Electret Phono Cartridge?

[imfree707]

Crazy as this sounds, I'm actually tempted to try it because it should be inexpensive and if executed properly, could produce a workable cartridge! Create an Electret Phono Cartridge by coupling a stylus to a pair of 45/45 degree mounted PanasonicWM-61A back electret mic capsules' diaphragms!

[thaumaturge]

Not so crazy. Been done of sorts in the early days of amplified phonographs. Needle hooked to a capacitive diaphram that would change frequency of an FM oscillator. Signal actually broadcast down arm to small receiver circuit then out amplifier.
Doc

[SY]

Good luck! Back in the late '70s/early '80s, a company called Microacoustics made a splash with electret cartridges. I had one and was unimpressed, but implementation aside, the idea was intriguing.

[bear]

Moving mass is your enemy, so things like glue and linkages will be troublesome...

could be intriguing...

_-_-bear

[imfree707]

Originally Posted by bear

Moving mass is your enemy, so things like glue and linkages will be troublesome...

could be intriguing...

_-_-bear

Absolutely! That's what discourages me from attempting. The tempting thought is that a successful Electret Cartridge could produce 100mv or better into 2.2K with a frequency response virtually immune to effects of electrical loading and immunity to magnetic interference!

[PRR]

> a successful Electret Cartridge could produce 100mv or better into 2.2K with a frequency response virtually immune to effects of electrical loading

True, only because it has a preamp IN it.

You could use SMD to build a gain of 10 preamp with 1 ohm output light enough to hang behind your regular cartridge. Yes, with more cleverness you could feed power down the existing leads.

As for adding mass (arm, linkage) to the microphone: it now resonates around 13KHz. Add mass and you could be down to AM quality bandwidth. OTOH, over the range from zero to the top resonance this mechanism would not need the "RIAA curve" as usually drawn with a steep slope. The natural EQ would be flat. For historic reasons you's need 6db rise from 500-2KHz (plus the 50Hz cut).

The diaphragm is VERY stiff, much stiffer than I think you want riding in your precious grooves. Yes, ceramic transducers are stiff, yet a few (a VERY few) were compliant enough for good record wear.