[bradzatitagain]

Why did Sony consider cooling the tube so important as to add the Peltier thing?  Is it a typical expression of their major gadget wizadry muscle or is does the cooling have some other effect, other than cooling off the tube and mic body?  Duka, how's your Sony clone behaving?  Does the mic body get more hot than your other tube mics?

Gus, I bet you've got an opinion here.  I'm damned curious, I am.

[gyraf]

IIRC, they got some 0.3dB better noise figure out of the tube this way.

I would certainly classify this as a gadget. Probably for the high recognition factor. Having an extention like that in the proximity of a microphone's receiving field is simply plain stupid, IMHO.

Jakob E.

[dukasound]

Duka, how's your Sony clone behaving?  Does the mic body get more hot than your other tube mics?

I didnt put peltier element (I havent it and I dont know much about this kind of cooling).
I make my mike like you can see and put a can outside tube with a two holes and I have some cooling. I didnt see that is hotter then other mike (I mean my mic). I think that 6AU6 work hoter that 6072 or similar triode.
Duka

[bradzatitagain]

IIRC, they got some 0.3dB better noise figure out of the tube this way.

I would certainly classify this as a gadget. Probably for the high recognition factor. Having an extention like that in the proximity of a microphone's receiving field is simply plain stupid, IMHO.

Jakob E.

Yeah, especially multipattern.  I'd bet a thicker wall thickness for the mic body could absorb some heat also if it were a true issue.

It get's my gadget fetish twitchin' tho, very Borg.

[bradzatitagain]

nada, ...'pologies, dorked out for a second.

[Gus]

The cooling is most likely for holding the atoms in the tube against the wall
There is a a term called adsorbed(not misspelled)
In a vacuum system the atoms that are bouncing around tend to stay on cooler surfaces
If the atoms are on the cooler surfaces they are not in the tube elements volume

Do the C800Gs have water inside by the tubes when serviced? Idealy you would want the tube and cooling parts in a dry gas so water does not condense from the air.

[gyraf]

yes, on humid days, water collects inside 

[squarewave]

Do the C800Gs have water inside by the tubes when serviced? Idealy you would want the tube and cooling parts in a dry gas so water does not condense from the air.

This is just a guess but if the space around the cold side of the Peltier element is filled with something other than air (like some kind of dense foam insulation) then there would be no condensation.

I was tinkering with a Germanium circuit that used a small Peltier element to bias otherwise leaky Germ transistors. I scrapped the idea when I realized that condensation would be a problem.

[JohnRoberts]

This is just a guess but if the space around the cold side of the Peltier element is filled with something other than air (like some kind of dense foam insulation) then there would be no condensation.

I was tinkering with a Germanium circuit that used a small Peltier element to bias otherwise leaky Germ transistors. I scrapped the idea when I realized that condensation would be a problem.

Dead thread waking?

I have done some work with peltier devices, if you insulate the cold side or hot side with something other than air, the device will have difficulty moving heat around.

JR

[Tubetec]

It just looks odd with the protruberance , Ive heard the 6au6's dont live very long in them ,the grid resistor  of 1G on a 6au6 ,thats probably questionable too . The C37 and C800 are both cathode followers , I have a handful of teflon 7 pin tube sockets , so I will be having a go at the sony at some point ,I see some cheaper ribbon mics with a case identical to the pivoted C37's .The 800G is  all gone a bit mad with the cooling section its like something that belongs in a Dr Who episode , like a deadly weapon that can wipe out the planet or something , tube mics are normally excellent even under condensing conditions , but doing the peltier for the sake of .3db is a load of baloney , while making the mic more suseptable to moisture in the process.

[squarewave]

Dead thread waking?

I have done some work with peltier devices, if you insulate the cold side or hot side with something other than air, the device will have difficulty moving heat around.

?

The foam filler would be around the thing being cooled. For example, for a Germanium transistor you could have a little block of aluminum with a hole for it. Then the foam filler would go around that. With enough insulation the air would not contact anything cold and thus no condensation.

[gyraf]

Crud collected by condensation slowly builds up across the peltier, eventually shortening it. And the supercap usually dosen't like the shortening game..

Jakob E.

[squarewave]

Crud collected by condensation slowly builds up across the peltier, eventually shortening it. And the supercap usually dosen't like the shortening game..

Wow. That's a disaster. Foul on Sony.

Now imagine some of that expanding Polyurethane foam injected inside so that it goes all around the edges of that Peltier. The air would never come into contact with it and so there would be no condensation. At least not on the inside. Maybe the body would on the outside if the insulation wasn't that thick but at least it wouldn't short out anything inside.

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