Cabinets/Speakers/Watts/Ohms/Stereo/Mono...etc...

[metalchurch]

In another thread I saw something about running an extension cabinet with two different speakers. I thought that this subject needed it's own thread because my reply and questions were off topic.

Orangekick:
You have a Marshall 1960B cabinet loaded with 2 Celestion Vintage 30's and 2 Warehouse Green Backs.

I also thought about either getting a 2-12 cabinet loaded with Celestion Vintage 30's, or perhaps a 1960A 4-12 cabinet loaded with 2 of one style and 2 of another like you did.

What benefits did you get by running 2 different sets of speakers?
Do they compliment each other, or provide 2 different distinct sounds?

I'm running 16ohm mono w/ my 1960B, so say I got another 1960A cab, what ohms would I need: 4-8-16?
Can I run both cabs in Mono?
Or should I run them in stereo?
Or do I NEED to run them in stereo?

I think my G12T-75's are 8 ohm speakers, so if I got a 1960A cab, would I need to have 4 -8 ohm speakers no matter the style?

I'm a little lost in the speaker/ohm/watts/mono/stereo thing, so any help would be awesome!!

[Ron]

All that I have are combo amps, but the speaker is the device that couples your instrument to your ears.

They definitely make the biggest difference in your sound compared to changing any other component.

I'm not sure about having two different speaker drivers in the same cabinet. It's a definite no-no for high fidelity applications, but guitar cabs are a different beast entirely. I'm guessing that it would take a lot of time and effort to find a winning combination of mismatched drivers.

[bassist_25]

I know that Kenny has two different drivers in each of his Mesa 2x12 Split cabs.

I could totally be off base here since I'm neither a guitar player nor an engineer (so please don't kick my ass too hard if I'm wrong), but one of the benefits of different drivers in the same box may be how they break up. If you have one speaker breaking up early, you still may benefit from the clean definition of a speaker that isn't totally broken up.

[metalchurch]

I know that Kenny has two different drivers in each of his Mesa 2x12 Split cabs.

I could totally be off base here since I'm neither a guitar player nor an engineer (so please don't kick my ass too hard if I'm wrong), but one of the benefits of different drivers in the same box may be how they break up. If you have one speaker breaking up early, you still may benefit from the clean definition of a speaker that isn't totally broken up.

I'm not sure either, but I'd say your theory is on par with why they do that. It definitely makes sense to me, and I have come to the same conclusion, just waiting for other's replies.

[Ron]

I can see how that makes sense, Paul.

I just wonder how you would come up with a good combination without using a known good mismatched setup. Just winging it and going through a bunch of not-so-stellar combinations sounds like it could be expensive and frustrating.

I know that some companies do sell cabinets with mismatched drivers.

[lonewolf]

Mesa started doing this in the 80s with the "halfback cabs", like Kenny's. I had one of those (stolen in 1990) and have done a lot of experimenting along these lines. The whole idea is the blend the qualities of 2 different speakers to get the best of both. Usually along the lines of tight bass response from one and "presence" from the other.

In the case of the Boogie cabs, they put the EVM12L in the closed back bottom to produce more definition and solid, tight bass. Many people feel that the EVM12L is a little vanilla sounding, so they put their Celestion 90s in the open back top to produce a more open Celestion sound. The result was more than the sum of the parts--it was a nice blend of two very different speakers. When doing open/closed back cabs, it works better if the closed back speaker(s) is(are) a little louder (higher sensitivity, not watts) than the open back speaker.

With fully closed back cabs, the effect is not as pronounced, but still works. You are better off if you put the speaker with the bass attributes across the bottom to take advantage of the 1/4 space condition from being closer to the floor. In a 4x12 cab, you will get best results if you place the same speakers horizontally rather than vertically and wire them in parallel with each other. This way they are under the same electrical and mechanical conditions and will acoustically couple better, acting more like one speaker and increasing bass volume in the process. In closed back cabs, the speakers should be very close, volume-wise (sensitivity, not watts).

Doing this with open back cabs & combos doesn't do a whole lot. If you have a 1x12 (or 2x12) open back combo, I would recommend getting a 1x12 (or 2x12) closed back cabinet for your "bass" speakers.

All in all, it works much better if the different speakers are sealed from each other.

[lonewolf]

I'm running 16ohm mono w/ my 1960B, so say I got another 1960A cab, what ohms would I need: 4-8-16?
Can I run both cabs in Mono?
Or should I run them in stereo?
Or do I NEED to run them in stereo?

