797 Audio CR998 Guts Pics

  • Thread starter Thread starter Recording Engineer
  • Start date Start date
Recording Engineer said:
tdukex,

You PMed me, but I never got it because my Inbox was full. I'll explain here what I was going to explain in private, once the dust has settled a little.

I've had internal struggle whether or not to let the cat out of the bag on this, fearing it might do more harm than good. But I've come to terms that openess with FACT is that way to go and shouldn't hurt anyone; at least I hope not!

I honestly hope I'm doing the right thing here. Most of you will probably not care or understand and ask what the big-deal was and won't be impressed when I fully explain, but it's the REAL people and REAL company I have an great admiration and respect for, whom I don't want to hurt!

P.S. What's YOUR comments on this mic? ;)
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RE, I did get your PM explaining the details and history. VERY interesting. But since you PM'd me, I figured you wern't ready to share the information publicly, so I have remained quiet.

I have always loved this mic on vox, acoustic guitar, and clarinet (that's all I've used it for). It has a big proximity effect and a very clear and smooth high end to my ears. Of course, I am inexperienced as it is the only LDC I own so I don't have much to compare it with. The other LDCs I have used have been at school or in other people's studios, and all were budget items like the C3000 and the NT1--I didn't like either through a Mackie.

Keep the great info coming.
 
Im looking at the photo's and it looks like a KK47(M7 replacement) Capsule used in the later non glued U48's(U47 with more patterns) that are also common to the U48's. There is a strong resemblance to the 797 audio mic cosmetics to a U48 long body but the insides are.... well uh..different with the exception of the capsule. I thought most of the MXL line was based off of the U87i's and they play around with various components to make transfomerless one tube one etc... So it would make more sence to me if SP went to the U48/48 as a jumping off point just to keep itself in a different arena in the first place. Somewhere I have gobs of pdf's of alot of Neumann stuff I accidentally found. Pretty technical information if I remember, have anyone else stumbled on those too? Thats what I think I know about the pics.

Did you know green is my favorite color?

SoMm
 
The capsule loks more like the kk67/87 dual backplate. The k47 is a single backplate like the m7. The cap used from the plate to the transformer should be around 1 uf. 1uf polypro at 250V are not to big it could fit in there somehow.

This looks like a standard type tube circuit to me, you can hear different tubes make a change in the sound.

The v69 is a different circuit the tube is used as a anode follower charge amp, if I understand it correctly. Its more of an inverting buffer gain -1. this minimizes the tube sound do the amount of feedback used. I have two V69ms I only changed 3 caps in each it was more of a "taste" thing.
 
Yeah, I was about to say... But Gus got to it before I did!

So based on that, what do you think it's cloned after? Yep, you've got it! But even then, it's not cloned after a stock one. So we're talking a whole different ball-game here!

Come-on... Think outside the box! You're doing SO well!

I feel like a school teacher... I'm simply helping you guys teach ME! I sure as hell don't know this stuff... I just act like I do. :D Shhh... ;)
 
Recording Engineer said:
From what I understand, last I heard, 797 Audio only deals with Studio Projects now, so...
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Nope... 797 Audio is still making their own mics and for others besides PMI.

Alan Hyatt posted the following just the other day when (in another thread) we were talking about the Behringer B5 looking a lot like the SP C4.

alanhyatt said:
Brent should answer this one, but it is ot the same mic. Same factory which pissed us off a bit, but not the same mic. According to the people at Behringer and the inside details from 797, it is a different capsule and thickness, and different electronics. Brent keeps updating the C4's along the way.

It was nice for Behringer to honor us by taking our model numbers and look....
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Gus,

Welcome!

<The use of the bigger r wattage wise for the plate load it looks like a 100k to me helps with noise.>

Replacing this resistor with SS constant current source would make the biggest difference. If we had some space, the choke loading would be a very nice solution. However, 150H choke would be way too big. With the CCS load tube will see very large impedance from AC point of view and very small impedance from DC one.
Besides of sonic improvement it would also improve SPL handling. The output will be hotter, as the gain becomes mu of the tube.
 
