Sony c48 half faulty
« on: June 23, 2019, 02:53:23 PM »
Hi,
I've got a used sony c48 mic recently and it sounds really good and clean, but it works only on the cardioid pattern.
How can I check the back capsoul?
Is there any typical problem with these mics. Someone mentioned that the pad switch might be faulty.
Any guide is helpful.
Thanks


duantro

Re: Sony c48 half faulty
« Reply #1 on: June 23, 2019, 04:50:38 PM »
Check capsule cleanliness. The foam in the cases are prone to drying out and flaking.

Re: Sony c48 half faulty
« Reply #2 on: June 24, 2019, 08:21:02 AM »
Hi,
It's not in its original case. Once I tried to open it in order to see the physical condition of the capsuls, but couldn't find the manual. I afraid to brake it.
Any clue?

Gus

Re: Sony c48 half faulty
« Reply #3 on: June 26, 2019, 05:53:51 AM »
Do a search for
"Sony C microphone manuals"

duantro

Re: Sony c48 half faulty
« Reply #4 on: June 26, 2019, 11:09:08 AM »
Flip the battery cover open, I'm pretty sure there are screws in there holding the headbasket on. Also be very careful if cleaning capsule. It's easy to destroy with one wrong move.  If you decide to let it go let me know.
« Last Edit: June 28, 2019, 06:38:57 PM by duantro »

Gus

Re: Sony c48 half faulty
« Reply #5 on: June 29, 2019, 08:57:11 AM »
Did you find the manuals?
look at the gearslutz one that should show with a search.

Re: Sony c48 half faulty
« Reply #6 on: July 10, 2019, 07:23:09 PM »
Hi
Thanks for replies. I could find one manual for c48, but it doesn't specify much about disassembling or servicing!

Gus

Re: Sony c48 half faulty
« Reply #7 on: July 11, 2019, 04:51:09 AM »
I just searched for
"Sony C microphone manuals"
the gearslutz link has a service manual

Sredna

Re: Sony c48 half faulty
« Reply #8 on: July 18, 2019, 06:03:32 PM »
I have a service manual for the C48, send me a PM...
Hmm... in which direction do the electrons actually go?

duantro

Re: Sony c48 half faulty
« Reply #9 on: July 19, 2019, 10:53:53 AM »
Sredna, your inbox is full


Re: Sony c48 half faulty
« Reply #10 on: July 20, 2019, 06:10:36 AM »
Sony C48 service manual attached, best,
Matteo

Gus

Re: Sony c48 half faulty
« Reply #11 on: July 20, 2019, 09:11:07 AM »
The above link  shows the same the manual that shows up in the gearslutz thread link.

If the capsule was replaced with a non isolated backplate you would have this problem.
Can you tell if the microphone was opened and worked on before?

Check the capsule to make sure it the same style as the first 87 with isolated backplates.

Check the switch for the pattern control with a ohmmeter.  Do the LEDs change?  if so you know one side of the pattern switch works.

The pad switch reduces capsule voltage this should not have anything to do with your issue.

The circuit is very much like the early u87 circuits.
« Last Edit: July 20, 2019, 09:44:03 AM by Gus »

Re: Sony c48 half faulty
« Reply #12 on: January 31, 2021, 01:16:14 AM »
Hi,
After long time, I could find someone who can take a look at this mic.
He said there seems nothing wrong other than an small hole on one diaphragm.
Is there any chance that I can find the exact replacement?
Any other replacement?!
What's the sony contact in this case?
Thanks

Gus

Re: Sony c48 half faulty
« Reply #13 on: January 31, 2021, 10:43:03 AM »
There is a possibility you a high resistance connection between the two screws in the picture.
The gold might be touching the backplate at the bottom hole, it looks like the gold covered Mylar is pushed in.
You might be able to test for resistance but you need to be mindful that DMMs have an upper limit of resistance some go to 50 meg ohms and anything above that will show as an open

The capsule should still work if the two are not touching. IF this was my capsule I would make a tiny hook to pull the bigger hole flap of Mylar out and try the microphone again

Is that the front or back side of the capsule?

Using the schematic draw out the capsule switching with the two points connected.

Do you have an inexpense China k67 k87 type isolated backplate capsule you can sub in to test the switch parts?

 
« Last Edit: January 31, 2021, 11:25:49 AM by Gus »

Re: Sony c48 half faulty
« Reply #14 on: January 31, 2021, 07:50:19 PM »
It's the back side. The front side sounds really good and clean.
Unfortunately, I don't have any other capsul, but if I don't find spares, I need to think about modifications.
I realy like the characteristic of this mic, that I don't want to miss it after the mod, but I need the figure 8 for my project in hand.
I will inform the technician who's working on this with hope.
« Last Edit: January 31, 2021, 08:00:55 PM by Aref »

kingkorg

Re: Sony c48 half faulty
« Reply #15 on: January 31, 2021, 08:20:49 PM »
I would personally try the same Gus suggested. The membrane probably shorted out, so if you have someone with steady hands, or confidence to do it yourself, try to pull out the part of the diaphragm that got inside.

I even repaired a hole on an Octava mic by closing the hole with a tiny piece of thinnest tape i could find. It measured no change in tone/performance.

The interesting part is that in cardioid mode the mic probably sounds better than stock because of that hole! It probably has great low end. I had a u87 with a similarly damaged back diaphragm, and it sounded better than the other one which was 'stock', consecutive snr.

You can have someone re-skin it, possibly bring it back to spec, but i am afraid you won't get the same sound out of it.

Iirc Klauss Heyne moded some k67 capsules on Neumanns by making small holes in the membrane part that's not gold sputtered.
« Last Edit: January 31, 2021, 08:26:51 PM by kingkorg »

Re: Sony c48 half faulty
« Reply #16 on: March 09, 2021, 01:50:28 PM »
I've got good news from the technician friend who's helping me working on the mic.
He managed to lift the membrane part which shorted out and now the mic is working on Omni and Cardioid patterns, but not on figure eight (Actually there is a sound, but very quiet. Blowing in it brings back the signal higher for a second, but it's too noisy). He also swapped the wires of the diaphragm with each other and still no sound on 8 pattern.
He checked the pattern switches, but he can't check the resisters because of his tool limitations.
Please direct us to repair that pattern. I desperately need it for MS recording.
With respect
« Last Edit: March 14, 2021, 04:50:47 PM by Aref »

Re: Sony c48 half faulty
« Reply #17 on: March 13, 2021, 04:55:01 PM »
Do you recommend exchanging the 100m resistor on the figure eight pathway with the one in the Omni circuit?
Please, tips will be so helpful.
« Last Edit: March 15, 2021, 12:24:36 PM by Aref »

Gus

Re: Sony c48 half faulty
« Reply #18 on: March 20, 2021, 10:00:43 AM »
I would try another capsule if possible you still could have an issue with the capsule

Re: Sony c48 half faulty
« Reply #19 on: April 07, 2021, 03:34:00 PM »
I don't have any other capsules.  :-\
According to the schematic, C1 and C7 are related to stage one amplification. and any problem with C1, C2, C3, C5 might cause such a problem.
Should I check that first?


 

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