JJ Audio

Hand crafted microphones for your recording pleasure
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Tube Microphones

Microphones have been around for a long time. They began in the mid 1800's with the development of the telephone. The first tube microphones were being developed around 1917 and were based on the tube amplifier that was developed two years earlier. The modern Tube condenser microphone was born.
The tube microphones we see today were developed after World War 2.
Neumann (formed in 1928) released the U47 in 1948. This microphone had a switichable patten and used the VF14 pentode tube.
AKG (founded in 1947) released the C12 condenser microphone in 1953. The C12 used the 6072 miniature 9 pin double triode. The Elam 251 was also made by AKG and used the CK12 capsule. The C12 and the M49 were the first remotely controled pattern selector.
Two other tubes used in modern condenser microphones, are the sub miniature tube and the Nuvistor.
 Neumann M49/M50 used the AC701.  AKG / Telefunken used the subminiature AC701 in the ELAM 250/251 (export models used the 6072).
The Nuvistor was the last ditch effort by tube manufactures to compete with the "new technology." The transistors made all electronics smaller. Radios, amplifiers, consumer electronics all became portable and compact.
Nuvistors were used as replacements for the VF14 tube. AKG used them in the C12A and other mics.
The era was comming to a close for the classic designs.


Tube Microphone Mods

Price List                             
All of the tube designs today come from the classic designs pioneered in the mid to late 1900's.
Within the past 10 years, many tube mics have been imported and flooding the market with products that have less than optimal components and quality control. The philosophy has been to make a product that works and at the least expensive price point. This has given the consumer products that sound harsh and hard compared to their elegant forefathers.
Some current production microphones have capsules, transformers, wires and capacitors that accentuate high frequencies and almost have a sizzle to them.
My philosophy is to use the best components possible to produce a microphone that has that "Vintage sound" and warmth. All of the mods that I do on tube microphones involve getting rid of the junk.
I use only high quality capacitors made by Axon, Solen, Black Gate, Rubycon, Elna and Nichicon.
The transformers are AMI, Cinemag, Jensen, and custom wound transformers made in the USA.
The capsules I use are ADK custom , Beeznees, Tim Campbell's CT12, Neumann reskinned, Peluso and Theirsh M7 capsules. I also have some
 JJ Audio capsules.
The typical tube microphone mod consists of:
Replace all of the electrolytic capacitors in the power supply.
Rewire the microphone with Teflon coated, Silver coated copper wire.
Change the microphone circuit to a "classic" design circuit or a custom designed circuit.
Burn in the microphone for three days.
In addition we offer:
Transformer replacement
Capsule replacement
Grill mod
Body paint

Basic Mod:  $350.00 6072 circuit
EF86 circuit add $75.00
Capsule change: $25.00
Transformer change: $30.00
Custom circuit board: $50.00
Grill mod: $100.00 without basic mod $75.00 with basic mod
Body Paint: $100 without basic mod $75.00 with basic mod (hammered finish)
Clear coat upon request
NOS GE 6072A tube:  Upon request
NOS EF86 tube: Upon request
Transformers and capsules are priced upon request. Some of the capsules are foreign and exchange rates change daily.
Submini Tube mods 
Submini tube mod pricing 
 The submini tube mods that I do, take your donor body and capsule and I make a custom circuit board to fit the mic and the tube. I supply and install the transformer. The capsule may be your stock capsule or optional capsule of your choice.
The mod can be a single pattern or multi pattern.
The submini tubes that I use are the 5703 and the 5840.
These tubes both have a big bottom end.
 The 5703 is a single triode that is similar to the AC701.  It  has a nice low end that works well with the brite capsules. It is rich and full and has a nice midrange detail.
The 5840 is the tube that David Royer made famous with his MXL mods and his Mojave microphone. I use a different circuit and power supply.  The tube sound is full and balanced.
Submini tube mod
5703 or 5840 with a Cinemag transformer :                              $450.00
Single power supply:                  $50.00
Multi pattern power supply:     $75.00
Jensen transformer:                   $50.00 
ADK Vienna or
Hamberg capsule                         $75.00
ADK TT Capsule                         $100.00
JJ12 edge
terminated dual                           $100.00
JJ67                                               $100.00