How to ground a positive grounded micpre w/phantom pwr?

[ihscoutlvr74]

Gents,

I recently build a pair of RCA germanium micpres with a positive ground and ph. pwr.  What is the proper to ground this unit for best performance?  My thought was to use some 100uF caps to block ph. pwr. DC from input XLRs and tie it to pin 1 on the outputs.  Is this a good way to do this or is there a better way.

Many thanks, Nathan

 

[PRR]

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[emrr]

Ground is ground.  Phantom is above, amp is below.  The B+ on these is grounded, the B- is the schematic power path. 

You don't need to block DC from the input transformer, you just need to be sure CT isn't grounded.  In fact, you could probably feed phantom through the CT with a 3.4K resistor if you feel like going old school. 

Am I missing any part of your question?

 

[ihscoutlvr74]

Thanks for the help, but this is my issue.

I'm currently using the 30v from the 31's psu for phantom power.  I haven't had problems with any mics I've used with 24v for phantom supply and was just use the 30v.  I wasn't going to block PP from the transformer. 

On another project , for relay pwr I put a 1000uF/16v from relay to ground and the other end to the main +-15v supply.  The relay 'saw' ground but blocked DC and worked fine without affecting the psu.  Here's what I was thinking about doing - didn't draw resistors to pin 2/3

Will this work??
Thanks Again Guys!  Nathan

 

[ihscoutlvr74]

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