C414 EB. I'm getting 9.6Vdc into the wires that would hook up to the DC board with it disconnected. And only about 8Vdc after I hook the DC back up. I've replaced all the Tant. caps, but I'm wondering how much point "A" in the schematic should be with or with out the DC board?
C414 with 9.1 zener issue / question
- Thread starter mkiijam
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Voyager10
Well-known member
Doesn't sound unreasonable, what's the problem with the mic?
pucho812
Well-known member
I’ve never seen schematics to list voltages for when things are not connected.
Then again it’s been a while that I have looked at the eb schematic so take it with a grain of salt.
Then again it’s been a while that I have looked at the eb schematic so take it with a grain of salt.
It's low and seems to lack bass. maybe around 10 dB quieter than I think it should be
Voyager10
Well-known member
On my C14EB I'm getting pretty much exactly 12V at point A (the red wire, from this schematic), +65V at point L, -65V at point M, and -21V at point N (with both boards connected together), so 8V sounds a little low.
XLR pins 2 and 3 are also at about +12V, with a regular P48 supply (yes, it sucks current). Have you tried with a different preamp, or a lab power supply + 6.8K resistors?
XLR pins 2 and 3 are also at about +12V, with a regular P48 supply (yes, it sucks current). Have you tried with a different preamp, or a lab power supply + 6.8K resistors?
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Voyager10
Well-known member
OK, it would be useful to know the voltage either side of R15, and also on XLR pins 2 and 3 is.
Voyager10
Well-known member
That's very confusing- R15 is shown as a 330 ohm resistor, so it's not plausible that it has nearly 30V across it, if it's working. Can you check its value, and check for continuity between either end and other parts of the circuit. And possibly re-check your measurement? 27V across R15 doesn't agree with 8 or 9.6V at point A.
I really would not power up the mic with the DC board disconnected, it may expose the other board to overvoltage.
I really would not power up the mic with the DC board disconnected, it may expose the other board to overvoltage.
Voyager10
Well-known member
Interesting... the manual shows that R14 is bridged out, both in the wiring diagram on p6, and the board photo on p4.
Did your mic have these pins bridged, and has it somehow been removed?
Did your mic have these pins bridged, and has it somehow been removed?
That bridge is to be cut for 48v
https://gearspace.com/board/so-much-gear-so-little-time/1298157-akg-c414-eb-48v-mod.html
https://gearspace.com/board/so-much-gear-so-little-time/1298157-akg-c414-eb-48v-mod.html
