We've Got A New "King Of The Low End" LDC...

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Marik said:
I am actually, not the only one who is "current hungry" :D. I remember reading Josephson proposing a new standard for phantom power of total 43ma available, with 2.2K resistors, each (of course, in this case all the Schoeps circuits will need to be re-worked).

Gus also posted about external PSU. While (I think) his ideas are somewhat different from mine, the bottom line, the external PSU would give quite a bit more flexibility in the design and open room for new topologies and design solutions, impossible for the current P48 standard.
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Well it's an idea, it just seems like it would make a bit of a mess to me. Already we have scores of noncompliant P48 gear on the market. I'd like to see AES develop an enforcement mechanism, say a voluntary testing procedure and an official logo or something. Not just P48, but why not VU=dBFS standard, among others?

I confess I don't get the need for extra power; isn't the noise limitation ultimately the FET? If you parallel a bunch of FETs to improve noise performance, don't you also increase input capacitance? This confuses me :confused:

Ah, I'm a small-capsule guy, any run-of-the-mill 3nV FET will do . . . :o




Well, at least they saved about $0.40 for an additional pair of BJTs, pair condensers, and couple resistors, which would take care of all the drawbacks of such topology. What a marvel of engineering approach :rolleyes: !!!

Which FETs do they use?
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I don't know, never seen one, I actually just gleaned that from their manual. They have a graph of gain according to load impedance, and doing the math it works out to 6k8 "source" impedance. What else could it be? Even if it's something different, the effect is apparently the same.

I will give away my latest find to DIY types: if you want to do an inline amp, use ADA4841-2. That thing is sexy, and it's going in my latest design. 1.1mA per channel, 2.1nV/rtHz, 12V/usec. Supply is limited to 12V, but do as I'm doing and use it as the front end to an instrumentation amp topology. That yields headroom of +16dBV, should be plenty for a mere 20dB of gain. Heck, make it 30dB. You're using this thing with a ribbon, right?

Guys, would it be reasonable to deduce that a "slower" response microphone tranducer,
ala a dynamic (or ribbon/subset), would help to mitigate this distortion vs. a condenser?
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Aliasing distortion? Well you have to understand that no modern converter should have that problem, they all have adequate anti-aliasing filters. So it shouldn't matter what your analog signal source looks like.

The problem arises with subpar digital processing where designers have not considered that their plug generates ultrasonic content that needs filtration (which has to be done with upsampling, filtration, and then downsampling).

The quick fix for a plug you love but it aliases is to run at 96kHz and use a good SRC back to 44.1kHz . . . according to the SRC's filter quality, the aliasing distortion should be driven down -100dB below signal.
 
chessparov said:
So...

a "slower" response microphone tranducer,
ala a dynamic (or ribbon/subset)...
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EXCUSE ME!!! :eek: :spank:

:D:D:D

mshilarious said:
I confess I don't get the need for extra power; isn't the noise limitation ultimately the FET? If you parallel a bunch of FETs to improve noise performance, don't you also increase input capacitance? This confuses me :confused:
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There is nothing wrong with the input capacitance if to know what to do with it :cool:, but there are also quite a few cool ways of minimizing that capacitance.

mshilarious said:
I will give away my latest find to DIY types: if you want to do an inline amp, use ADA4841-2. That thing is sexy, and it's going in my latest design. 1.1mA per channel, 2.1nV/rtHz, 12V/usec. Supply is limited to 12V, but do as I'm doing and use it as the front end to an instrumentation amp topology. That yields headroom of +16dBV, should be plenty for a mere 20dB of gain. Heck, make it 30dB. You're using this thing with a ribbon, right?
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I am kinda a discrete components guy. I don't see a good reason of using a couple hundred active devices in a chip for the work which can be done with two jFETs two BJTs and a few resistors (or even better, FETs and transformer)

Best, M
 
Marik said:
I am kinda a discrete components guy. I don't see a good reason of using a couple hundred active devices in a chip for the work which can be done with two jFETs two BJTs and a few resistors (or even better, FETs and transformer)
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Size, mostly. Eight pins for two channels (or five pins for one) vs. probably three times that for discrete. I don't think I could match distortion performance with four transistors, especially at high level or high gain. I think at least ten would be more realistic. But if you stipulate a ribbon mic input and 20dB gain, I could do four . . . certainly a LOT better than two!

One advantage of discrete in this context is you don't have to regulate the power supply, just get parts that can take the voltage . . . can't do that with ICs. That saves a few parts.
 
How did a discussion about the MXL2003A become a discussion about blah blah blah blah blah blah blah.....???:D:laughings::laughings::laughings:
 
mshilarious said:
Size, mostly. Eight pins for two channels (or five pins for one) vs. probably three times that for discrete. I don't think I could match distortion performance with four transistors, especially at high level or high gain. I think at least ten would be more realistic. But if you stipulate a ribbon mic input and 20dB gain, I could do four . . . certainly a LOT better than two!

One advantage of discrete in this context is you don't have to regulate the power supply, just get parts that can take the voltage . . . can't do that with ICs. That saves a few parts.
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Size and/or saving a few parts???? Not something I want designers of my mics concerned with.

