Page 15 of 17

Re: GReg-Electrical Tech Journal Redux

Posted: Thu Jul 17, 2025 4:27 pm
by Greg
Studio B-

Condenser mic connected to the mic pannel channel 16 not working.

Bad shield connection for that mic snake pair to the patch bay punch block. Re-punched, and checked the other pin 1s.

AKG CK1 capsule has quiet popping noises on a bunch of different 451s.

I'm going to see if the humidity is getting to it buy sealing it a bag with some desiccants, then testing it again after a month. Just curious...

Neve 3115 #2 gain switch jumps in level unpredictably.

Could not reproduce. Input patch point was really dirty, however. Maybe it's as stupid as that...

Re: GReg-Electrical Tech Journal Redux

Posted: Mon Aug 04, 2025 6:12 pm
by Greg
Studer A820MCH (1" version)-
Parameter Data Loss error message showing on power up. All the presets and calibration settings resort to factory defaults.

Pulled all the MPU cards and checked their batteries. A couple of the cards didn't have the reset modification done, so I did that, and erased all the RAM chips. Replaced a particularly grungey looking ic socket, and suspect solid aluminum cap. Installed, made "soft" changes, powered down and back up again to see if it remembered. It did. I'll check again tomorrow and the next day.

A day later, the memories are storing, but the meter bridge would stay in self test mode until I reset the MPUs. This problem doesn't reoccur regularly. Awesome.

Later-
Replaced battery, and RAM chip in the MPU VU panel.

Re: GReg-Electrical Tech Journal Redux

Posted: Tue Aug 05, 2025 4:56 pm
by Greg
Schoeps 221b "RTF" version.

Something loose rattling inside the mic.

Discovered a loose set screw in the capsule assembly (no where near the diaphragm). It's one of 6 that mount the outer housing to the inner collar.
I put it back.


Fuffling noise when handling the cable near the mic side.

Strain relief chuck was loose, and wires were a bit crushed at the solder cups. I cut back the cable and resoldered everything nice and fresh.

Built another passive guitar splitter for FM Tim Midyett

Re: GReg-Electrical Tech Journal Redux

Posted: Fri Aug 08, 2025 5:22 pm
by Greg
Finished more DI Boxes.

Looking around for a neighborhood noise...

Re: GReg-Electrical Tech Journal Redux

Posted: Fri Aug 08, 2025 5:27 pm
by tallchris
Greg wrote: Fri Aug 08, 2025 5:22 pm
Looking around for a neighborhood noise...
Oh no, those printers get back out in circulation?

Re: GReg-Electrical Tech Journal Redux

Posted: Mon Aug 18, 2025 6:04 pm
by Greg
tallchris wrote: Fri Aug 08, 2025 5:27 pm
Greg wrote: Fri Aug 08, 2025 5:22 pm
Looking around for a neighborhood noise...
Oh no, those printers get back out in circulation?
No, thankfully. This one ended up being our HAM radio neighbor. He was part of an encrypted mesh network, which involves repeating signals, or broadcasting verification signals occasionally. His antenna's 15 feet away from Studio B's wall... Going to see if he can put it on top of their roof (5 stories higher). The interference dies down significantly with distance (inverse square law).

At least it wasn't some piece of equipment, like a half a million dollar induction oven in the new restaurant down the block. Ugh!

Re: GReg-Electrical Tech Journal Redux

Posted: Tue Aug 19, 2025 10:56 pm
by Greg
Studer horseplay. Updates above...


-Elsewhere-


Finished and tested a version of my MXPre amp - two channel rack with front and rear Inputs + DI inputs.

Re: GReg-Electrical Tech Journal Redux

Posted: Wed Aug 20, 2025 4:53 pm
by Greg
Neumann U67 n. 5714-
Low rumbling noise.

Replaced tube with a fancy Mullard 6267. After 4 hours so far so good. Also refreshed the connection to the capsule assembly.

Re: GReg-Electrical Tech Journal Redux

Posted: Thu Sep 04, 2025 4:51 pm
by Greg
Coles 4038
Stretched ribbon

Royer 122
Stretched ribbon

Re: GReg-Electrical Tech Journal Redux

Posted: Mon Sep 15, 2025 1:33 pm
by Greg
Update to the M201 post above.

Beyerdynamic M380 (test stooge)

Replaced the old replacement headphone driver with the one remaining "good" one we had. I was reluctant to do this for a while, because I think the problem is the vintage diaphragm material degrades over time, nothing do to use, but because of what they're made of. Another reason being, it had a "STILL FARTING" label Steve wrote on it. Running out of these little "notes".