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Old 2nd July 2003, 12:23 AM   #1
jarthel is offline jarthel  Australia
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Default help with elma rotary switch 2x24 position

Well I plan to make a stepped attenuator out of it.

My question is, where do I start soldering?

on the front of the switch, there are numbers from 0 to 22. From what I understand, I'll be needing 23 resistors for each pole.

In this diagram from Goldpoint (http://www.goldpt.com/schm_ser.html), there's are some tips on on how to solder it.

My question is, do I start with pin 0 and pin1 as my R1 and so on.

Thank you.

Jayel
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Old 2nd July 2003, 12:42 AM   #2
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Hi,

First of all you should have 23 useable pos. from a 24 pos. rotary, # 24 being taken by the stop.

Quote:
I'll be needing 23 resistors for each pole.
You probably mean for each deck?

In the case of a series attenuator you should solder 23 R inbetween positions of the switch.So R1 connect from pos. 1 to 2,
R2 from pos. to 3 etc...till you arrive at pos. 23 which normally has no attenuation, so a jumperwire is often used there.

There are better ways to make a series attenuator though.

Cheers,
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Old 2nd July 2003, 01:09 AM   #3
jarthel is offline jarthel  Australia
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Just a question.

On the rotating part of the switch, there's a "tab" with the letter A in it. It's in position 1 right now (the last position when I turn it counter clockwise).

1 position = 2 pins. In position 1, the first pin of position 1 is ground. right?

The 2nd pin of position 23 is the "input". right?

Thank you

Jayel
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Old 2nd July 2003, 01:42 AM   #4
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Default THE ENTIRE KAMASUTRA...

Hi,

The idea of a series ladder is to add one resistor in series with another so that at maximum att. the resistor value is a short from input to ground.

IMO, this position is wasted on a rot. switch and best replaced by a mute switch.

Now, assuming you want to build a stereo series att. using a double deck rot you need to define in and output.
In the case of GP series att where are Rs are seried, the input is at the end of the series and the output follows the wiper pos.

I don't know what Elma type you have...but if I read you correctly I think you've figured it out correctly.

Just keep in mind not to wire the whole shebang backwards...that would make for some getting used to.

Cheers,
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Old 2nd July 2003, 01:47 AM   #5
jarthel is offline jarthel  Australia
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Thanks Frank. You've been vey helpful.

Jayel

ps. that wink of your sometimes make me skeptical
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Old 2nd July 2003, 02:18 AM   #6
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Hi,

Quote:
ps. that wink of your sometimes make me skeptical
Actually, it should...I know I can't be trusted...Heck, I don't even trust myself nowadays.

The wink emoticon sig originates from one of our mods, namely Peter Daniel who's sense of humour I much admire.

Kinda puts things into perspective, doesn't it?

Happy building,

\The use of another sig emoticon is intended...
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