Stereo System: Time to make some changes: Dynaco Stereo 200 PLUS Banana Plug lesson.

Gentle reader,

I just posted a list of all my blogs about my stereo equipment adventures. After this, why not take a look: UPDATED Every Stereo Equipment Blog post I have done!

Here's the deal. I started looking into PROTON equipment because the same company that made them also made the revitalized Dynaco line when Panor Corp. bought the name rights. I always wanted some of that new Dynaco equipment and at last found a Stereo 200 power amplifier on eBay and snatched it up! It was part of the all-new audiophile equipment they were putting out as well as selling new Stereo 70 tube amplifiers. By the name, one can tell a Dynaco amp's output, the 200 is 100 watts-per-channel.

So, I found a PROTON D540 integrated amplifier which has their phenomenal "Dynamic Power On Demand" circuitry. I bought it to use as a preamplifier to replace my Yamaha C-45. After a while, I decided to try it as it was designed. Well, the stuff works. That little amplifier is amazing at producing prodigious power! It took everything I threw at it and asked, "Is that all you got?" OK, I may be being a little silly. If you Google PROTON D540, you too can learn about the magic they achieve from a 40 watts-per-channel amp.

So, anyway, I was playing LP after LP and all of a sudden there was a roaring noise, like Pink Noise, along with the music, but only on the Phono circuit. Fortunately, I had bought a spare D540, via eBay, so I wasn't too concerned.

Since I was going to unwire everything I decided to put the Stereo 200 back to work. I rearranged somethings too. Took me many hours. Here's what it all looks like now, and yes, I DO have the cover for the Discwasher components:
The OPPO universal player (has headphones on top of it) and the Adcom power supply were moved from the right side. The TDK CD recorder was moved from the left side and the D540 was moved (and replaced) from the top right to where you see it now. The Dynaco (and the D540 before) has to be on top to hook up all the speaker cables.

Here's the wide angle  view of the above photo for reference:
And here's what it looked like before, except those Philips speakers now live elsewhere:
One thing I do not like about the PROTON models is the speaker terminals LOOK like they have three-way banana/binding posts, but they do not. They accept bare wire from the top down into the terminal OR some fancy bent-pin terminals as seen below:

As you can see, it makes for some odd restriction on how one hooks up speakers. Nope, one cannot slide banana plugs in those holes. They do not fit, and there is no continuity in those holes either. They just allow the red and black knobs to rotate.
Below is a close-up of the best conducting banana plug in the world next to the bent-pin terminal. Both are made for Nakamichi in China. I know, I had to get the bent-pin terminals all the way from China.
You see that split zig-zag? They make for ultimate connectivity. Sometimes a little too much as they can be hard to pull back out. Note how the outside cover for the bent-pin units have to be slid onto the wire/cable before putting the terminal on the bare copper. The banana plugs go on first and then the outer cover screws on. For the BEST banana-shaped banana plugs, Nakamichi also sells these:
No, they are not levitating. Though the magic of Photoshop, I rotated the photos 180 degrees. MOST banana plugs, even Monster Cable's do not look like these. If you look closely, the have a little bump on the end and the expanded part can spin around. This makes for easy assembly but poor contact. 
Banana Plug lesson is over. Please let me continue the tale by showing how I wire my system to be able to drive up to four pairs of speakers with no danger of too low impedance for the amplifier to handle.
Above and below is the LEGEND LE412 speaker switch I found years ago. Go ahead and try and find one yourself. They seem to have been all sold. What's unique is it has three-way binding/banana terminals AND they are spaced 3/4 for using double-banana plugs which is what you see plugged into it. They are Monster Cable brand and yes, they have spinners.
To secure the switch to the top of the amp, I made round feet out of Blu-Tak which is sticky Playdoh-like material. It sticks but does not leave residue. Those funny looking things on top of the front of the switch are iron weights. I do not remember what they came out of, but they are perfect to prevent the LE412 switch from rearing up like it's doing a wheelie. The LEGEND switch designers never figured someone would use heavy cables like I do. 

The gray, (or is it grey?) cables are Monster Cable M-Series and are 10-gauge copper with different sizes of wires making up the conductors. The theory is bass will flow on thick wire, treble on thinner. Can't prove it, but is sells cables.

