Check out the "C12s" I made..

Lets hear em!! Post up a sample. They look great.

Check the first post, there's a little link right before the pictures.  The files were too large for this message board, so you'll have to go through Box.net.  I couldn't find a more convenient way to do it, that's just one extra click.  There's a little player right on the Box.net screen you can listen on.

TonyCamp-- They started as Apex 460s, and went through many revisions (almost past 251 and C24 but not quite, but those were cool sounds) and ended up very close to the vintage 1953 AKG C12 schematic.  One of the most important revisions was modding the PSU to provide -1 Volt tube bias on pin 4 of the cable.  That really kicked into "vintage C12" mode, or as close as I'll get.  The transformer is a Peluso T14-1, which has a slightly higher turns ratio than the vintage specimen.  The capsule is the Peluso CEK-12.  When you adjust the high frequency just right, this capsule is very smooth and buttery or whatever, but, if you let the high end run free, it will just rip your head off and sound so thin.  Too much dampening is not good either.  Peluso is nuts in his love of brightness, but he is almost genius otherwise, if you can find ways around his brighter tendencies, which I have here and in my 2247 SE.  The trick in this mic was to use a 100 pF cap like the ELA M251 to roll off some of the very top.  This was the main deviation from the C12 schematic, but it made so much difference with the CEK-12, all the difference in the moon, actually.  I used a silver mica cap, and I like the tone.  Tube is a JAN GE 6072a, which is quite a bit beefier than the somewhat decent baseline $10 EH tube.  Gotham tube mic cable, Neutrik connectors, polystyrene, polypropylene film, and Russian paper-in-oil caps (for the big cap), some Dale, Vishay, and Ohmite resistors (haha).  I used your duct seal trick in the heads!  Headbaskets are from Chunger, they really set the thing off, and I swear they sound good, too.  Shockmounts are imported by a company called Acme I think, they weren't quite the right size and I had to modify them.

I must say, I am absolutely sick of working on these mics and I am so pleased with how they are now, I can't wait to use them on a session, try them on overheads again (since the final tweaks), a female again, find a piano, etc.  I also can't wait to tackle a 251-style build, hopefully with a little more quickness.

I am even considering trying to sell a few, if anyone is interested.

Are those Peluso T14/1 a copy of the Hiller T14 or the Haufe T14/1? I'm gonna have to ask John.

How do you feel about Peluso's 251 model? And the VTB? I have both. I found his 251 to be really really nice, not really getting a sense of the high end deal you're talking about with that mic though. I've opened them both up, pretty simple designs. There are some things in there though that could be changed that might possibly improve the smoothness, like replacing the electrolytic's with Elna's. I love those caps, they're great, but the size's and value's are somewhat limited and sometimes you've got to be creative with making space if the cap has the same value but is larger. 

Cool C12 reps though, I'm thinking about doing one myself on the apex frame. I'd def go Peluso for the capsule, probably do a lot of the same as you did with changing up some values and cap/resistor choices. 

I haven't tried the 22 251, it sounds bright to me in demos, though. I don't know anything about the VTB.

My 2247 SE was "modern" sounding kind of bright, never harsh. I softened it up a bit with an old red NOS RCA tube. And also swapped the Xicons (don't like) for Vishay/BC Blue caps which I like better, just like you said. I do like the Elna Silmic II caps I have tried in other things. I liked opening up that mic, the work is really neat on the inside. One day I'm going to try a Thiersch Blueline M7 capsule...

The CEK-12 capsule itself was incredibly bright, I couldn't handle it, I had to dampen it a bit. You could apply the same technique to the 22 251 if you wanted to, probably. I haven't looked at that circuit.

The CEMC6 pair I had was a bit painfully bright, so I sold them. They did have some cool realness and detail to them though.

That's most of my Peluso experience to date.

@sinsay...

I would love to hear what Shannon could do with a 2247LE...Isn't it an EF12 or EF14 or something? Then put one of Shannon's caps in...

Shannon has kind of convinced me that the capsule is 75% of the sound - but the Miktek does seem to have a beefy AMI tranny in it already, so maybe that's why it's such a good starter mic. I'm gonna keep a look out for a used 2247 and see if I can get @sinsay to dead out match one of Blackbird's 47's...

Thanks! No it's good, I like this Peluso modifying idea, it's what I'm doing to mine. I like the general quality of discussion on this board, it seems higher than average, not a lot of low level beginner issues and whatever.

Well, Tube LDCs are essentially PSU modulators when you think about it.

My experience with PSU on cheap anything, is they just barely have enough to meet minimum voltage and current requirements, they usually suffer when pushed, and offer no headroom causing that lurchy strident thing. 

Great post, svart.

The Apex 460 is already really close to the C12 and 251.  Just swapping a couple wires and you are already mostly there.  Reduce the 100nF output caps to 1nF(or remove them) and put in a 12AT7 or 12AY7 and put in an edge terminated capsule and you have a C12 clone.  Add a couple more parts for a 251.

No need to change transformers to expensive things.  Changing the output caps fixes the transformer overshoot, and changing the capsule fixes the pre-hyped K67 capsule issue.