Life, The Universe, and Everything

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Here, you can discuss anything (well, anything legal and not offensive) you want to. Use this for gassing about any half-baked theories, general getting to know one another, and other things that as someone once said, should be forgotten after awhile. This sub forum is set to auto-remove threads that haven't been posted on for a couple weeks, emptied like the office trash can. Almost anything goes here, the idea being to keep the other forums and threads more on topic but in a maximally friendly way. If anything actually worthwhile should wind up here, let me know and I will make it immune from being removed.

Re: Life, The Universe, and Everything

Postby Doug Coulter » Wed Mar 14, 2018 4:32 pm

In the spirit of just blabbing around the water cooler...

Today I learned that if you have no credit rating (which I already knew was in some ways worse than having a bad one) - our Social Security Agency is unable to create a "MySSA" account.
After a few tries and oddball errors, I called their help desk and got this info - it's confirmed by them. Even with a valid SSN and plenty of other info...they can't confirm you are you.

Much diligence. Much competence. Wow!

Some of the services one could reasonably consider essential (an important legal term in the paperwork reduction law) cannot be accessed without such an account.

So, the government is relying on a putatively independent set of businesses - which recently had pants-down grade leaks (Equifax)...to prove I am myself! I guess NSA doesn't answer phone calls from that agency.

Didn't know there was effectively a penalty for not paying rent to banksters.

We of course have to pay all of them anyway...
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: Life, The Universe, and Everything

Postby Doug Coulter » Sun Mar 25, 2018 8:22 am

Marge, how'd we wake up in Minnesota? I don't remember signing up for Minnesota. (with apologies to the fine folks there).
20180325-0915-snow-1.jpg
Even the generator exhaust had to dig out

Solar panels? Nice that it's a clear sky, but....
20180325-0916-snow-3.jpg
Panels...photons not going anywhere for awhile.

Don't think I'll be seeing solar today.
Even the TV antenna!
20180325-0916-snow-4.jpg
Sticky stuff



Note, here in Floyd, we usually put in the frost sensitive garden plants right around 2 weeks from today...somehow I think "it's different this time".

Guess I'll sit around and write code and do sysadmin stuff. I did get a raspberry pi to do some interesting things with audio, like
stream background music from Greece (there's a nice Baroque station) while still allowing messages like "motion detected" to be played
by the software that watches the camera, while serving web pages and doing database work for the homestead...
This is without an external USB sound card, and it's loafing ... nice. I'm going to integrate this into one of the always-on
pies for the homestead, along with a sometimes-on 10" LCD display that will also come on automatically in response to events,
a nice accessory for the living room (and another window via camera, along with audio from outside, on demand).
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: Life, The Universe, and Everything

Postby Bob Reite » Sun Mar 25, 2018 2:14 pm

I wonder if this is the same storm that dropped two trees across my road and took out my cable modem Internet for two days. Then again, I think this is the one that missed us and got you Doug.
Last edited by Bob Reite on Mon Mar 26, 2018 5:42 pm, edited 1 time in total.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Re: Life, The Universe, and Everything

Postby Donovan Ready » Mon Mar 26, 2018 3:15 pm

Bob, did you typo, or is that an inside joke?
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Re: Life, The Universe, and Everything

Postby Bob Reite » Mon Mar 26, 2018 5:42 pm

FIxed the typo.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Re: Life, The Universe, and Everything

Postby Donovan Ready » Mon Mar 26, 2018 9:51 pm

Image
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Re: Life, The Universe, and Everything

Postby Doug Coulter » Tue Mar 27, 2018 9:24 am

I saw the original message but didn't have sharp enough eyes to see the typo, sigh. Yeah, this storm mostly went south of me, so I guess Bob missed this one. It did take out internet and power for a lot of people around here, I lost DSL for a few hours, but of course for me it was "what power outage?".

Speaking of which...there are ~ 1.5kw worth of solar panels lying in my garden, awaiting a roof repair to install (materials for that also lying around), and 2200 lbs of new batteries coming tomorrow, which I hope will go on a lowboy I'm going to borrow from a neighbor today. But then what? At 173 lbs/cell, these are not going to just be offloaded by tossing them. I'm now missing all the young hard partying punks the neighbors used to complain about. Usually a couple cases of beer would get this kind of thing moved into place while having some fun. This is now practically a retirement community.

When I take a break from being grumpy old man, I can still be amazed by things. My first car stereo was a 10 tube am/fm tuner I lashed under the dash of a '66 Valiant. It had 2 williamson 6l6 output power amps in the trunk, along with the FM multiplex adapter that wouldn't fit in the front, and it all got B+ from a dynamotor. OK, so I was an early adopter of that and some other things...

I'm right now listening to this thing:
20180326-2111-switcher-1.jpg
Class D amp running on tiny switcher

Which would be 50w rated if that tiny supply would do it - but even that is plenty for "too loud for the living room" normally...the whole mess is more efficient even at low level than the theoretical best class B setup. And it sounds great - with 1.2 mhz switching, class D amps are a lot better than the days of slew rate distortion...

Oops, i caught a USB3 drive that was laying there because it was too small at a mere 64 gb for a job I had. EG, it's more capacious and faster than 32 of my first "big" drives, which were 2 gb mfm seagtes (not counting some real early stuff). Even if I'd had 32 and put them in Raid 0. I only had 2 though, but when I checked a couple years ago, they still worked. Sigh, now I don't think I have a motherboard to run those anymore, so I have a search and send to dumpster mission - which inevitably will take place a week or two before some museum calls me to enquire about preserving stuff like that.


