2x12 wired in stereo question.

[hamerhead]

I want to run 2 amps into a 2x12 cabinet, each amp driving a single speaker.

Can I use a single stereo jack and a TRS plug wired to 2 separate mono plugs, or will there be a grounding (or other) issue? Or do I need to keep them completely separate (2 jacks/2 plugs)?

Thank you in advance for keeping me from doing something stupid.

[tomteriffic]

Just for safety's sake, use two jacks and plugs.  Otherwise you've got a common ground going to both amps.  If those amps have different ground potentials to the power source, the two may try to make up the difference via your guitar.  That's only one reason I can think of right off the bat.

 

[gorch]

Yep, for the sake of stupidness, ideally, separate the wiring to give each amp its own speaker. Otherwise, it’s not only about common ground since the output signal of one amp would equally abut to the power amp out of the other amp. Whatever effects that could have when the other amp is either switched on or off.

[tomteriffic]

54 minutes ago, gorch said:

Yep, for the sake of stupidness, ideally, separate the wiring to give each amp its own speaker. Otherwise, it’s not only about common ground since the output signal of one amp would equally abut to the power amp out of the other amp. Whatever effects that could have when the other amp is either switched on or off.

Which is why amp switcher boxes use break-before-make switches. 

[gorch]

2 hours ago, tomteriffic said:

Which is why amp switcher boxes use break-before-make switches. 

Therefore, the rather better solution would be buying an amp switcher box.

[Dutchman]

6 hours ago, tomteriffic said:

Just for safety's sake, use two jacks and plugs.  Otherwise you've got a common ground going to both amps.  If those amps have different ground potentials to the power source, the two may try to make up the difference via your guitar.  That's only one reason I can think of right off the bat.

 

Agreed!! Two amps to two speakers same cabinet = two mono jack’s wired to each speaker!  ABY to the amps. I used to run one edge of breakup and one pretty heavily distorted... it really brought a lot of definition to the heavy sound. Playing with the EQing between created some really great cut thru the mix. Fun Stuff but a whole lotta gear to lug. I later did the same with one amp, a Reinhardt 18. With one kinda clean and the other side a lot more gain. Ran that into a 1- 12 Cab. Less gear and the Reinhardt sounded awesome combining both channels. 

[Hbom]

I went with 1 of these. Works with all my heads and stereo too.

https://www.tubesandmore.com/products/jack-plate-plug-and-play-mono-stereo 

[django49]

1 hour ago, Hbom said:

I went with 1 of these. Works with all my heads and stereo too.

https://www.tubesandmore.com/products/jack-plate-plug-and-play-mono-stereo 

Thumbs up on that product. Comes with wiring instructions.  You just need to cut out a bigger opening to install it. It allows you to use two 8 ohm speakers (one for each input) but still use it as a 2 x 12 in mono at either 4 or 16 ohms.

For maximum stereo effect, get (or build) the 2 x 12 with speakers angled to the sides........

(Note that this one is a 2 x 10, but I made a near identical one with 12s)

 

[killerteddybear]

15 hours ago, hamerhead said:

I want to run 2 amps into a 2x12 cabinet, each amp driving a single speaker.

Just to be clear, are you aiming for stereo operation or amp switching?

[hamerhead]

Stereo.

I have a Mojotone cab that has a single jack plate and no room to drill for a second jack short of cutting the hole bigger and installing a bigger plate. Not a huge deal but I was hoping to avoid that.

The 'Plug and Play' unit looks pretty smart. Thanks, Hbom!

[tomteriffic]

The Plug And Play jack setup is pretty snifty.  I have one on a 2 x 10 cab.  Yeah, it takes a little extra jigsaw work, but now I can run 4 ohm, 16 ohm, single 8 or stereo 8 out of one cabinet.  It makes impedance matching to a given amp tons easier.

 

[hamerhead]

Liked it so much I just ordered two Plug and Plays, one for the Mojotone and a second for a Lopoline cabinet. It opens up so many options it just seems like a no-brainer, scarecrow. They should be standard equipment on all 2x and 4x cabinets.

Thanks again, Doug, for the heads-up!

[mathman]

So, what I want to do is not exactly what the switch is intended for but I can’t find information online that answers my questions.

so, anyone who has one of the plug in play jacks. Do you have to use both of the stereo connections or is it possible to use either left or right independently.

 

to explain what I want to do.

i have four speakers in a cabinet.  I want to be able to play through all 4, just the top two or just the bottom two.  Trying to determine if this would be possible with the plug and play jack.

thanks

[Studio Custom]

On 1/5/2020 at 11:33 AM, Hbom said:

I went with 1 of these. Works with all my heads and stereo too.

https://www.tubesandmore.com/products/jack-plate-plug-and-play-mono-stereo 

That is very cool!

[hamerhead]

14 hours ago, mathman said:

So, what I want to do is not exactly what the switch is intended for but I can’t find information online that answers my questions.

so, anyone who has one of the plug in play jacks. Do you have to use both of the stereo connections or is it possible to use either left or right independently.

 

to explain what I want to do.

i have four speakers in a cabinet.  I want to be able to play through all 4, just the top two or just the bottom two.  Trying to determine if this would be possible with the plug and play jack.

thanks

From what I gather, you can use either side in mono as long as you put a dummy plug in the unused side.

