kooma

Transient analysis (in the attachment).
Only 446mV * 2 = 892mV out amplitude. And this is with a fully twisted potentiometer P1!
is bias ok in this?  :)


RuudNL

I never had a situation  when the bias was set correctly with a 'fully twisted potentiometer'.
(In that case the potentiometer wouldn't be needed...)
There is a solution for every problem!

http://www.vansteenisaudio.nl

dima_k85

I repeat again: Stop spamming in my topic! Want to talk about Schoeps circuit - create a topic about it.

dima_k85

Now let's talk about this "wretched" impedance "balanced" CM-1A circuit which is only "balanced" as long as you use it on an low impedance transformer balanced input.  If you use this circuit on a modern electronically balanced microphone preamp (which are the majority today) there will not flow any current through the "balancing" resistor (R15) and therefore the microphone will be in fact unbalanced.  This is ok if you use the microphone with a 2m short cable on your desk, but not if you run the microphone over a 50m long cable in an environment with dimmers and let's see which circuit behaves better.  The "wretched" CM-1A circuit or the Schoeps circuit ?

Oh, you can't find a dimmer pack in your simulation program ?  How sad...... but that's real life....

OK, let's talk about the CM-1A if you have anything to say on the case.
The balancing circuit is bad, doesn't suit you? Have you seen the AKG C414 XLS microphone balancing circuit? - So, my friend, it is exactly the same as that of the CM-1A! Maybe C414 a bad microphone? Is it poorly balanced? Maybe AKG engineers doesn't earn their keep (their daily bread)? - NO!
To talk about what currents flow to where you need to analyze the CM-1A circuit not only for DC, if you did not know about it. But you do not seem to need this knowledge, so don’t be clever, your knowledge at the elementary school level, pull it up, and then teach me, okay?
« Last Edit: April 14, 2020, 12:05:31 PM by dima_k85 »

dima_k85

PCB coming soon…
Based on previous developments, I have traced a new PCB with revision 1.1 (in the attachment) for installation on the BM-700 / BM-800 microphone frame. Now it will be possible to connect not only condenser capsules, but electrets too.

dima_k85

Bottom view (in the attachment).

dima_k85

To simplify the assembly, I panelized boards of 6 pieces. And ordered their production.
Next week I will have boards.

shabtek

Looks good! There are more shortcomings from the body than either wretched circuit.
To be clear, this is copy of akg 414xls not schoeps?
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

Khron

1) Check the title.
2) Read the first post in this thread: https://groupdiy.com/index.php?topic=74818.msg947939#msg947939

Looks good! There are more shortcomings from the body than either wretched circuit.
To be clear, this is copy of akg 414xls not schoeps?
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans

dima_k85

To be clear, this is copy of akg 414xls not schoeps?
This is an improved RODE NT1-A replyca for BM-700 / BM-800 body.
« Last Edit: April 14, 2020, 12:17:12 PM by dima_k85 »


analogguru

OK, let's talk about the CM-1A if you have anything to say on the case.
The balancing circuit is bad, doesn't suit you? Have you seen the AKG C414 XLS microphone balancing circuit? - So, my friend, it is exactly the same as that of the CM-1A! Maybe C414 a bad microphone? Is it poorly balanced? Maybe AKG engineers doesn't earn their keep (their daily bread)? - NO!
To talk about what currents flow to where you need to analyze the CM-1A circuit not only for DC, if you did not know about it. But you do not seem to need this knowledge, so don’t be clever, your knowledge at the elementary school level, pull it up, and then teach me, okay?
"There is a sucker born every minute" - and I don't know why so many are trying their luck in the audio industry.
« Last Edit: April 14, 2020, 01:25:18 PM by analogguru »

JohnRoberts

OK kids... lets keep the comments about things not people.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

dima_k85

Today I got PCBs (in the attachment). It's time to assemble.

dima_k85

Bottom view (in the attachment).

dima_k85

PCBs are assembled and depanelized (in the attachment).
During assembly, I used only branded SMD components: low-noise precision thin-film resistors, highly stable NP0 ceramic capacitors (where possible), isolation and filtering electrolytic capacitors the same as in the AKG C414 XLS microphone.
« Last Edit: April 29, 2020, 11:40:16 AM by dima_k85 »

dima_k85

Top view (in the attachment).

dima_k85

Bottom view (in the attachment).

dima_k85

Top view on microphone frame (in the attachment).

dima_k85

Bottom view on microphone frame (in the attachment).

dima_k85

I also made a 3D model for mounting a 34mm condenser capsule to the BM-700 / BM-800 microphone frame for 3D printing.
« Last Edit: May 07, 2020, 08:36:02 AM by dima_k85 »


 

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