I think my G12T-75's are 8 ohm speakers, so if I got a 1960A cab, would I need to have 4 -8 ohm speakers no matter the style?

I'm a little lost in the speaker/ohm/watts/mono/stereo thing, so any help would be awesome!!

That all depends on the amp. If you have an 8ohm output on your amp, you can use 2-16ohm cabinets in parallel. In 4x12 cabs wired series/parallel, the impedance of the cab = the impedance of the individual speakers.

[metalchurch]

Jeff, my Poweramp is 8 or 16 switchable.

So in parallel mono it would go like this?:
Poweramp: 8ohms
1960A: 16ohms mono
1960B: 16ohms mono

How would I run it in stereo? Just connect 1 cab to each speaker out on the Poweramp?

What would I then set it at?
Poweramp: ?ohms
1960A: ?ohms
1960B: ?ohms

Thanks

[metalchurch]

PS, thanks for the reply Lonewolf, you definitely cleared up alot of my questions so far.
That closed back bottom/open back top sounds like a nice setup, and I see the benefites now from running such a combo.

And also the 'bass' speakers + the 'treble/mid' speakers for cutting through sounds sweet. That's kind of what I was getting at with the stock 1960B + the Vintage 30 equipped 1960A.

Kind of along the same lines of bassist using a 1-15 on bottom, and a 2-12 or 4-10 on top, right?

[lonewolf]

Jeff, my Poweramp is 8 or 16 switchable.

So in parallel mono it would go like this?:
Poweramp: 8ohms
1960A: 16ohms mono
1960B: 16ohms mono

This is the setting if you are only using one channel of the amp. If your amp has Marshall's "dual mono" mode where a mono input signal is distributed to both power amps, then you would want to set the amp to 16ohms and use both channels.

Jeff, my Poweramp is 8 or 16 switchable.
How would I run it in stereo? Just connect 1 cab to each speaker out on the Poweramp?

What would I then set it at?
Poweramp: ?ohms
1960A: ?ohms
1960B: ?ohms

Thanks

Using the same 16ohm cabs:

Poweramp: 16ohms
1960A: 16ohms, channel A output
1960B: 16ohms, channel B output

[JackANSI]

There are a ton of things to consider and explain.

First off, an amps output is mainly a ground centered sine wave generator. The "+" side of most amps should actually be called the "live" and the "-" side should be called the "neutral". Those familiar with AC wiring should recognize those terms. There should be no DC power reaching your speakers. This in turn means that in addition to resistance in a load there is the loads reactance. Resistance is always a positive number (8 ohms, never -8 ohms), but reactance can be positive or negative.

In speakers this is important to consider. The electrical signal can change as fast as the slew rate of the amplifier driving it (which can be well faster than the audible range of humans), but a speaker has mass to consider. The reciprocation of a speaker cone's mass can only happen so many times in a given period as well, limited by the amount of power driving it vs its mass + the mass of the air it is moving.

So what you say? When the signal changes directions faster than the actual mechanics can follow this causes a "reactance" of the load to the input. Effectively changing its resistance. An 8 ohm speaker could very well peak at 100's of ohms in its natural "free-air resonance" point, or its point of most efficient movement. Which I think (for memory here) is roughly equal to the mass of cone vs mass of air. In addition I think making the cone change direction faster than its stability allows is the technical side of a speakers "distortion" or "break-up" (its actually distorting the shape of the cone).

This is also why tweeters are very small in diameter. Less mass = high resonance and a much greater ease of getting that cone to "turn around" at high frequencies.

So matching two cones with different response/impedance curves can make your tone really "pop". Even putting varied sizes of cones together is possible, just be sure keep the air moved by a larger speaker seperate from the smaller one (or use an open back). The amount of air moved by the larger cone can and will cause unwanted motion in the smaller one. But hey maybe you were going for that sound (I believe a cone's movement at its rated RMS wattage/freq is labeled as Xmax by most makers. You would want a woofer with an Xmax of 14mm in a sealed box with a mid with a 4mm, you'd be banging on the back of that poor little speaker extremely hard when it was close to its Xmax. This is why in most 2 or 3 way home stereo speakers the mid and tweeter are usually of the sealed back variety)

Ohms: First its the ohms of the speaker, then how its connected. You can use the same method with resistors to create a value you may not have with two or more of those you do have. We usually assume static resistance measurements and do not include reactance, plus we'll be dealing with even numbers of drivers to make the math small. But accounting for reactance at multiple frequencies can really make an excellent speaker combination (even using multiple identical speakers), but that is well beyond what I can explain on here. I'll put in a bit about it after the basics.

