BLA "sparrow" A/D Converter - anyone have/use one?

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Post by puffpastry » Mon Jul 07, 2008 10:19 am

OK 15 dB means the 003 has a minimum of 5.6 times higher rails than the 002. Unlikely, but possible I guess.
I'm not sure where you're getting 5.6 times. Decibels are logarithmic. You can't simply multiply by a given number to get the answer. Since you're such an expert, Ned, here's a test of your knowledge:
6 volts= ? dBV
12 volts = ? dBV

That means their claim is that their modded 003 has 27 dB more headroom than an unmodded 002. That means their analog section power supply is over 22 times higher voltage than that of an 002. That means that if the 002 is, say, running from +/- 12 volts (which I think is correct), then their supply is.....drum roll.....

+/- 250 volts!!!!!
Again, not sure where you're getting that number. The difference in dB can't be accounted for by simply multiplying the power supply by 250. It's the amount of difference between supply rails and the resulting output swing capability converted into a decibel figure based on a 1 volt reference.

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Post by nclayton » Mon Jul 07, 2008 10:58 am

puffpastry wrote: I'm not sure where you're getting 5.6 times. Decibels are logarithmic. You can't simply multiply by a given number to get the answer. Since you're such an expert, Ned, here's a test of your knowledge:
6 volts= ? dBV
12 volts = ? dBV

Hi. The number 5.6 comes BLA's 15dB claim and from the definition of a general scaleless decibel.

dB = 20 * log(ratio)

or

ratio = 10 ^ (dB / 20)

If dB is 15, that gives you a ratio of 5.6.

Since an opamp can usually put out a voltage pretty darn close to the voltage of the rails, the headroom of a stage like this is almost always totally determined by the voltage of the rails.

If you're talking about a voltage decibel then getting 15dB of extra headroom is predicated on getting about 15dB of extra power supply voltage. You can't get a higher voltage out than the supply rails. (unless you're using a step-up output transformer, which I don't think is part of the BLA mod)

So if the 002 has 12 volt rails and can put out a signal within about a volt or so of the rails, in order for an 003 to put out a 15 dB bigger signal (5.6 times bigger) the rails need to at least about 67 volts. Or else you have to use a step up output transformer. (By the way, that's plus and minus 67 volts, so really over 130 volts total, and that only includes the first 15dBs, not the second 12 delivered by the mod. It's that final 12 that puts the total voltage over 500).

It's pretty simple.

I assume everyone on earth knows that 6dB is a doubling of voltage, and so it should be easier to see that 12dB is a quadrupling of voltage.

Also I assume it's well known that 20dB is a decade, so 20dB means 10 times more voltage. Since the BLA modded 003 has a claimed 27 dB more headroom than the 002, than means (if you're talking about scaleless voltage dB's) that since 27 is more than 20 + 6 that it should be clear we're talking about more than a 20 times ratio. You can't get that much extra voltage output unless you have supply rails with that much voltage to begin with.

Of course this all changes if you're talking about power dB's like dBm's, but if you do that you really need to talk about the impedances involved, and BLA doesn't do that. Also, even then, I'm still skeptical that they could get the improvements they're talking about unless they're referencing to an unusually low impedance, or in other words, some dB scale they invented themselves.

I'm not going to do your quiz, but thanks for giving me the chance to improve my cred.



Ned

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Post by Dakota » Mon Jul 07, 2008 11:03 am

I would be interested to see a detailed review of the sparrow, particularly compared against a benchmark adc or something in that zone. Anyone have links?

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Post by puffpastry » Mon Jul 07, 2008 11:08 am

The 15dB increase in headroom comes from Digi's own documentation. Since the output swing capability of the stock 003 is 6 volts greater than the stock 002, the increase is 15dB. 6 volts dB with a 1v reference is roughly 15dB. I'm sure you can do the math.

If we increase output swing capability by 14 volts, the amount of difference goes up. 14 volts using a 1v reference is roughly 20dB (actually, it's almost 23dB).

We don't ADD it all together. It's the voltage swing difference (6 volts or 14 volts) converted to a dB figure using a 1 volt reference. I think you're starting from a different premise than we are.

Let me clarify:
Assume that a stock 002 can swing within a volt of each rail. That gives us about 21-22 volts of output swing capability. If we increase that swing capability to 28 volts, that's a 6 volt difference in capability. 6 volts using a 1 volt reference is 15 dB. Even Digidesign uses this figure when comparing headroom capability of the 003 vs the 002.

Now assume that we increase that swing by 13-14 volts. That difference in swing capability is what we're quoting. Use a 1 volt reference, and you get just over 20dB.

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Post by nclayton » Mon Jul 07, 2008 11:38 am

According to your logic, since the stock 003 added 15dB and the 003 mod only adds 12 dB, that means the modded 003 actually puts out 3dB LESS than the unmodded version!!! In case you don't see where my numbers come from, 12 is 3dB less than 15, and they're BOTH referenced to 1 volt, right? OF COURSE NOT. Obviously we're starting from different premises, but mine is correct. Of COURSE the dB's add. That's the whole point.

