Beyerdynamic schematic - say it 10 times!

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dmun1

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Does anyone have a schematic for a Beyerdynamic CV710N microphone?
 
No...but I said it 10 times. Do I win something?

Good luck on your quest...
 
Ask Beyer themselves (try the UK service dept. too) as they can be quite helpful.

I have two of these (or the CV720... can't remember). They are great as you probably already know.
 
I've got one of those too, with the omni capsule. There's very little info on it on the internet. Beyer is probably your best bet. Great mic though.
 
Thanks, but...

Congrats to those of you who can say that 10 times. You don't win a prize, but you already possess lingual skills that are most likely very appreciated by your respective partners - a prize of it's own.

I've emailed the Sound Surgeon (Beyer's approved service), and they haven't even had the courtesy to formally reject my request. Classy.

Using only a multimeter, I've determined that on the output side of the transformer there's a large resistance between the black and red wires. But between the brown (from the transformer) and either red or black wires there's no path - it's open.

So isn't this transformer supposed to be a center-tapped output? The red and black are on either end and the brown coming from the center? If so, this would mean that I need a new transformer for it. I'd really like to see a schematic before I go ordering parts though.

Any thoughts?
 
Ooops

I screwed up on those resistance measurements of the transformer.

Should read:

between black and red = 50 ohms

between brown and either red or black = 20 mega ohms, but the meter never really stabilizes.

Doesn't seem right to me, but I don't want to rip apart my other Beyer to take measurements.
 
dmun1 said:
I screwed up on those resistance measurements of the transformer.

Should read:

between black and red = 50 ohms

between brown and either red or black = 20 mega ohms, but the meter never really stabilizes.

Doesn't seem right to me, but I don't want to rip apart my other Beyer to take measurements.
Click to expand...

That sounds reasonable to me. The output transformer will not be centre-tapped. The brown wire is probably either an internal shield or attaches to the can (you can test if it connects to the can).

Maybe post the tansformer model number here if you want wiring details. I'd be doubtful it's faulty though.

You might want to measure the voltages at the FET in case it has turned faulty. Don't get the top end of the PCB dirty near the Hi-Z area or the mic will become noisy.
 
rodabod said:
That sounds reasonable to me. The output transformer will not be centre-tapped. The brown wire is probably either an internal shield or attaches to the can (you can test if it connects to the can).

Maybe post the tansformer model number here if you want wiring details. I'd be doubtful it's faulty though.

You might want to measure the voltages at the FET in case it has turned faulty. Don't get the top end of the PCB dirty near the Hi-Z area or the mic will become noisy.
Click to expand...


Thanks Rod! The brown wire doesn't show continuity with any other wire, or with the case. That part puzzles me, but I don't know anything about mic design.

The wiring:

pin 1 = brown xformer lead, ground from the can & ground from mic body.
pin 2 = red wire
pin 3 = black wire

there are 2 small capacitors between pins 1 & 2, and pins 1 & 3.

The part number on the transformer is: TR/BV 359 207 004.
 
Brown = internal shield.

Black/Red = Secondary.

Blue/Yellow = Primary.

The transformer is 1:7 (wied as 7:1 to lower the output impedance and balance) as can be seen here:

http://www.brianroth.com/library/beyer/Beyer specs.pdf

As I said before, it's not the most likely part to fail. I'd look elsewhere. And I'd also take your post to the prodigy-pro forum (Group DIY) where there is a lot of knowledge kicking around.
 
rodabod said:
Brown = internal shield.

Black/Red = Secondary.

Blue/Yellow = Primary.

The transformer is 1:7 (wied as 7:1 to lower the output impedance and balance) as can be seen here:


As I said before, it's not the most likely part to fail. I'd look elsewhere. And I'd also take your post to the prodigy-pro forum (Group DIY) where there is a lot of knowledge kicking around.
Click to expand...


Thanks again. I know it's not the most likely part to fail, but because the brown didn't show any continuity to any other lead, and the previous owner had mentioned that someone had fixed the grounding, I thought it possible that they overheated that lead. That's the trouble with a little knowledge, I guess - it can lead you down the garden path!

Regards
 
dmun1 said:
Thanks again. I know it's not the most likely part to fail, but because the brown didn't show any continuity to any other lead, and the previous owner had mentioned that someone had fixed the grounding, I thought it possible that they overheated that lead. That's the trouble with a little knowledge, I guess - it can lead you down the garden path!
Click to expand...

Check the basic wiring to the boards if someone has had work on it before.

You can see a picture here:

beyer%20dynamic%20cv710%20pre-amplifier%20-%20inside%20and%20socket%20wiring.jpg


Looks like the PCB is varnished which will make testing voltage a bit tricky.
 
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