Wiring your drivers in series (amp+ -> speaker1+ -> speaker1- -> speaker2+ -> speaker2- -> amp-), you are effectively multiplying the resistance by the number of devices. So if you have 2 - 8ohm speakers in series they appear to the amp as one 16ohm load (8 * 2). 4 - 8ohm would be 32 ohm (8 * 4).

Wiring your drivers in parallel (amp+ -> speaker1+ -> speaker2+ | amp- -> speaker1- -> speaker2-). you are effectively dividing the resistance by the number of devices. So if you have 2 - 8ohm speakers in parallel they appear to the amp as one 4ohm load (8 / 2). 4 - 8ohm would be 2 ohm (8 / 4).

Now you can hybrid these designs to get new impedences. Lets say you have 4 - 8ohm speakers but don't want 2 or 32 ohms. You can wire them up as 2 sets of 2 - 8ohm speakers in series, then wire that up as parallel. So first you have your 2 - 8 ohms in series (2 * 8 = 16) so now you have (to the amp) 2 - 16ohm speakers. If you wire those as parallel you now have 1 - 8 ohm again (16 / 2).

Now you might say "what if I reverse that?" They don't call it ohm's LAW for nothing. 4( 8 ), 2 parallel 2( 2 / 8 = 4 ), 2 series 1( 2 * 4 = 8 ).

Now once everything is connected, you want to go by the power handling of the lowest value as your guide usually. Also once you have everything wired up that 4x12 cabinet @ 8ohms can be factored with another 4x12 cabinet in the same formulas, just treat each cab as one speaker.

This is where knowing reactance can make a difference. There is always interaction with multiple speakers, acustically AND electrically. Sometimes the electrical reactance of the speakers place nicer one way, sometimes its the other (in dealing with our 4 - 8 ohm example above).


Now with different ohmages (look I made up a word I think) the amp will react differently. Lower the ohms, higher the current. A dead short is usually 0 ohms, thats bad for an amp. 2 ohms is only ok if the amp is "2 ohm stable". 4 ohms is normally the smallest load a majority of amps can handle.

If you noticed how power amps have a 1000W @ 4 ohms, then a measely 400W @ 8 ohms, this is why. More ohms = less current = less total power. But with decreasing ohms comes more leakage in the transistors, which means more heat vs output power. Usually the difference in a "2 ohm min stable" amp and one that does 4 ohms min is the bigger power supply (to offset the leakage) and size of the heatsink.


Someday I'll come back and post the stuff for odd impedances, odd numbers of speakers, what all this does to power handling, and 2xR + 4xR combos....


ok post too big... time for dinner... later....

[metalchurch]

Ok, so basically if I used only 1 speaker out, it is mono?
If I use both speaker outs, it would be stereo, regardless if I had 1 or 2 cabs?

If I split my 1960B cab to 150w@8ohms & used both inputs it would also be stereo, right?

*Also one more question:
My Power amp is 100watts and is switchable between 8 and 16ohms
My 1960B cab is rated @300w mono / or 150w stereo

So regardless whether my cab is set to 150w@8ohms or 300w@16ohms, the Poweramp is still pushing it's 100w, right?

What are the advantages or disadvantages of either or?

Thanks Jeff, this is getting confusing and I'm trying real hard to stay focused.

JackANSI, you're an animal!!! I'd love to pick your brain on this subject sometime.

[lonewolf]

Kind of along the same lines of bassist using a 1-15 on bottom, and a 2-12 or 4-10 on top, right?

Kind of, but those usually have separate poweramps and a crossover so each speaker cab only plays a range of the frequency spectrum. With traditional guitar cabs, the full range sound goes to all speakers, so you want one of the speaker models to be "vanilla" sounding, but with definition and the other to have the "color" you are looking for.

In general, speakers that are designed for modeling amps fit the "vanilla" sounding category. Find one with a good tight bottom and you're set. The EVM12L is a great speaker for this, but if you load 4 of them in a cab, you will need a crane to move it. Another one I have used is the Celestion Century G12, but they are very loud (high sensitivity) and would be hard to match up with. I once loaded a Marshall 4x12 with 4 Century G12's and it was just way too loud and over the top. They are better suited to the bottom of the Boogie halfback cabs or in a small modeling amp. I use two of them in a Mojotone Bassman cab for modeling and they are perfect for that. They only weight 4.5 lbs., so they really reduce a cab's weight too.

