414 EB P48 Repair / low output
« on: September 10, 2020, 03:21:44 PM »
I found a shorted tantalum and replaced it, which got the mic working much better, but it still seems "low" At least compared to a MXL Chinese clone mic. How does one "know" where the output should be?

I'm like the 10th tech to work on this mic, lots of poor work all over... dirty (flux) PCB, on both sides, but it looks like flux from the factory... hard to say.

Does anyone have a voltage chart or anything to help diagnose where the issues may be? Or any advice. I'm getting 38.5 VDC on the transformer, is that too low?
« Last Edit: September 10, 2020, 03:48:24 PM by mkiijam »


rockinrob86

Re: 414 EB P48 Repair / low output
« Reply #1 on: September 10, 2020, 03:28:34 PM »
The output will be lower than most chinese condenser circuits.  I do not recall specifically, but mine is similar to old u87, sm7b, re20, etc.  my “old” mics.  I find chinese condensers typically need several clicks less gain on any preamp

I replaced all electrolytics and tant caps in mine, and it works and sounds good.  It’s a go to room mic, acoustic guitars, misc stuff like percussion, etc. 
« Last Edit: September 10, 2020, 03:31:42 PM by rockinrob86 »

Re: 414 EB P48 Repair / low output
« Reply #2 on: September 10, 2020, 03:47:48 PM »
Thanks for the info,

What did you replace the tants with? More tantalum or like Panasonic FC's or something?

Re: 414 EB P48 Repair / low output
« Reply #3 on: September 15, 2020, 08:29:10 AM »
And now there is the report that the transistors were replaced with generics....

rockinrob86

Re: 414 EB P48 Repair / low output
« Reply #4 on: September 17, 2020, 12:16:15 PM »
I used new tants.

Good luck on the transistors,  but also they could potentially be stock... you'll have to do some research. what is in it?


 

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