Speaker selection switch, and more than you wanted to know!

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Harold_V
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Speaker selection switch, and more than you wanted to know!

Post by Harold_V »

One of my primary interests in life is music, which automatically leads me to high end sound gear. I've been addicted since I was a lad, working on the stage crew at Jordan High School, in Sandy, Utah.

While I have a small radio in my shop, I'm not easy to please where music is concerned (and I offer no apology). My main interest is in jazz, the cool, west coast type of sound being my favorite; I adore Brubeck. I also listen to classical, favoring the Baroque. I'm a real snob where both genre are concerned, and don't like a lot that is played on the air, in spite of the fact that I have access to a full time classical station, as well as a jazz station. Those of you who like jazz likely understand that such stations are not common. For that reason, I have sound piped to my shop, so I can enjoy the type of music I prefer.

A few years before we made our move to Washington State, where we now reside, I was perusing the local newspaper and found for sale a used set of JBL C-50 Olympus speakers with the S8R speaker option (their ultimate speaker offer). They are a duplicate of the set I use in my stereo room, along with a JBL D44000 Paragon. The used speakers, while in rather poor condition cosmetically, perform perfectly well, so their overall appearance was of little concern, as my purpose was to use them in my shop.
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These speakers are intended to be floor mounted. They're 40" wide, and about 27" tall. The inner panel mounts the speakers in an upward direction, about a 5° incline, so the sound is projected upwards. As I have them mounted high on the 12' walls, I placed them upside down, to project the sound towards the floor, with the right speaker becoming the left, and the left becoming the right. That is done because the speakers are handed, with the tweeters set at the outside edge of the enclosure. I make mention that they are mounted upside down so you understand why there's a projection on what now appears to be the tops. It's the recessed foot.

In order for me to be able to listen to the stereo in the shop, it requires that I have the ability to switch speaker sets. Susan, my wife, may need silence in the house, so I must address that need, although, in general, she enjoys the same music I do and listens almost constantly. I set the volume a little on the high side in the house, and can control my listening level in the shop, as I have a pair of autoformers which allow me to regulate the volume. The extra loudness in the house is of little concern, because the stereo room is on the top floor, so the listening level in the balance of the house is actually quite acceptable.

The two sets of speakers in the house are wired in parallel, and are, as original, 8 ohm speakers. Combined, they are driven by the 4 ohm speaker outputs from the amplifier. The set in the shop, being a duplicate of one of the sets in the house, are 8 ohm speakers, and must use the appropriate output when operated alone. Combined (in parallel) with the sets in the house, they would be 2.67 ohms, which is an outlet I don't have on the amplifier, but I suspect that they'll operate just fine using the 2 ohm outlets.

Before getting too deeply involved in this project, I made an inquiry of McIntosh Labs to see if the speakers could be switched under power without damaging the amplifier. I was informed that they could, but that there are no common leads, so both sides of each outlet (both red and black) must be switched when I go from one output impedance to another. That means that I must switch four circuits each time the handle is moved, and I will use all three outlets (2 ohm, 4 ohm and 8 ohm), depending on the speakers selected.

I have on hand a multitude of material types. I throw almost nothing away, and I have excellent storage to accommodate my crow-like behavior. That made making the required switch considerably easier, although in the interest of not spinning my wheels making terminals, I ordered off Ebay, as it was far cheaper to buy them than to buy the material required to machine them. I also purchased from Ebay the flexible #10 wire used to wire the switch.

I started with some red ¼" glass reinforced resin board. From that material I made the four contact carrying plates, as well as the two end plates. It machines nicely, although it's easy to chip. I ran a vacuum cleaner during all cuts, to avoid breathing the resulting glass fiber/resin dust.
DSC00001.JPG
Each plate has seven silver contacts, with the wiper completing the circuit from the amplifier to the speakers. In order for the shop and house speakers to be combined there's two contacts, one which connects the shop speakers, the other which connects the house speakers. That one is the 2 ohm circuit. By connecting them in this fashion, I avoid powering the individual speaker sets with the improper connection.

I used a couple short rems of black Delrin to make the carriers for the copper wipers. The carriers are double keyed (1/16") to the shaft, which is 3/8" diameter 303 S stainless, and operates in a pair of sintered bronze bushings, one in each end of the switch assembly.
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The wipers were made from some rems given to me, years ago, by my good and faithful friend Dennis Jacobs. Jake ran a small commercial shop, just as I did. I had stored the pieces for no fewer than 25 years, secure in the knowledge that the day would come when they'd be needed. Thanks, Jake. You've always been there for me!
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The contacts for the wipers were made from two late 1800's silver dollars, each of which was so badly worn that they had no collector value (similar to those shown in the second photo, above). Made it much easier than pouring silver then machining. Each dollar provided four rectangular wiper segments, and some waste. The segments were soft soldered to the wipers, using 8% silver bearing solder.

