Sunday, July 5, 2015

Explanation A, B, or S ?

I just described how I determined, by process of elimination, that a signal dropout problem I was having in FM playback was not caused by the tuner, but apparently by the twin-lead antenna routing.

That was for my tuner #2, which is slated to be a remote control tuner.  Tuner #1 is the non-remote tuner always tuned to the classical station.  Both tuners play anywhere and sometimes nearly everywhere in my house through Sonos, and playback of sources in other rooms is a key feature which made me choose Sonos over SqueezeBox.  I actually do that as much as or more than playing music files, and mostly now for the tuners (although also LP's and cassette tape).

After doing those tests and writing that post I switched back to using Tuner #1.  Actually it was almost a day later and I was setting up Tuner #1 to record through a repurposed Zoneplayer now serving my cassette deck and turntable.  So this was new, though I had set up the Sonos box before.  I added an Insteon switch to the cassette deck so it would turn on at 7pm to record the classical station.  I got everything set up just before 7:00, and it started as it was supposed to.

But right away there were dropouts again.  I made sure the Tape/Source switch was set to "Source" and there were still 5 or more dropouts in the first 30 minutes.  Some of the dropouts were extremely messy sounding.

I hadn't heard the dropout problem before with Tuner #1.  Tuner #1 has always sounded perfect.  So what happened?  First I panicked worrying that I had damaged the Pioneer F-26 (which, btw, some people are now selling as an ultimate, as they should, for collectable prices like $36,000, which sounds too high, I paid $1000 for mine, but I'd think they should be priced about the same as TU-X1 if not slightly higher).

Remember than in the previous day's testing I had connected the F-26 to the antenna used by tuner #2, to make sure the problem that the KT-6040 was having hadn't been caused by the antenna.  Then when all the testing was done, the F-26 had been disconnected, so I reconnected it to Antenna #1, which is a twin lead dipole on the southeast side of the living room--best for KPAC.  It is connected via a 10 foot length of coax to the tuner…coax is used specifically to eliminate interference with all the other gazillion wires it must run next to, so it couldn't have the kind of problem that had happened with the twin lead signal being periodically interfered with by the AC in the power cord (or so I thought, anyway).

During that moment of reconnection I almost wondered if I had felt a slight shock as I rehooked the antenna, no I don't think I actually did--but I hadn't done my usual thing of deliberately discharging the hot wire, but then I though to myself at the time I was holding the F connector with my bare fingers and also holding the chassis with the other hand, there couldn't be that much of a built-up potential.  But being obsessive, I alway worry about such things.

So anyway, I dismissed the thought at the time I was reconnecting the antenna, but now that I was hearing dropouts my first worry was that I had damaged the tuner itself when reconnecting the indoor antenna, just as I had momentarily worried when doing the reconnection.

Well that wasn't likely true (and doesn't appear to be true either) but the next thought was that I might not have reconnected the antenna well, I might not have fully tightened it (though I had taken several minutes in tightening and had tried to make sure it was turned as hard as I could by finger).  Another weird concern is that there might have been some kind of conductive dirt on the F-connector of the 6040--and the very thing that had caused it to malfunction perhaps in this case--which in the process of testing had gotten transferred to the F-26, and therefore the F-26 had been "infected" by the disease that the 6040 had previously had, because the cable had been changed from one to the other and back.

As I was hearing these dropouts get recorded on my new but flawed automatic recording system, I had been planning to take a nap, and I found the frequent dropouts disconcerting, so I muted the Sonos volume for the bedroom.   I'm actually having trouble remembering exactly what I did when I got up, and in what order, but I think I probably first tried simply "Pausing" the Living Room (which was playing Tuner #2), to see if Sonos interference hadn't caused the problem.  Well it still seemed to have dropouts, though less frequent.  So then I removed and reconnected the antenna, this time wetting both the conductor and shield thread surfaces, and even a tiny bit on the back of the connector surface, with DeOxit Gold, which makes for better conduction AND is actually an insulator on insulated surfaces.  I inspected the cable and there was no dirt inside the connector that I could see.  I observed this time just as I had before that the reception was perfect from the moment I brought the connectors together and before I even got the threads mated, and remained perfect as long as the connectors were together, even as I was turning and tightening them.  I felt that the tightening was a bit smoother the second time, possibly helped by the deoxit application.  It been a bit tricky the first time, but did not show serious resistance as it would have if it had been cross threaded.

Even before that I pulled the 75 ohm coax from the very bottom of the pile of wires in from of the equipment, and re-routed it loosely above all the other wires, then pulled of the bit of dust and cobwebs the connector picked up from being pulled under all the other wires.  And I think before I tried that, I had simply tried re-inserting the 300 ohm transformer on the other side, and when I was done cleaning, treating, and re-connecting the cable I did that again.

