Search found 2564 matches

by The Scum
Wed Feb 03, 2021 12:13 pm
Forum: Creative Recording
Topic: making a mix room in a long narrow space
Replies: 7
Views: 292

Re: making a mix room in a long narrow space

Reducing your longest dimension pushes low frequency problems up higher...it also cuts into space that you could use for treatments. Any regularly sized room is going to start out squirrley in the frequencies below 150 Hz or so. Room treatment can tame the squirrels. The high ceiling is a blessing -...
by The Scum
Wed Feb 03, 2021 12:00 pm
Forum: Creative Recording
Topic: Low Phantom power from 500 rack?
Replies: 58
Views: 1155

Re: Low Phantom power from 500 rack?

Keep following the Adj pin: What's beyond the 15k4 resistor?
by The Scum
Wed Feb 03, 2021 11:59 am
Forum: Creative Recording
Topic: Low Phantom power from 500 rack?
Replies: 58
Views: 1155

Re: Low Phantom power from 500 rack?

Analyzing a little more, the LM317 seems to be configured as a ~42V regulator. 475 Ohm feedback resistor, 15,400 ohm shunt. 1.25*(1+(Rshunt/Rfb)) = 41.77. (or use this calculator ) It it were standing on a 5 or 6V Zener, then we'd be in the ballpark. The regulator should develop a 1.25 V offset betw...
by The Scum
Wed Feb 03, 2021 11:29 am
Forum: Creative Recording
Topic: Low Phantom power from 500 rack?
Replies: 58
Views: 1155

Re: Low Phantom power from 500 rack?

Those are likely 1N400x, just basic power diodes, as shown in the datasheet. If the transformer gets disconnected, they discharge the output caps...as shown in Fig 15 of the datasheet. (No guarantee about what 1Nxxxx device is. They come in plain silicon, Schottky and Zener.) Can you trace the Adj p...
by The Scum
Tue Feb 02, 2021 9:42 pm
Forum: Creative Recording
Topic: "Studio Grade" stud finder.
Replies: 8
Views: 387

Re: "Studio Grade" stud finder.

So I got the Bosch. $75 at McGuckin hardware.

Initial experiments tell me that it's more repeatable than the zircon.

I'll really put it through it's paces doing baseboards on Saturday and report back.
by The Scum
Tue Feb 02, 2021 9:38 pm
Forum: Creative Recording
Topic: Low Phantom power from 500 rack?
Replies: 58
Views: 1155

Re: Low Phantom power from 500 rack?

The question in my mind is whether the regulator is standing on top of a zener diode, to boost it's operating range. If the zener failed short, the regulator would still regulate, just without the boost.
by The Scum
Tue Feb 02, 2021 5:09 pm
Forum: Creative Recording
Topic: Low Phantom power from 500 rack?
Replies: 58
Views: 1155

Re: Low Phantom power from 500 rack?

The circuit in the closeup of the 317 appears to look a bit like Fig 15 in the datasheet.

https://www.ti.com/lit/ds/symlink/lm117 ... 2289239523
by The Scum
Tue Feb 02, 2021 5:05 pm
Forum: Creative Recording
Topic: Low Phantom power from 500 rack?
Replies: 58
Views: 1155

Re: Low Phantom power from 500 rack?

OK, that LM317 is the one we're interested in. The 7915/7915 are +/- 15V voltage regulators, the LM317 is an adjustable regulator, the HVT is a version that can take a 60V max input. So it looks like they've bypassed a couple of the flakier design options with the HVT part. But the 63V you get at th...
by The Scum
Tue Feb 02, 2021 4:42 pm
Forum: Creative Recording
Topic: Low Phantom power from 500 rack?
Replies: 58
Views: 1155

Re: Low Phantom power from 500 rack?

In the top picture, center-left, there's a little black cylinder with a silver stripe on the end. Can you read any of it's markings?
Does he say "ZPY33"?

Can you measure voltage across him?
by The Scum
Tue Feb 02, 2021 4:13 pm
Forum: Creative Recording
Topic: Low Phantom power from 500 rack?
Replies: 58
Views: 1155

Re: Low Phantom power from 500 rack?

Testing 48v OUT gave me the same 15v DC But testing 48 PRE gave me 67v DC I'm hoping this means the problem is somewhere between these 2 points. I will have to unscrew the PCB (which will involve unscrewing a handful of other attached components) to see what's between those 2 points. Your gut feeli...
by The Scum
Tue Feb 02, 2021 11:49 am
Forum: Creative Recording
Topic: Low Phantom power from 500 rack?
Replies: 58
Views: 1155

Re: Low Phantom power from 500 rack?

Have you peeked in the power supply? First thing would be to make sure nothing is obviously burned/scorched. Second thing is to see if there's a fuse on the 48V line, and make sure it's good. Third thing would be to make sure all components are visibly OK - soldered in place, no legs broken off, etc...
by The Scum
Tue Feb 02, 2021 11:39 am
Forum: Creative Recording
Topic: Acoustic Panels (DIY? Cheap?)
Replies: 19
Views: 504

Re: Acoustic Panels (DIY? Cheap?)

More seriously: do you know the path the sound is taking to get upstairs? MSE's got the recipe if it's going through the floor (I'd compromise from what he describes, insulate between the joists and hang drywall regularly). But are there other paths it might be taking - ductwork, windows, stairway, ...
by The Scum
Tue Feb 02, 2021 11:34 am
Forum: Creative Recording
Topic: Acoustic Panels (DIY? Cheap?)
Replies: 19
Views: 504

Re: Acoustic Panels (DIY? Cheap?)

Get the dog it's own guitar, then it'll worry less about yours.
by The Scum
Mon Feb 01, 2021 10:27 pm
Forum: Creative Recording
Topic: shedshrine build 3.0 - furniture, cats, gear, enlightenment, and yer mom, man
Replies: 250
Views: 12376

Re: shedshrine build 3.0 - furniture, cats, gear, enlightenment, and yer mom, man

That headstock was probably made on the jigs left over from the Fender Katana.

Or by someone who really enjoys brie & crackers.
by The Scum
Fri Jan 29, 2021 11:03 pm
Forum: Creative Recording
Topic: Silly electronics question.
Replies: 8
Views: 336

Re: Silly electronics question.

This isn't for a critical application. Then do whatever is close & convenient. Got a 500 pf? You'll be fine. Or two 220's in parallel...or 5 x 100's...or two 1nF's in series... (the tolerances on the cheap "lentil bean" caps are often +/` 20% anyways...so you'll be in the neighborhood, if not exact.)