Replaced capsule in 3 pattern mic but only figure 8 is working

[pderbidge]

Here is an pic that captures the angle of the TAC1100 headbasket. You can see that It's not quite like a U87 as the mesh goes up a bit more before angling off. My Rode NT2a headbasket is probably more U87ish so I have no idea how this might affect the sound but thought someone might be interested. Still, the TAC1100 headbasket is more U87 like than the P420 (obviously) for what it's worth. I don't have a real u87 to compare to the TAC1100 so I'm basing that off of my observations of pictures of the U87 online.

 

[pderbidge]

Here's another angle for another perspective. Notice how the angle does not come all the way to the bottom of the screen/mesh. In my previous pic there is the illusion that one side is different from the other. This is NOT the case. both sides of the headbasket are exactly the same. Camera angles can play tricks on the eyes.

 

[157audio]

Thanks for posting what you posted! I agree, without mods it has a pretty good sound. I like it better with the flat k47, but stock it is lower certainly useable.

I was going to post here today that they put the mics back at their sale prices. It’s most definitely a good deal.

The tac700 was much easier to replace the capsule by the way as the board is all one piece, and the xlr connectors are part of that board as well. It also has a round headbasket. But, I do feel like the circuitry in the 1100 may be a better fit with the capsule. Maybe it’s the transformer giving it some weight or something.

I’ll post some pictures of the 700 when I get a chance. I’m fighting the flu/cold/respiratory thing that’s going around so when I’m not feeling like a truck ran over me…

 

[micolas]

Hi @157audio !
Did you buy the TAC1100 mics directly from the Adorama store in New York?
I'm very sorry that I can't buy it here in the EU.

 

[157audio]

Yes, I live close to the city and picked up the second batch of them in person.

As I browsed other mics though in the past couple of weeks, I get the feeling that this same mic is out there under other names. There’s a CAD 3000 mic that I wonder if it’s the same (I think that was the model). Externally it certainly looks the same but internally may be very different, I don’t know.

If anyone has experience with other mics that may be the same, can you post this models here in case people are in that situation of not being able to order from adorama? It sounds to me like it’s been determined that 797 Audio made these.

 

[micolas]

Yes, I live close to the city and picked up the second batch of them in person.

As I browsed other mics though in the past couple of weeks, I get the feeling that this same mic is out there under other names. There’s a CAD 3000 mic that I wonder if it’s the same (I think that was the model). Externally it certainly looks the same but internally may be very different, I don’t know.

If anyone has experience with other mics that may be the same, can you post this models here in case people are in that situation of not being able to order from adorama? It sounds to me like it’s been determined that 797 Audio made these.

Yes, they are rebranded 797 CR86

 

[pderbidge]

Yes, I live close to the city and picked up the second batch of them in person.

As I browsed other mics though in the past couple of weeks, I get the feeling that this same mic is out there under other names. There’s a CAD 3000 mic that I wonder if it’s the same (I think that was the model). Externally it certainly looks the same but internally may be very different, I don’t know.

If anyone has experience with other mics that may be the same, can you post this models here in case people are in that situation of not being able to order from adorama? It sounds to me like it’s been determined that 797 Audio made these.

The CAD 3000 is a flat circuit without negative feedback, so it's different.
http://recordinghacks.com/microphones/CAD/GXL3000

As far as I can tell, the tac1100 is the only multipattern mic with negative feedback and u87 style of headbasket in the low budget chinese brand of mics, which makes it an intriguing mod platform for sure.

 

[micolas]

There’s a CAD 3000 mic that I wonder if it’s the same (I think that was the model). Externally it certainly looks the same but internally may be very different, I don’t know.

If the TAC1100 schematic you drew is good then CAD GXL3000 is different.
His audio circuit is a 2 stage design, with the 2SK170 jFET feeding an emitter follower (a second BJT stage).
That allows the use of a cheap lo-tech output transformer (low ratio ~ 2:1)

 

[157audio]

I’ll have to take some time to digest what you all just said and try to understand it!

Does the negative feedback you speak of address the peak inherent in other capsules? I know that I like the way the flat 47 sounds in it.

 

[micolas]

I’ll have to take some time to digest what you all just said and try to understand it!

Does the negative feedback you speak of address the peak inherent in other capsules? I know that I like the way the flat 47 sounds in it.

NFB (negative feedback) is a circuit that performs a process of injecting a fraction (as level and frequency band) of the amplified signal, back to the input but with the phase reversed. Thus, certain frequencies are reduced, attenuated, at the same time distortions and noise are also reduced.
So the electronic circuit is not flat.
U87, for example, uses capsules with exaggerated highs, then through the deemphasis circuit, i.e. through NFB, it reduces those exaggerated high frequencies, avoiding the own noise of the electronic circuit, and makes the sound flatter,with less distorsions.

https://en.wikipedia.org/wiki/Negative-feedback_amplifier