Secret project (Svart AD/DA converters)

Did some listening tests over the weekend while I worked on the studio's wiring. I don't hear much difference between the AC coupled and DC coupled versions of the ADC.

I think I'll bring both up to Nashvegas next week and see what others think before choosing which version to ship.

There will be 2VDC coming out of the input connectors unless the capacitors are populated.  Most signal sources have some kind of AC coupling on their outputs, but not all do.  Because of this, it would be safer for me to populate the capacitors.  They would be the only ones in series with the audio on the ADC board, so there wouldn't be much of a performance hit at all.

On the other hand, I can't expect everyone to know or understand the whole AC/DC coupling aspect of something like this.  Someone might read the documentation (IF they read it at all) and simply disregard it and end up damaging their system or the ADC board.  Then what happens?

However, I'm still finding it hard to decide to include them simply because so many people have been convinced that all caps are bad caps and I don't want to alienate customers.  That's simply not true in most situations (and for good quality caps) including electrolytic caps, but I can't spare the time or energy to debate with those who would fight to protect their capacitor beliefs.

I also don't want folks messing around too much with the internals, especially with soldering..  Solder slag tends to fall off irons and stick between IC pins, traces get pulled up, etc.

Installing a DAC board is about the most I want someone to do, and even then it's not totally trivial.

The board is already done, no plans on doing a 2nd rev to add jumpers.

Also, how do you reconcile the opinions of other top designers that have effectively proven that adding film bypassing does not affect electrolytic frequency response, nor does it change series impedance at audio frequencies?

how many caps would you need to use? I'd just put elna silmic ll's in there, they sound as good as any electro out there, have super low esr and DA, put the film cap across the top of the leads just under the cap, and leave a little bit of lead exposed so an end user can cut them out if they choose? I know i'm FOS 8) but I can indeed hear diffs in caps also, i've proven this in blinds set up by buds, on many occasions.


I think jim uses his ears to make judgements beyond what his Precision rig tells him with his eyes. I've learned Jim has tremendous ears, much better than mine, maybe it's because he before/after listens for a living and has learned through experience how to focus in on certain things? i don't know, but it's DEFINITELY there.

I also agree that adding bypass caps does not show measurable differences on my AP test gear. That test gear is very good but it's used to find errors and performance limitations. It won't tell you when something sounds good. The bypass caps do make a sonic difference that the best test gear cannot detect but the better ears do. Thousands of customers agree as do many audio manufacturers like Levenson and Mytek. Most higher end speakers use them as well, JBL has for decades. I doubt they would waste the money on them if they didn't make an improvement.

On the Soundcraft Delta current feedback suming amp re-design, I use 3 sections of caps to assure all the details are heard. There is a 1000uf Panasonic FR electrolytic, a .1uf MIT MultiCap and a 1000pf/1k volt WIMA FKP-3 polyprop film and foil. With .7 nv/hz/sq Renesas discretes and the 1900v/us slew rate, 130 mhz bandwidth LME49713 CFA, any caps removed are heard. Smoothing out the sonics using el caps alone is perhaps helpful with edgy, digital DAW productions, but a purest analog or high end digital acoustic performance will benefit from using the best caps where needed and no caps where not.

I make these suggestions not because I want to be a svart-@ss, but only because I want to see success on every level. I don't have a dog in this fight other than to want to see the best sounding stuff made by everyone. Pointing out pitfalls I've crossed before doing DAC designs is about all I can do, I hope it's taken without any offense.

Thanks, I appreciate you sharing your opinions and having a willingness to discuss these topics.  Don't worry, you weren't being offensive.  

(momentary OT) I think it's very cool for Jim to lend his expertise, this is way over my head of course, but i have to say since i own one of these, it does indeed sound ridiculously great, big buttery beautiful, but in a very transparent and realistic, conversational sort of way. I'm hyper sensitive to S's, this board is the closest thing i've ever heard to real life sound of language, especially in the sibilance ranges. Just what i hear, YMMV. I wonder how wiz feels at this point.

funny you should mention that, one of the reasons i'm lagging bringing my delta 8 master to JW for mods is because i want to Post a comparison thread. I will run some audio through a pair of stock delta strips into the stock delta 8 master section and recapture. Then i'm going to run the same exact audio with identical settings through 2 JW modded channel strips into a JW modded master section(I already own this, done as JW mentioned above). Then i will repeat the process of running both modded and unmodded ch strips into the modded master to see just how much the channel strips improve things on their own? I've already done the latter, and it's significant to my ears, curious to how others will hear it? i believe wiz has done this as well, maybe he'll chime in with his thoughts eventually?

sorry, back to the not so secret secret project AKA "Svarticus RGO Limited edition™"

false economies of scale, its all in one box so the cost of shipping the DA afterwards ; doesn't make sense!

where is here ?


those in the US , have no exchange rate concerns, but I guess wiz , you and I are all prepared to pay for conversion for , ah,  better conversion; right, wiz, that's way we do it ?  ?

Interesting project! Definitely interested. I use a RMA Superbeast with the ADA's so expect this will perform just as well.

Speaking of which, I may or may not have the settings working in the software now. More testing is needed. I might have it fully working by sunday, but that might be a longshot.