New B1 = better than ever

[Nik Keefe]

Hello chaps,

Just a few lines about the new B1 that's out and about now ..... bought a pair for a project studio I'm setting up in a local youth centre. Now admittedly I only had a B3 before, never the actual B1, but I do love it very dearly.

But these new B1s sound absolutely superb - in an untreated room and through no better than average preamps we are getting the most wonderful vocal sounds, particularly a female singer who I am now trying to find musicians for because she NEEDS to get an album together! They are low noise and have the high-end just right to cover most bases - sweet and clear without harsh transients or annoying hyping. Love it!

Yet to really explore them with acoustic guitars, but have got surprisingly good results on flute and on drum OH duties too so far.

Unfortunately I'm not in a position to upload any clips as all of these kids are under-16 and to get parental consent would be tricky and possibly inappropriate. But I'm really happy and wondering about adding a couple of these to my home collection.

Another hit!

Nik

[Alan Hyatt]

Thanks Nick...New C4's are also amazing...152dB SPL and very smooth

A good deal of changes are happening in the entire line, and some of the most radical changes are coming in 2008....Very Good Things!

Glad you like the new B1's...wait until you hear the next series....

[Nik Keefe]

Thanks Nick...New C4's are also amazing...152dB SPL and very smooth

A good deal of changes are happening in the entire line, and some of the most radical changes are coming in 2008....Very Good Things!

Glad you like the new B1's...wait until you hear the next series....

Are they out now? I got burgled over the summer and my C4s got thrown down the stairs ... oddly enough they don't sound the same now so insurance are eventually going to pay out for a new set.

[Alan Hyatt]

Are they out now? I got burgled over the summer and my C4s got thrown down the stairs ... oddly enough they don't sound the same now so insurance are eventually going to pay out for a new set.

Yes, new C4's have the new red SP metal tag at the base...that is how you know the new mics. No more of all the engraved lettering on the face of the mic that acted as an SP billboard!!!!

New SP C4's are killer Nick. Not bragging here, Brent did a great job with them.

[Nik Keefe]

I'll be sure to get a set of the new ones when I finally get paid out on my insurance and look forward to trying them out!

Used the B1s again last night on a couple of different vocalists. They really are very reliable - when you have inexperienced users (or just don't have time to go through mics trying to get the best sound), these two seems to be 'near enough' every time.

[mhelin]

So what's so different with the new C4's ? Are they more transparent than the old ones? How do you compare them to Rode NT5's with almost equal specs?

Also they are said to be "FET driven", does it mean the output (driver) stage too is a FET-pair, not bipolar like earlier one (that would explain the higher output impedance, right?)?

[Brent Casey]

So what's so different with the new C4's ? Are they more transparent than the old ones? How do you compare them to Rode NT5's with almost equal specs?

Also they are said to be "FET driven", does it mean the output (driver) stage too is a FET-pair, not bipolar like earlier one (that would explain the higher output impedance, right?)?


First off, a quick correction - the new C4 mics are capable of handling SPL levels up to 159dB without any significant distortion. This is quoted earlier in the thread as 152 dB spl.
As for the term "FET driven discrete balanced output" on the new website - that also needs correcting: The impedance conversion is handled, naturally, by a JFET in the high-z section of the C4. The active devices in the output are bipolar transistors. Furthermore, the output is not balanced.

I looked at the specs for the NT5 and found them to be more or less the same as the C4's, other than our distortion measurements into 1k are specified at 0.5% THD, rather than 1%. That said, the C4 will start showing around 1% THD in the ~143 dB spl neighborhood, so I'd say that the two mics are pretty closely matched up in specifications. I would however, be interested to conduct a subjective self noise comparison between the two mics as the C4 is wicked quiet for a small condenser mic. I suspect that the noise spectra of the C4's is in a "less offensive" area, given that one can barely tell when they are up until someone bangs on the piano, effectively projecting your monitor speaker cones two inches out of their enclosures.

That the C4, the NT5 and also the Neumann KM130 series all have similar specifications, suggests to me that the three mics are probably up against the limits of design for a p48 transistor circuit buffering a ~20mm electrostatic transducer with a metal evaporated plastic diaphragm. There may be means by which we can incrementally improve a given area in the specification set - indeed we have our ways, but it would inevitably involve a substantial cost increase for higher tolerance components, etc and therefore may not be a sensible design decision.
I think that a hallmark of good design is proper component selection that does not rely on highly specialized parts in order to achieve a specific design goal. In other words, if you can't make it work by good design and layout alone, then you're doing it wrong. That said, I spend A Lot of time specifying components in order to ensure that the signal integrity is held to the highest standard possible. Basically, to eliminate any Achilles heels in the circuit. However, I don't specify seven to ten dollar resistors that have their own serial numbers and are rarely seen outside of the field of missile guidance. This would be silly, although I would enjoy test firing a C4 at some point to see if I could take out an inbound Russian mic.
As for the sound of the C4's, there may be some sonic differences, but I would suspect that these are most notable at higher SPL's.
The new C4 circuit is basically superior in every way to the old C4 circuit, so I would think that it is possible for the new mics to sound better than the old ones. They certainly sound better to me.

