Any interest in GC input buffer and power supply regulator pcb's?

[cjd]

mmmm. How're the Z-horns? I have some dirt cheap drivers here I have pondered making a z-horn for but I don't know if it's worthwhile.

On subject...

Non-inverted board and inverted board layouts with care to keep all the power, inputs, and outputs in the same spots...



I believe this all has the right schematics. I have holes for a bypass cap if you choose, as well as a zobel. Both of these would "float" above the board, but since they're optional things that most don't use and whatnot...

One of the design goals here was to make these "stackable" so you could bridge or parallel the circuits by running solid core through the inputs and outputs (turn a mess on their side for a standard case). I believe that has been achieved here. R1 on the NI board might get switched to a cap when run bridged, and R2 would get left off the NI if you parallel them, with a resistor run right at the input to ground I think. Maybe.

Regulated power, with the reg moved further away and the space used for (optional) additional caps (C3 and C5). This is just one side.



The OPA627 buffer option has had no comments, so I assume (dangerous I know) it's OK. Using schematic by Carlos.



And JFET buffer, first pass, using Pedja's circuit...



I will very likely be looking to etch some of these and try them out in the semi-near future, so any additional feedback would be most welcome - particularly, significant mistakes pointed out would be helpful.

C

[Sheldon]

Originally posted by cjd
mmmm. How're the Z-horns? I have some dirt cheap drivers here I have pondered making a z-horn for but I don't know if it's worthwhile. C

Very nice, actually. The're easy to listen to and have decent bass for such a small driver. I have a slight echo quality, but I did not add any material in the horn to control higher frequency reverb. I suspect a little felt in the comp. chamber and in the mouth will tame that quite well. I found them worthwhile, but it is a bit of work to cut and fit all the pieces. You might find they work will with your drivers, but if not you can always get some better ones for not too much.

Sheldon

[Variac]

CJD:
Some of those boards are like works of art -especially the 3886 boards!I'm talking visually- what do I know about circuits? - the next paragraph will prove it

On The OPA 627 Carlos board, the upper regulator has the center lead to ground, the lower doesn't. I assume that's because they are 2 different parts and are wired differently? (Otherwise I assume you'd have them facing in the same direction)

[cjd]

Well Variac, this'll prove it for you. Maybe. I have a degree in Fine Art (drawing). I like solving puzzles, especially visual types. And I can (usually) read a schematic.

Yes, different chips for each of the regs - actually, that's the case on both buffer boards. I do believe that is the usual way, though not an available option on the chip power boards so they use the same reg for both rails.

C

[Variac]

Ha! caught you- you visual guy you!!!
I knew they were different parts, I just was wondering if the pins were wired differently. On Carlo's schematic, the leg to ground is the center one, and on your lower reg I didn't think it was, BUT I didn't look up the part....and I don't know the conventions... BUT I did suspect you were wiring the regs differently consiously since one is 90 deg different iorientation than the other.

Actually they I think they could both face the same direction and the traces would work out...

[cjd]

You'd better take a look at that schematic again and read pin numbers on it. At least, that's why I have it the way I do (and I did check the data sheet which, IIRC, checks out as I have it as well).

Yes, I could have them "face" the same way, but the traces wouldn't be as clean. No reason for that with these regs.

C

[Variac]

pin numbers - that's the ticket!!
When I said "I caught you" I meant the artist part - not that the pins were wrong.

Any way I am visualizing a medium sized board with scoring that can be broken into all your small boards as required. Then everyone can play with inverted with buffer, NI with buffer, regulators. A regular Child's Garden of Chip Amp Topographies!!

Whooeeee!

[Sheldon]

Originally posted by Variac

Any way I am visualizing a medium sized board with scoring that can be broken into all your small boards as required. Then everyone can play with inverted with buffer, NI with buffer, regulators. A regular Child's Garden of Chip Amp Topographies!!

Whooeeee!

That's what I was hoping to sucker (err, entice) someone into doing. Seriously though, it would be pretty cool - the all out (close to all out anyway, cause there's always another tweak waiting in the wings) chip amp for beginners and neat freaks, and those who want design art on the inside of their projects. Oh, and if you want the hassles of dealing with the DIY public, consider this an order for a set (pedja buffer, reg board, amp board, especially if it's for the 3886 (for the mute).

Sheldon

[troystg]

Hi All-

I will ask BrianGT where he gets his boards made(best I have seen or worked with so far) and see if I can have some of these made.

Only concern is have these circuits (which look great) been proofed to see if they are ready for mass production in a GB?

Also, can we get a show of hands on how many people would be interested?

A simple post with "I'm in for one" will suffice. If we get a good response we can start an order thread with all the formal details.

Thanks,

Troy

[carlosfm]

Hi CJD,

C2 should be near pin4 on the op-amp, and not on the opposite side.
When I mean near the op-amp's PSU pins, I really mean near .
So, I suggest that you move C2, along with the reg and it's input cap too.
The reason to move the reg is that you should have caps near it's input and output pins. If you just move C2, you should ideally use an extra bypass cap on the reg's output.
Sorry, I know that with my suggestion you will have to make some major changes on that board...
But, believe me, it's worth the trouble.
Oh, btw, you may also find space, really on the op-amp's pins, to use 0.1uf multi-layer ceramic caps (from + to ground, - to ground).
Those caps are very small, just use them before the electrolythics.
Make it as tight as possible!