What can one do with a single speaker? Why not make a monophonic system! Mono? Sure Mono LP records!

Gentle reader,

This will be a relatively short post. As you have read in my recent post, the replacement SEAS H 086 tweeter finally arrived from Poland (I LOVE EBAY!) and at last I had two working Dynaco A25XL speakers.

Well, I then parked the now unneeded A25 speaker in a corner. In the past, I would have simply put it on eBay and sent it off to a new home. However, some items I've enjoyed until something else came along that caught my eye, and then of course I sold them, I now regret selling. And now the prices are too high to re-buy that which I once owned!

Also, I also had my "spare" PROTON D540 integrated amp which has PRE-OUT and MAIN-IN RCA terminals with "U" shaped jumpers in them. One can use such integrated amps and receivers made like this  as either a preamp or as a power amp by removing the U jumpers and hooking up another preamp or power amp to the appropriate terminals. A photo of the back of a D540 is further down in the article. In fact, the first PROTON D540 I bought specifically TO use it as a preamp until the day that I bought the PROTON 1100 preamp seen below.

Now, who can tell me, aside from the LP records, what is different in this photo? Look closely, now. What? You clearly can't remember what the last photo shows? OK, I'll take pity on you and ad that photo.

Now, surely you must see the difference..........Right! The subwoofer and awesome dragon are gone. Well, only moved. I had taken the sub out of the system anyway. It was to enhance the tiny speakers at the top of the totem-stack. However, despite their tiny 4" mid-bass drivers, they sound like they are bigger. Don't worry, both the sub and dragon are in the corner in which the A25 was. I can display the dragon on top of the LUXMAN turntable. It may look like aged bronze, but it isn't. So, the weight is not significant. Those clever Chinese!

Believe it or not, stereo music recording and reproduction was invented sometime in the 1930's and patented. However, there was no practical way to build and market the technology. So, mono was IT for decades. It wasn't until the mid-1950s that someone realized that a LP record's groove could carry one channel's sound on one side and the other's on the opposite side of the V shaped groove. Some artists, especially the Beatles, preferred to make their records in mono. But the powers-that-were, prevailed by compromising, thus both mono and stereo pressings were made. The mono ones being the more valuable.

ALSO, until there was FM-Stereo radio, all records played on the radio were mono. Most of my PROMO LPs are monophonic.

Here is a closeup of the A25 with my D540 atop it. Normally, I would never place a component on top of a speaker. But this is just an experiment. The D540 has TWO power transformers to supply their patented Dynamic Power On Demand circuits, so the left side of the amp is considerably heavier than the right. Plus, to avoid scratching the vinyl veneer on the speaker, I placed the last four of my special rubber isolation feet under the amp.

Who can tell me the 1st year the Long Playing 33 1/3rd RPM vinyl records first hit the market? Don't all raise you hands at once. Give up? The answer is 1949! I came across this LP's date when creating my searchable data base of all my records. The cool thing is it is of the only opera I like. 

A now-former coworker (since I'm retired) and fellow stereo enthusiast gave me this cool record player. It is of course mono only. Plus it's portable because it runs off D-cell batteries. I wired in a transformer to play it in the house. Sound quality and record wear are concerns, however.

BACK to the subject at hand. My mono experiment. The Dynaco PAT-5 (silver one in the photos at the very top) has two pairs of audio-output RCA plugs, as seen below. 

As you can see, all the RCA terminals are very close together. When these came out there were no "audiophile" RCA interconnects with their thick heavy plugs and cabling. So, to wire my recreation of my 1976 stereo system, I had to buy the cheap thin cables they had in the 1970's. So, anyway, I decided to use the second pair of outputs to hook up to the D540's MAIN-IN terminals. Here is the back of a D540, showing the terminals with the U shaped pins in them:

Here's where it got weird. I attached a second pair of cheap RCA stereo interconnects to OUTPUT 2 on the PAT-5 to both MAIN-IN 2 terminals above after removing the U pins. I was getting a loud 60 Hertz hum, even with the volume at zero and the woofer was visibly moving in and out. Whiskey Tango Foxtrot? I unplugged the cables, hum is gone. Looking at how I routed the cable, there was no contact nor close alignment with any AC 120 volt cable. So, I got a portable CD player, turned the volume down on it, attached the appropriate patch (interconnect, in this case with 2 RCA males on one end and a 1/8" or 3.5mm stereo-headphone plug on the other) between the Discman and the D540 MAIN-IN terminals. Pressed play and slowly raised the CD player's volume. Nice hum-free music was coming out. Hmm. No pun intended. So, what gives?

This made no sense! So, to complete the test, I decided to put the U pins back in their holes, and plug the RCA cables from the PAT-5 into the CD inputs on the D540. This worked, with no 60Hz hum, nice clean sound. I hooked only ONE speaker cable to the LEFT (or RIGHT, doesn't matter) speaker terminal on the D540 and into the A25 speaker and turned the Balance control all the way to the left. I chose a short piece of Monster Cable speaker cable that I once used years ago then stopped using.

The cable on the left, above, is the "umbilical cord" as my wife dubbed it. The M-C I used is to the right and also below. Sorry for the blurriness of the above photo.

Take a look at the photo above. See the extra silver "wire" inside the clear covering that houses the twisted cables? I forget what Monster Cable called it, but it is not wire at all, more like kite string! Yet, they intimated that it serves some mystical purpose.

Well, first of all, as the photo above shows, aside from looking silly with the amp atop the speaker and off-center, the speaker is at floor level which is not ideal except for large/tall speakers because the tweeter is so far below ear-level. Secondly, I hate things that are done slipshod like this. Like the power cord for the amp just limply hanging there. Uggh!

Above is more my style, everything neatly routed. AC cords/cables kept separate from the signal (music carrying) cables. Of course, these are good RCA interconnects, not the cheap/thin ones I have to use with the PAT-5. As a matter of fact, the lighter blue ones are Liberty Cable and the darker blue ones are Monster Cable.

AT ANY RATE, about the sound. Aside from the aforementioned speaker placement, something didn't sound right. Couldn't put my finger on it, but the more I thought about it, I started to remember why I stopped using these clear covered, twisted pair M-C cables. Because they don't sound good!

Here's the thing, aside from that magical string, that M-C does with all their speaker wires and cables: Inside the twisted strands of fine copper wires is what they call the "Flux Tube". Can you think of another thing with flux in it's title that does magical things? That's right! The magical "Flux Capacitor" of the time traveling Delorean car in the Back to the Future movie series. So, although the copper wires appear to be, say, 14 gauge, once you cut off the little piece of clear tubing inside the stripped wire, and re-twist the copper, do you realize, the actual conductor is a LOT thinner than it appears.

THIS SAGA IS NOT DONE, I am going to get a proper power amp, such as an old Dynaco one, and place it somewhere more suitable and perhaps raise the speaker some too.

Stay tuned for further episodes in my building a monophonic setup to listen to monophonic records in the state they are meant to be listened to.

Thanks for looking,

Scott