Confessions of a Frustrated Audiophile

Magnavox Portable Stereo Record Player

I have been an audiophile ever since my Grandfather gave me a homemade cabinet containing an Electro-Voice SP12B speaker with an Atlas horn tweeter. At the time (1970), I had a portable Magnavox stereo.

I think the Magnavox had about 3 watts per channel into those 3x6 oval speakers shown in back. Well, I found some RCA plugs and just paralleled the outputs together and hooked them to my Grandfather's single mono speaker (not recommended for audiophile work). But it worked, and the amplifier didn't seem to mind. The sound blew me away. The high end and the low end were like I had never heard before, even from the "hi fi" my parents had in the living room. I was hooked.

The next task was getting back to stereo. So I hunted down a source of EV SP12B speakers. Unfortunately, the one my Grandfather gave me was from the late '50s, and the new ones were of a slightly different design. No matter. I only had $50.00, so I could only afford one. I built some cabinets from a project in Popular Electronics (I think it was), that used some mail-order tweeters from Mouser Electronics. The cabinets were designed for some Radio Shack woofers, but the specs were similar enough to the EVs that I decided to go ahead. I finished building the cabinets, and now I had full range stereo. At 3 WPC. With a ceramic cartridge. Still, I remember it sounded great! I got a lot of enjoyment playing Nilsson Schmilsson, Abbey Road, Ram, Straight Up, The Best of the Guess Who, and ... and I think that was the extent of my record collection then. I had some singles, Joy to the World, American Pie, Albert Flasher, a few others.

BSR 610 Automatic Record Changer

I started reading Stereo Review, and from there I realized that I would need a magnetic cartridge. Also, I started to notice thumps and rumble coming from the record changer in the little Magnavox. Plus, I wished it could play a little louder. My fascination with electronics had led me to get on the Heathkit mailing list, and they always had the most beautiful audio gear (for the time). It was time for an upgrade (such as my meager income could afford). So I bought a Heathkit AA-1214 amplifier and a BSR 610 record changer (with a Shure M71 cartridge). I eventually got matching woofers and purchased EV "building block" midrange horns, tweeters and crossovers.

BIC 980 Belt Drive Turntable

The BSR turntable also had thumps and rumble, so eventually I upgraded it to a BIC 980 with a Shure V15 Type III (I was making more money by then). I used the BIC until about 1984, when CDs started coming out. I bought a Magnavox 4X oversampling CD player (which was actually a Philips, which contained very good electronics and converters). In those days, it was nearly impossible to build a 16 bit D/A converter that was actually accurate to 16 bits. But Philips made 14-bit oversampling converters. The 4X oversampling produced the additional 2 bits by duty cycle modulating bit 0 of the 14-bit converter for 16-bit accurate output. It was ingenious, and it sounded great. So much so, that I started to wish I had a better turntable. Which brings me to the subject of this article. (That's the longest intro I ever wrote).

Dual 505-2 Belt Drive Turntable

Here's my confession: I love my Dual 505-2 turntable! I think it cost me about $300.00 in the day. The salesman talked me into a Denon high-output moving coil cartridge. Moving coils were all the rage in those days. But the Denon never sounded great to me. For one thing, my Heathkit AA-1214 had kind of a noisy phono preamp, and even though the Denon was "high output" for a MC design, it was lower than any moving magnet cartridge. So I purchased an Ortofon OM-20, which is one of the highest output moving magnet cartridges out there. I was kind of a Shure bigot, though. I only went with Ortofon because of the high output, and I had read that Ortofon and Dual had teamed up to match the 505-2 tonearm with the OM-20.

Ortofon OM-20 Phono Pickup

When the cartridge arrived in the mail, I hooked that baby up, and put on my Mobile Fidelity copy of Abbey Road. Wow! I was hooked. That was about 1986. My vinyl collection didn't get as much use in the CD era, or in the MP3 era, for that matter. But what I didn't have in digital format, I have played on vinyl. Over the past few weeks, I have been spinning a lot of vinyl, and really enjoying it, on a turntable and cartridge that is now 27 years old. The OM-20 stylus is still in good shape (I used to replace my old Shure stilii every year or two - don't ask me why the Ortofon has stood up so well). Fortunately, OM-20 replacements are still being made.

Here's the bottom line: Audiophiles and vinylphiles are quick to poo-poo any turntable that costs less than $1000.00, and is built with anything less than unobtanium parts and magical wire, broken in for three months. Well, the fact is, that old Dual is still kicking (after a belt replacement and a few other maintenance repairs), and it is capable of producing sound that is as good as can be stored on vinyl. A 50-lb platter just doesn't turn any more evenly or quietly than a well-engineered lighter one.

