metaruss

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.

These are the output tubes on my Thomas amp. You can see the blue glow against the glass from stray electrons. This is very common with Sylvania tubes. Behind the blue glow, is the red glowing line from the electron beam hitting the plates (I can’t get the bias to go any lower with this amp). The two together look purple to the camera.

I have read contradictory discussions about blue glow against the glass envelope. Blue glow coming from inside or near the anode or other structures is normal, but some say that blue glow outside of that means a soft vacuum. Sylvania claims the opposite and that fluorescent glow inside the envelope is normal for some tubes. It results from stray electrons bombarding near the glass envelope and will change in brightness depending on the intensity of the signal passing through the tube. This is exactly what I see with these Philips JAN tubes, which are basically Sylvania. In fact when I push the amp really hard well into cut-off, the tubes will flash brightly signaling me to back-off

The “Winged-C” SED EL34s in the Dynakit seem to fluoresce at the screen behind the plate:

All the best stuff comes from Chian.