Leaderboard

Pre-made dinner for tomorrow night's pre-ride feast. Certainly appears to be sufficiently juicy, hopefully it'll reheat acceptably.

Tonight I had a couple prime ribeyes and I did the reverse sear in the oven at 180 with a probe in the steak. I removed the steaks at 115 degrees and had a cast iron pan very hot and ready. Seared the top, bottom, and two long sides. Came out great for doneness, texture and crust.

No pics. Did my first tri-tip on Labor Day. Served with smoked mac & cheese for the neighbor ladies. Who knew 3 petite senior ladies could put away so much food. Leftovers were one serving only. The tri-tip was ridiculously easy to make and had incredible flavor. I'll have to do another.

The site defaulted me back to light theme after the upgrade. In other news, I am now officially blind.

T2 first listening impressions. wow..... erm.... wow..... erm..... wow The first thing that strikes me is marco dynamics are amazing, on recordings that are not that dynamic the amp does not exaggerate the dynamics, but on dynamic recordings like full orchestra the dynamics are so powerful but not overdone. This is backed up with bass is far more defined, less mushy, more full than my other stax amps but the bass is not not dry or hard or overblown Stereo images are more solid and tangible and more precise than any other stax amp I have, its so close to the experience my Quad 2805 speakers..... Detail is amazing, but the detail is not thrown at you and its therefore not tiring to listen to. But I do notice tape edits, dropped violin bows, musical score page turns more... but it just adds to the experience that tens of musicians in a room can't be totally silent all the time. when music gets complicated there is far less tendency for sounds to just clump together into a messy mushy ball. However you still get the feeling of musicians playing together and the detail is not analytic. The amp just says here is all the detail let it wash over you and you decide how much you want to listen into the detail and how much you want the whole music. This is the first time I have been satisfied with the bass and dynamics from my sr007a mk2. I think it shows that my stax sr007a just need as much drive as they cant get. My journey: stax srm006 (piece of mushy yet bass light and less bass the higher the volume, undynamic, undetailed, poorly constructed, stereo thick soup, gloop with the sweetness of a lemon), hi-amp alpha centauri (improvement in every way over the srm06, its an upgrade but you still feel there is music missing. Overall you get the impression is nothing special and has but poor bass, slightly deeper than the srm006, but mid and upper bass is almost non existent. Bass loss with volume is far less), blue hawaii (murders the alpha in every way but maybe slightly hard sounding for me and a bit of a tiring long term listen. It was a very enjoyable build and a considerable step up from the alpha but I rarely could relax into the music), Mini T2 (better micro dynamics, smoother and more refined more listenable than the hawaii but lacking in some drive and macro dynamics, detail and bass. I still got the feeling with it that it was struggling with the sr007s a bit) and finally the T2 (im sure I will eventually find something wrong with it... that's just the way my brain works but for now im content [which is rare])... So whats next after the T2? (other than building a second one).... Many many thanks to Kevin for the T2 and joamat for the modified T2 and mini T2, spritzer for providing the nos transistors and everyone for their encouragement and help.

Seems fine to me.

Vava brand air purifier, the one with UV light for bacteria. They are cheap silent so get multiples to spread around your crib. For masks look for three layer cotton preferably with pockets to allow for insertion of non woven poly propylene fabric (Etsy, Admathagifts). As for locust hords and boils I recommend Ortho Home Defense Max and a topical steroid cream.

Corrupted by cuteness!

Who are you, and what have you done with Shelly?

I've got mad skills.

Or use active speakers from the pre-outs?

Lips | American Head

This guy's use of the Deluge is at least demigod level - he did all audio for this in the Deluge, including mixing/mastering. And I want to know more about his video sampling technique.

Tough day at work and xmas music rejuvenates. It’s like Popeye’s spinach. Don’t ask me how many hours I listened to the day after W. was re-elected.

Nice, Al! Looks great, Nate! Always need more tri-tip!

Haven't heard that album.

The dark theme needed a swift kick in the ass, the menu pops up correctly with it now.

This is now fixed in the dark theme. New forum software version + clean install of the theme did the trick.

Hail to the chief.