BTW, you don't have to complete a fundamental AC circuit analysis to load guitar cabinets. Just stick with the numbers that Marshall and Celestion rates their stuff at....they already did the math.

[orangekick]

In another thread I saw something about running an extension cabinet with two different speakers. I thought that this subject needed it's own thread because my reply and questions were off topic.

Orangekick:
You have a Marshall 1960B cabinet loaded with 2 Celestion Vintage 30's and 2 Warehouse Green Backs.

I also thought about either getting a 2-12 cabinet loaded with Celestion Vintage 30's, or perhaps a 1960A 4-12 cabinet loaded with 2 of one style and 2 of another like you did.

What benefits did you get by running 2 different sets of speakers?
Do they compliment each other, or provide 2 different distinct sounds?

I'm running 16ohm mono w/ my 1960B, so say I got another 1960A cab, what ohms would I need: 4-8-16?
Can I run both cabs in Mono?
Or should I run them in stereo?
Or do I NEED to run them in stereo?

I think my G12T-75's are 8 ohm speakers, so if I got a 1960A cab, would I need to have 4 -8 ohm speakers no matter the style?

I'm a little lost in the speaker/ohm/watts/mono/stereo thing, so any help would be awesome!!

Basically I had a Marshall 4x12 that I got for super cheap, so I felt that messing around with it was probably a good idea. I went into this knowing that I tend to prefer Celestion Vintage 30's for just about everything. The Marshall cab came with G12t-75's. Those really didn't do it for me. They had a natural scoop in the midrange that I just wasn't digging. I can see why those speakers are coupled with most Marshall amps though, Marshall amps tend to have a lot of upper mids.

Anyway... I started out by taking out 2 of the G12T-75's and replacing them with V30's. Bogner sells this combination in their Uberkab. It was pretty good. The V30's have a mid spike that the G12T-75's were lacking and the combo sounded pretty good. I tried this at band practice and found that it was still lacking a bit of mid character. The Warehouse speakers were still quite cheap at the time, so I looked through all the options that they had. I checked with some people that I know on other forums and they reported that the Warehouse Green Berets sounded almost exactly like Greenbacks with one small exception. The Warehouse speakers are much more efficient. This means that the Green Berets can be paired with V30's which are quite loud. The Green Berets have a much earlier breakup than the V30's. The mix out front is one of huge thump from the V30's and the crunchy break up of the Green Berets. Both speakers have a different break up point as well as different EQ curves.

I only mix things up because I just can't leave things alone. I actually find that I can simply switch which speaker the mic is on when we're recording. Occasionally that's all I need to do to find "the tone" that is working for a particular tune.

[sunsetbass]

There are a ton of things to consider and explain.

First off, an amps output is mainly a ground centered sine wave generator. The "+" side of most amps should actually be called the "live" and the "-" side should be called the "neutral". Those familiar with AC wiring should recognize those terms. There should be no DC power reaching your speakers. This in turn means that in addition to resistance in a load there is the loads reactance. Resistance is always a positive number (8 ohms, never -8 ohms), but reactance can be positive or negative.

In speakers this is important to consider. The electrical signal can change as fast as the slew rate of the amplifier driving it (which can be well faster than the audible range of humans), but a speaker has mass to consider. The reciprocation of a speaker cone's mass can only happen so many times in a given period as well, limited by the amount of power driving it vs its mass + the mass of the air it is moving.

So what you say? When the signal changes directions faster than the actual mechanics can follow this causes a "reactance" of the load to the input. Effectively changing its resistance. An 8 ohm speaker could very well peak at 100's of ohms in its natural "free-air resonance" point, or its point of most efficient movement. Which I think (for memory here) is roughly equal to the mass of cone vs mass of air. In addition I think making the cone change direction faster than its stability allows is the technical side of a speakers "distortion" or "break-up" (its actually distorting the shape of the cone).

This is also why tweeters are very small in diameter. Less mass = high resonance and a much greater ease of getting that cone to "turn around" at high frequencies.

