BLA MK2 Black, Red and White

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DCrippa
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Post by DCrippa » Mon Apr 18, 2011 7:00 am

Nice! Please do post up your impression. I'd buy one if I had the loot... I've heard nothing but good things from reviews. I will go the poor mans DIY route since I can't quite spring for one yet and I enjoy the personal satisfaction that comes from projects like these in general.

I just wish there was more concise information on the build and recommended components... I'm not sure if the power supply posted above is the best suited for this build.
Just because you can doesn't mean you should.

Jim Williams
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Post by Jim Williams » Mon Apr 18, 2011 10:26 am

The EVM module is self contained. It has everything onboard. There are XLR inputs, XLR/RCA digital outputs, all the sample rates can be switched onboard via dip switches. You will need the documents for it as all the choices are spelled out there. I run mine on the table, no case, don't need one. If you can solder 4 wires and twist them on to binding posts, you can put this together.

This is the top-o-line ADC converter chip set on the market today. You will be hard pressed to find any of the pro converter makers using it, they mostly use lower cost AKM stuff. Therefore, it is better than most all of the commercial designs. The fact that you can get in for under a 150 bucks says it all, this IS a tape op project if there ever was one.
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DCrippa
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Post by DCrippa » Mon Apr 18, 2011 10:44 am

Nice! - no case that's bad ass - better not spill the coffee.
Thanks for clarifying the fact that it's pre built - I am definitely am going to do this - for $150 + and additional $50 -$60 for a power supply it's worth a try.
What power supply did you end up using for your build / would you recommend?
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BenjaminWells
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EVM

Post by BenjaminWells » Mon Apr 18, 2011 10:46 am

Please post a "how to" for ultra stupid dummies when you are done! Jim, please post a picture of yours!

DCrippa
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Post by DCrippa » Mon Apr 18, 2011 11:03 am

Will do - may be a while - gotta finish a few projects I'm still working on...

Jim - I read your post on the "other site" :

"It's possible the front end differential opamp stage got damaged. It could be a result of excess DC as there are no coupling caps to block it. There are pads on the eval pcb to install them. It's also possible the opamp was damaged by what is known as transformer flyback, a pulse from an audio transformer stage preceeding it. I would feed the input with a variable 1 k tone and examine the signal at the 3 test point pins ajacent to the opamp stages for levels with a scope. If you find 13 volts DC, it's fried. If it puts out a limited signal compared to the signal you fed it, it's fried.
Replacing it is difficult as it's very small surface mount part. On mine, I bypassed it and installed a breadboard to fit a dual opamp in a standard dip package.
TI seems to be backordered on these, to many slutz, not enough eval boards..."

That it is possible to blow up the op-amp stage - how to prevent transformer flyback - could you explain that a bit further? As you say, there are pads on the pcb - what "coupling caps" would I need to get to install them?

Thinking of getting this powersupply - seems others have used it: http://html.alldatasheet.com/html-pdf/3 ... -3003.html

or this one:

http://search.digikey.com/scripts/DkSea ... 71-2289-ND

thoughts?
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Post by Jim Williams » Mon Apr 18, 2011 11:16 am

The EVM has pads provided to fit a pair of surface mount el caps to block input DC. They come unmounted. The data sheets explain they should not be needed if the dc is controlled, it sounds best without any caps. Then again, that 2.5 volt bias may affect a transformer secondary feeding it, but since it's common mode, it should not be a problem.

The safe way to avoid output transformer flyback is to be sure that gear is never turned on or off when connected to the EVM, that's pretty simple and logical for anything.

My console did output a couple hundred milliamps of DC offsets with the current feedback opamps I use in the balanced output stage. I found that excessive and re-mounted caps back in the console, real good ones, like silver foil and other exotics.

I leave my EVM direct coupled at all times. There is 2.5 volts of DC bias present at those pins too, it should not effect the source gear feeding it. That is the DC bias of the modulator, it's set to 1/2 the 5 volt digital power rails. All other ADC's with that design have input blocking caps used, this is the first one without them. It sounds real sweet without any caps as most gear does too.

The Power One 3 output jobby should work fine as a power supply. I built my own using 2 LT1085 regulators and a LT337 reg for the negative audio rail. I used premium caps and very large ones, fast recovery rectifiers and a 24 volt 3 amp power transformer. I have a thing for removing ripple. I like my power supplies to measure -125 dbu noise. That way they don't mess up the sonics.
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DCrippa
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Post by DCrippa » Mon Apr 18, 2011 11:22 am

Got it. Basically don't be an idiot with it during operation and use common sense connecting and powering down it should be no problem.

Sweet! Thanks a ton for the info - for real.
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Post by calaverasgrandes » Mon Apr 18, 2011 4:04 pm

I keep meaning to jump on that and always forget to visit "my TI" account when I have the cash in hand. Sure $150 isnt much. Tell that to my mechanic.
??????? wrote: "everything sounds best right before it blows up."

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BenjaminWells
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BLA Sparrow MK2 Red

Post by BenjaminWells » Wed May 25, 2011 7:45 am

I ended up with the Red Sparrow MK2. Simply put, it sounds amazing. The converter I was using before was the Motu Ultralight. Now, for tracking, I'm taking signal directly from the mic preamp, to the red sparrow and into the computer via S/PDIF to optical in. This method removes software from the signal chain and reduces the gain stages by one. It also ensures that the last piece of equipment to touch the signal is my highest quality piece.

I would characterize the sound as very smooth... like velvet. Not colored, mind you. Just complete. It's a revelation to me actually. I could not be more stoked.

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Post by KennyLusk » Thu May 26, 2011 12:46 pm

Bro Shark wrote:
BTW, they have a D/A coming out next, and then an full-fledged interface in a year or two. Which might be interesting.
Waiting for that day myself and saving pennies.

I'm pretty solidly hooked on BLA ADAC.
"The mushroom states its own position very clearly. It says, "I require the nervous system of a mammal. Do you have one handy?" Terrence McKenna

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