View Single Post
Old 27th May 2009
  #16
Lives for gear
 
Tube World's Avatar
Quote:
Originally Posted by drtaudio View Post
Hello, I think you mean the Peluso 2247SE compared to our CM47?

The capsule in our CM47 is made from the same brass metalwork as the Peluso used in the 2247SE so it is basically a CEK367 capsule but it is skinned in China to our specifications. Once the microphone arrives here we check them to make sure they are consistent and we have plenty of replacement capsules. We also polarize the capsule in our CM47 at the same voltage as the original U47. As the polarization voltage increases the upper midrange response of the capsules increases and the capsule becomes more sensitive. We also take care to make sure the capsule is mounted at the same height in the head grill as the original U47 which helps diffuse some of the sibilant frequencies.

The CEK367 and the CK67 capsule that we use in our CM47 has a low to midrange response similar to a K67 capsule used in the U67 and U87 Neumann microphones. The high end is not quite as bright as the K67 but a db or so brighter than the K47 capsule above 5khz to 14khz.

The 2247SE uses a traditional Neumann type single stage tube circuit with an older metal UF14 type tube which can be very expensive to replace as is the tube in the Wunder Audio C47. In my 45 years of experience working with tube circuits I cannot justify the extra expense of these esoteric old metal tubes compared to the later more HiFi specs of the 6072 which are still very reasonable. However, the circuit must be optimized for the 6072 which is what we spent a lot of time doing.

With our microphone if the tube fails which is unusual you can simply pull a 12AT7 from any Fender tube guitar amplifier and put it into the CM47 with about a 2db difference in level. You will be able to finish the vocal session without having to order in a tube that can cost nearly half as much as our CM47 microphone.

We use a two stage tube circuit which has a front end (capsule to tube circuit) similar to a the ELAM 251 and the second half of the 6072 is configured as a CF output line driver amp that feeds the same transformer as the 2247. The transformer is a dual bobbin with a BV8 turns ratio and the CF output drives this very nicely as it is a great choice for driving transformers because of the fast damping fact.

The Wunder Audio C47 uses a larger transformer based on the original transformer used in the first 200 Neumann U47 microphones. These transformers were wound onto a power transformer core and the HF response rolls out quicker than the later transformers. This is why the Wunder C47 is darker sounding.

In our CM47SE which are custom build we use the Peluso PK47 capsule which has the same single backplate and drilling pattern as the original K47 capsule used in all U47 microphones made after 1958. The lower midrange has a bit more authority in the PK47 when used in Cardiod and the proximity effect is a bit wider.

Interestingly, during my tenure at Ocean Sound in Vancouver we had two U47 microphones. One was made in 1953 and the other in 1958. One was darker than the other but both microphones sounded very good. However, the difference between these two stock U47 microphones was greater than the difference between any two of our CM47 mcirophones.

Recently, Paul Hyde of the Payolas was recorded with our CM47 and CM12 for his latest Solo CD. In solo the CM47 was the overall choice of the producer and engineer but when the two microphone were compared to each other in the track the brighter CM12 was chosen.

As Kirk states, the CM47 can sound almost identical to the C47 with just a tweak of EQ which can save you nearly $6000.

Cheers, Dave Thomas
Advanced Audio Microphones
Dave, please advise what kind of warranty you have on your mic's.

Thanks