Question about RCA 44-BX and various models

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drybones
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Question about RCA 44-BX and various models

Post by drybones » Mon Apr 15, 2019 4:41 am

All,

Ever heard the old term "The more I learn the more I realize how much I don't know?" That is how I feel about the RCA 44 and 77 series mics. I am a freak about these two models and know a good bit. (I even figured out that the acoustical labyrinth of a 77 is 42.75" if stretched out!) I own 3 44 BX and 13 RCA 77 D and DX mics. Yes, 13, I know that is insane. I love these particular mics and the guys like Clarence Kane, Darrin Warner and Michael Farabee who maintain them. I don't know Mr. Sank even though we lived 90 minutes away in Arizona at one point.

Anyway, the RCA 44-BX is broken down by its MI classification. To date, I have been able to document the following by combing the Internet and reading every RCA catalog from 1939 on. And yes, I have scrubbed the Coutant site. A special thanks to Professor Coutant. We have exchanged mails of the years, what an amazing man. Here are the versions I know of:

MI-4027-B (first in 1941 catalog)
MI-4027-D
MI-4027-H
MI-4027-J
MI-4027-K

These are all the "high fidelity" models made from 1941 (Model B). I have also found two other versions:

MI-4027-G (Another high fidelity version)
MI-4027-E

The mystery mic to me is the Version E. I now own one. I can find precious little data on the E. I have seen them on eBay, Gearslutz and even the mic Vintage King is restoring in its excellent video. Yet, even with all the resources of the Internet, I can't find any data about the E, when it was released and what makes it different from the rest. The only person I suspect who might know is Fletcher. I got to have lunch with him in 2014. He rode his Harley up to my place to have lunch and talk audio. But he is out of the business now so I won't bother him.

So, who can fill in the blanks?

Regards,
Curt "Siege" Vincent - aka Dry Bones

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ShinyBox
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Re: Question about RCA 44-BX and various models

Post by ShinyBox » Mon Apr 15, 2019 7:26 am

Wow, that's a nice stack of mics!

Have you talked to Clarence Kane about them? Having worked there, I would think he might have some info regarding the model classifications?

I would be curious to know if there are any functional differences between the models, or if they are related to body styling and features( how it mounts, did it include a base, etc.), or to signify different production runs?

44BX is one of my favorite mics, and I've had the fortune to hear a bunch of them!

Regards

Jon

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emrr
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Re: Question about RCA 44-BX and various models

Post by emrr » Mon Apr 15, 2019 2:27 pm

I haven't looked into the 44 so closely, but at times with RCA the -'X' can be a color difference, sometimes it's more than that. Like if something came in 3 colors, A/B/C would be the first variation, D/E/F the second, etc.

Example:
36-A equipment shelf (2nd version)
MI-4681C black
MI-4681E transmitter gray
MI-4681G umber gray

Note the 44-B is MI-4026-A.
MI-4027-B / 44-BX is in the 1939 catalog.

Also from Coutant, Sank is quoted as saying:
“There is virtually no difference between the Type 44-B and the Type 44-BX, except that the Type 44-B cable exits straight down from behind the bottom, whereas the Type 44-BX cable exits at the bottom of the back of the base housing, straight backwards. Later in the Type 44-BX, a significant change was made to the internal damping screens, where the cross-shaped, perforated metal/cloth-lined screens were eliminated in favor of the fine metal mesh screens on the pole pieces. This cured midrange response anomalies and provided particle protection.”
Which MI-4027 was the first with the internal screen change?

The 44-A appears to predate the use of MI- numbers. The earliest article mentioning it by name appears to be Oct 1932, along with sales bulletins for it, and the 41-A which appears to be the first microphone preamplifier fitting the description of a preamplifier as we know it today. I'd like to know if anyone still has a surviving original 44-A windscreen, I've never seen one. Similar to the -X in the MI series, the 44-A has variations relating to the mounting style: 44-AP, 44-AA, 44-AS.

So, are you gonna fill us in on what all the differences are for the ones you listed?
Doug Williams
ElectroMagnetic Radiation Recorders
Tape Op issue 73

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emrr
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Re: Question about RCA 44-BX and various models

Post by emrr » Sun Apr 21, 2019 8:59 am

I just saw an MI-4207-L with it’s original shipping box, 1957 date on it.
Doug Williams
ElectroMagnetic Radiation Recorders
Tape Op issue 73

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