Bruce (kor27) wrote,

Video and Sound

I of course didn't make it to the bar by 7:00pm last night. For one thing, I went back to sleep, and woke up too late. For another, I had to make a round of stores...

The main problem I needed to fix with the flatscreen last night was the ground loop. For those that don't know, which would be most, different electrical circuits in a building end up with varying voltages. In some cases - and by design - 60Hz voltages that are completely out of phase with each other (don't worry if you don't know what that means). This mostly comes down to the fact that the whole power distribution model was designed mostly for simple motors back in something like 1920. It sucks for audio and video.

This comes into play when you've got, as in our case, video distributed throughout the building, meaning video cables whose "grounds" are connected together. Each local "ground" is supposed to be held at the voltage of the local, well, ground, but... they aren't. And each one is different. This means that you get wonderful - and sometimes very loud - 60Hz hums fed back through these connections.

This was being a problem with the flatscreen because, since we had the cable there for the projector, we hooked up the s-video cable from the DVD player to the flatscreen. It's difficult to remove ground loops on an s-video cable (I believe the last time I checked it, the filters cost around $150), and we certainly didn't have anything in place.

For my setup, it simply meant some uglyish moving horizontal bars on the screen. For Julz and Dana, who connect unfiltered baseband video from their machine to the DVD player, it meant the 60Hz hum from hell.

So, I had two things to do - replace the s-video cable with a normal coax connection, but also filter out the ground loop. The proper way to do that is to buy a filter. I have one on my setup - it's a Jensen VRD-1FF (if you follow the link, scroll down). It costs around $50, more or less. I wasn't gonna even bother asking Paula, especially since there's a cheaper, if inferior, solution.

Putting two 75Ω to 300Ω transformers back to back will create an effective filter, if one of those doesn't have a connected ground. Yeah, I realize you don't know what those are. Don't worry, you've seen them. OK, you weren't worrying - but I was.

The problem, and the reason for all this blather, is that I had to go to several stores, buy several cheap gadgets, take them to the car, test them, say "nope," and head on to the next store in line. This took a little time.

I got to the bar around 8:15pm, just in time to interfere with Julz and Dana's setup. Still, the new cable was run, and the new filter in place, before they were supposed to start at 9:00pm. Plus they really didn't get going until 10:00pm.

It was in some ways gratifying that their show was even deader than my Thursday. In fact, it turned out the largest part of the crowd was family.

Speaking of Thursday, I had to deal with Paula doing her "What are we going to do about Thursdays?" bit. I just love that she does that every time we have a bad night - even if the previous week was excellent.

Still, even though they insist on using their speakers (which are OK), and putting them directly behind the singers (I had to keep moving off the stage to avoid feedback), it was a fun evening. Failing voice or not, I ended up staying until around 1:15am, hanging out initially with Cheri, and later, when he dropped by, trivialt. That was nice - I don't get around to talking to Stanley much. At least, not in person.

There was a little talking with the elusive-but-lovely alphaba, as well, before she sped off.

It's also too much fun finding the obscene songs in Julz's collection that she didn't know were there.

My plan had been to go grab dinner at TGIFriday, but it was getting late for that, so I decided on the Cardinal instead. It had been a long time. The usual slow service, but quite decent food.

Then home, and, eventually, some sleep. I've been "up" since about noon, though I really need to clean up for the day, and see if I'm going to the parents' or not. It'll be their decision. I'm still kinda sniffly.

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