Cool use for Primo EM200/204

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k brown

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San Francisco
Was reading about the concept behind the Schoeps V4U, and decided the EM200 was a good candidate for a DIY version of something similar, since it has such unusually flat response. Looking at the response of the V4U, that could only come from a flat-response capsule, as the HF lift would be created by the 33mm ring around it.

I cut a ring from high density fibreboard, filed/sanded it to the beveled shape, and epoxied it to a piece of carbon fibre tube. Other end fitted to an empty DIN plug shell, with a hard-wired cable. Electronics in a separate box at end of cable; adapted from a Samson C02.

For those unfamiliar with the V4U, Schoeps wanted a vocal mic with LDC qualities, but utilizing an SDC capsule. The 33mm ring provides an LDC-like top boost, as well as increasing the capsule's proximity effect, and making it more directional; transitions from cardioid below frequencies related to the size of the disc, to supercardioid above that point. V4 U | Studio Vocal Microphone | SCHOEPS Microphones The DIY version exhibits all those attributes, and the differences in sound between the 'naked' capsule and one with the ring are quite remarkable.

It's overall sound on voice at close distance is amazingly similar to the Oktava 319 and AT2035, but rejects much more room sound than either of them.

I'll try to record some comparisons (just my voice).
 

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k brown

Well-known member
Joined
Jul 6, 2021
Messages
69
Location
San Francisco
Some tests (with just my voice).

First comparison is with AT2035. Mics were nearly touching, and about 1 foot away.

Same with second test, but with massively modified Oktava 319. All electronics replaced with crazy-simple tube circuit based on Royer's 'Country Boy's' project, but using a 6AU6 pentode instead of 5840 submini. Literally all there is in the mic is the tube itself; the capsule is connected directly to the tube and is polarized by grid leakage. The cathode resistor is in the power supply. Capsule resonator disc removed, and body shortened and heavily damped inside. Stock meshes left in place.

When I get time, I'll post comparisons to the same capsule without the ring, to demonstrate the changes in tonal balance and directivity.

Here's another candidate for this: JLI-1318. No built-in FET. I have two on the way; I'll pair with 2SK660, since I have several biasing/powering modules for those already.
 

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