Adding to the apocalypse documentation. Approaching noon in Mtn View. Was brighter after sunset. Keeping on eye out for boils tomorrow.

The Schiit or the Sphinx?

I've always seared first, but I'll have to try this method.

Also, I really like the Bad Gear youtube channel, if anyone here doesn't know it.

The other one is back in her spot, too.

Dunhill has reacquainted himself with home, after a week in North Carolina. Silver has too, but she is in a box. I've gotta brush that Pendleton blanket. Dunhill goes out of his way to be a hallway obstacle in the dark.

I am just envious of Nate's gravity-defying beer skills.....

photos here

https://youtu.be/wsOHvP1XnRg not sure why preview not showing, but it’s “Cities in Dust”, dedicated to my West coast friends

It’s very Christmasy

So far I dig it, dark pads or the ones with the cloth liner are really needed. Noticeable etch without them... with them tho a touch smoother without a massive lose in tactility. Overall pleasant, good tonality and detail with a nice stage. I'll have more in a few days once I get a chance to really listen. Comparisons to 009, 95X with Vesper and hopefully L700 Mkii if it arrives in time

Scroll to the very bottom of the page and you will see a Theme drop down. Choose Deflection or whatever it is called now.

I love Phoebe.

Nate's gonna knock me off the head-case Strava leader board this weekend

Plus it comes in black! I will forward the suggestion, thanks!

Maybe it was triggered by me selecting an alternate image size from w/in IOS? I'll check when I get back to my phone. It's in a drawer far away at this point and I am officially lazy.

Didn't happen for me either

The Winix 5500 seems to be the best bang for your buck. But this is Head-Case, so I'll shut up.

no 5.1k series resistors on the outputs is a super bad idea. definitely bad for the headphones and a safety issue if the mosfets ever short.

FTFY...

Nothing to Burn?

I'd have to hear it to get the effect, but it sounds interesting. Both subs are the same? I've often thought about a quick 10" sub, supported by a deeper 15".

try not to kill the user until AFTER they have finished paying for it Equal rights for electrons! they should be allowed to travel freely and not be constrained by insulation... If they want to travel through your heart it just their way of being loving and friendly.... they are so misunderstood.

Have I mentioned how much I love Gunship?

The haze cleared long enough to get a view of Mt Tam this afternoon.

listen to it? if you check my todo list nowhere does it say listen to it... measure it yes... listen to it? why would I do that? 🙃 latest update, internal signal wiring done (silicone not cardas - I need to buy more cardas chassis wire) and front panel completed. Both channels powered up at the same time for the first time. No drama so far. The heatsinks around the el34s runs a bit hotter than joamats mini T2. I not done any temperature checks look good. All transistors seem ok and so do the high power resistors. .6922 heater voltage is a little high at 6.35V so I will need to add some dropper resistors. All other voltages are spot on. El34 heaters are at 6.1V which is about the same level as my mini T2. I found my first issue, the DC balance between + and - halves of a channel is fine <50mv BUT the DC offset to ground started at -85V and even adjusting the offset pot all the way I only got it down to -33V. Exactly the same on the other channel due to close matching of components and matched valves. So I will need to replace the dc offset adjustment trimmers with something 2-3x the range. Anyway I know you have been waiting for the money shot: glowing leds and heaters so enjoy: Im currently going for an extended power on idle test and will be periodically checking voltages and temperatures on both the amp board and psu. If that passes it will be time to feed it some test signals... I hoping for more detail in the square waves, more dynamics in the triangle waves and smooth fatigue free sine waves. Here are the first measurements. Distortion 1Khz input Total Harmonic Distortion to 49Khz is around 0.0063% unweighted (average of 20 measurements) 2nd harmonic is around -90db and third slightly higher at -87db. The other harmonics are very low all less than -105db. total harmonic distortion plus noise is better than 0.018% (im not using shielded cables for this test AND the amp and psu do not have top lids and the cases are not grounded so the amplifier is almost certainly has better thd+n than I am measuring in this setup. At around 575V rms 5th harmonic starts to rise and at 600Vrms output all harmonis increase and odd order are higher than even order harmonics. NOTE this measurements where taken with around 35V DC offset so it is possible clipping may occur a little later with less offset... Noise, THD, THD+N and level of distortion harmonics at 575V RMS, 1Khz output: Noise, THD, THD+N and level of distortion harmonics at 600V RMS output 1Khz: The THD up to 49Khz is still less than 0.05% The amp runs quite a bit hotter than the mini T2, heatsinks near the EL34s run at 40C and power consumption is close to 205W. The mini T2 is around 153W. The power supply is also is less efficient than the golden reference HV, the 3W resistors between the ksa1156es and ksc5026 run close to 90C and dont have a lot of room around them, on one side there is a large 0.1uF 1KV film cap and on the other 5 closely packed transistors... So the T2 needs good heat sinking and the psu boards could do with lengthening a little to give the 3W resistors a little more air flow around them and drill holes under them. Update DC offset fix, The 5K pot in parallel with the 510 ohm emitter resistor gives a minimum resistance of about 461ohm which still gaves me ~ -33V offset. With the 5K pot in the middle you get around 423ohm combined resistance and ~ -85V offset. So I replaced the 510ohm with 604ohm and this gives enough adjustment range to get <1V DC offset. (I would have implemented joamats suggestion but I did not have any 10K pots)

