Weird Audio 47 Mod 1 Upgrade Service

The "Mod 1" edition of the Weird Audio 47 mic uses a CCDA circuit, popularized in the Apex 460, Avantone CV-12, and other common Chinese tube mics. The tube is a 12AX7, which was never used in any vintage European tube mic. The capsule is not a K47 type, which is ironic given that the mic sort of looks like a U47. 

Our upgrade service for this mic incorporates the following changes:

• We replace the capsule (which is not a K47 type) with a K47 type. The new capsule supports multipattern operation.
• We remove the oversized RF filter caps, which are unneeded and which typically add huge amounts of distortion to the circuit.
• We replace the 12AX7, which has too much gain for this mic circuit, with a tube that is more suitable for use in a microphone. (The original 12AX7 would be returned to you; it would likely work well in a guitar amp.) In the Weird 47 mics we have tested, replacing the tube with one of our selected tubes cuts second and third harmonic distortion by 12-20dB, while simultaneously lowering the noise floor significantly. 
• We review the PSU voltages. Most China-made tube mic power supplies overdrive the B+ circuit, resulting in too-high voltage at the capsule. The mod includes a fix for that problem. If your mic's PSU also runs the heater circuit at too-high voltage, we would also fix that problem.
• We replace the transformer, whose turns ratio is too high for this circuit topology. Our transformer is custom wound with high nickel lamination; it is much closer to the specs for the BV8 transformer (used in Neumann's U47) than is the Alctron-style transformer found in the Weird 47.
• We upgrade the input coupling capacitor to a film-and-foil type.

Here is the mic's signal path: capsule -> input cap -> tube -> output capacitor -> transformer. This upgrade replaces everything in that list except the output capacitor. (We would replace the output cap too, but there is no room for a better one.)

How it Works

After you buy this service, see our Service Policies page for instructions on packing and shipping your mic. Be sure to print the Service Request form linked from that page.

Send us the microphone and power supply. It is not necessary, nor recommended, to send us the shockmount, cables, or case. But it is critical to pack the mic and power supply carefully; both are heavy enough to damage themselves if the box is dropped. Pack both the PSU and the microphone in 3-4 inches of cushioning material, and use a sturdy shipping carton (not a used Amazon box) to avoid damage in transit.

The typical turnaround time is 5 business days. We can provide more detailed turnaround time estimates after you purchase the service.

Compatibility

This upgrade is compatible with the Weird Audio 47 Mod 1. We cannot advise about compatibility with other versions of the Weird 47, or any other "47" microphone.

Costs

The mod service includes the parts, installation, testing, and return shipping (domestic US only) from our shop back to you. 

Availability

This mod service is open to US residents only, or to non-residents who are shipping the finished mic to a US address.

(Residents of other countries might find that it costs less to purchase a finished microphone.)

Optional Upgrades

We build custom tube mic cables with Gotham GAC7 wire and Neutrik connectors. This cable is superior to the thin, compromised stuff that claims to be Gotham brand sold on Amazon. We source the cable directly from Gotham in Switzerland.

If your budget allows for a superior power supply, see our VPS options.