[Hbom]

14 hours ago, mathman said:

So, what I want to do is not exactly what the switch is intended for but I can’t find information online that answers my questions.

so, anyone who has one of the plug in play jacks. Do you have to use both of the stereo connections or is it possible to use either left or right independently.

 

to explain what I want to do.

i have four speakers in a cabinet.  I want to be able to play through all 4, just the top two or just the bottom two.  Trying to determine if this would be possible with the plug and play jack.

thanks

 

31 minutes ago, hamerhead said:

dummy plug in the unused side.

What hamerhead said about the left & right singles. I usually just leave the other head plugged in but not powered up.

Can't answer about the 4 speaker question.  But they show 2 different 4x hookups in the spec sheets and both appear to separate the 4 into 2 left and 2 right. So... maybe.

https://www.tubesandmore.com/sites/default/files/associated_files/s-h700_speaker_z.pdf

[hamerhead]

Just turn your head sideways when looking at that diagram.

[django49]

1 hour ago, Hbom said:

 

What hamerhead said about the left & right singles. I usually just leave the other head plugged in but not powered up.

Can't answer about the 4 speaker question.  But they show 2 different 4x hookups in the spec sheets and both appear to separate the 4 into 2 left and 2 right. So... maybe.

https://www.tubesandmore.com/sites/default/files/associated_files/s-h700_speaker_z.pdf

Or just use a dummy plug into the side you are not using, when you want to play the other. Note how their wiring diagrams for a 4 x 12 do NOT show 8 ohm speakers and that the 4 ohm and 16 ohm are specifically wired in serial for one, parallel for the other. If my semi-educated read is right, that would present the equivalent of an 8 ohm load to either mono input (or 8 ohms to each amp if used in stereo), with either a 4 or 16 ohm load when actually used as a full 4 x 12. The goal is to avoid presenting an "unfriendly" load to a tube amp and still have the flexibility of all input options. .

[hamerhead]

One thing that would have been handy is having the 4 wires labelled L+, L-, R+ and R-. I printed the diagram out in black and white, so it wasn't much help. D'oh!

I did this for future reference (when the instructions are long gone):

So if you install one of these, do your future self a favor.

And no - I'm not done yet. Dammit. One of my donor speakers is 16 ohm. So much for my 10 minute project...

 

[mathman]

On 1/7/2020 at 2:09 PM, django49 said:

Or just use a dummy plug into the side you are not using, when you want to play the other. Note how their wiring diagrams for a 4 x 12 do NOT show 8 ohm speakers and that the 4 ohm and 16 ohm are specifically wired in serial for one, parallel for the other. If my semi-educated read is right, that would present the equivalent of an 8 ohm load to either mono input (or 8 ohms to each amp if used in stereo), with either a 4 or 16 ohm load when actually used as a full 4 x 12. The goal is to avoid presenting an "unfriendly" load to a tube amp and still have the flexibility of all input options. .

Can I test Ohm load on the speakers with a regular electrical tester using the ohm setting?  I would think I could but have never tried....

Heading out to get it now and try.

 

The plug in play came in this morning, so I have a project.  This is the homemade cabinet I made a thread about last summer.  It is a bit of a mish mash.  I have two 4 ohm and two 8 ohm speakers.  Wired so I have an 8 ohm and 16 ohm pair but independent in the same cabinet. One side is being driven by a solid state amp and the other by a Tube amp.  

[gtrdaddy]

On 1/11/2020 at 1:12 PM, mathman said:

Can I test Ohm load on the speakers with a regular electrical tester using the ohm setting?  I would think I could but have never tried....

Yes.

[mathman]

 Just a quick post to say the plug and play seems to be working perfectly. Save me the trouble of trying to create the wiring myself to do this.

[hamerhead]

Yeah, finally got mine in yesterday.

The Lopoline cabinet (on the left) had the square hole already in it, just turned the wrong way. It looks crooked AF in this picture, but it's really in there straight. About a 5 minute job. Plus, being sideways like that makes it easier to tell that the top speaker is the right channel and the bottom is left.

The Mojotone (right) had just a small single round jack hole, which leads to my first bitch: No template. The 'Plug and Play' people could have made the installation go a lot smoother with a simple template. Instead, it was break out the speed square and grease pencil and try not to mess up an otherwise really clean cab. It worked out better than my typical DIYs, but leads to the second bitch: No screws. After a 1/2 hour of carefully butchering a hole in there, I had to scrounge up screws to mount it. WTFF? They could at least provide screws.

So, I give them 5 stars for the product (very well-made and works excellent, should be in every cabinet with more than 1 speaker), and 1-star on completeness. Because I'm a whiner.

I want to thank Hbom once again for the heads-up on a 'duh, why didn't I think of that' product. Everyone should go buy one (or 2).

[gtrdaddy]

3 hours ago, hamerhead said:

So, I give them 5 stars for the product (very well-made and works excellent, should be in every cabinet with more than 1 speaker), and 1-star on completeness. Because I'm a whiner.

I don’t think you’re a whiner. Valid gripes. They should absolutely provide a template and appropriate screws. That’s just plain crap. They should hear about it too.

[Hbom]

Glad it worked out for you HH. Agree the template and screws would be handy. I was just glad that it did what I wanted and I don't need to spend 10 minutes trying to figure which hole to put the plug in every time I switch from one head to another anymore.

[hamerhead]

1 hour ago, Hbom said:

...trying to figure which hole to put the plug in...

My wife hates that.