MASantos Posted January 29, 2012 Report Posted January 29, 2012 Nice! Were there any changes to the previous layout and schematic? could you post the final layout you sent to LK?
kevin gilmore Posted January 29, 2012 Author Report Posted January 29, 2012 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.
MASantos Posted January 29, 2012 Report Posted January 29, 2012 I might have already asked this, but what would be the problem of using just one board as single ended?
kevin gilmore Posted January 29, 2012 Author Report Posted January 29, 2012 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.
MASantos Posted January 29, 2012 Report Posted January 29, 2012 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?
deepak Posted January 29, 2012 Report Posted January 29, 2012 I'm interested in single ended as well, but not a big deal building full balanced and using adapters.
kevin gilmore Posted January 29, 2012 Author Report Posted January 29, 2012 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.
deepak Posted January 29, 2012 Report Posted January 29, 2012 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.
kevin gilmore Posted January 29, 2012 Author Report Posted January 29, 2012 (edited) 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, 2012 by kevin gilmore
kevin gilmore Posted January 29, 2012 Author Report Posted January 29, 2012 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.
MASantos Posted January 30, 2012 Report Posted January 30, 2012 Cool!! I don't antecipate balanced gear in the near future and this looks quite good!
swt61 Posted January 30, 2012 Report Posted January 30, 2012 I find that it falls off the shelf if it isn't balanced.
Lil Knight Posted February 18, 2012 Report Posted February 18, 2012 (edited) 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, 2012 by Lil Knight
kevin gilmore Posted February 18, 2012 Author Report Posted February 18, 2012 Its gonna be a busy spring and summer.
swt61 Posted February 18, 2012 Report Posted February 18, 2012 I don't need a pre-amp, but now I really want one anyway!
Craig Sawyers Posted February 18, 2012 Report Posted February 18, 2012 ^ I know exactly what you mean! I'm there too.
guzziguy Posted February 18, 2012 Report Posted February 18, 2012 Me too, and I have an integrated amp.
ujamerstand Posted February 18, 2012 Report Posted February 18, 2012 Those boards looks huge. What are the dimensions?
kevin gilmore Posted February 18, 2012 Author Report Posted February 18, 2012 (edited) 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, 2012 by kevin gilmore
Horio Posted February 19, 2012 Report Posted February 19, 2012 Looking good... I do need a pre-amp, and I can't wait to get going on this one.
swt61 Posted February 19, 2012 Report Posted February 19, 2012 What's that saying Horio? It's just as easy to build 3 as 1?
Horio Posted February 24, 2012 Report Posted February 24, 2012 What's that saying Horio? It's just as easy to build 3 as 1? Why just 3?
Shaman Posted March 5, 2012 Report Posted March 5, 2012 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.
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