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The microphone has elements of a few microphones. Neumann type capsule like used in the u87 u67. Body and color kind of like an AKG. 1/2 a 12at7 like of like a a neuman gefell um57. U67 use a plate load of 150K elam 251 with 6072s use a 100K.

Not tracing the circuit I don't know what one it is it could be something like um97 not sure if that the right model #. If it is about 200 v supply u67, 120v supply ela m251 etc etc. Doe the other side of the transfomer primary go to ground or to the top of the cathode resistor if it has one??????
 
Just a peripheral note on 797 audio. I only have two of their mics that I know of - the SP B1 and the Behringer B1. I had them both apart today, and the build quality of the mics is superior to the MXL's and far superior to the Oktavas I've seen. These things are built like brick shithouses with quality workmanship and components. I wouldn't hesitate to use either as a hammer to pound nails into the wall. :)

I don't have any higher end mics to compare them to, unfortunately.
 
Crazydoc, I've been saying the same thing about the SP B1 all along: it's almost unbelievable how well those mics are made. Wima film caps in a low cost mic is indeed an unusual sight. The PCBs look clean, too. Note also that the noise level is lower than that of MXL mics (although the MXLs' S/N is perfectly acceptable). I wish there was a SD mic in the B-Series ("B4" I guess).
 
Rossi, I agree 100%.

I think there is a rough parallel in mic design and construction today, to what happened in the optics/camera world after WW2. The sine qua non were the Leitz (Leica) and Zeiss products. Along came Japan with the copies (Nikon, Canon and Minolta among others), which were at first frowned upon, but have subsequently become the standards. The USSR gave it a try (Krasnagorst -Zorki, and Kiev Leica copies) but the build and durability were horrible.

Today I think we have a similar, albeit delayed situation with mics. The Chinese are emulating the standards (Neumann and Telefunken) and starting to do a pretty nice job. 797 Audio - the Nikon of mics!
 
So tell us already...

Recording Engineer said:
...I've had internal struggle whether or not to let the cat out of the bag on this, fearing it might do more harm than good. But I've come to terms that openess with FACT is that way to go and shouldn't hurt anyone; at least I hope not!

I honestly hope I'm doing the right thing here. Most of you will probably not care or understand and ask what the big-deal was and won't be impressed when I fully explain, but it's the REAL people and REAL company I have an great admiration and respect for, whom I don't want to hurt!...
Click to expand...

So, RE. When are you going to solve this puzzle for us?
 
crazydoc said:
Just a peripheral note on 797 audio. I only have two of their mics that I know of - the SP B1 and the Behringer B1.
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As I have just bought a SP B1 to go with my Berry B1. I would be interested as to you opinions re. the diif. in sound between the two. I have just started to do comparisons.

I agree about the build quality how can anyone complain for the money.

Tony
 
If I had the information RE put in a PM to tdukex, I think that would confirm my thoughts in regard to a correct answer.

RE and the rest of site admin are AWOL, so I wouldn't hold my breath waiting for any response.

:-)
 
RE has a day job right now to support his habit. He hopes to be back in the studio again soon, and back online once back in the studio. His HR connection sits right on his console.

I've got some new toys to share with him (C4, AT4040, V67M, D4, ATM23), and we don't have concurring schedules to hook up yet. I swear he's as busy as I am right now.
 
bgavin said:
RE has a day job right now to support his habit. He hopes to be back in the studio again soon, and back online once back in the studio. His HR connection sits right on his console.
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Then maybe he'd like to pass his moderator (non)responsibilities onto someone with more time and interest. This forum could use some moderation upon occasion when some of us children lose all control, and with RE there's just no one here.

This forum has more wasted bandwidth and more useless, uninformative and vitriolic posts than any other I have seen, although it does give us an outlet for our little tantrums.

With some moderation this place could be about microphones, and we could post our other stuff on www.fuckyouasshole.com.
 
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