Well despite all this fiddling, I was still hearing dropouts in 2 or more tests I did, though it also seemed they were getting less frequent and severe.  So this is how things go in casual experimentation, nothing seems to fully work, but there may be smaller effects one isn't sampling enough to have any clear ideas which things are helping more than others, but it does seem to be getting better.

I had becoming more concerned, however, that it was the Sonos system that was glitching, because of piping multiple line-in sources to different rooms.  So after having shut things down, and still reach a level of decisive indeterminacy about what was going on, I decided to go back the other way and see if Sonos could handle a full many-to-many with line in.  BTW I had also done this test before, and since I installed the gigabit managed switch at the center of my LAN there have been no problems.

I set up Bedroom #2 to play Tuner #1 (which is the Living Room Sonos Connect).  I set up Living Room to play Tuner #2 (which is Living Room 2 Sonos Connect).  I set up Tape & Turntable to be playing Tuner #1, recording onto the Nakamichi, and using Source Monitor to go to the main Bedroom system.  And then Kitchen was playing Bedoom, which was the Souce output of the Nakamichi.  As I was resting in the Kitchen, I could listen to the end product of several different links in series.

The end result of all of this was--hardly any dropouts at all.  In fact the first dropout that I did hear, I was suspicious that it was just a small bit like 0.5 second of dead air during station switching.  Unlike previous dropouts that tended to occur on peaks, this occurred during a silent interval, so it seemed qualitatively different and perhaps not even the same kind of thing.

As the night went on, it seemingly just got better and better, even with all this Sonosnet activity going on.  After a few hours, I'd say it was close enough to perfect that I might have been ignored it like this before.

So maybe it was Sonos after all, but just running Sonos to the max on blasted all the carbon out of the cylinders (that was a pseudo rationalization a teenage friend of mine gave for flooring his GTO, only for the first time protesting that I didn't necessarily see why it would not be blowing more carbon in than out…but now I feel this sort of strategy is not a bad thing in limited or applicable doses…some things like Halogen lamps even require being operated at full brightness regularly).

Or maybe not.  Maybe the deoxit in the F connector took some time to do all its deoxing.

The point I'm trying to make here is that "results" from trying to fix things are often useless in developing a model of "what was wrong" for use in creating a definitive similar problems (though they can become a set of possible hints).  I believe that many people premature leap to conclusions that might be less than fully explanatory, and even maybe not explanatory at all.  Any kind of real world activity involves many microscopic actions which may not be replicable or reversible.  I pay much more attention to these tiny details than most people, but even I don't and can't pay attention to every detail that might include the most uniquely effective details.

And then too, the goal counts.  My goal was firstly to fix my system, and only secondly to determine exactly what the problem had been.  If it had been the reverse, I might have spent weeks exhaustively trying tiny changes and establishing baselines and doing sampling and so on, with statistical verification, and still not know because some small change might have happened without my notice that caused it all to change.

Given the reality that we will never exactly know how things work, or what we should do when they don't, the best approach is to be flexible and patient and not leap to conclusions.  One other things is that things that are working reasonably well seem to improve over time to working nearly perfectly.  Things that haven't been used for awhile, such as the repurposed Sonos node which had been take offline for awhile, and the Nakamichi, may take awhile to fully "remember" (that's what an engineer once told me) "what they are supposed to do."  And the Sonosnet itself, which is an aggregate of many active players.

That's just the way things are.  Most things that happen are far below our notice, and we only become aware of the aggregate affects of complex systems, and complex systems are weird in many ways.

I often think of how Western Electric had a standard for making 300B amplifier tubes, and the standard was very careful and detailed about how everything should be done, and then, after everything was made by specification and the newly created tubes were meeting specifications, you kept making tubes continuing to meet specifications for another 6 months before you made tubes for field usage.

Following a sensibility like that, keeping the Sonos line inputs running may be a good thing.  The system is prepped to do that, and it seems it irons out irregularities over time.

Sunday night: no confirmed glitches.  Last "glitch" was actually Nakamichi flipping the tape I was listening to, so it wasn't really a glitch.  BTW the Nakamichi is sounding fabulous too, and some of my greatest elation has been hearing a college FM radio recording I made on the Nakamichi RX-505 (can't remember the tuner, possibly Kenwood L-1000t), played on the Nakamichi, through Sonos to the Living Room.  Despite all that processing, still sounded perfect and good enough for bliss.

Wiring all Sonos Connects (and ZP80, ZP90's) straight to my managed gigabit switch would probably be the way to go, and I can do it with a few changes in my video networking.

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