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Post by anders on May 18, 2024 4:48:29 GMT -6
There is a perforated metal "cross" inside the RCA 44 BX covering the ribbon, which I assume serves as some combination of pop shield and mechanical protection from wayward screws.
Several mics don't have this, so: How important is it? What does it mean sound-wise?
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Post by andersmv on May 18, 2024 7:02:30 GMT -6
Are you talking about the internal screen? Ya, the design of those on various 44 revisions is all over the place. I’ve seen some without them at all. It’s there to help protect the ribbon, AEA does the same thing in their 44 as well as the 84. I would guess it probably changes the sound a bit, but definitely needs to be there. Maybe someone here has taken their out and can comment, I’m a bit curious but don’t really want to tear my PB-90 apart to try it…  |
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Post by chessparov on May 18, 2024 7:23:31 GMT -6
That cross was obviously... Mass produced.  |
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Post by EmRR on May 18, 2024 7:32:48 GMT -6
It’s the earlier protection design, at some point it’s gone with a smaller screen instead, said to improve the midrange.
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Post by anders on May 18, 2024 7:48:39 GMT -6
Thanks guys! It’s the earlier protection design, at some point it’s gone with a smaller screen instead, said to improve the midrange. Would that be a finer vertical mesh placed much closer to the ribbon, and around 3-4x as wide as the ribbon itself, or is that mesh present in all models? (It's hard to see from pictures, as the cross obsures the view of the ribbon) |
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Post by EmRR on May 18, 2024 7:49:59 GMT -6
I think Coutant has plenty of pics?
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Post by anders on May 18, 2024 8:02:09 GMT -6
I think Coutant has plenty of pics? Good idea! So just to be sure: The ones seen on this page www.coutant.org/rca44bx/index.html have not had anything (apart from the outer grille and silk) removed for the photo? |
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Post by EmRR on May 18, 2024 13:23:23 GMT -6
The D has the cross removed. You can see the mount points. The H never had it.
Mine is an E, has the cross. E also has a different set of transformer connections than most.
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Post by anders on May 18, 2024 15:36:17 GMT -6
The D has the cross removed. You can see the mount points. The H never had it. Mine is an E, has the cross. E also has a different set of transformer connections than most. The plot thickens! Thanks. |
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Post by hadaja on May 18, 2024 16:24:21 GMT -6
EmRR - H0w do you tell what version your 44bx is?
Thanks
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Post by EmRR on May 18, 2024 21:59:25 GMT -6
EmRR - H0w do you tell what version your 44bx is? Thanks It’s on the internal sticker |
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Post by teejay on May 19, 2024 21:26:13 GMT -6
I don't have a 44BX, but I do have a 44A (in my avatar), which also has a windscreen/damping screen. The tech who recently serviced it suggested it be removed (but I can easily swap it in and out). Here is his reasoning/comments. "BTW, the damping screens I referred to deleting are flat sections of windscreen inside the mic, right in front of & behind ribbon, added to artificially "brighten" the sound. It was at the expense of actual sound quality, due to the deliberate bouncing of sound back & forth through the ribbon, causing reflection distortion & uneven response in mid-high & highs.
Half the time I open up a 44A, etc., or more, someone has bits of ancient rubbery material between the screens and the top & bottom ribbon clamps. And 99% of the time, I don't test with the screens in place, mainly 'cause the old ribbon is toast. I'd always thought it was just a sad attempt at making the screens double as particle protection. But I got the nickelplate 44A from my collector friend recently to service in advance of finding a buyer, and it happened to have a good, old ribbon in it and no added rubber bits. I noticed I got a low mid ringing with every bump in handling the mic that sounded like feedback, but was level independent. Those screens ring like a tuning fork! With a decay time of several seconds. Should have been obvious to me that they would do that."Here are pics of my mic: i.postimg.cc/8cXSV2ch/RCA1.jpgi.postimg.cc/jqMKN7cL/RCA2.jpgi.postimg.cc/TYhxc3NQ/RCA3.jpgI have noticed when it is removed it is a bit more open/more clarity, a bit more sibilant, and has a bit less of what I would describe as the vintage ribbon sound. There were some rubber bumpers on the internal side of the lower four corners of the screen, presumably to add damping to offset the potential ringing. They were hardened up however, so per his advice I removed them. Still debating which way is sonically preferable. Certainly have to have a pop filter up when it's removed. |
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Post by EmRR on May 20, 2024 6:47:01 GMT -6
The 44-A is certainly a different beast. I can’t say I’ve ever heard comments about the screen being partially about increased treble, though it is a technique that’s used on through today to good effect in many mics, not so much in others.
A peice people don’t know is that RCA designed holistic systems; the preamp had a treble boost to counter the mic losses. There are cases of multiple amplifiers with various corrections for the previous amplifier. All the power amps have EQ corrections for the expected speaker, so you can imagine that people hook up any one piece to some modern piece and don’t like the result.
When the 44-B came out NBC/RCA issued a tech bulletin to remove the treble boost from the preamps, since the mics no longer needed it. That one’s funny too, they did an additional eq patch that wouldn’t alter the gain versus actually removing the eq, which would have boosted gain. Not an ideal sonic solution….but….more color!
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