Hopefully, this helps with your inquiry. Please let me know if I can answer any further questions.

Sincerely,

Brent Casey
Design, Engineering

[mhelin]

Brent, thanks for your reply, it was good (really, sounds lame).

First off, a quick correction - the new C4 mics are capable of handling SPL levels up to 159dB without any significant distortion.


So that's 139 dB without the pad. Now this what I'd like to ask: I've seen many mic schematics, and on many mics the pad is implemented using a small cap to do something, I guess lower the impedance or roll off highs or both (I know some electronics but aren't pro in that area), it's usually connected before the JFET across the large resistor on it's gate (or by using negative feedback, a cap connected from the drain to gate). However, mics like AKG C451 use pad resistors between the JFET and the bipolar transistors (quite a strange way which looks like it bypasses partly the transistor driving the transformer). So is this in principle the way new C4 pad is implemented? I mean I feel it might be a better way than driving a high impedance source to low impedance circuit which must affect to sound like when you try record electric guitar directly to the line input of computer sound card or something.

The impedance conversion is handled, naturally, by a JFET in the high-z section of the C4. The active devices in the output are bipolar transistors. Furthermore, the output is not balanced.

Interesting, the last sentence (not balanced). If it's not balanced then the other bipolar is used as a current source unless they make a darlington pair which would also make sense - feel free to expose your secrets :)

That the C4, the NT5 and also the Neumann KM130 series all have similar specifications, suggests to me that the three mics are probably up against the limits of design for a p48 transistor circuit buffering a ~20mm electrostatic transducer with a metal evaporated plastic diaphragm.


Yes, I think you mentioned on GSltz forum (I don't visit that site often) you would have needed to use some full metal diaphragm for even better SPL handling.

Anyway, thanks, I'm now fully confident that C4's are well worth of every penny they cost. Suddenly I believe in Santa Claus (or Joulupukki as we call him in Finnish)..

[Brent Casey]

Brent, thanks for your reply, it was good (really, sounds lame).



So that's 139 dB without the pad. Now this what I'd like to ask: I've seen many mic schematics, and on many mics the pad is implemented using a small cap to do something, I guess lower the impedance or roll off highs or both (I know some electronics but aren't pro in that area), it's usually connected before the JFET across the large resistor on it's gate (or by using negative feedback, a cap connected from the drain to gate). However, mics like AKG C451 use pad resistors between the JFET and the bipolar transistors (quite a strange way which looks like it bypasses partly the transistor driving the transformer). So is this in principle the way new C4 pad is implemented? I mean I feel it might be a better way than driving a high impedance source to low impedance circuit which must affect to sound like when you try record electric guitar directly to the line input of computer sound card or something.



Interesting, the last sentence (not balanced). If it's not balanced then the other bipolar is used as a current source unless they make a darlington pair which would also make sense - feel free to expose your secrets :)



Yes, I think you mentioned on GSltz forum (I don't visit that site often) you would have needed to use some full metal diaphragm for even better SPL handling.

Anyway, thanks, I'm now fully confident that C4's are well worth of every penny they cost. Suddenly I believe in Santa Claus (or Joulupukki as we call him in Finnish)..



mhelin,

The purpose of a pad in a mic such as this, is to reduce the capsule voltage in order to prevent the microphone circuitry from overloading. To achieve this task, the pad circuitry is generally located between the capsule and the impedance conversion device. Therefore, I would think that the circuitry that you are referencing in the AKG mic is used instead for setting the operating points of the active devices. Which 451 model are you looking at? As for the pad circuitry in the C4, it is not capacitive.
Regarding the output section of the C4, the simple answer is, "no". The circuit itself is capable of drawing current in both directions.
In the United States, except for parts of Minnesota, Joulupukki has most likely been condensed to "Jolly" due to pronunciation concerns. In the lower states, people have a much easier time with "Santa". There are many Santas already in Southern California. So many in fact, that when I moved here, I was under the impression that it must be easy to become a saint. I have not found this to be the case, however.

-Brent Casey

[mhelin]

Brent,
I was looking 451EB schemactics (http://www.gyraf.dk/schematics/AKG_C451EB.GIF) but when I look it more closely it seems to have only the HP circuit, or it acts for both purposes. Anyway, 451B circuit (at www.akg.com) seems to have a 10k resistor there just for that purpose (two switches). "Not capacitive pad" sounds fine for me. Rearding Jolly he will unfortunately not be visiting us this Christmas because our 8 years old daughter no more believes in Jolly but she still want's presents (Nintendo DS lite with Sims game is #1). -Mikko

[Johnherpes]

sorry dude, but that was wat the admin suggested to me... i can also get a PuzzleProz DIY, it does not matter to me cause this will be my first DIY i would be getting... from wat i get, i might even buy both... from there i can then judge on which is better... and about cubesmith, are the stickers good? better than PuzzleProz stickers?