The claim is that the stock 002 can put out some number of dB's (unspeficied but unimportant), and the 003 can put out 15 more dB's than that (which is 5.6 times more no matter what the reference is) and then the claim is that the modded 003 can put out an additional 12 more than that. So whatever the stock 002 can put out (definitely more than 1v=0dBv) no matter how you look at it, no matter what the 002 could put out, they are claiming their modded 003 can put out 27dB MORE. The reference point is totally irrelevant, but I think it's actually about 18 dBv for what it's worth (the level the 002 outputs clip at if I'm not mistaken).

That would mean (if we're talking about voltage dB's into an arbitrary load) that the BLA modded 003 can put out 45 dBv (27 + 18). That would convert to 177 volts rms regardless of the rails or any other details of the circuitry. Plug it into your web-based dB calculator. Do you think the BLS modded 003 can put out 177 volts rms? Do you think anyone would want it to?

Anyway, I'm sorry about the thread, and I THINK I'm done griping about this crap. Plus I'm embarassed to stick my head out on this, but false and/or retarded claims irritate me and should not stand.

Ned

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Post by nclayton » Mon Jul 07, 2008 11:58 am

puffpastry wrote:
Let me clarify:
Assume that a stock 002 can swing within a volt of each rail. That gives us about 21-22 volts of output swing capability. If we increase that swing capability to 28 volts, that's a 6 volt difference in capability. 6 volts using a 1 volt reference is 15 dB. Even Digidesign uses this figure when comparing headroom capability of the 003 vs the 002.

Now assume that we increase that swing by 13-14 volts. That difference in swing capability is what we're quoting. Use a 1 volt reference, and you get just over 20dB.
Who am I talking to here? Do you represent Black Lion? You keep saying We.

If one device can put out 17dBv and another can put out 20dBv, you can't say that's an improvement of 15dBv. That's an improvement of 3dBv.

If the numbers you gave me there are correct, then the 002 puts out 17dBv

The 003 puts out 20dBv (3dB more than 12, NOT 15dB more.).

The modded 003 puts out 22dBv.

That's a 2dB improvement over the unmodded version. That's totally respectable! But it's not 12dB. And it's definitely not 27dB over the 002.

I still think if they don't quite know how to add dB's, I'm probably not going to trust them to mod equipment.

Ned
Last edited by nclayton on Mon Jul 07, 2008 12:09 pm, edited 1 time in total.

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Post by jaguarsg » Mon Jul 07, 2008 12:07 pm

nclayton wrote:Who am I talking to here? Do you represent Black Lion? You keep saying We.
check the link in his signature.

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Post by puffpastry » Mon Jul 07, 2008 12:38 pm

According to your logic, since the stock 003 added 15dB and the 003 mod only adds 12 dB, that means the modded 003 actually puts out 3dB LESS than the unmodded version!!!
No. Once again, you're misunderstanding us. The Tweak 003 adds another 15dbV to the headroom of the existing stock 003 design (I see that the website says 12; that's a typo, our mistake. It should say 15dB). Again, that's dBV referenced to 1 volt based upon the differences in output swing potential. We're not scaling the dB upon the existing headroom, we're quoting the difference.

You are basing your reference on 5.6 times the existing headroom, whereas we are basing our reference on the difference between the two.
That would mean (if we're talking about voltage dB's into an arbitrary load) that the BLA modded 003 can put out 45 dBv (27 + 1Cool. That would convert to 177 volts rms regardless of the rails or any other details of the circuitry. Plug it into your web-based dB calculator. Do you think the BLS modded 003 can put out 177 volts rms? Do you think anyone would want it to?
Except we're claiming about 30dBV total when the modification is finished. That's about 34 volts of potential swing. But the difference in dB's we're quoting between stock and modified is the 6 volt difference in swing potential (15dB).
Anyway, I'm sorry about the thread, and I THINK I'm done griping about this crap. Plus I'm embarassed to stick my head out on this, but false and/or retarded claims irritate me and should not stand.
It's neither false or retarded. We're simply basing our numbers on something entirely different than what you're basing your numbers on, and although you may disagree with how we do it, there is certainly precedent in the pro audio community for doing it the way we're doing it.

I realize that there are LOTS of people in pro audio that completely hate us, and hate what we're doing. Believe me, I deal with comments like this every single week. We have people that are insistent that we are liars, hucksters, scientologists, and God knows what else. It gets exhausting defending what we're doing, and most of the time the argument goes nowhere.

I've been running this company for three years as a full time venture now. In that time, we've grown enormously--I've gone from working by myself in my apartment to having eight employees and a 4500 square foot facility, all with little to no promotional budget. Do you think we could have grown that much if we weren't at least doing something right? Give me some credit--I'm not Einstein, but I'm not an idiot either. I may have typo's on my site sometimes, and we may not be the slickest company in the world, but I do know at least a little about what I'm doing.


Sorry if I forgot to sign earlier.

Matt
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Post by trodden » Mon Jul 07, 2008 1:02 pm

nclayton wrote:
Anyway, I'm sorry about the thread, and I THINK I'm done griping about this crap. Plus I'm embarassed to stick my head out on this, but false and/or retarded claims irritate me and should not stand.

