiphoton]

thanks for checkin' it out...i don't see where you're seeing it as wired wrong...

neither r1 or r2 are connected to ground...the bottom strip of vero is the ground plane, the top the b+.
maybe i drew it up wrong, but a1 is the b+ connection.

b2 is audio in

c11 is audio out

f1 would be ground.

the resistors will be mounted standing, to save space. i dunno how to do that yet, just started messing with the program this morning.

here's a more compact layout...trying to make it as tiny as possible.

[pinkjimiphoton]

Looks good to me.

thanks tr, just trying to see if i got it right before i build it. i've been messing with schematics for years now, it looked good to me, too, but i just wanted someone more familiar
to take a look in case i screwed something up! 

peace!

[trjones1]

I think the confusion is that the component numbering on the layout doesn't match the numbering from the schematic.  However, I don't think this makes any difference because (1) the numbering on the schematic is messed up already and (2) if it is just for your personal use you can number the layout however you please.  Even if it's not for personal use, I think that it's clear enough for people to follow.  

Good job on your first layout.  Making layouts is one of my favorite parts of building.  It scratches the same itch as doing a crossword, imo.

[deadastronaut]

 ..heres a quickie



dunno why i did it, yours look fine to me....

[deadastronaut]

 It scratches the same itch as doing a crossword, imo.

me too!..

[pinkjimiphoton]

sweet, thanks guys...


yah, i can see where the confusion came from now...i was just figuring i'd number stuff from left to right in the order it came up in the circuit.
my bad!

thanks for the alt layout, rob...it makes sense to me looking at it!

i was just trying to make it as tiny as i thought i could...took a few tries before i had something, and then i just kept trying to condense it smaller and smaller.

just out of curiosity, how the f*** do ya draw up a battery in layout creator?? i'm stumped!! lol...

guess it's time to heat up the ol' soldering iron....   

i'm hoping to add this to rob's tremoloooooooo, see if it cures the little bit of loading in the existing circuit, and trying to use only parts i have on hand.

hope i don't screw it up TOO bad, lol...thanks again for the help peeps!!

peace!

[pinkjimiphoton]

and yes, i agree...it is kinda addictive like crosswords or sudoku!!

like...i need MORE addictions...

hee hee...

[Gus]

using the schematic
I would reduce the 100K values at R1 and R2 and maybe make R2 a bit higher value than R1 to offset for the Vbe drop and what load the buffer is driving, and add a cap from the R1,R2 and the other R2(510K) node.  

R1 22K and R2 33K will give about 5.4VDC -.6VDC ABOUT 4.8VDC at the emitter  use a 10uf or > cap to bypass noise from the 9DC supply

9VDC/55K =about .163ma,   .163ma x 33K= About 5.4VDC

[pinkjimiphoton]

using the schematic
I would reduce the 100K values at R1 and R2 and maybe make R2 a bit higher value than R1 to offset for the Vbe drop and what load the buffer is driving, and add a cap from the R1,R2 and the other R2(510K) node.  

R1 22K and R2 33K will give about 5.4VDC -.6VDC ABOUT 4.8VDC at the emitter  use a 10uf or > cap to bypass noise from the 9DC supply

9VDC/55K =about .163ma,   .163ma x 33K= About 5.4VDC

i will try that tomorrow gus, thanks...i built this thing tonite, EPIC FAILURE.
makes a nice unity gain fuzzbox...just kidding, it hums like it don't know the lyrics, and is NOT clean or transparent...probably cuz i didn't use the specified transistor in the schem, i imagine?

i'm trying to understand what you're saying...do you mean change the two 100k's to 22k and 33k respectively?

i can see where it needs the power supply filter...duh!! i can't believe i didn't notice that freekin thing not being filtered. oops!

should the 9v bat have a 55k resistor in line with the cap, do you mean?

and where should i put the small cap? sorry, like i said, a newbe so i appreciate the help!!

i think you mean between the junction of r2/r3 and the 510 k resistor? do you mean like a small pf cap, or another electolytic like the 10mfd you'd suggested?

good lord, i'm lost...lol!!

