metaruss

While the merits of Comcast’s Digital Transport Adapters are debatable, there is one useful side effect to their existance. Because the are so cheap, they lack a POD tuner. This means that the channel tables are broadcast in-band, which in turn means that a normal QAM tuner can find them. There is a tool called scte65scan that can find these tables using a regular DVB tuner (it also supports the HDHomerun).

At some point we will become another victim of Comcast’s digital cable “upgrade” plans. We’ve been an analog cable customer of theirs for about 8 years. The only reason we’ve stuck with them is because they are the only provider that can give us good ol’ NTSC on our coax. That is the only way to have all of our cable programming on more than one TV without paying extra each month for each. In addition to the 3 TVs we also use MythTV for our DVR system, which has 3 NTSC and 2 ATSC/QAM tuners.

We are still getting the analog feed, but last week I finally installed the new digital equipment. Their marketing B.S. is confusing and intentionally misleading, but here is what I have learned from the experience:

“Extended Cable” customers are being migrated to the “Digital Starter” package. You get one standard digital cable box, which comes with their “On Demand” feature, and up to two “Digital Transport Adapters”. They give you the impression that the DTAs are you help make up for the loss of analog service on your other TVs, but this isn’t really true (more on this later). After the migration, you will supposedly be left with your primary local stations and a few other useless cable stations like QVC on analog channels 2-17. The rest are only available as digital QAM channels.

This is where it gets ugly. A subset of our old cable lineup is available as unencrypted QAM256 channels, but the others are all encrypted. Some are flagged as encrypted but are actually clear while the rest are fully encrypted. They also sit on random QAM channels/programs that don’t correspond to how they appear in the lineup on the cable box. Comcast is free to move the channels around and play with the encryption whenever they please because they can just reprogram the cable box and DTAs remotely. This makes using your own QAM tuner frustrating, especially since you can’t receive arbitrary basic cable stations due to encryption (like Discovery Channel in my case).

The DTAs are a joke. Comcast makes sure that the channel lineup is only a tiny subset of the lineup you are paying for. They want you to rent real cable boxes, which makes them no better than DirecTV or U-Verse. The DTA will mainly just tune in your “extra” local digital stations in standard definition, but they do NOT tune in your main local stations. For example, if you have a local broadcaster on channel 10, they transmit high-def over the air on channel 10.1 and also probably broadcast a few extra programs on channel 10.2 and 10.3 or more. The DTA will let you view channel 10.2 and 10.3 on your old NTSC TV, but it won’t tune the main channel 10! Comcast provides those as standard def analog stations, but the DTA can’t tune those and the DTA won’t act as a pass-though when it is off like a VCR would (in fact, you can’t turn DTAs off at all). So to watch channel 10, you need an A/B switch on your antenna to switch between the main cable feed and the output of the DTA. The other stations besides the locals that the DTA will receive are fairly useless (more QVC-like stations, Lifetime, and one or two others I’ve never heard of).

So unsurprisingly, Comcast continues to offer less for more. If they provided basic cable stations on unencrypted channels that would be one thing. The only good news in my eyes is that they offer nothing over what you can get from other communication carriers now. All I have to do is put an antenna on the roof.

Release a new CVS snapshot for nedit, mainly to ease installation on top of the snapshot that comes with Ubuntu 9.10.

Re-rewelded the driver’s seat frame. It was broken into three pieces and was being held in place by an empty cat litter container. I added some steel to it, so I don’t expect it to break again, at least on in that spot. The bottom cushion has a weird feel to it now, probably because it is being properly supported for the first time in years.

The UltraFlo muffler rusted-off. That thing only lasted 3 years…not impressive. Put the Super Turbo back on there…it’s no quieter than the UltraFlo (at least on the inside), but maybe it’s quieter for the neighbors.

The water pump housing has been leaking for years, but now coolant is dropping at an alarming rate. Not sure if it was the leak or something else, but the housing is now resealed. The car suddenly started using more oil than before as well, so something is clearly amiss. Last time I had the turbo intake off, I saw oil in there. There is still a very small amount of oil in the coolant. Now sure if it’s just leftover film or if there is a leak or crack somewhere. I’m guessing that I will find out sooner or later what the issue is/are.

I haven’t done anything to this car since last July other than drive it. It’s been daily driven for an entire year. 3rd gear is still jacked-up, but got a little better over time until recently. Now I can hardly get it in, but I can say that it is the shift pads again. 4th is starting to give a little trouble too, so I think I will swap the whole 3-4 gear pack for one from an ‘89 A555. I wish I could buy new stop rings for less than the cost of an entire transmission. That damn short DSS axle ripped through it’s inner boot again, this time it wore through the inside. Aside from being shoddily assembled, they obviously don’t intend anyone to use these on the street. Pretty lame, given what they cost. This time the spring broke inside the tripod, probably because it can’t sit flat on the shaft end due to those welds.

Last week was really hot, so that motivated me to try to fix the A/C. Had to fix the air compressor first and various other things, but finally got it done. There was a slow leak at the H-valve due to a poorly machined surface on the hoses. Crappy aftermarket parts. The compressor has been holding up so far, so we’ll see if it makes it through the summer. I would be impressed.

It’s finally done.

more

All of the cutting and milling and drilling is finally done.

Here are all the various bits and pieces, made mostly from scraps, all put together:

More about the build here. Next step is paint….

With a custom power transformer from Edcor, I could finally try this amp with some borrowed 300Bs. This transformer’s primary is tapped so that it can be used with either 300Bs or 45s:

XPWR131 - 330-260-0-260-330 @ 175mA, 6.3 V CT @ 4A, 5V @ 3A

Voltages came in a bit high, even under load. The top row is the Tubelab SE in “45 mode”, with about 25mA per tube. Meters are reading: 660VAC winding, 520VAC winding, B+ at the filter cap. Bottom row is in “300B mode”, running Shuguang 300Bs (not mine) at about 28mA per tube. First two meters got swapped: 520VAC winding, 660VAC winding, B+.

With the 300Bs biased to 80mA, the 660VAC winding gets pulled down exactly to spec: 660VAC. B+ sags to around 370-375 VDC. Supposedly this is the ideal spot for the 300B. These tubes are Shuguang’s aptly-named “300BS”, which have mesh plates and globe-shaped glass. They have a weird blue glow on the glass, presumably from electrons flying through the gaps in the mesh.

With the right iron, the Tubelab Simple SE comes to life. After a sanity-check with cheap Chinese tubes, here is the amp running with JJ 6L6GCs strapped as triodes. The amp sounds sweet with a bit more power than the Tubelab SE.

This coincides with the new speakers that I recently got off of Craigslist: a pair of Klipsch KLF-10s. The horns on these do cause ear fatigue on the Dynaco, but with this amp it is more subdued. I am hoping that the DHTs in the Tubelab SE will be even better.

The basement in currently under construction, so the setup is a bit MacGyver.

So I’ve finally built-up this Tubelab SE, a small, single-ended, 2 watt amp. It’s currently in breadboard form, but it sounds amazing. Awesome detail, impressive bass, and something warm about the sound.