For the round contacts mounted in the plates, I wasn't so fortunate, as I had no round silver material. Using the waste from the silver dollars, along with some silver contacts that I had removed from several relays, making up the balance with some pure silver, a poured the required material. I made a mold from some gray iron to pour ¼" round silver, each piece 2" long. Because of my history of refining precious metals, I am familiar with the melting and pouring process, although I was really rusty, not having poured any metal since 1994. It went well enough, but I'd have been better served to have used all virgin materials, as I did get a little porosity in the material. Not a problem, but not something that made me proud.
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continued in next post
Wise people talk because they have something to say. Fools talk because they have to say something.
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Harold_V
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Re: Speaker selection switch, and more than you wanted to know!

Post by Harold_V »

Picking up where I left off:

The original design had excessive friction, because the contacts weren't lifted when the switch was turned, so I altered the design by removing some white Delrin spacers, replacing them with a pair of steel balls (under each wiper). The balls cause the wipers to lift as they begin to rotate, and drop the contacts when the proper location is selected. That made a huge difference in how the switch operates.

While the switch rotates reasonably well, I made a large dial type handle, to ensure easy operation. It was made from some old scrap I had on hand. Looked terrible in the raw form, but it turned out quite nicely, although it will need a final polish before being placed in service.
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With the mechanical portion completed, and the switch assembled, the next operation would be to wire the switch.
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Wire lugs were crimped on the #10 wire, then the lugs were soldered to the contacts, using the same 8% silver bearing solder, with the opposite ends attached to the appropriate connector, where they were secured with the provided nut and washer.
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The switch will be permanently installed in the wall cabinetry that houses the sound system. All that will be seen is the handle, as the front plate of the switch is bolted directly to the back side of a walnut panel, exposing only the heads of the two (flat head) screws used, and the shaft on which the handle mounts. The two screws will be hidden by the handle.

I most likely will anodize and dye black the handle assembly at some point in the future, but that's a huge project, as I don't have an operational anodizing line at the moment (although I do have the necessary equipment and supplies).

H
Wise people talk because they have something to say. Fools talk because they have to say something.
LIALLEGHENY
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Re: Speaker selection switch, and more than you wanted to know!

Post by LIALLEGHENY »

Harold ,

Looks like you have a very nice setup. That a nice piece of work on selector switch as well. I too enjoy music, especially when I am in the shop working. Many years ago a friend donated some equipment to a charitable cause....Me! A pair of EV 2 way horn loaded cabinets, double 15" low end cabinets and a pair of 18" subs, included were some Kustom power amps, and an amp for the subs. Granted I have a large shop, 4000sq ft, with 16 ft ceilings, but the system is overkill, and I love it that way. As much as I like my rock music, I especially enjoy listening to organ music. It's almost as good as being in a cathedral.

Nyle
Russ Hanscom
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Re: Speaker selection switch, and more than you wanted to know!

Post by Russ Hanscom »

Most impressive.
SteveM
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Re: Speaker selection switch, and more than you wanted to know!

Post by SteveM »

A selector switch worthy of McIntosh.

Steve
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SteveHGraham
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Re: Speaker selection switch, and more than you wanted to know!

Post by SteveHGraham »

That's really beautiful.

Friend of mine texted me this week to tell me he bought some used Magnepans. He always asks me the same question: am I still using Home Depot electrical cord with mine?

He spent around $400 on the speakers, and now he says he has to spend $600 to repair a flapping panel. I told him to buy some glue and watch Youtube. I don't think he believes me. I wish I had a store and five hundred customers just like him. I would get rich selling Shakti stones and $10,000 silver interconnects.

Have you ever listened to Kanye West? I think you'd really enjoy it.
Every hard-fried egg began life sunny-side up.
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Harold_V
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Re: Speaker selection switch, and more than you wanted to know!