[pinkjimiphoton]

is this a little closer to what i think you mean? the circuit checker gizmotron says all the connections are good... but...

we'll see!!

[slacker]

That's right except the negative ends of C1 and C3 should be going to ground.

[pinkjimiphoton]

i thought the negative ends were the ones with the stripe? man...now i'm all confused....lol.

so the shaded side is the positive with layout creator? cool...thanks bud, i'll try it again one more time!

[slacker]

Not sure which end is negative in DIYLC, which ever end it is needs to go to ground though not how you've got them now.
What I mean is the positive end of C1 should be on a4, you don't need the trace cut there, the negative end should be on f4.
The positive end of C3 should be on c9 and the negative end should be on f9.

Just noticed you also need a jumper from the collector of Q1 to row a.

[pinkjimiphoton]

i did notice that i spaced the jumper. shoot...back to the drawing board. i DID get this thing working, believe it or not...but only if i short the freakin' ground to the + terminal on the output jack...really, really weird..reversing the power supply makes absolutely no difference, too...aye, carumba, my brain hurts!!

i'll add the jumper, it's on the earlier attempt, can't believe i spaced it.

on this one (the one i built last nite that was an epic epic failure) i changed the audio in to b1, and put a 100mfd cap from a1 to a3, and put the 9v to a1 as well...now it works, but like i said, only if i connect ground from the battery to the hot terminal of one of the jacks :

[twabelljr]

i did notice that i spaced the jumper. shoot...back to the drawing board. i DID get this thing working, believe it or not...but only if i short the freakin' ground to the + terminal on the output jack...really, really weird..reversing the power supply makes absolutely no difference, too...aye, carumba, my brain hurts!!

i'll add the jumper, it's on the earlier attempt, can't believe i spaced it.

on this one (the one i built last nite that was an epic epic failure) i changed the audio in to b1, and put a 100mfd cap from a1 to a3, and put the 9v to a1 as well...now it works, but like i said, only if i connect ground from the battery to the hot terminal of one of the jacks :

Revision D should have worked the way you have it shown here. When comparing it to the schematic, everything looks right. Are you saying Rev D did not work, or is it a correction? If it doesn't work as shown, I would suspect bad trace cuts or off board wiring problems. The vero looks nice.

[Gus]

Here is another take on a NPN buffer. Just add a cap to the schematic above.
http://www.diystompboxes.com/smfforum/index.php?topic=90701.0

High input resistance, good drive, will  bias up with a number of transistors without changing values.

Who needs Jfet source followers?

Have Fun.

[pinkjimiphoton]

i did notice that i spaced the jumper. shoot...back to the drawing board. i DID get this thing working, believe it or not...but only if i short the freakin' ground to the + terminal on the output jack...really, really weird..reversing the power supply makes absolutely no difference, too...aye, carumba, my brain hurts!!

i'll add the jumper, it's on the earlier attempt, can't believe i spaced it.

on this one (the one i built last nite that was an epic epic failure) i changed the audio in to b1, and put a 100mfd cap from a1 to a3, and put the 9v to a1 as well...now it works, but like i said, only if i connect ground from the battery to the hot terminal of one of the jacks :

Revision D should have worked the way you have it shown here. When comparing it to the schematic, everything looks right. Are you saying Rev D did not work, or is it a correction? If it doesn't work as shown, I would suspect bad trace cuts or off board wiring problems. The vero looks nice.

well, it looked good on paper....but it wouldn't work when i tried to splice it into an already existing circuit...


i'm thinking in retrospect, that it could be because i didn't add a voltage divider to the 9v power supply.
gonna go back and tweak rev d one more time, remove the 100mfd cap i added, and see if it works just as it is. i double, triple, quadruple checked the board and traces, so it should work! really weird!

let me go try and change it back, will post the results shortly...thanks!