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Thanks a lot for all your inputs, Kerry and simmconn. Now it seems I’m back on track (knock on wood). Since “reflowing” the board and a new HN4A51J the PSU has been working for almost 24 hours with several on/offs. Voltage is stable, decreases some tenths of a volt from cold and than bang on the intended 150V. After some struggling, I managed to measure the three faulty HN4A51J. All Q5:B are unknown components on the tester while Q5:A are PNP with hfe of 4 or 5?. Now the angels are singing on my modified T2 with EML tubes.

Amidst the Chaos: Live from the Hollywood Bowl Sara Bareilles 2021 https://album.link/i/1563327630 Example: A live album that I missed. Big fan of Sara's. Overall a really good live album. The example track just kills me with the delicacy and power. A song from her Broadway musical - Waitress.

JH13s

The golden reference supplies work very well in the T2. I've been using it for a while now with no issues. You do need to take the raw DC after the 10m90s current limiters though. I'm using a single IXTP08N100D to limit the current for each supply. You should be able to get away with a single 10m90s for your 150V supply if you adjust the set resistor accordingly. The current draw there should be around 50mA. I've added a protection diode (1N4007) with the cathode connected to the base of Q6 and the anode connected to 0V. I also got rid of D3. Here's my T2 supply (I've been meaning to post this for a while) - all the high voltages are Golden Reference supplies (even the -60V using a negative version of the GRHV79xxx). I've very pleased with how it performs Good luck!

@jp11801 started talking about this meet in a different thread about a different meet, but if we're going to make something happen then we need a proper meet thread. This could be an opportunity to get the old Travel Team together again! @shellylh claims to be making the trip and Claire and I are considering going too. Some locals like @bozebuttons and @Kerry -- MOT MOT MOT! -- will be there. Not sure if @Iron_Dreamer or @justin are working the show, and even if he's not promoting ECP Audio, @dsavitsk is not far away. So, who else feels like it is safe to come out and play again?

Latte art is sure hard if you aren’t making 100 lattes a day and/or are not a robot.

PBHV2160Z is nice due to its high HFE and low Cob. I'll be using PBHV2160Z and PBHV3160Z in my upcoming GRHV build with off-board e-caps. From simulations using those transistors I learned that C5 needs to be increased to 15pf to 22pf for best phase margin, and 47n is still the preferred value for C4 that provides a low and consistent output impedance across the audio frequency range. Another interesting find is that the circuit needs about 100uF output capacitance to be stable, and increasing the value of that cap has a diminishing return in the performance, unless the cap has really low ESR (such as film caps). In case the cap's ESR is high, some additional compensation can be added to ensure stability (hundreds of pf across R7). The above findings are for the original GRHV with 400V output. YMMV if the output voltage changes.

I use PBHV2160Z instead of STN0214. You can also try STR1550. I also changed C4 to 1000pF.

Here is the balanced Dynalo with 220 ohm loads RMAA test with RME ADI-2 PRO. Signals levels set to RMAA test levels as before. RightMark Audio Analyzer test _ 220dynalo RME ADI-2 Pro.pdf

@JoaMat Did you measure the removed part and see which transistor and which junction failed? If it takes a while to fail, chances are the power dissipation is over spec. Something else could be leaking that causes excessive current through the part. An IR camera would be handy in troubleshooting problems like this. The STN0214 may have a different Cob than the original part KSC5026, and the closed loop gain of the regulator is also different (20x vs 40x), the compensation capacitor values may need to be adjusted to maintain stability.

I don't have channeling issues very often. I do have to play with the grind setting as I purchase new coffee, or adjust a smidge as the beans age but these are very minor tweaks to grind setting (well less than one tick on the Niche). I pre-infuse with the Lelit Bianca at 2 bar for roughly four seconds and then swing the paddle for higher pressure until the gauge hits 9 bar. Seems to work pretty well. One thing I have concluded is I can torture myself with a less roasted bean trying to hit the sweet spot for espresso or I can purchase a bean clearly roasted for espresso (plenty dark) and make my life much easier hitting my marks. Much darker notes on the heavily roasted beans so it's a taste thing. HS

50yo Something / Anything? Todd Rundgren 1972 https://album.link/i/1084074389 Example: I thought I knew this album. I really didn't. It really is something/anything. I will stick with the something (example). There are a couple of great tracks on this double album, and there are tracks of anything that in some ways pissed me off. Thinking back of someone just buying this double album, and thinking, what did I just pay for? But don't get me wrong, big fan of Todd's and this album is full of great tracks. It just also has skippable sections.

RIP, Angelo. Your music was a key character in my favorite TV show ever.

RIP Brian Duffy, aka Jet Black. Longtime drummer for The Stranglers, though he retired in 2015. Got to meet him and the band back in 1982 or 83 when they played Boston. A college dorm-mate worked as an intern for CBS records and we took the bassist to WZBC for an interview. Then met the band back at the hotel, and after the show got backstage with them. Jet was a very cool and interesting guy.... https://www.bbc.com/news/entertainment-arts-63904248