RCA/Shure Model # MI-559156
Greetings,
I've a RCA/Shure Model # MI-559156 that I am trying to find a schematic or user manual for.
This mic looks like a 444 or 444D & has a Shure Brothers sticker on the bottom but has some unique circuit construction in the base.
The mic element has only 2 connections so it is not the 444D element.
There are 3 or 4 resistors & a capacitor inside the base and has black, white, red, green cable wire.
I did search old messages here & the interweb but haven't found anything.
I also contacted Shure to no avail.
This is my last hope!
?
73 Bob
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Re: Grounding Issue with TSB2590
#P48mems
On Wed, Feb 12, 2025 at 12:26 PM, @MusketenManfred wrote:
Id like to try the metal strainer approach. Where do I ground this to tho? Would I use a ground of one of the xlr connectors?
Yes, connect the metal strainer to pin 1 of one of the XLR connections. It's easy to test if you can borrow a metal strainer from your kitchen. A test lead with alligator clips is useful here.
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Re: Grounding Issue with TSB2590
#P48mems
Id like to try the metal strainer approach. Where do I ground this to tho? Would I use a ground of one of the xlr connectors?
?
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I cant imagine this being the case. As I said in the other thread, apart from the electrical buzz they sound fine. But I think the capsules are different because there wouldve been at least some other people having the same problem with the originals as I just followed the Instructable of the ambi alice. Everything works fine so the Circuit works except for the emi shielding, wich I think is the difference between the originals and the "fakes". I had previously built this mic with 4 em272 primo capsules wich worked great so Id just like to upgrade the capsules to working ones so I dont have to alter the design.?
The easiest solution imo would just be to replace the capsules with original ones.
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Re: What is the role of the capacitor in Simpl48 circuit?
This is different than the schemo in your previous post.
The former has a capacitor to isolate DC, the latter has none.
Both may work but require different values for the resistors.
Le 12/02/2025 ¨¤ 15:57, Adam Jo5eph via
groups.io a ¨¦crit?:
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Show quoted text
Another picture for assembled components.
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Re: What is the role of the capacitor in Simpl48 circuit?
Another picture for assembled components.
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Re: What is the role of the capacitor in Simpl48 circuit?
This is the snapshot from the original video.
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We read about your buzz/hum issue, and threw out some solutions for that. Beside that issue, did your 2590 lookalikes work at all? They usually do, even though their specs aren't quite the same.
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Be warned that "real" 2590s will also show all the same issues, if there are problems with your circuit or shielding. So I would suggest that you keep experimenting with your clones to get them working nicely. You might be happy with the results, and if you do decide later to upgrade, you will be installing the new capsules into a working design.
?
?
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Re: Merging three Capsules on two Preamps?!
Hey Scott,
Pls allow me some beginners questions.
Is what you are describing similar to the simple P48 circuit just with a smaller resistor?
And would 4,7 uF be a "nice big" capacitor?
And the 9V is connected just as Phantompower would be connected?
If you could briefly sketch the schematic you suggested that would be amazingly helpful!
?
Thanks a lot!
?
?
?
?
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Re: Alctron MA-1 Schematic question
Le 12/02/2025 ¨¤ 03:34, Dan KE6PO via
groups.io a ¨¦crit?:
S1 & S2 is understandable, but the power issue still
escapes me. The only point at which V+ power can reach the
circuit is from XLR2. But I don't see how power gets
distributed. If V+ is present on pin 2 or 3, it will only feed
the drain of Q3 or Q2. Assuming that there is sufficient Vin
generated by the microphone to trigger the gates of Q1 & Q4,
there is no V+ on the drains of Q1 & Q4 to feed through to
the gates of Q2 or Q3.?
?
Clearly, I am missing something about FET functionality.? Can
I get a clue?
There is conduction between drain and source in a properly biased
FET.
From pin2, current flows through Q3, then Q4, then R6 and R7, back
to pin1.
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Re: Merging three Capsules on two Preamps?!
So this setup could be built actually fairly simply - no need to have phantom power or anything like that. Too complicated.
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Going back to the kind of electret capsules that kick-started the mic DIY boom, you should just be able to feed them all from a 9v battery through something like a 10k resistor to each.? Then collect your audio output through a nice big capacitor (to strip off the DC), and you've got something easily compatible with your recorder's inputs.? Unbalanced, but over a few inches or feet it won't matter.? You can do your custom summing with resistors and/or potentiometers.? There will be a little interaction, but something you will be able to cope with.
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Re: Alctron MA-1 Schematic question
S1 & S2 is understandable, but the power issue still escapes me. The only point at which V+ power can reach the circuit is from XLR2. But I don't see how power gets distributed. If V+ is present on pin 2 or 3, it will only feed the drain of Q3 or Q2. Assuming that there is sufficient Vin generated by the microphone to trigger the gates of Q1 & Q4, there is no V+ on the drains of Q1 & Q4 to feed through to the gates of Q2 or Q3.?
?
Clearly, I am missing something about FET functionality.? Can I get a clue?
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Hey so it looks like im out of luck with my tsb fakes. Would you still be Interested in trading? I saw you wanted to build a new mic with the tsbs. If ur Interested, as I dont have any use for the primo capsules Id like to trade them :)
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Re: Alctron MA-1 Schematic question
Sorry, forgot to include the schematic.?
