AKG C414E (C) COMB Schematic almost complete :)

Little update of the topic!

Right now we are finishing complete schematic for the first version of C414 (E COMB).
Values are taken from the real circuit (incomplete).
Values of parts marked blue are taken from similar circuits of C451 and C414EB.
It will be updated after Bowie check the rest of the parts in his C414E.

ln76d said:

I started tracing the circuit - right now preamp only. It share similar topology and component values to the oder AKG mikes - C451/C452 for example

Click to expand...

Is that the COMB schematic?  I can't tell on my phone.  I ask because I have one and need to locate a schematic so I can give it a check-up.  Thanks.

Yes, it's COMB .

It's also similar to the C412 model.

I have some problems with DC converter PCB, becuase there are missing components...
If you have option to check some values, it would be great

ln76d said:

Yes, it's COMB .

It's also similar to the C412 model.

I have some problems with DC converter PCB, becuase there are missing components...
If you have option to check some values, it would be great

Click to expand...

Sure, I'd like to help.  I hate opening it up because because that precious CK12 capsule is in there, but if you're not in a rush, let me know specifically what you need checked. 

Thanks!

I will let you know soon, right now my eyes are tired and i don't see well.
I need to finisch checking  components which i have

CK12?
Capsule is capsule, if you broke it, you can always replace it with microphone parts version or this from groupbuy
And seriously -  you don't need to remove the grill, so it would be safe.

DC converter is the circuit in the "can".
Easy to remove - two screws on the mounting frame.
Leads should be long enough to pull it out.
There is missing:
- two resistors
- three capacitors
- D2, D3, D4 - there's no model marking!

Which resistors and capacitors i will let you know

If someone have C414EB, please check diodes model, it should be the same or similar

You mean this?

On the other hand, going by all other mic dc-dc converters i've seen, the diodes can be as small (and fast) as you can get, provided the reverse voltage is comfortably higher than the end-result should be. Filter caps = 10-470nF, resistors = around 1Meg or so.

You'll see similar values in the U87A, for instance And in the Schoeps, as well.

Thanks,

right now i know, that it isn't BAY45 - these are bigger and black.
It much more looks like 1n914 or 1n4148, i will check is there something similar in C451.
Yes, there could be many types of diodes here, but finally it would be good to make complete original schematic, since AKG doesn't have it or don't want to share

It's just a plain (or, well, fast/ultrafast) old friggin' DIODE Are you worried it'll sound different or something? It's not even in the signal path...

Bigger and black, like this?
http://www.radiomuseum.org/tubes/tube_bay45.html
http://www.hqelektronika.hu/newpic/2/101000000066039877.pdf

Khron said:

It's just a plain (or, well, fast/ultrafast) old friggin' DIODE Are you worried it'll sound different or something? It's not even in the signal path...

Bigger and black, like this?
http://www.radiomuseum.org/tubes/tube_bay45.html
http://www.hqelektronika.hu/newpic/2/101000000066039877.pdf

Click to expand...

Discussion about the diodes is pointless...
It only make a longer and not readable topic
As i stated, i know, that  could be used a lot of different diodes.
By ocassion i want to make historically correct schematic - that's it!

By bigger and black, i had in mind BAY diodes
One diode left in the circuit i have is orange and smaller - like 1n914 or 1n4148

Here it is DC converter PCB (1962 Z 0502) for reference.
There are clearly visible empty places of missing components.
For reference, which side of the board it's - there's only one tantalum capacitor in left upper corner.

Here's updated schematic with parts which could be possibly correct.
Recordinghacks EB schematic isn't correct. I found some errors comparing to the service manual.
All missing parts values are blue.
C4 - had the same value on each version of C451 and C414EB - it's probably same here.
R4, R5 - everywhere are 4.7M
C5, C6 are 470pF on other schematics.
C451 use mostly black BCY (different models) diode.

Bowie!
Could you check those parts for me?
Resistor are color coded and capacitors should have described values.
Please look also for diodes, any markings and they color

It's almost done

ln76d said:

Bowie!
Could you check those parts for me?
Resistor are color coded and capacitors should have described values.
Please look also for diodes, any markings and they color

It's almost done

Click to expand...

Yes, I just had a boatload of work come through so it may take me a few days to get to it.  I'll take detailed pics for you and document whatever I find.  If you don't hear from me by next weekend, send me a reminder.  I won't mind.

I have a C414P48  - I know that is a pretty different microphone, but if there are any parts questions, I'd be glad to check

Thanks rockinrob86!

I also have EB P48
Unfortunately, this is the model where's no DC converter.
Last few missing parts we need from DC converter