But hey, that's just MY perspective. I'm sure there are people out there that actually care greatly about that.

So, I'm with philgood. Let's get back to the 2003a. Anyone had the opportunity to try one yet. I hear they've got the old skool heavy brass bodies. True?
 
drBill said:
Size and/or saving a few parts???? Not something I want designers of my mics concerned with.

But hey, that's just MY perspective. I'm sure there are people out there that actually care greatly about that.

So, I'm with philgood. Let's get back to the 2003a. Anyone had the opportunity to try one yet. I hear they've got the old skool heavy brass bodies. True?
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Yup BIG and heavy brass! Should pull any microphone stand right over. :eek::eek:
 
That's why I really like Michael Jolys "Ratrod" look and stripping the finish off to reveal the brass then it starts to age .....mmmmmmmmmm;)






:cool:
 
moresound said:
Yup BIG and heavy brass! Should pull any microphone stand right over. :eek::eek:
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I don't understand where the idea that heft has anything to do with whether a mic's build is good? U47's are pretty light weight because of the aluminum bodies. There really nothing in them to make them heavy.
 
drBill said:
Size and/or saving a few parts???? Not something I want designers of my mics concerned with.

But hey, that's just MY perspective. I'm sure there are people out there that actually care greatly about that.
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Oh please. We are talking king of the low-end LDCs. You think the 2003A circuit is optimized, and is compromise-free?

Anyway, there is more than one way of looking at the IC vs. discrete battle. Clearly there is a problem with too few parts. We've seen that already in this thread. Too many parts is a waste of money and perhaps could compromise sound. But there isn't a defined number of parts that are correct. If there was, this game would be quite simple.

John Roberts has frequently stated that he feels modern ICs are so good that he doesn't do much with discrete anymore. On the other hand, there are the guys designing the discrete opamps--but the only spec where they consistently beat the top ICs is on power supply; many can tolerate 48V. And a lot of people dig that.

Now, in a mic circuit we might ask do we really need an opamp? No, not really; we don't even need a differential amp, so long as we are careful to match gain through the circuit where it is double-ended (it's easiest to avoid that), and match impedance on the output.

I used to do all-discrete circuits, now I use ICs in mics. It was a simple matter of wanting to add components to enhance performance but not having enough space to go discrete. That actually cost me money in the design, because I traded 6 $0.10 transistors for a $2 opamp. It did save assembly time, as that's 8 pins vs. 18 and one component to place vs. six. But the bottom line was it made a better product. Design a mic circuit in 0.5 square inches and you'll see what I mean.

In an LDC, the circuit designer has all the room they want because we are conditioned that an LDC body should be large enough to hold a tube and transformer, even if there are none there. So if I were designing an LDC circuit, I might have stuck with discrete.

Preamps I do a blend of both. I use discrete where I can't get an IC that does what I want, but that has a cost in assembly time and more importantly board space. I'm not going to do a discrete design for pride if it doesn't sound any better and if that means a larger, more expensive product. My customers want small.

Yes, there are many people that care about small. Broadcast engineers don't want mics visible on camera, so they lean towards DPA and Schoeps. Guys doing location recording on battery power care very much about size and power consumption. Some drummers want small mics on their rack toms so they don't whack them. Other drummers don't mind a CAD M179 sticking up there--which uses an IC, by the way . . . as do a couple of classic European mics, for that matter . . .
 
PhilGood said:
I don't understand where the idea that heft has anything to do with whether a mic's build is good? U47's are pretty light weight because of the aluminum bodies. There really nothing in them to make them heavy.
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Yeah I know PhilGood. You would think there should be a move towards plastics just like everything else in the world is made of.






:cool:
 
moresound said:
Yeah I know PhilGood. You would think there should be a move towards plastics just like everything else in the world is made of.






:cool:
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Carbon fiber!:D:cool:


...and Titanium!!


I might not record as well, but my drives would be 300+ yards!
 
moresound said:
Yeah I know PhilGood. You would think there should be a move towards plastics just like everything else in the world is made of.
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It would have to be conductive plastic, you don't want a massively high impedance circuit unshielded . . .
 
mshilarious said:
You think the 2003A circuit is optimized, and is compromise-free?
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How should I know. I've never heard one. I'm on this thread (originally at least) to see what people's thoughts were. I'm afraid most of the actual users have probably fled for thier lives by now......:laughings:

So you'll have to tell me if it's optomized and compromise free. You seem to be the expert. I just USE the damn things.

Or we can talk about distorted anti-aliasing sound libraries. :laughings::drunk::laughings:
 
Well Marik, my last post WAS only intended to be funny, sometimes that's even managed intentionally. This thread was rapidly becoming mandatory reading for wannabe MENSA aspirants. :) (FWIW highly respect the skillset of those like yourself posting here)

Chris
 
drBill said:
Or we can talk about distorted anti-aliasing sound libraries. :laughings::drunk::laughings:
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No, if they have anti-aliasing, then they don't distort. Well, they shouldn't, that is.

As for the 2003A, well we need somebody to trace the circuit and post it. There really isn't any such thing as a perfectly optimized circuit, and every circuit is a compromise anyway. But it would give us something to scratch our heads over . . .
 
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