So matching two cones with different response/impedance curves can make your tone really "pop". Even putting varied sizes of cones together is possible, just be sure keep the air moved by a larger speaker seperate from the smaller one (or use an open back). The amount of air moved by the larger cone can and will cause unwanted motion in the smaller one. But hey maybe you were going for that sound (I believe a cone's movement at its rated RMS wattage/freq is labeled as Xmax by most makers. You would want a woofer with an Xmax of 14mm in a sealed box with a mid with a 4mm, you'd be banging on the back of that poor little speaker extremely hard when it was close to its Xmax. This is why in most 2 or 3 way home stereo speakers the mid and tweeter are usually of the sealed back variety)

Ohms: First its the ohms of the speaker, then how its connected. You can use the same method with resistors to create a value you may not have with two or more of those you do have. We usually assume static resistance measurements and do not include reactance, plus we'll be dealing with even numbers of drivers to make the math small. But accounting for reactance at multiple frequencies can really make an excellent speaker combination (even using multiple identical speakers), but that is well beyond what I can explain on here. I'll put in a bit about it after the basics.

Wiring your drivers in series (amp+ -> speaker1+ -> speaker1- -> speaker2+ -> speaker2- -> amp-), you are effectively multiplying the resistance by the number of devices. So if you have 2 - 8ohm speakers in series they appear to the amp as one 16ohm load (8 * 2). 4 - 8ohm would be 32 ohm (8 * 4).

Wiring your drivers in parallel (amp+ -> speaker1+ -> speaker2+ | amp- -> speaker1- -> speaker2-). you are effectively dividing the resistance by the number of devices. So if you have 2 - 8ohm speakers in parallel they appear to the amp as one 4ohm load (8 / 2). 4 - 8ohm would be 2 ohm (8 / 4).

Now you can hybrid these designs to get new impedences. Lets say you have 4 - 8ohm speakers but don't want 2 or 32 ohms. You can wire them up as 2 sets of 2 - 8ohm speakers in series, then wire that up as parallel. So first you have your 2 - 8 ohms in series (2 * 8 = 16) so now you have (to the amp) 2 - 16ohm speakers. If you wire those as parallel you now have 1 - 8 ohm again (16 / 2).

Now you might say "what if I reverse that?" They don't call it ohm's LAW for nothing. 4( 8 ), 2 parallel 2( 2 / 8 = 4 ), 2 series 1( 2 * 4 = 8 ).

Now once everything is connected, you want to go by the power handling of the lowest value as your guide usually. Also once you have everything wired up that 4x12 cabinet @ 8ohms can be factored with another 4x12 cabinet in the same formulas, just treat each cab as one speaker.

This is where knowing reactance can make a difference. There is always interaction with multiple speakers, acustically AND electrically. Sometimes the electrical reactance of the speakers place nicer one way, sometimes its the other (in dealing with our 4 - 8 ohm example above).


Now with different ohmages (look I made up a word I think) the amp will react differently. Lower the ohms, higher the current. A dead short is usually 0 ohms, thats bad for an amp. 2 ohms is only ok if the amp is "2 ohm stable". 4 ohms is normally the smallest load a majority of amps can handle.

If you noticed how power amps have a 1000W @ 4 ohms, then a measely 400W @ 8 ohms, this is why. More ohms = less current = less total power. But with decreasing ohms comes more leakage in the transistors, which means more heat vs output power. Usually the difference in a "2 ohm min stable" amp and one that does 4 ohms min is the bigger power supply (to offset the leakage) and size of the heatsink.


Someday I'll come back and post the stuff for odd impedances, odd numbers of speakers, what all this does to power handling, and 2xR + 4xR combos....


ok post too big... time for dinner... later....

ok slow down i'm still trying to comprehend what you taught me at the most awesoem bass get together that ever happended.

[metalchurch]

Ok, so basically if I used only 1 speaker out, it is mono?
If I use both speaker outs, it would be stereo, regardless if I had 1 or 2 cabs?

If I split my 1960B cab to 150w@8ohms & used both inputs it would also be stereo, right?

*Also one more question:
My Power amp is 100watts and is switchable between 8 and 16ohms
My 1960B cab is rated @300w mono / or 150w stereo

So regardless whether my cab is set to 150w@8ohms or 300w@16ohms, the Poweramp is still pushing it's 100w, right?

What are the advantages or disadvantages of either or?

Thanks Jeff, this is getting confusing and I'm trying real hard to stay focused.

JackANSI, you're an animal!!! I'd love to pick your brain on this subject sometime.

Jeff, could you answer this when you get a chance? This thread was getting out of hand and it may have gotten lost in the mix?