And the baroque music is coming from Athens Greece (Audiophile Baroque) at 320kbit/sec, through a raspberry pi that has more compute power than this whole basement had when I was growing up. Not shown here, but there was a quite powerful analog computer (hoist needed to change the patchboard...) there too, which wasn't surpassed by PC's until around pentium 3's. But the pi kicks butt over the couple of PDP-8's (there's one in the background too) and the 286 I was working on (ECGA - real IBM vid card and monitor!).
Basement.jpg
My Dad's basement, not your Mom's....

Some pretty cool but obscure stuff in that pic - like the 300 cpm paper tape reader I interfaced to the 8, the hughes mem-o-scope, the vibralizer, the...
I appear to come from a line of pack rats...I still have some thousands of vacuum tubes from that basement...

We live in amazing times if you have that perspective.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: Life, The Universe, and Everything

Postby Bob Reite » Tue Mar 27, 2018 3:35 pm

I looked into class D when I was designing stuff for the now defunct Reite Audio company and found class D wanting in the area of IM distortion. I had better results designing an 'old school' class B amp with bipolar transistors. Actually, only the "finals" were class B, all the driver stages were class A, as at that power level in the circuit, the efficiency was not a real deal killer. The only amps that sounded better that the audio show we went to were some offerings by MBL and a now defunct company that I don't remember the name of that had a MOSFET class A amplifier both of which sold for four times what we were asking for our 400 watt monoblocks.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Re: Life, The Universe, and Everything

Postby Doug Coulter » Tue Mar 27, 2018 10:23 pm

Oh, I went super hardcore into audiophoolery before I became a serious musician...and worked for a couple decades improving Dan Meyer's Tiger .01 design...
To the point it became utterly pointless as well as exposing some puff in the audio biz.
The result was a class...hmm, what to call this - AB mosfet output design with DC to 4Mhz flat response, and .00027% IMD measured at 100:101 khz 1::1 at any power I could see any IMD at at all.(*)
Not a typo. Three zeros.

With two months of building test gear and frontends to existing stuff to measure anything wrong at all (well, it sometimes had DC offset in the 10's of millivolts and drifted a little).
I can publish the schiz if anyone cares, and I'm still using the prototype because I have it. No golden ears can hear any difference between this and any other very good amp, on any source or speakers we've come up with - we hit the limits of what humans can perceive in this setting.

And what made me quit the audio biz...
I sold them for $400 a channel (which was ~ 10x parts) and sold diddly. No one believed it could be that good, though I sold some tens to people who used them as servo amps.
So, I jacked the price up to $3k and put together a fancy anodized finned spaceship case and sold the whole run right off. "Negative elasticity" as an economist would say,.

I felt so dirty I couldn't keep doing it. I went into more honest work....

Anyone familiar with the design I started from could assimilate what I did with a few word of description of the mods I did....it's not that crazy, just matching, better current sources, burn more current in the front end quad (see national's tutorial on what makes for fast slew in closed loop amps), some changes in the bias and values in the gainy output stage to accommodate the FETs tempco and also the gate capacity. Nothing that special, actually. Since you couldn't get truly complimentary N and P fets then (maybe still) the N fet had a little extra source resistance added to match the trans-conductance. Everything in there was hand matched.

Yes, they make a pretty good LF linear (to 80 meters), and I had to add a lowpass on the input to keep them from being transmitters if people ran crappy cables or had bad ground loops.
20180327-2322-amp-3.jpg
In its accustomed place - my main squeeze

20180327-2322-amp-4.jpg
innards, works despite the dust

The sharp eyed may note the accidental dead bug technique here.

And yes, class D used to stink universally. Either quantization noise, or slew limiting (like happens still in many sigma delta a/d's which help promote the myth that super fast sampling and more bits/sample are the answer when it's just that a 16bit/44.1k a/d is really only 12 bits good and slew rate limits at anything over 5khz full scale amplitude due to *design*).

But this one doesn't suck, and only cost ~ $12! Hence the amazement. I'd have to hook it up to my $20k monitors to be sure, but with some decent bookshelf speakers and a good d/a, nothing is obviously wrong, which wouldn't have been the case a couple years ago (and still in most class D stuff).

* In this design, neither side of the push pull ever really turns off, but does get down to a quiescent value fairly early in the off part of a cycle. But it stays on some, to facilitate instant recovery and keep the charge carriers alive...But it's not class A either - the "off" side is nearly off...

Edit: Based on this: http://baselaudiolab.com/TIGER-01-207B.pdf Just burn a hell of a lot more current in the emitter followers in the output stages, change a few loop time constants, put fets as output devices, balance it all up.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: Life, The Universe, and Everything

Postby Bob Reite » Wed Mar 28, 2018 9:51 am

When my business parter died unexpectedly I gave up on Reite Audio as I am not a sales type (he could sell refrigerators to Eskimos). One of the criteria for the amps was they had to be idiot proof so we would not be stuck with warranty repair that was not really our fault. I'm using a pair of them with a function generator for the 30 KHz drive for my fusor high voltage supply. That is a nasty load, especially when the fusor arcs over. Worst that ever happens is the rail fuses sometimes blow. Put in new fuses and the amps are as good as new.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
User avatar
Bob Reite
 
Posts: 142
Joined: Wed Nov 11, 2015 1:02 pm
Location: Wilkes Barre / Scranton PA

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