Here are the various cables on the wall waiting to be reattached: 
The black cables are Monster Cable Z-Series and go to the subwoofer and from there to the modified Minimus 7W speakers. Both Minimus speaker sets and others I have modified can be found in the links as seen in: UPDATED Every Stereo Equipment Blog post I have done!
Here is a close-up of the Monster Cable Z-Series:
"Z1R Reference Energy Time Coherent Time Correct Winding" is what it says. Again, it sells cables. And they DO sound fantastic which is why they connect to the incredible and ONLY ones in the world, modified Minimus 7W speakers.
The thicker blue and white ones are the larger BLE Design units comprised of ten separate conductors woven together. They are for the Cerwin-Vega LS-12 speakers. The ones sheathed in clear plastic which my wife says looks like umbilical cord, go through the attic into this room and connect to the BOSE 301 speakers in here. My wife bought the 301 speakers for me. She's like that, and yes she does have two older sisters. One is not married. The smaller BLE Designs cables go to the modified Minimus 11 (silver) speakers.  

Below shows the much neater cabling as plugged into the Dynaco with proper speaker terminals:
Those particular Monster Cable M-Series cables are not marked for polarity. So, red and black Sharpies to the rescue. If you are into stereo/surround speakers, buy a digital ohmmeter. They make it easy to determine polarity on speaker wiring.
So you may be wondering just how can I run up to eight speakers at a time? Well, I don't actually. The Dynaco and PROTON both have speaker selector switches which are designed to handle two pairs of speakers in parallel. The LEGEND LE412 speaker switch also has internal resistance for the same purpose. The load never drops to a dangerous level.

You also may be wondering what's up with the black cables plugged into the double-banana plugs on the inputs of the LEGEND LE412 speaker switch? As stated above, the cables go to the subwoofer and then on to the Minimus 7W speakers. To play just those speakers, I choose B on the amp and do not press either switch on the LE412. Should I choose to play the Minimus 11 and/or the BOSE 301 speakers, I simply slide the red plugs out of the double-banana plugs and choose switch 1 or switch 2 or both on the LE412. Also, of course choosing B on the amp. Confused yet? Believe me, it works and I measured the impedance in each case, all is well. Here are the terminals on the back of the subwoofer:
Aren't Nakamichi speaker terminals lovely to look at? They truly are the best and I highly recommend them. As you can see, the Monster Cable Z-Series IS marked for polarity.

To quote the famous and fictitious, Forrest Gump, "That's all I've got to say about that."  

Thanks for looking!

Scott 

 
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INDEX PART ONE To Every Article: Stereo, Quad, Home Theater, Speakers And More

Updated April 3, 2020

Gentle reader,
The largest collection of articles are a passion I have had since 1975: Good stereo sound on a budget. As a result, I have had to divide the list of links into THREE PARTS.
 
Early on, I did not know how to add photos to the articles and I was not very verbose in my titles. I have learned a lot since 2008.
 
PART ONE: The list starts with the oldest at the top to newest at the bottom.
 
Thank you SO much for your interest in my humble blog!

Scott
April 3, 2020
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BACK to: My First Stereo 1976 Dynaco PAT-5 SWTPC Tiger 01

Gentle reader,
My previous post: COMPLETED: Creating a searchable database of all my thousands of LP recordings. has generated unprecedented response from readers with almost 400 page views the first day which pushed page views to over 100,000! I am VERY grateful to you and all the others around the world that take the time to read my humble blog. When I started I figured very few would be interested. You all have proved me wrong and I am SO happy about that!

I attended High School in the Mile High city of Denver, Colorado in the 1970's. My family moved from there right after I graduated in 1974, to Richmond, Virginia. At the time, I had a plastic fold-up suitcase style stereo that I was perfectly happy with. Or so I thought.

Then I met Phillip. He invited me to see/hear his stereo. His poor parents and neighbors. Phillip had constructed huge plywood speakers with eighteen inch woofers, a six inch midrange and I don't recall what kind of tweeter. Driven by a Pioneer integrated amp that put out 60 watts per channel. He had a Revox fifteen inch reel-to-reel tape deck and I don't recall what type of turntable. He played Pure Prairie League's Two Lane Highway for me and I was completely blown away! It was SO LOUD and clear! I went home, looked at my plastic piece of crap and sighed.

Being short on money, I started with a Quadraphonic receiver, Electrophonic, I think was the brand, it was cheap, had a built-in 8-track which also played Quad tapes, and had a ceramic phono input. Came with four matching speakers. Sounded OK to me. Here is a link to one that seems to be the same one I remember:
Vintage Morse Electrophonic AM FM Multiplex Stereo Receiver 447 & 8 Track Player • $51.00 - PicClick

I found an ad in Stereo Review for a book called Audio Alternative by Mark Tobek and ordered it. With knowledge gained by that book, I set out to build a stereo. 

