797 Audio CR998 Guts Pics

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Recording Engineer

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There was a bit of interest, so here are a few HUGE pictures of inside one if my 797 Audio CR998, that I took quite some time ago.

Power supply pics were requested also, but I need to get a hold of that digital camera again.

http://home.comcast.net/~mw18/Pics.html
 
but at least it does have a tube in it :D I'd also be interested how it sounds like
 
AllOrNothinEnt,

How so?

Rest,

How it sounds on what? I'm not gonna try to describe it with words... That's pretty damn pointless.
 
Remember this is an older design from the 797Audio factory. It reminds me more of the MXL V69 than of a SP design. Although I must admid I haven't looked inside a SP *tube* mic yet.

Well, the cap floating above the PCB does look a bit funky, but otherwise it doesn't look that bad to me. The caps are quality Wima film caps (the SP B1 I once opened has those too). And it's a true tube design, no silicon in the signal path. The output is transformer ballanced which may or may not be a good thing, depending on its quality. The MXL V69, by contrast, is transfomerless, which to many tube enthusiasts is a no no, but I found it to be a very decent sounding mic.

Component-wise I'd say this mic looks a bit better than an MXL, especially when it comes to the caps. But that doesn't necessarily mean it sounds better, too. The good thing about MXL and SP is that they cater to western tastes, which are quite different from Asian tastes. What sounds good to a Chinese engineer may sound harsh to an American or European guy. But that's a cultural thing, not a matter of component quality.

Anyway, that's my two cents. So what's the sound like?

BTW: note the replacement tube in the case!
 
It sure doesn't have the cheap run-of-the-mill Chinese transformer I'm used to seeing. Do the MXL tube mic transformers look anything like this?

Gus, if you're looking at this, tell us what you think.
 
Thanks for posting this, RE

AllOrNothinEnt said:
That does NOT look like quality to me.
Click to expand...

I dunno, it looks pretty clean and good to me, but I don't know shit.
 
RE,

Thank you for posting it. The capsule is a Neumann style, so there is no way that this is an AKG C12 clone, as somebody wrote earlier. The pencil marks on the capsule suggest some kind of QC. As Rossi wrote, the Wima capacitors are better quality ones, the resistors look like carbon and metal film, except of bigger one, which is metal-oxide. The transformer also looks of better quality--it is potted, and definitely doesn't look like chipo MXL stuff.
RE, if somehow you'd be able to make pics of traces I can draw schematics.
 
In case someone didn't already know, at one point (when all these mics were released):

Studio Projects T3 = 797 Audio CR998 modified with Studio Projects specified changes
797 Audio CR998 = ADK A-51TT - Both by 797 Audio
797 Audio CR100 = ADK A-51TC & MXL V77

From what I understand, last I heard, 797 Audio only deals with Studio Projects now, so...

I've some VERY exclusive info on the CR998 design... Now that you've seen its guts, tell me what it is; especially you AllOrNothinEnt, since you seem to know so much about the look of quality.
 
Marik said:
The capsule is a Neumann style, so there is no way that this is an AKG C12 clone, as somebody wrote earlier.
Click to expand...

Now we're getting somewhere... You're absolutely correct! A Neumann-style cap and NOT a C12 clone! I bet you'll get pretty close to what kind of clone it is, but even then, we're talking it potentially having a whole different ball-game here.
 
Marik said:
RE,

Thank you for posting it. The capsule is a Neumann style, so there is no way that this is an AKG C12 clone, as somebody wrote earlier.
Click to expand...

That was me, and I was actually asking if anybody knew because I had heard something to that effect. Anyway, this is very interesting and I'm looking forward to your further examination and comments on this mic.:)
 
Most of the current mics out of China appear to use circuit designs that share a similar heritage.

While I waited.....and waited.......and waited for these pics to d/load, I opened up my SP T3............and while there are similarities. there are some differences in component values and layout, so they are not direct copies of each other.

Hope that satisfies inquisitive minds.

:cool:
 
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? ;)
 
ausrock said:
I opened up my SP T3............and while there are similarities. there are some differences in component values and layout, so they are not direct copies of each other.
Click to expand...

Right... Essentially what I said.
 
Marik said:
The capsule is a Neumann style, so there is no way that this is an AKG C12 clone, as somebody wrote earlier...
Click to expand...
Yep, I noticed that too - you can tell right off it's a 797 Neumann style capsule. I didn't catch the eariler comment about it being like a C12.
 
AllOrNothinEnt said:
That does NOT look like quality to me.
Click to expand...

Electronically, it looks like a quality build. Mechanically, it looks like every other chinese 797 mic.
 
Flatpicker, the only MXL tube mic I saw "naked" was the V69, which is transformerless. There is a sealed (silicon) circuit, possibly made of SMD parts, which I suppose is the output stage. Even though it's not a pure tube design, the mic does sound good.
 
I like the multpattern 797 capsules. I have beringer B2 pro that I am going to use the capsule with a sony c800g type circuit I built.

The use of the bigger r wattage wise for the plate load it looks like a 100k to me helps with noise. The transformer looks different that other china built microphone transformers I have seen.

from the pictures it looks like it might be using a electro cap from plate to transformer. If so i would replace it with a film cap with the same ratings size and >=voltage.

The wima cap in the air is a good thing that is the very High Z section of the circuit. It also takes longer to build.

If the unit is cathode biased I would upgrade the electro cap across the cathode R.

I someone could trace the circuit I could give more suggestions

Gus
 
Hey Gus, thanks for the info on the hovering cap. I see you know your shit. I suppose it would be either very expensive or impossible to replace any of the electrolytics with film caps. From their size I would guess they're about 100µ. Perhaps RE could tell us the values.
 
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