Found a bunch of old rca microphones. What is uniaxial?

[i am monster face]

Hi everyone. I recently stumbled upon a bunch of old microphones at a garage sale and bought every last one for $15 (about 20 in all). I'm doing research on them to find out what exactly they are. They're all in decent shape and most work. Also in the box were some old Shures, Western Electrics, and Turners. Wile researching my first one, the RCA BK-5B I came upon a listing on a description describing the microphone as a Uniaxial. All the other mics had either dynamic, condenser, or ribbon. This one had Uniaxial. At first i thought it might have meant unidirectional, but that's listed in a seperate description. Help!

[swingdoc]

Holy carp!
you da man! jealous jealous jealous
BK5's are awesome.
What other RCA's were in your windfall?

Here's some technical stuff for ya:
http://www.coutant.org/bk5a.html

[thunderboy]

Uniaxial as opposed to Biaxial (Figure-8) I would assume...
Nice score!

jt

[chetatkinsdiet]

Wow...I'm sure you're overwhelmed trying to research all of that old junk. Why not send 4-5 my way...I'll be glad to help "research" them for you.
later,
m

what a find.....

[i am monster face]

the other mics I bought were as follows;
two shure unidyne (?)
EV 623
EV 664
Altec D81
2 Shure SM33
1 Shiel m102
2 Shure 737 A Crystal
Turner Crystal l40
rca BK5
THE FOLLOWING AREN'T WORKING
RCA MI-4036
RCA MI-6203B
I was walking to work at about 8:00 and this church was having their annual fund raiser thing. I walked through it, (picking as I usually do for odds and ends) and found a box full of mics. i immediately bought them and got home. it's gonna be a good night.
Ian

[Scodiddly]

You fucking lucky bastard. I hope you have a heart attack and die, and when your widow is selling off your junk I happen to walk by.

[i am monster face]

hmmm...

[rhythm ranch]

Congratulations! That's great, there's nothing better than a serious score. If the BK5 needs work, let me know and I'll hook you up with repair info.

Yay for you!
Mark

[musikman316]

I think we should all go to monsters and play! Good for you, hope you're happy with your new mics... I wish I had new mics... mmmm mics, I'm going to get the Visa out and buy a new mic! Yeah, I'll just car pool for a couple of weeks!

Later,
musik

[Professor]

Wow, that's a pretty harsh response to another man's good fortune there Scodiddly - you OK there?

Either way, that is a tremendous find - and certainly delightful to know that there is still inexpensive stuff available at rummage sales, even in the days of eBay.
I'm not sure of the story of uni-axial. It really doesn't make much sense since it would mean 'picking up along a single axis' and an axis goes clear through a polar pattern as opposed to a radius that would half an axis from the center out. But then, the BK5 is a very old RCA ribbon, that I'm pretty sure predates the 77, 44, and others of that family. At the time, the verbal descriptions weren't very standardized, and uni-axial may have been meant to mean uni-directional, or bi-directional (I could se it for either one) and if it is a ribbon it would indeed be a bi-directional mic. But, in the RCA 77 they incorporated a movable damper system to baffle the ribbon and turn the mic from a cardioid to omni to figure-8 in a very rudimentary, mechanical way. The BK5 may be an earlier version of trying to create a directional mic out of an inherently bi-directional element.
Regardless of whether I'm right or not on that, I know I've seen several BK5s go by on eBay, usually running in the 250-500 range depending on the condition. Hunt around a little. There's also a guy on eBay who sells nice little reprints of old RCA manuals including the 44 and 77 and he might have a BK5 one. Ironic that it might cost you $20 for a reprinted manual when all those mics cost $15, but hey, that's still a bargain. If you re-ribbon one for $200 it will be worth $500. Here is a guy selling a BK5 with wind screen and stand for $1100.

Now the question really should be... did you haggle? Like were they marked at $15 for the box, or $1 each, or did they want $25 and you offered $15. Because it was a church fundraiser, and you don't want to go to hell. You might need to drop an extra $20 in the collection plate tomorrow at that church, just to fend off the angry and vengeful gods.

-Jeremy

[joel hamilton]

The BK5 is one of the best ribbons ever made IMO. I love them. I have used a bunch of them over the years, and they have all rocked, except one that didnt work. Professor, was it you that claimed they were originally made to record the sound of artillery guns for the military?

I believe it. I have recorded SCREAMING marshall amps with a bk5 right up on the grill, not batting an eye...

Nice score, it will be worth the effort to research these mics, even if it is a quick search of "completed items" on ebay, to let you know what a score this truly is.

You got roughly 1500 dollars worth of mic for 15 dollars. Nice. Like the Prof, it makes my heart sing to hear that rummage sale deals are still being had in this day and age!

[eeldip]

i have a 6203, aka the sk-50, aka the varacoustic.

it sounds neat- get it reribboned. one of the earliest RCA designs. if you watched that PBS special on the blues you would see that it was the mic of choice for radio stations and live venues and even recording sometimes in the 30's.

they go on ebay anywhere from $225-$500, yep a wild market.

[i am monster face]

Thank you guys very much for the words of wisdom. After I sort this all out I will decide if I want to sell them or not. No, I did not haggle, and the lady at the church, (small baptist church) did not even know if they worked. She actually offered her husbands services to drive them to my house because I was walking.

I made it just fine.

[Professor]

Nope, t'weren't I that new about them being designed for artillery, but that's a neat story. I've always seen the BK series RCAs described as television broadcast mics while the 44,77, 74, etc. were radio broadcast - but here again I'm fishing through scattered facts. I'm really not too sure.

I'm glad that wasn't a haggled price, but I still think an extra bill in the collection plate might be in order. And believe me, I don't even go to church. I know that I haggle at music stores and pawn shops, and I don't pass too many rummage sales at churches - guess I'll have to start watching for them.

Enjoy the new toys, and I would strongly recommend not selling them. You'll never find another score like that, so just box them neatly and work on one at a time until you have a whole collection of fine vintage microphones.

-Jeremy

[joel hamilton]

Yeah, I agree. Dont sell them. Fix them up slowly, wait 5 or 6 years, then sell them and buy a jetta....