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Re: Grounding Issue with TSB2590
#P48mems
If you are using SimpleP48, you should download the latest version of SimpleP48.pdf from my Files.? Among other issues ...
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- 100k is almost certainly too large for TSB 2590.
- I pontificate at length on the shielding required.
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Re: Merging three Capsules on two Preamps?!
No problem you can power that circuit from a 9v battery sans phantom power? Best Regards,
Jules Ryckebusch?
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Show quoted text
On Feb 11, 2025, at 14:43, martenberger92 via groups.io <martenberger92@...> wrote:
?
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On Tue, Feb 11, 2025 at 02:08 PM, Jules Ryckebusch wrote:
The ?OPA Alice is designed for capsules without a FET, to run off of Phantom power, and to drive balanced signals into a mic preamp or recorder. It really isn¡¯t applicable for this application?
Hi Jules, thanks for clarifying.?
I checked out your M/S mic today, where you created a figure of 8 by wiring to cardioid capsules in series. And that gave me an idea?
Couldn't I then if I want to merge Stereo AB with the Mid Mono mic wire the Mono Capsule in series with the A & B capsules?
Essentially forking the Mono Capsule and feeding it then into capsule A & B. Would that be worth an experiment?
Maybe I should add: The Stereo AB will be approx, 20 cm apart. And the Mid Mic is about 30cm closer to the source as the AB. Like a mini Decca Tree.
Then I could run this three capsule on a dual channel OPA alice board provided I have added phantom power and plug it right in my Sony Cassette Recorder.?
Btw Jules, thanks a lot for creating all this amazing content!
@James B: Yes I could use my Sound Devices Recorder and I do it all the time. But this project is really all about the fun and playfulness of old school cassette recorders. But still I want to record songs and capture the ambience simultaneously. So a Stereo AB is not gonna cut it.?
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Re: Merging three Capsules on two Preamps?!
?
On Tue, Feb 11, 2025 at 02:08 PM, Jules Ryckebusch wrote:
The ?OPA Alice is designed for capsules without a FET, to run off of Phantom power, and to drive balanced signals into a mic preamp or recorder. It really isn¡¯t applicable for this application?
Hi Jules, thanks for clarifying.?
I checked out your M/S mic today, where you created a figure of 8 by wiring to cardioid capsules in series. And that gave me an idea?
Couldn't I then if I want to merge Stereo AB with the Mid Mono mic wire the Mono Capsule in series with the A & B capsules?
Essentially forking the Mono Capsule and feeding it then into capsule A & B. Would that be worth an experiment?
Maybe I should add: The Stereo AB will be approx, 20 cm apart. And the Mid Mic is about 30cm closer to the source as the AB. Like a mini Decca Tree.
Then I could run this three capsule on a dual channel OPA alice board provided I have added phantom power and plug it right in my Sony Cassette Recorder.?
Btw Jules, thanks a lot for creating all this amazing content!
@James B: Yes I could use my Sound Devices Recorder and I do it all the time. But this project is really all about the fun and playfulness of old school cassette recorders. But still I want to record songs and capture the ambience simultaneously. So a Stereo AB is not gonna cut it.?
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Re: Merging three Capsules on two Preamps?!
Forgive me if i'm way off base,? but couldn't you use your?Sound Devices Mixpre10ii multi inputs to record and "mix" your channels post production?
On Tuesday, February 11, 2025 at 02:50:01 PM EST, kennjava <ken@...> wrote:
On Tue, Feb 11, 2025 at 02:08 PM, Jules Ryckebusch wrote:
The ?OPA Alice is designed for capsules without a FET, to run off of Phantom power, and to drive balanced signals into a mic preamp or recorder. It really isn¡¯t applicable for this application?
Hi Jules,
?
I only suggested the OPA-Alice as inspiration - it showcases a suitable opamp for battery-powered use, some practical considerations around single-ended powering, and then I'd expect the OP or whoever to use standard audio opamp practice when designing the required blocks.
?
I didn't mean to imply that the complete OPA-Alice would be a drop-in solution. Sorry if that wasn't clear.
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How to combine two different capsules in one body
Hello everyone, I'm looking for a bit of advice on combining two different kind of capsules (electret and MEMS) into one microphone body. What things should I consider when in comes to phasing, polarity, ext. Not only that, but how would you overcome the challenges? I'm thinking that the microphones should be set at a 10 degree angle towards each other and no further than 1mm apart. I also realize that in my board I need to be careful with the polarity of both capsules. Do you have any ideas on the best way to mix the two signals, not to clip. Is turning down the amplification enough? or is it not that simple in this circumstance? Would love any and all advice and considerations I haven't thought of.?
Thank you everyone!
-Soundwich
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Re: Merging three Capsules on two Preamps?!
On Tue, Feb 11, 2025 at 02:08 PM, Jules Ryckebusch wrote:
The ?OPA Alice is designed for capsules without a FET, to run off of Phantom power, and to drive balanced signals into a mic preamp or recorder. It really isn¡¯t applicable for this application?
Hi Jules,
?
I only suggested the OPA-Alice as inspiration - it showcases a suitable opamp for battery-powered use, some practical considerations around single-ended powering, and then I'd expect the OP or whoever to use standard audio opamp practice when designing the required blocks.
?
I didn't mean to imply that the complete OPA-Alice would be a drop-in solution. Sorry if that wasn't clear.
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Bob W8RMV
