See any issues with this 'hybrid' capsule polarization?

[k brown]

Thinking about adapting the simplified 'Schoeps' circuit used by electret mics like the Monoprice SC100/LC100, Samson C02, etc. for use with externally-polarized capsules, any reason why this wouldn't work, as opposed to adding a complex voltage multiplier, to get capsule polarization?

Would it stress rechargeable batteries to be in series with the circuit voltage?

The batteries and everything past the FET, would be in an external enclosure, not in the mic body.

 

[Khron]

Would it stress rechargeable batteries to be in series with the circuit voltage?

It wouldn't stress any sort of batteries in any way. At least in the circuit you drew there, one end of the batteries would be floating (no DC path to ground).

You might want to turn them around so the positive (longer line of the battery symbol) is towards the capsule, otherwise the voltage getting to the capsule will be that 30v minus the battery voltage.

You'll want to pay attention to the lifetime of the batteries though - put a sticker on the mic with the date you installed them and swap them out every couple of years, before they end up leaking and corroding everything in their path...

 

[k brown]

Thanks.

Wow, I never realized that all these years I've been drawing the symbol for batteries backwards!

The 9v I use are lithium-polymer, and I'd just recharge them between gigs.

 

[Khron]

Depending on the self-discharge rate of those, remains to be seen if they'd need recharging even monthly. Keep in mind, there's no real current draw there, and as i mentioned, there's no DC path.

 

[rogs]

I've been using THIS CIRCUIT with LDC capsules.
Simpler than the Schoeps - no batteries - no need to regulate the DC - no need to calibrate FET bias - and no voltage multiplier.
Works very well. The audio output is single sided - although as you can see, the line remains impedance balanced.
Similar technique to that adopted by Neumann, with some of their transfomerless output mics like the TLM103.....
I notice that companies like dbx and Soundcraft also use this single sided audio 'balanced impedance' approach.
A 'win win' option for them...... Lower noise and lower cost!

 

[k brown]

I've been using THIS CIRCUIT with LDC capsules.
Simpler than the Schoeps - no batteries - no need to regulate the DC - no need to calibrate FET bias - and no voltage multiplier.
Works very well. The audio output is single sided - although as you can see, the line remains impedance balanced.
Similar technique to that adopted by Neumann, with some of their transfomerless output mics like the TLM103.....
I notice that companies like dbx and Soundcraft also use this single sided audio 'balanced impedance' approach.
A 'win win' option for them...... Lower noise and lower cost!

Yes, I've seen that - very clever indeed. But I already have Monoprice circuit boards.