Post by Harold_V »

Hey, Nyle!
Your EV 2 system, along with the subs. sounds like you should be generating a serious sound level. I like to feel the music as well as hear it, and the sub would go a long ways towards that goal. The friend who donated to your worthy cause is a friend indeed! :wink:

The S8R system is limited to one 15" woofer, but the R designates a passive radiator. It's a voicecoiless speaker, intended to allow the woofer to throw a greater distance (and operates 180° out of phase, as it's driven by the woofer movement). They did that to compensate for the limited cabinet size, which is infinite baffle. That said, the S8R's don't generate the same low end that the Paragon does (which is a folded exponential design), all with a single 15" (per channel), so it's a welcome addition to the stereo room. Besides, I just plain love the looks.

I was introduced to the Bozak line about the same time I learned about the JBL line. The Bozak Concert Grand series were really nice, but they were multiples of cone speakers, and performed best with huge power. By contrast, the JBL line is primarily horn type (only the woofer is a cone speaker), and can be driven by reasonably small amplifiers.

I had to chuckle when you said your system was overkill. Is there really such a thing? If I had means, I'd own one of McIntosh's 2,000 watt amps, although I have no idea what I'd do with the power.

Thanks for your very welcome comments.

H
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Harold_V
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Re: Speaker selection switch, and more than you wanted to know!

Post by Harold_V »

Russ,
Thanks for your kind words. I have to confess, it was a fun project.

SteveM,
Thanks! I'd like to think my effort was worthwhile. If nothing else, it was a fun challenge.

H
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Harold_V
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Re: Speaker selection switch, and more than you wanted to know!

Post by Harold_V »

SteveHGraham wrote: Thu Sep 19, 2019 11:23 am That's really beautiful.
Thanks. I try to make things look like they're built by someone who has skill. Doesn't always turn out that way, though. :-)
Friend of mine texted me this week to tell me he bought some used Magnepans. He always asks me the same question: am I still using Home Depot electrical cord with mine?
There's a thriving industry of promotion of wires, and that includes on the pre-amp side. They try to have you believe that the insulation even influences the resulting sound, which has yet to be proven to be true.

I don't know if you're interested, or not, but my stereo room is on the top floor of the house, and it's about 45 feet from the shop. I installed 2" conduit from the shop that runs to the house, and have sets of #10 stranded THHN wire that ties the shop speakers to the amplifier. The overall run is about 100 feet. Works perfectly well. There's absolutely nothing wrong with your wire choice, assuming you don't have excessive output, or that the wire size is undersized and a long run.
<snip>
Have you ever listened to Kanye West? I think you'd really enjoy it.
Well, no, I hadn't. Not until just a few minutes ago, and then only because of your recommendation.
My thoughts?
He's certainly no Nat King Cole, nor is he a Mel Tormé.
Sorry to report, I don't care for his work, what little I heard. I certainly wouldn't spend time listening, especially considering my time is running short on this planet and I don't want to waste any of it. But thanks for the kind thoughts.

Now then, have you listened to this one? http://www.youtube.com/watch?v=qQf3HOWEvZ8

H
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SteveHGraham
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Re: Speaker selection switch, and more than you wanted to know!

Post by SteveHGraham »

I hope you realize I was not serious about Kanye West. He actually does have talent, but he uses it to make music for idiots.
Every hard-fried egg began life sunny-side up.
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Re: Speaker selection switch, and more than you wanted to know!

Post by tornitore45 »

Inspiring. A way of saying: Never settle for good enough, if something is worth doing is worth doing well.
Mauro Gaetano
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Harold_V
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Re: Speaker selection switch, and more than you wanted to know!

Post by Harold_V »

SteveHGraham wrote: Fri Sep 20, 2019 9:15 am I hope you realize I was not serious about Kanye West. He actually does have talent, but he uses it to make music for idiots.
I've long understood your weird sense of humor, but was not sure if you were sincere (or not) in this instance, thus my simple exploration. One never knows when one might be pleasantly surprised. Unfortunately, this wasn't one of those times. :lol:

I'm real strange about the music I tolerate. I enjoy a mixed bag, but it most likely wouldn't make sense to most folks.
One of the longest hours of my life was the day I attended a performance by Ladysmith Black Mambaso, a group that I thoroughly enjoy. As their "warmup" performance, I had to endure a whiney female folk singer.

I am well known to switch stations when listening to the radio. Can't stand Norah Jones, but I adore Ella Fitzgerald. Don't tolerate Kurt Elling very well, but really like Sinatra in the 50's. Love jazz, but don't like Coltrane. Rarely did he perform anything I tolerate. Paul Desmond? Can't think of anything he did that I don't like. The consummate jazz alto sax player.

I should note that while Coltrane played the alto early in his career, he is best known for his tenor work.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
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