[rsabo]

UPDATES AT BOTTOM

I was bored this weekend and started playing around in eagle. This is essentially bits and pieces of several of tangent's amplifiers.

without silkscreen

-PINT-like power supply, complete with charging circuit
-ground channel, from pimeta
-single op-amps for each channel
-HA-5002 buffers
-everything but op-amps and buffers is through-hole (whether that's a plus or minus is your opinion)

some stuff I know I should fix:
-smaller wire pads
-clean up board layout

any comments?

 

[ATAT]

Hey cool, I went through your thought process a while back.. I never really liked using the HA3-5002 at low supply voltages, the really nice current output specs are for the +-15 volt supply... at +-5 volts, its MUCH lower. I assume you're running off +-9 at least? (nvm. saw the M+/- pads)

Is your topology pretty close to the pimeta? I'm guessing since you dont have separate opamp rails and you have a 3 channel topology..

Not sure why you make opamps SMD and other parts not.. the opamp might need to be rolled, the resistors not so much..

Also, why do you only have only one rail cap? seems overly small for something like the pimeta, why not add two.. you'll have the space after shrinking hte pads.

btw did you use the autorouter? you have two completely unused vias near your OPA134s. and you could definately make the ground plane more continous.. take the trace that cuts the pot pins.. you could rout those around.. IMHO a continous ground >> a trace that's a bit longer.

 

[kin0kin]

nicely done, but the chips can use some bypass caps...btw...what enclosure is this made for?

one rail cap = hornet style

 

[rsabo]

ATAT: I'm afraid I can't blame the autorouter for the sucky job; it's all human error.

Would you mind pointing out the two unused vias? It's too early, I can't seem to see what you're talking about.
The SMD op-amps/thru-hole everything else thing was taken from the MINT.
I'll probably add a second rail cap.

kin0kin: will do. Bypass caps are just 0.1 mF from power input to ground, right?

I had thoughts of designing it to fit in a mint tin, but if I had to build one and put it somewhere, I'd put it in a serpac h-65 case. Using my laser-accurate measurement technique (holding up the case behind a 1:1 printout to a light), the board as it stands now would probably fit in an altoids tin with 1x9v battery. The serpac looks like it would be able to fit in two most comfortably. I'll check out what hammond case it'll fit in when I get a chance to measure it.

If anyone wants a schematic or .brd file, send me an email.

 

[kin0kin]

yes that'd do but there is little room fo film, you'd wanna go with 1206 ceramic instead. if there is still extra room, some 10-20uf tantalum would help, and at least a fair amount of rail capacitance.

 

[rsabo]

Ok I have rough measurements for the board (taken looking down, pot is in upper right hand corner):
right side is 50 mm
top is around 63 mm
bottom-right is around 43 mm

unless I'm mistaken this means that the board (just the board (and maybe some panel components)) will fit in the smallest hammond, and it might fit in the next one up with a couple batteries.

 

[rsabo]

new version:

changes:
-new routing:
I think this is an improvement, but some parts are still wonky, esp. with the ground plane. (see C4R+s connection to ground)

-per ATAT's recommendation, another rail capacitor:
had to widen the board 1 mm and remove some of that cut out area to make it fit, leaving a large empty space in the bottom, which as you can see is available for advertising space.

-bypass capacitors, just for kin0kin
-smaller wire pads

 

[ATAT]

a). you sure you're using the right resistor sizes? they seem big

b). you've extra space beneath the pot, move the pads to the left of the pot, and move everything up.. should be able to fit that rail cap and make it smaller.]

c). you can move the SMD components to the back layer of the board and save some space.. every bit counts

you'd want to use a serpac case, for the HA3 buffers you definately want 18 volts.
nvm on the via.. the diode square bad threw me off...

 

[rsabo]

another update:

no silkscreen:

changes:
-moved SMD parts to bottom of board
-added a charging LED (CLED & CRLED)(edit: wired wrong in pictures, now fixed)
-smaller resistors
-much smaller board (approx. 47mm x 43mm)

 

[rsabo]

Yet another update.

changes:
-added a op-amp to the ground split.
-added bypass caps to ground (one's in a bad spot, but it's the best I could figure out)
-fixed the error with the charging LED.

oh, I gave it a name too

SPLINT - because it sounds cool and rhymes (maybe) with pint and mint.

forgot the website:
http://sabo.homeunix.org/~ryan/splint.html