Sony C37A clone?

Thanks Marik.
In any case, as it appears Sony are not only still making this capsule, but making it available for a reasonable price, it would seem out of bounds for fair copying (except perhaps for experimental purposes).

I'm more curious as to how it compares in design with Dale's capsule, which was different in that it was center-terminated, but did at least have the 16 blind and 4 through holes in common.

cheers
Dave (shaggy)

shaggy said:

I'm more curious as to how it compares in design with Dale's capsule, which was different in that it was center-terminated, but did at least have the 16 blind and 4 through holes in common.

Click to expand...

The one I have here has 8 through holes. Probably this is to compensate for a lack of additional chamber of the original capsule. Other differences are the original capsule has a tunable diaphragm tension and its OD is larger.

Generally, this capsule is not very complicated--it has a single backplate with only 20 holes to drill, with no tapping involved and a plastic piece (which is a bit more involved). Its main setback is a low output and high noise, so if used in a tube mic you might have hard time finding a very quiet tube...

Best, M

shaggy wrote:

"Maybe just another close-up of the front side? "

"PS - And could you measure the OD? 8>]"

Here you go.

FWIW - There is a protective plastic ring around the capsule that is removed when mounting, it might be adding a mm or so to the micrometer's reading.

Joe

Thanks Joe, much appreciated!

Dave

Marik said:

Also keep in mind this capsule uses higher than normal bias voltage at 120V.

Best, M

Click to expand...

Marik, are you sure it is that high? I've read the polarization voltage is higher than usual, but 120V seems a lot for an LD capsule.

About the Dale capsule. I think I remember Dale stating that the Sony capsule, while not center terminated, had some sort of mechanical support in the middle, so it basically behaves like a center terminated capsule.

BTW: Josephson Engineering's C615 microphone uses a capsule that is very much like those old sony capsules. It's a very natural sounding microphone combining many of the desirable attributes of LD and SD designs.

These capsules being low output and sounding fairly uncolored, I think a clean solid state circuit (such as Josephson's) likely complements this capsule better than a tube circuit. Also keep in mind that Sony used a cathode follower circuit, which is about as uncolored as tube circuits can get (with the downside of about 6-12 dB gain loss in the step down transformer).

IMO a good match would be a unity gain FET circuit.

Rossi said:

Marik said:

Also keep in mind this capsule uses higher than normal bias voltage at 120V.

Best, M

Click to expand...

Marik, are you sure it is that high? I've read the polarization voltage is higher than usual, but 120V seems a lot for an LD capsule.

Click to expand...

Rossi,

In fact, it is 140V. It is not even about SD or LD capsule, but mainly the distance to backplate and stiffness of the diaphragm tuning. Also interesting thing, the oscillation spec'd pretty low at 20Hz.

Rossi said:

About the Dale capsule. I think I remember Dale stating that the Sony capsule, while not center terminated, had some sort of mechanical support in the middle, so it basically behaves like a center terminated capsule.

Click to expand...

Not sure what he means. There is no any mechanical support there, but a glued piece of film to prevent the diaphragm from sticking to the backplate...

Rossi said:

BTW: Josephson Engineering's C615 microphone uses a capsule that is very much like those old sony capsules. It's a very natural sounding microphone combining many of the desirable attributes of LD and SD designs.

Click to expand...

I am sure you meant C715--very interesting microphone with foamed Aluminum as a head grill.

Rossi said:

These capsules being low output and sounding fairly uncolored, I think a clean solid state circuit (such as Josephson's) likely complements this capsule better than a tube circuit. Also keep in mind that Sony used a cathode follower circuit, which is about as uncolored as tube circuits can get (with the downside of about 6-12 dB gain loss in the step down transformer).

IMO a good match would be a unity gain FET circuit.

Click to expand...

Yes. Actually, some gain in the head preamplifier would not hurt, either...

Best, M

Yes, sorry, I meant the C715. A very unique mic! Josephson uses a transformer coupled FET circuit and is about as low output as the Sonys .

A unity gain circuit would give quite a bit more sensitivity, and that's probably what I'll be doing next with my Dale C37 and C800 style capsules. I did, in fact, build a circuit with some additional gain (about 10 or 12 dB, IIRC). I was quite happy with that mic ... until I compared to the Josephson C715. The Josephson just sounded cleaner in a pleasant way.

You wouldn't think headroom is a problem with a low output capsule like this, but it has excellent transient response, so high peak voltages may occur. And I think i did compromise that by adding some gain in my circuit. Thats why I think a unity gain circuit may be best for this sort of capsule as it gives high headroom and decent output.

BTW, anybody had chance to look into Groove tubes MD-3 Josephson capsule design more closely?

I also found an old thread where J.J. Blair said:
"...a friend called Sony and the C800 capsules are available for $590, each "
http://repforums.prosoundweb.com/index.php/topic,22407.45.html
So is it possible that more than a twice price difference over 38B capsule is just due to sony'  replacement parts marketing? Or C800 capsule is in fact a different one?

moomilk said:

BTW, anybody had chance to look into Groove tubes MD-3 Josephson capsule design more closely?

I also found an old thread where J.J. Blair said:
"...a friend called Sony and the C800 capsules are available for $590, each "
http://repforums.prosoundweb.com/index.php/topic,22407.45.html
So is it possible that more than a twice price difference over 38B capsule is just due to sony'  replacement parts marketing? Or C800 capsule is in fact a different one?

Click to expand...

c800g capsule is a exact copy of k67 directly interchangeable. I've done it quite a few times with no sonic differences.

Price markup is that Sony make it.

As far as I know C800G and C800 have different capsules - the one in C800 suppose to be very closely related to C37A

moomilk said:

As far as I know C800G and C800 have different capsules - the one in C800 suppose to be very closely related to C37A

Click to expand...

I believe thats correct from my memory but I've never seen or used one.