Ned
Wow Ned, you're a real joy to hang out with today... bad case of the Mondays?

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Post by Dakota » Mon Jul 07, 2008 1:55 pm

*ahem*

What I do know: Matt has been great to communicate with in regards to mods being done. I also know that my stock 002 originally sounded "about what you'd expect for mid-prosumer audio but no better", and after the tweak head it sounds like "whoa, an 002 sounding like actually usable pro audio??? WTF?"

Whatever the math is, the improvement is in no way subtle. Width and depth and clarity and transient snap and small details and general "musicality" are dramatically better. The prosumer digital "grey hash" in the mids and highs is gone.

I'd still like to hear people's word on the sparrow.

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Post by nclayton » Mon Jul 07, 2008 2:16 pm

puffpastry wrote:

No. Once again, you're misunderstanding us. The Tweak 003 adds another 15dbV to the headroom of the existing stock 003 design (I see that the website says 12; that's a typo, our mistake. It should say 15dB). Again, that's dBV referenced to 1 volt based upon the differences in output swing potential. We're not scaling the dB upon the existing headroom, we're quoting the difference.
Hi. I admit, at first I didn't understand what you were saying, but now I do see where you're getting your numbers from and how your method works....but it is wrong. You're taking how much scalar voltage you add, converting it directly to a dBv, and saying that's how much headroom you add in dB's. Unfortunately that just isn't right. I don't usually think of myself as a jerk, although I am a jerk sometimes, but honestly I just want EVERYONE to have the right info, and am more than willing to help. Right now your site is giving the wrong info! If you get it right, maybe the pro-audio people you referred to would take you more seriously. I'm glad to help! If you send me the actual voltage improvements your mods make (compared to original) I'll happily convert them to the correct dB improvements and you can make your site accurate. I won't even charge you! I JUST WANT RATIONALITY TO BE TAKEN SERIOUSLY SO EVERYONE CAN HAVE THE RIGHT INFO!

According to your method, if you had a really assy converter that could only put out, say .000001 volts, and you multiplied that by a MILLION times to make it put out 1.000001 volts, when you did the math you'd find you added ZERO DECIBELS since you only added 1 volt, and 1 volt referenced to 1 volt is 0dBv. Thank god you never did a mod like that -- what a waste of time! In fact, you could add 1 volt to any voltage you wanted and according to your method it would ALWAYS add exactly 0 decibels no matter how many times you did it. Or what if you accidentally did a mod that only added .5 volts to something? Calculate THAT in reference to 1 volt. That totally sucks because by adding .5 volts you accidentally DECREASED the headroom by 6dB! It doesn't make sense. The ONLY way to calculate increases in dB is the simplest possible way...you subtract one dB value from another. It's the ONLY way! It's why the db scale was invented in the first place!

If there's precedent for your method in the pro-audio world (which I've never seen that I can remember) it's only because someone else made the same mistake. I'm sorry to have been confrontational, but at this point, I just want you to see how it works so you can correct your info. Your method might not have been retarded....if I'd known you were on here I'm sure I'd have been a bit more restrained than to have said that kind of shit....but it is wrong. I'm sorry, but it's not my fault it's wrong.

Ned

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Post by jaguarsg » Mon Jul 07, 2008 2:33 pm

i'm no EE, not at all, but this thread reminds me of when two music theory guys get together and argue over a jazz chord.

they're both arguing from different perspectives but it's essentially the same chord.

is it just me?

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Post by jv » Mon Jul 07, 2008 2:41 pm

Ned is right (I am an EE). I've heard lots of good things about Black Lion, so I'm sure they're doing a lot of things right, but this way of of spec-ing is just plain wrong.

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Post by puffpastry » Mon Jul 07, 2008 2:41 pm

Hi. I admit, at first I didn't understand what you were saying, but now I do see where you're getting your numbers from and how your method works....but it is wrong.
Well, as I said before, we aren't the only pro audio company that uses this method, there are several others, and Digidesign is an excellent example. When they released the Mbox 2, they cited a 6dBV increase in headroom over the Mbox 1. Their basis for this? A 2 volt increase in output swing capability. The same goes for the 003--they cited a 15dB increase in headroom over the 002. The basis? A 6 volt increase in output swing capability.

You may disagree with the methodology we're using to calculate these figures, but we're certainly not alone and won't be changing it any time soon.

Matt
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Post by jv » Mon Jul 07, 2008 2:54 pm

puffpastry wrote:
Hi. I admit, at first I didn't understand what you were saying, but now I do see where you're getting your numbers from and how your method works....but it is wrong.
Well, as I said before, we aren't the only pro audio company that uses this method, there are several others, and Digidesign is an excellent example. When they released the Mbox 2, they cited a 6dBV increase in headroom over the Mbox 1. Their basis for this? A 2 volt increase in output swing capability. The same goes for the 003--they cited a 15dB increase in headroom over the 002. The basis? A 6 volt increase in output swing capability.
Well then, somebody should call out Digidesign, because that's just plain wrong. Probably somebody in marketing made that crap up.

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