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Not my usual lane but good music is good music.

Country super groups are hard to come by. Only one other springs to mind.

Hit a couple of record shops today. This was playing when I walked into one of them…

Problems with a red plinth…. clashes with purple. Where was @swt61 when I needed him.

Put up a French cleat wall to utilize some space behind my saw station. Testing using T-track and dowels for my red tools. Will build something proper soon.

Their catalog is finally on streaming services as of today!

So I did indeed install 150K and 200K chain for the bias resistors of the C2M1000170D when I first built my Carbon. Today I replaced the 200K with a 150K, I had also dialed the bias back to 18mA and disengaged the servo. Then took a few measurements after letting the amp warmed up. Now the PZTA42 Vce is around 13.7V, voltage drop of the 20K R is 25.4V and the Vgs of the C2M1000170D is around 3.3V. And I did not blow up the amp.

Garbage's first album, for some reason. Prior to that, I was stuck on Black Sabbath's Technical Ecstasy and Simple Minds' New Gold Dream (gosh I love those albums so much) for some reason. Probably because I haven't been liste ning to music, so my mind mentally replays whatever I know most well. So...those three albums.

Likewise, A follow on from The Wire, sadly(?) based on true events in Baltimore. You are taken on the journey, and some uncomfortable questions are asked, without seeming contrived or preachy. With "The War On Drugs", be careful what you wish for. https://www.theguardian.com/tv-and-radio/2022/apr/25/we-own-this-city-david-simon-show-baltimore . John Bernthal, a Harvard man, is a stand out as Wayne Jenkins, decidedly not a Harvard man.

You can put together a test circuit using a trimmer pot and dial in the target current with say, 50V across the CCS and get the resistor value, something like the post here. It's okay if the actual current is a couple of mA higher than designed. It will turn to heat on the Zener diodes and won't burn a hole on your board.

I’ve been watching “We own this city” on HBO. Hooked on it. https://www.hbo.com/we-own-this-city

AHS season 11. Instead of dragging on, this season is my favorite yet. Without giving anything away, it takes place in NYC circa early 80's. Specifically the gay scene in NYC. So, lots of leather and a mysterious illness.

I'm really out of touch. The only one I recognize in that group is Brandi Carlile.

You can use just about any NPN transistor with sufficient BV(CEO) and BV(CBO) rating and not too much Cob (usually means not a high current part). If the Cob is too small on the replacement part, you may want to increase the value of the compensation cap (5pf). For the 10M90S, rumor says (in its SPICE model notes) it has an internal OPAMP so it would be more complex than just a depletion mode MOSFET. In fact the actual part performs even better than the SPICE model which only has a depletion mode MOSFET and a body diode. I guess that makes the G/A/K notion more appropriate and the manufacturer can continue to charge $4 a pop.😉 You can use IXTP01N100D to replace the 10M90S in most places if you can't wait to get the amp up and running. Some resistor values need to be tuned to get to the current the circuit was originally designed for.

Throw some yellow paisley stickers on it. Problem solved. BTW, "Problems with a Red plinth" sounds like Stings latest album.

A View From The Top Of The World Dream Theater 2021 https://album.link/i/1576732163 Example: These guys have been consistently prolific for so long that sometimes I forget how hard that is. And as always their caliber of play is impeccable. Shame that I have only seen them once live.

3/9 also sounds bigger than 1/3

Put it back together and that was the problem. Offset and balance adjusted fine. I was a bit concerned when I first turned it on as it started to come up but blew the fuse (3.15A Slow blow). Replaced the fuse and it came up fine. No soft start or anything. Lights didn't dim or anything. Not sure if this is a problem or not. I'll see how it starts up in further starts to adjust and implement the opto servo. Bias is ~17mA; heatsinks don't seem to be warming much, but I didn't run it much (5 minutes). Might turn it up to 20mA bias, need to read the thread more (again) to see user comments on that. Can't believe I hadn't noticed that solder bridge before, but glad I don't need to try to source any unobtainium parts right now

Viva = Verified Insufficient Voltage and Amperage

In a previous post I mentioned the less-than-ideal performance when Carbon is powered by a ±400V supply, and I suspected that the lower Vce on the PZTA42 is the culprit. Now it's been proven. The PZTA42 being a high voltage transistor, has a non-linear region at low Vce, as the slanted curves you can see on the upper left side. With 407V on the negative rail, the transistors on my board works at Vce=8.4V and Ic=20mA, right around the knee. The global negative feedback would have a hard time correcting that non-linearity. It also explains why some people prefer setting the Carbon at a lower current when powered with ±400V supply, as it also improves the linearity of the PZTA42, albeit to a lesser degree. I guess Kevin chose the high voltage PZTA42 to deal with the power-on transients. I have a quick and dirty fix. Just bias the SiC MOSFET a little higher to give the PZTA42 more headroom. The SiC MOSFETs are biased by two 175k and an 20k at the gate. Reducing either 175k or increasing the 20k would do. The goal is to move the PZTA42 operating point to the right, well into the constant-current region (parallel lines). I would use Vce=14 to 15V. Pushing it even higher would increase the power dissipation on the PZTA42, eat into the max output voltage swing and have diminishing return. What I did was to put a 260k resistor in parallel with one of the 175k resistors. YMMV because it has to do with the operating point of the PZTA42 in your circuit, the Vgs(th) of your SiC MOSFET, etc. After the quick fix, one of the channels now measures as good as with the ±450V supply. We can see that the max output voltage is slightly less compared to with ±450V supply. The difference is subtle with the log scale, though. Now I'm continue to work on the other channel and see if I can find something else.

Andrew Klein. He also made a cool app for confirming bandsaw blade tension by tone and a crazy invisible screw thingy. Fucking piece of shit Bosch mitre saw is giving me some massively out of square end cuts on the legs. If I had the room I would go buy something else and build a mitre saw station instead of this bench. Between the loose lock downs and the worst designed stop block in the world, this thing is about five minutes from going in the lake. Now going to try to further calibrate this thing as my delve square shows the blade is pretty square to the table and the fence.