Affordable 4pdt on-on-on toggle switch for a small power attenuator

Started by heep, March 26, 2018, 05:05:22 PM

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heep

Hi people,

I know I could use a rotary switch; and I have some; but for convenient usage ( the box could be posituoned high for example ), I want to use a 4pdt on-on-on type 2 to switch two attenuation positions and a bypass.

Do you know some affordable items of that sort ?

Thank you.

PRR

Welcome.

Confused; on-on-on implies 3T switch.

And 4P is a lot for what I think you are describing.

"Power": milliWatt or Big Watts? A 4P3T is the limit of 1-buck 50mA switches.

Above that, folks tend to use multiple switches. Or if power is at hand, relays.
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heep

Ah sorry... Yes I did mean 4P3T.
Like the Dimarzio ep1111... but affordable  :o

Lets say 20w max with 8 ohm so something 1.5A.
Quote from: PRR on March 26, 2018, 07:28:33 PM


And 4P is a lot for what I think you are describing.
Well...

Maybe you will see the flaw in this design to be able to use a 3P3T ?

And sorry for the bad drawing but Im even worse at Paint  ;)

Phoenix


PRR

A 4P3T has 16 terminals. Your drawing has 12 terminals. I'm not sure what it means to do.

Considering brain-pain to trace-out 16 terminals, and the likely absurd cost of a speaker-power 4P3T, two DPDT may be a better path. Here's a sketch.
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Phoenix

Quote from: PRR on March 26, 2018, 07:28:33 PM
Confused; on-on-on implies 3T switch.

There are double throw (as opposed to three throw) switches which are on-on-on, they have alternate poles where in the center position, one common will switch to the "second" throw, while the next common will stay connected to the "first" throw. So with a 4PDT on-on-on, in the center position, the first pole common would connect to the "first" throw, the second pole common would connect to the "second" throw, the third pole common would connect to the "first" throw, and the fourth pole common would connect to the "second" throw.
I'm surprised you've not encountered these before Paul?

PRR

I've seen the 2P version of that. This form is quite obscure; I didn't know they grew to 4P.
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amptramp

Maybe ON-OFF-ON can do what you want.  Look at the schematic in the lower right of this picture for the JBL G-730 speaker (I have two of them) in the tweeter area:



Replace C1, C2 and C3 with resistors - the smaller the capacitor, the larger the resistor and you will have a three-position attenuator with an ON-OFF-ON DPDT switch.  The only problem is the OFF setting would be in the middle and C! would be replaced by an open circuit.

Rob Strand

QuoteI've seen the 2P version of that. This form is quite obscure; I didn't know they grew to 4P.
Me either.  The C&K toggle switch catalogs are a good source for weird-ass switches.

People often build attenuators  to the amp side impedance but they don't match the source impedance seen by the speaker.   You aren't going to match the milli-ohms source impedance of a solid-state amp but you can make an attempt to match the impedance of a tube amp.

http://www.rfcafe.com/references/electronics-world/images/resistive-attenuators-pads-electronics-world-may-1966-3.jpg
Send:     . .- .-. - .... / - --- / --. --- .-. -
According to the water analogy of electricity, transistor leakage is caused by holes.

heep

Ok...
I found a much simplier and much affordable way to do this.
By simply using a DPDT on-on-on switch :


Rob Strand

QuoteI found a much simplier and much affordable way to do this.
Neat.
Send:     . .- .-. - .... / - --- / --. --- .-. -
According to the water analogy of electricity, transistor leakage is caused by holes.