B2 mic mod thoughts?

Discussion in 'DIY Pro Audio Forum' started by fum, Feb 2, 2004.

  1. fum

    fum Guest

    hey there,

    I've started a couple mic mod projects, the Royer 2001 mod, and I'm looking at a Behringer b2 with that strange look on my face like its up on the chopping block.

    All right, well it's further than that, the things in pieces, as I wanted to get a peek at it before I came up with something to try.

    Once opened, I find that the capsule has three wires coming off it. Most mic schematics I've seen are in the 2 or 4 wire category.

    Any suggestions as to microphones that might have a similar capsule type that I could look at for ideas?

    I've got one three way switch and one two way switch on the front to play with.

    Something tube might be nice, but I'm open to ideas. =)

    Regards

    ju
  2. gus

    gus Guest

    B2 transformer or B2 pro? The B2 pro I have has a kk87 type capsule.
  3. ssltech

    ssltech Guest

    The B2 may have a different capsule to the B2Pro... the B2 is , the B2Pro is cardioid/Omni/fig-8. If the B2Pro has both outside terminals at or close to ground potential then it might need a split center terminal (to get the different backplate potential for the Figure-8 pattern) and thus a fourth wire leading from it.

    Keith
  4. gus

    gus Guest

    Look at A c12 schematic or a newer U87 schematic etc. for a 3 wire hookup, most capsules now that are multipattern are 3 wire.

    Often the front is at ground the center is were the signal is sensed and the back is were the voltage is changed. If both are at the same it is a omni pattern, if the back is disconnected or at the same voltage as the center it is a cardiod, if the voltage is invertered it is a fig 8. Var patterns are from a pot wiper that can divide the voltage to the back from + to - capsule supply.
  5. zebra50

    zebra50 Guest

    ....Gyraf's G7 works like this - just three connections with a common backplate. The operation is explained very well on that site.
  6. Flatpicker

    Flatpicker Guest

    Anyone know what kind of capsule is in this thing? Shanghai or 797. If 797, wouldn't it be the same as a SP C3 or T3, assuming it's 6-micron? If it's 3-micron, it's probable like the SP B3.
  7. fum

    fum Guest

    This is the straight B-2, no transformer. It don't say anything pro anywhere, not on the mic, not on the box, etc. =)

    The G7 looks like it could be a good candidate, may need to do the layout myself, for space considerations ( I'll print out the pcb, and see if I can stuff it in the mic =) )

    The b-2 has installed switches already, which could be used for the pattern select.

    So it looks like what your saying is that the capsule could be treated similarly to say the capsule in the U87, just that in the schematics for the U87, the two wires which act as ground plane are only one from the capsule?

    Thanks for the pointers =)

    ju <-- new to this microphone stuff
  8. gus

    gus Guest

    The newer U87 schematic with the DC to DC converter.

    I bought a B2 pro to check it out. The microphone is not bad stock.

    It looks like beringer took some of SP ideas the use of wima caps and other good parts and what looks like a 797 6 micon capsule, little or nothing to upgrade in parts. It is a good sounding SS microphone stock IMO.

    I don't think it it going to sound better with a different SS circuit. Maybe a tube circuit I would try something like 1/2 of a stereo C24 schematic or the G7 schematic.

    I am still working on my c800G type circuit body I might use the capsule from the B2 or my MXL2003.
  9. ssltech

    ssltech Guest

    Gus and Zebra,

    Yeah I understood that for a 3-wire, but I think some manufacturers have used 4-wires before now, so that they can keep bith outsides at zero volts, -right? (Although I do understand that the vast majority use a 3-wire setup!)

    Keith
  10. fum

    fum Guest

    I am looking at a tube circuit, for certain. I've got two of these mics, so will keep one stock, and use the other as an experimentor.

    G7 or thereabouts is probably where I'm headed. =)

    Regards

    ju
  11. gus

    gus Guest

    If you build a tube circuit I think it is a good idea to have a pattern switch or pot that why I posted about the c24 maybe a G7 with a pattern with more than 3 patterns.

    Say you want a little more prox one or two clicks from cardiod to fig 8 can make it sound like a different microphone. FWIW my modded, not much left stock, tcm1050s sound a little "thin" at cardiod one click more to Fig 8 so much better.

    The in between 3 standard patterns settings are very usefull.
  12. zebra50

    zebra50 Guest

    Absolutely! With the AKG CK12 capsules I got for my G7s, the backplates are separate and I had to wire them together. So I guess separate isolated backplates give you more options for how you implement the different patterns.

    It should be fairly straight forward to add extra patterns to the G7 supply - just make a string of 4 resistors from (rather than just two) from 160V to 0V.
  13. ssltech

    ssltech Guest

    yeah... one wonderful thing about using a split backplane is the reduced electrostatic attraction... filth on the 'back' capsule could be an issue of you do a lot of figure-of-eight... but otherwise not really too much of a problem.

    Keith
  14. ljudfinnen

    ljudfinnen Guest

    Does anyone have any suggestions for a single diaphragm microphone. I have a capsule from a cheap china mic that I would like to make something of. Tubes wouldn't be wrong. Can the G7 schematics be converted in some way to suit a single diaphragm capsule?

    /Anders
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