Thorens TD 235 Semi-Automatic Turntable

And here's a really interesting tidbit. I was looking at Thorens* turntables with the thought of updating (just because). Guess what I found? One of the midrange Thorens turntables is a dead ringer for the Dual 505-2, and I'm not just a-woofin'. Check it out: The tonearm is identical (right down to the gimbals and headshell), and the semi-automatic operation is as well. The plinth as been redesigned slightly (possibly for easier manufacture), but the look is nearly identical. MSRP: $1000.00 US.

I might buy the Thorens TD 235 someday, but for now, I still love my Dual 505-2 and that sweet sounding Ortofon OM-20. As long as I can still get parts.

* Thorens makes very high-end turntables for the rarefied audiophile community.

WxService Update Available

WxMonitor ow4j130929

• Modified the Wind Vector to show the wind direction in blue when the average wind speed is zero. The reason for this is that when there is no wind, the wind direction is meaningless. The wind vane will be pointing somewhere, but the direction is completely arbitrary. What's more, without the wind and its turbulence to buffet the wind vane and dither the data, the displayed direction will only be precise to the nearest compass point. When the average wind picks up above zero, the indicator turns red to indicate active status. 

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Going Down! (For Maintenance)

I will be taking the weather station offline for a short time while I upgrade my weather server computer. I hope that this interruption will be brief (less than a day).

Update: We're back!

WxService Update Available

WxMonitor ow4j130826

• Fixed discrepancy with event intervals when wind speed and wind direction both contribute to a single composite value (wind history).  
• Changed wind history display defaults to 120000 msec. (two minutes) interval and 3600000 msec. (one hour) length; updated config.html to document this.  

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Building Your Own Computer? Important Safety Tip!

If you are building your own computer, or replacing a motherboard, or moving cables around, here is an important safety tip: Due to atrociously bad engineering, motherboard headers are physically identical for USB and firewire. However, the power and signal assignments are quite different. If you accidently connect your front panel USB ports to a firewire header on the motherboard, then any USB device that you connect to those ports will be destroyed instantly. It may also destroy the firewire port on the motherboard as well. My son and I found that out the hard way, but if you Google it, you will find that we are far from alone.

USB Header Pin Configuration

Firewire Header Pin Configuration

This is an easy mistake to make, especially if it is not the initial build, where you have the motherboard layout docs handy. The headers may not be clearly marked, and often the header nomenclature will be obscured by other components, and board real-estate for silkscreened labels sometimes puts the labels ambiguously far from the thing being labeled.

Update: It is also possible to sabotage your front panel USB jacks by plugging the internal connectors on backwards if the case uses connectors split down the middle. On such a connector, there is no key to prevent reversal, in which case the data polarity is reversed, and worse, +5 goes to GND and vice-versa. The power swap will destroy any attached USB devices. 

How Vector Average Would Sum to Zero

In my post Consensus Averaging vs. Vector Averaging, I mentioned that adding two opposing vectors could produce undefined results. In a wind vane data averaging scenario, this would be extremely unlikely.

Assume the following conditions: A sample interval of 1 second, an average interval of 2 minutes, yielding 120 samples per average result. Incoming data is aligned on 16 compass headings:

It is quite possible for any two vectors to sum to zero. But we have 120 vectors to sum. In order to cancel out completely, we would require one of the following:

• 60 vectors symmetrically distributed on either yellow or violet line.
• 30 vectors symmetrically distributed on both the yellow and violet lines.
• 30 vectors symmetrically distributed on any red, green or blue rectangle.
• 15 vectors symmetrically distributed on all points.
• Other permutations of symmetrical distributions on the various lines and rectangles and their rotations.
• Equal numbers of samples from the northeast and northwest will result in a north vector that could be canceled by some number of south vectors. 

This list goes on, but when the wind is blowing, by far the most common scenario will have chaotic or turbulent input data in which more than half of the input data will be in the general direction of the prevailing wind, providing a dithered average with good resolution.

WxService Update Available

WxMonitor ow4j130809

• Widened Add Property dialog input field labels to display correctly on OpenJDK in Linux.

WxService ow4j130809

• Refactored WindVane averaging algorithm to use pre-calculated sin and cos values, since we know what they are all the time. Looks up the values based on one of the 16 cardinal compass points. 

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