Planning to build a Cabinet - Advice needed

[EGRENIER]

I've been fighting GAS for a while on buying a Amp Head... Or is this AHAS ?

Anyway, pulled the trigger recently and I'm now planning a Cabinet build. Now for some reason, I can't do something simple. My thought is: I want a highly flexible Amp Cabinet. So I came up with this wiring to be as versatile as possible:



The idea is a 3-way switch that would allow me to run it is 2 different mode:

Pos 1: Two speaker in parallel runnig at 4 ohms
Pos 2: One speaker running at 8 ohms
Pos 3: Two speaker running in series at 16 oms

Now here's my questions:

- Did I get the wiring right ?
- What type of switch would allow me to do this ? (Does it even exist?)

I know, I'm a bit stupid, but hey who wants to do something simple ?

 

[EGRENIER]

I realised I had my colors mislabeled, so I made a update to the legend.

I'm still hoping someone could point me to the right type of switch for this application.



Thanks....

 

[EGRENIER]

So I did a lot of research to figure what kind of switch could work. I came up with this:

NKK has a switch, the M2044SS1W01, that actually is a 4PDT that can be use as a DP3T if the right lug are jumped.

Tech spec here:

https://www.nkkswitches.com/pdf/MtogglesBushing.pdf

From what I understand this would work.

Now for the difficult question. Is 6A @ 125V be sufficient for this application.

My understanding is that I need to support my highest Amp load based on the Watts and Ohms.

Amp = Sqrt (Watts / Ohms)

In my case that would be 2 X 70 watts speaker running at 4 Ohms:

Sqrt (140 / 4) = Sqrt (35) = 5.91 Amps

Am I cutting it close ?

I need help from our electronics gurus such as @fig or @Chuck D. Bones . Gentlemen your help would be greatly appreciated.

Thanks.

 

[mnemonic]

If you want to avoid special switches (that would be my preference as the backs of my cabs are hard to reach and switches can get bumped), you can do this with three switching jacks. you could also go ‘easy mode’ and just buy the ‘plug and play’ jack plate (but where’s the fun in that).

Here is the schematic for the plug and play jack plate which can do either mono 16 ohm, mono 4 ohm, or stereo 8 ohms each side, depending what plugs have something in them:

https://www.amplifiedparts.com/sites/default/files/associated_files/s-h700_plug_drawing.pdf

Jack Plate - Plug and Play, Mono / Stereo | Amplified Parts

The Plug and Play eliminates the confusing switch found on most stereo cabinets. Just pick your impedance and plug in. Label is set at the common 4/16 Ohm Mono and 8 Ohm Stereo. Ready to install with a steel dish, wires, and speaker connectors.

www.amplifiedparts.com

When I built a 2x12 cab a while ago I tried incorporating a heavy duty dpdt switch so I could switch between 4 ohm and 16 ohm, but the switch I chose was adding about two ohms of series resistance when I measured it after wiring up so I gave up and just wired it for 16 ohms.

 

[EGRENIER]

If you want to avoid special switches (that would be my preference as the backs of my cabs are hard to reach and switches can get bumped), you can do this with three switching jacks. you could also go ‘easy mode’ and just buy the ‘plug and play’ jack plate (but where’s the fun in that).

Here is the schematic for the plug and play jack plate which can do either mono 16 ohm, mono 4 ohm, or stereo 8 ohms each side, depending what plugs have something in them:

https://www.amplifiedparts.com/sites/default/files/associated_files/s-h700_plug_drawing.pdf

Jack Plate - Plug and Play, Mono / Stereo | Amplified Parts

The Plug and Play eliminates the confusing switch found on most stereo cabinets. Just pick your impedance and plug in. Label is set at the common 4/16 Ohm Mono and 8 Ohm Stereo. Ready to install with a steel dish, wires, and speaker connectors.

www.amplifiedparts.com

When I built a 2x12 cab a while ago I tried incorporating a heavy duty dpdt switch so I could switch between 4 ohm and 16 ohm, but the switch I chose was adding about two ohms of series resistance when I measured it after wiring up so I gave up and just wired it for 16 ohms.

Oh Man !!! I've working on figuring out wiring and switch and this comes in a single jack plate for 20$ !!!

LMAO, well this was a nice learning experience...

I may not give up on the switch though... there has to be a way to calculate the resistance the switch will had to the cab with the switch I found.

I'll have to research that now

Thanks for the link...

 

[fig]

I need help from our electronics gurus such as @fig or @Chuck D. Bones . Gentlemen your help would be greatly appreciated.

Thanks.

Cool, I see you found a solution. I was going to mention my Marshall 1936V has an auto-switching jackplate. Using a mechanical switch would likely cause some heavy popping.

I do feel I should set the record straight though;

While I am extremely flattered to have been mentioned in the same sentence with @Chuck D. Bones in reference to electronics knowledge, I have zero formal education in electronics, and only a rudimentary understanding (at best) of circuitry. I learn everyday, from all of you...and some light reading on the side

 

[EGRENIER]

Cool, I see you found a solution. I was going to mention my Marshall 1936V has an auto-switching jackplate. Using a mechanical switch would likely cause some heavy popping.

I do feel I should set the record straight though;

While I am extremely flattered to have been mentioned in the same sentence with @Chuck D. Bones in reference to electronics knowledge, I have zero formal education in electronics, and only a rudimentary understanding (at best) of circuitry. I learn everyday, from all of you...and some light reading on the side

So first, I appreciate your transparency in terms of "qualifications", however self-taught or formal education is just irrelevant to me, all that matters is knowledge and experience. I could be wrong, but the lasting impression you left is that you understand very well most of our challenges and therefore were one member that popped in my mind as a source for help. And hopefully I didn't insult @Chuck D. Bones by listing you and him as gurus

Now for the popping, I hear your point, however switching Ohms setting while connected to a live Amp would be suicidal... Just like I would never think of changing the cable from one jack to another in a switching jacks configuration.

At the end, the switching jacks plug and play jackplate is the easy solution.. However, I think the DT3P switch is the more elegant one.

I'm still hoping someone can confirm if I did the research right or not, even tho I will likely just get the 20$ Jackplate. This whole thing is to me also a learning experience...

 

[Stickman393]

I'd say the Jack plate is the more elegant solution here, personally.

I say that because a mechanical switch adds unnecessary complexity...plus...to my mind, a potential user error point.

Plug into single jack, select correct ohm rating: two step process, potential to forget step #2.

Three jacks: ah, oh shit, that's right. What am I plugging into this again? Ah yeah, needs to be a 4 ohm load. And I choose my four ohm plug, and presto! One step. No potential to forget to choose the correct impedance.

That's just the way my ADHD brain works though.