After thoroughly studying the book and the author's results from his testing and listening, I decided upon a kit Dynaco PAT-5 which was their new flagship solid state preamplifier. Since I couldn't also afford their ST-120 power amplifier, I instead chose South West Technical Products Company's Tiger .01 mono amplifier kits. Two mono 60 watt amps verses the Stereo 120 which had the same output in one stereo chassis.

I built the PAT-5 first which was a good thing because it was much easier and gave me lots of soldering practice. I took it to Audio Art in Southside Richmond. Here is a link to their FaceBook page: Audio Art They tested it and pronounced it ready to use.

Next, I tackled the two Tiger mono power amp kits. I was just 19 and had little electrical knowledge, but even so managed to get them both built and Audio Art stated they each slightly exceeded their rated output.
Above is a photo of a later PAT-5 I owned for a while. Here is a photo of the rear:
I won't go into all the specifics of the PAT-5, but note the speaker terminals which allowed for switching to another pair via a switch on the preamp.

Below are a couple of photos of the plans for the SWTPC Tiger .01 mono amps that I found on the "Tigers that Roar" website:

A clever compact design made so four side-by-side could fit on a 19" wide rack-mount shelf for a Quadraphonic system. Remember, Quad was all the rage in the 1970's a was what eventually became Dolby Surround Sound.

I did not own a camera, other than a JCPenny 110 film camera in the 1980's, until April, 1995. So, below are photos of my stereo in the basement apartment I lived in:
Note that my first PAT-5 had a silver faceplate without the beveled top and bottom edges seen on the one at the top of the page. It is all that remained of my original stereo. The Tigers had died of some unknown reason.
Note one of the two Dynaco A-25 speakers that I also chose based upon Audio Alternative recommendations. I bought the pair from Dixie HiFi also in Richmond. They were floor samples so I got them for $99.00 for the pair. I found out decades later that they had substituted the drivers in one with cheaper ones and stuffed that cabinet with fiberglass. The grilles were glued on at the factory so it wasn't until I detected a buzzing in one woofer and pried off the grilles did I see what they had done. So much for my having "golden ears"! 
I don't recall the brands of any of the other components, other than the Dynaco FM-5 I added later. Note in the photo below that the PAT-5 is missing. One channel had stopped working and I eventually sold it via eBay.
Below the FM-5 is my first CD player. Below is the genuine SEAS woofer and tweeter from the unmolested A-25 that I sold on eBay as well. The cabinets were so bad, I didn't consider finding and buying a pair of the correct drivers. I wish I had.
As far as turntables, and the book's advice, I chose a B.I.C. 940 and I sprang for the walnut base and smoke dustcover. It came with a cartridge, but I don't recall which one it was. Here is a photo from the web of a 980 I found on this blogger's page:POLITICS / THE USA / SPORTS / WEATHER / TRUCKING / LIFE / HEALTH / FAITH/ GOD: 12/1/09 - 1/1/10
I do not know how to credit the photo other than including a link to the page I found it on. I hope that he/she is OK with my using it.
Above is a photo of one of our "mitten kitten" cats, Leah, squeezing past one of the reel-to-reel tape players I owned later. Not clear enough picture to tell any brands. This photo was made with that JCPenny 110 camera.

Below, are the A-25 speakers atop a pair of the infamous "white van" speakers I found in a thrift store. Again, since I do not have "golden ears" those sounded fine to me too:
This image is from this room. At the time, the kids still lived here, so no listening room.

A LOT of equipment has come and gone in the decades since. I've lost a lot of hair too! We do tend to nostalgically wish we could go back in time and tell our then selves to NOT get rid of things, don't we?

Of course, my current components blow away anything I had then, as seen below:
The Philips speakers are gone now and the modified Minimus 11 speakers now sit there.
Since completing them, the screws/washers have been painted black. Here is a link to the final results of the extensive rebuild: NOW finished: Upgrading old diecast Realistic Minimus 11 speakers Part 2.5 

Thanks for looking!

Scott 
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The 500th Article Of The Robb Collections! Thanks To All Of You! Indexes To All Categories!

  October 24, 2024 #500 Gentle reader, First of all, THANK YOU for taking the time to read my writing and viewing my images! This article, s...