My black cats who have been stepped on because I mistook them for puddles of shadow beg to differ.

Well, I think things are a bit more complicated than that. For speaker amps, you generally need a lot of power unless you have very efficient speakers, e.g. horns, which is another topic altogether. We're talking about 50-100 watts per channel or more. So the amp needs to produce 40 volts peak for a 100 watt amp, and on the order of 10 amps if we have a 4 ohm speaker. Now, a class A push-pull amp has a maximum theoretical efficiency of 50% (single ended class A has a max efficiency of 25%), so that means it runs at 100-200 watts/channel all the time. This means lots of tubes (old days) or lots of heatsink for solid state. All this means lots of heat and lots of money (and that doesn't even include the cost of running the damn things). So basically, until Mark Levinson and Krell came along, pretty much all amplifiers were class AB because nobody thought that there was a big enough market to support a class A commercial amp. Class AB was considered the best compromise between cost, efficiency and sound quality. It was never considered the best, just that Class A was considered too expensive. The first Mark Levinson Class A amp was rated at 25 watts (but was reportedly class A down to 2 ohms, at which point it was a 100 watt amp), was mono, and was big, heavy and cost a few thousand dollars - I think you could have bought over 100 NAD3020 integrated amps for the same money, and the 3020 was stereo, had roughly the same power rating, and included a phono section. But, it turned out that there was a market for it, and Krell came out with stereo class A amps that had more power and generated more heat. And it's gone on from there. The limiting factors for speaker amps is basically how much power do you need and how much money (and size, and heat) do you want to spend getting it. For non-electrostatic headphone amps it is significantly different. Here, you only need a few watts at most, into higher impedances than speakers have. So low to moderate voltages (say 15 volts at most)and relatively low currents (an amp or so at most). Based on specs, the least efficient non-electrostatic headphone is the HFM Susvara, and 5 watts into that should produce 120 dB, which is enough to give you hearing damage in minutes if sustained. So in theory, a class A headphone rated at 5 watts into the Susvara's impedance should do the trick. Which means that an amp that draws 25-30 watts from the wall should be able get you close to the threshold of pain In that case, there isn't a lot to be gained by dropping back to class AB. That said, some cheap headphone amps ARE run in class AB because the manufacturer doesn't want to lay out money for heatsinks. Every penny counts. For electrostatic headphones, it is different again, stat headphones have very high impedances, so you need very high voltages but relatively minuscule currents - a few mA. because you need to have high voltage - the Stax amps generally have +/-350V supplies, the KG amps generally run +/-350V to +/-450 volts, the Stax and DIY T2 run +/-500V supplies. Now the Stax amps run around 5-7 mA/output device, the KG amps up to 20 mA/output device, and there are 2 output devices per channel. So given that, the Stax amps draw about 40-55 watts from the wall, the KG amps run about 140 watts to more than 200 watts (the latter from a DIY T2, which also has 8 tube heaters using energy).