Nice! Were there any changes to the previous layout and schematic? could you post the final layout you sent to LK?

http://gilmore.chem.northwestern.edu/inputboard5.jpg

the pass thru is much more easily done in software given the posibility

of unbalanced input, balanced output.

maybe a completely single ended version in the future.

I might have already asked this, but what would be the problem of using just one board as single ended?

the first thing that happens is that all inputs get converted to balanced.

So to use the thing as single ended you would need a bunch of dual rca to

xlr adapters, and you have to jumper across the input amp, then it actually

would work. The tape out would be unbuffered this way.

I do have the cardas stacked rca jacks in house, so i could do a single ended

board.

Couldn't I just use the + signal for left channel and - signal for the right one and share the ground? Or is this incompatible with the ic used?

I'm interested in single ended as well, but not a big deal building full balanced and using adapters.

Fine, i'll make a single ended version. I may be able to get both on the same board if i make it a bit bigger.

Then you stuff it one way for single ended and another for balanced.

The input chip is not compatible with single ended. So there will have to be 2 different single ended front

ends.

Fine, i'll make a single ended version. I may be able to get both on the same board if i make it a bit bigger.

Then you stuff it one way for single ended and another for balanced.

The input chip is not compatible with single ended. So there will have to be 2 different single ended front

ends.

I'm fine with building a full balanced version. I'd rather have a full balanced one that is prototyped and known to work perfectly than screw with perfection.

well this should confuse most people

http://gilmore.chem....inputboard6.jpg

Stuff it with one set of parts and its balanced, and you need 2 boards,

stuff it with another set of parts and its unbalanced and you only need 1 board,

to keep it the same size, for unbalanced you give up an input.

The unbalanced input buffer is an lme49720 dual opamp, or your favorite

in a gain of 1 setup.

Needs a bit of checking now.

Edited January 29, 201214 yr by kevin gilmore

Man your quick.

Man your quick.

QFT

I'm efficient

I had been thinking about how to do this from the very start, so once i got the

cardas parts, it was actually pretty easy. The fact that cardas can't even supply

a dimensional drawing of what is supposed to be their own part is very sad.

Cool!! I don't antecipate balanced gear in the near future and this looks quite good!

I find that it falls off the shelf if it isn't balanced.

unbalanced/balanced input board, multiamp and blackhole.

Anyone in the US interested in prototyping the blackhole and multiamp? I have 1x set of blackholes and 1x set of multiamp (2 boards each, no PSU) that I can spare. No cost, just pay for shipping.

Edited February 19, 201214 yr by Lil Knight

Its gonna be a busy spring and summer.

I don't need a pre-amp, but now I really want one anyway!

^ I know exactly what you mean! I'm there too.

Me too, and I have an integrated amp.

Those boards looks huge. What are the dimensions?

Preamp board is 12.4 x 6 inches

multi amp is 6.1 x 3.4 inches

black hole is 3.5 x 3.62 inches

Edited February 18, 201214 yr by kevin gilmore

Looking good...

I do need a pre-amp, and I can't wait to get going on this one.

What's that saying Horio? It's just as easy to build 3 as 1?

What's that saying Horio? It's just as easy to build 3 as 1?

Why just 3?

Hmm.. This baby is going to need two full size enclosures

I'm thinking 4 x preamp boards + 1 x input board + 2 x KG attenuator boards + local regulation in "audio box".

Transformers/rectifiers/1st bank of caps (or PS with remote sensing skipping regulation in audio box) + display + arduino/whatever in the "noisy box".

I2C and Power supply (and potentially remote sensing) connections between the boxes.