Leaderboard

Finished, with minutes to spare a set of these. Kasia asked, of course, why there are two openers on each and the answer, of course, was because this is fucking Head Case. and not that I gave fuck all thought to where screws were coming through the front when laying out the keyholes in the back

Homework! The interview I had earlier this week gave me homework, so that's a good sign.

Went to one of my local dealers today, got to listen to the LX-60's as well as the LSX II's. The 60's are amazingly balanced top to bottom, very smooth yet detailed sounding; the bass is deep yet very tuneful I'd say. Yet at times I thought it was still a little too polite...maybe TOO refined..... The LSX II's were a little more bloomy in the mids; I actually heard more of the room & reverb on a couple recordings. It may not have been as flat as the LS-60's tonally, but it was not glaring, and it sounded quite nice. I think the LSX II's with the KC62 subwoofer (they have a line level output for subs I believe) would be an awesome pairing at about 1/2 the cost of the LS-60's. But damn do those 60's look nice!

I thought it was just stereo...

Maybe because I'm struggling a little with this exact question, but found this video refreshing and thought others may enjoy too.

If you're having issues with a 4 amp fuse at 240VAC you may have something wrong. Make sure it is a slow blow fuse. They start with a T in front of the of the value (i.e. T2A @ 250V).

normally if you go from 120V to 240V you half the current draw power = current * voltage so you may have a problem. Assuming the amp did not blow fuses when set to 120V the same value fuse should not blow at 240V... fuses can weaken over time and they do vary considerably. EEV blog on you tube did some interesting experiments and found the fuses ratings to be at best a guestimate. With large variations in the fail current for fuses from the same batch. There are multiple versions of the DIY T2 and the choice of valves effects power consumption a little. My T2 consumes about 205W once warmed up (mostly modern T2 with tung-sol el34 and genalex 6922, kghssv psu). there is a high voltage delay built in to allow the tubes some warm up before applying high voltages. When the high voltage psu switches on it initially has to fill the filter caps and this makes short duration current surge of more than 4A. Assuming there is no short circuit in your high voltage rails and you have not wired up your transformer incorrectly, its this initial charge that's blown your fuse. I am currently running 5A slow and that been fine for many months. 4A slow blow might be ok too. Having said that I always specify my transformers with resettable thermal fuses built in for a bit of extra protection.

Listened to it yesterday at NPR's.

Live music adjacent Halibut Risotto

Say, didn't we see this band in Golden Gate Park? Why yes, yes we did see Wreckless Strangers. But without the "modern parenting" that is the fashion in San Anselmo Bless.

Workin' on a pork chop, mashed taters and peas.

The pentode experiment gets a little twist - with a beam tetrode. In my search for an acceptable output device, I went through the popular low-power transmitting tubes. The 807/6L6 family has such a wide, kinky curve in the low current region with typical Vg2 (250V) and was rejected as a candidate at the first glance. However, the curves around zero Vg1 looks quite linear. Lowering the Vg2 could sort of 'bring them down' to the low current region. With about 60V on the G2, the kinks are largely gone, and the linearity looks pretty good (pictured below X= 100V/div, Y= 5mA/div, Vg1= 0.5V/step). Another benefit is that Ig2 comes down considerably with such a low Vg2, which allows me to use the same simple G2 supply used with the GU-50 (zener diode paralleled with a 10uF cap). I compared quite a few tubes on the curve tracer. The National Union 807s (shown above) from WWII era seem to have the best linearity and are the most stable. The RCA and Sylvania tend to oscillate on my test jig. 1625s are about the same. Unfortunately I don't have enough National Union for a matched quad. The earlier 6L6/6L6-G are not officially rated for 400V plate voltage and have to be excluded. The Tung-sol 6L6WGB/5881 (the real deal, not the 'reissue') looks much more linear compared to the 6L6GC. The Sylvania 5881 (shown above) although has the same internal structure as the Tung-sol, doesn't seem to be as linear. The 1624 would be an interesting direct-heating variant that has a bit higher gain than the 807. The 2E26/2E24 brothers are suitable, too. Here are the 807s on the test bed: The result is convincing: The 100Vrms output FFT shows harmonics -115dB below the fundamental: The 1624 turned out to be a disaster. It was hard to get a clean, low capacitance filament supply. When attached to the signal path, the common-mode noise would kill the S/N and the capacitance would mess up the frequency response and THD. I have to admit I don't have much experience with direct-heating tubes in circuits where every uV counts. It would be nice if the few exotic direct-heating tube eStat amp owners can get their units measured and share their secret to success... The grounded-grid cascode output stage is such a nice thing that it allows us to play with many tube types, as long as they have enough plate voltage and power ratings and are reasonably linear. We could end up having unique amps that still have top-notch performance.

Another way to build floating shelves, without purchasing the steel supports.

@jamesmking The amp been sitting gathering dusk for a while over 12 month up to 24 month. All tube been replaced with new quad matched one. Maybe the initial draw is too much. Thanks @Kerry for clarifying what type of fuse to use, I'll replace the fuse with a new one and see how it goes. If it doesn't blow I'll replace it with a 2A fuse.

Somewhere Different Brandee Younger 2021 https://album.link/i/1572278902 Example: New Artist for me. Jazz Harp, you say? Well okay then. Enjoyed the album, a nice vocal track in the middle. Had a Chuck Mangione vibe for me, that I liked. I will check out her other work.

I have some split boards available, anyone in need for them 😀 just let me know.

True Loves Sunday Afternoon, for a few bucks you can get the whole discography (digital). Music | The True Loves (bandcamp.com)

I dunno, I find the 007 Mk 3.14159265359 has a more... well-rounded presentation.

The best is the 007 Mk 2.718281828459045.. or 007 Mk e for short. It’s the most natural.

I'm reposting my parts list as someone requested it. Probably needs to be double checked Project_Nov08_0152PM.xls