Thanks

[JackANSI]

From what I know about tube guitar amps (which is limited, I'll admit), is that output transformer matching game balances things so its 100W on a single output. But I very well could be wrong as the only experience with tube amps I have is from a few old school AM radios and my bassman 10, which are not known for their output configurability

I'm guessing that it only has 4 output tubes so there is no way you'll pull 200W out of it just by going to stereo mode.

I would have to assume that in stereo mode the amp is seperating the output stages into 2x2 instead of combining (1x4). Which i would have to put the 2x2 config somewhere around 50watts +/- 15.

[lonewolf]

From what I know about tube guitar amps (which is limited, I'll admit), is that output transformer matching game balances things so its 100W on a single output. But I very well could be wrong as the only experience with tube amps I have is from a few old school AM radios and my bassman 10, which are not known for their output configurability

I'm guessing that it only has 4 output tubes so there is no way you'll pull 200W out of it just by going to stereo mode.

I would have to assume that in stereo mode the amp is seperating the output stages into 2x2 instead of combining (1x4). Which i would have to put the 2x2 config somewhere around 50watts +/- 15.

His amp is a dual monoblock (2 individual amps with separate power supplies) 100W per side rack mount with 4 power tubes per channel. If you match the output transformers' impedance (either 8 or 16 ohms) with the cabs and crank it, you will get 100 watts, but it sounds more like 1000.

[lonewolf]

Ok, so basically if I used only 1 speaker out, it is mono?
If I use both speaker outs, it would be stereo, regardless if I had 1 or 2 cabs?

If I split my 1960B cab to 150w@8ohms & used both inputs it would also be stereo, right?

*Also one more question:
My Power amp is 100watts and is switchable between 8 and 16ohms
My 1960B cab is rated @300w mono / or 150w stereo

So regardless whether my cab is set to 150w@8ohms or 300w@16ohms, the Poweramp is still pushing it's 100w, right?

What are the advantages or disadvantages of either or?

Thanks Jeff, this is getting confusing and I'm trying real hard to stay focused.

JackANSI, you're an animal!!! I'd love to pick your brain on this subject sometime.

All your statements are true, as long as they are wired correctly. You will lose a little bass response if you run a 1960 cab in stereo and actually manage to get a significant stereo spread.

I never liked the idea of running stereo in one cabinet unless the 2 sides are completely sealed from each other. Even running 2 separate cabs, the stereo effect is minimal unless you ears are directly in front of them or you put the cabs at opposite sides of the stage. Thats why Marshall calls the EL34 100/100 a "dual monoblock" amp instead of a stereo amp. It isn't really meant for stereo...its meant to power two cabinets with a ridiculously loud 200 watts of raw tube power.

[metalchurch]

I am just asking for when I get another 1960 cab, should I just run it 16ohm mono like I am right now?
Or should I run it 8ohm stereo?

I heard that by running mono it is using more of the available power, and I was mainly concerned about power loss, not trying to double my existing 100w into 200w.

[lonewolf]

I am just asking for when I get another 1960 cab, should I just run it 16ohm mono like I am right now?
Or should I run it 8ohm stereo?

I heard that by running mono it is using more of the available power, and I was mainly concerned about power loss, not trying to double my existing 100w into 200w.

As long as you match the impedance to the speaker, you will get 100W from each side of the amp. The amp doesn't care if its mono or stereo. The perceived volume from the speakers will be a little more in mono than in stereo.

If you run both cabs 8ohms stereo and wire the cabs' sides in parallel, you will end up with 4ohms per stereo side and will fry your amp.

Your best bet (since you already have a 16ohm cab) is to get a 2nd 16 ohm cab and power each cabinet with its own amp channel. If you stack the cabs, you may as well run a mono signal, but it really won't matter if you run a stereo signal.

The best way to run stereo is to have identical cabs and run them side by side instead of stacked. Each full cab gets a stereo channel.

[metalchurch]

Jeff,
I'm confused, it's getting dark out, I forgot my meds, and there's wolves after me.

My questions have even got me confused, so if you wouldn't mind can i switch this to some PM's and I'll start all over.
I didn't get the important questions answered that I wanted and this shit got all twisted up and confused. It was no one's fault, I think it was mine cause I would ask 2 questions for every 1 answer, and then you were answering something from before and I'd ask yet another one and so on and so forth....

I'll begin my first question via PM tomorrow sometime.
Thank you!

[orangekick]

If you're running each side of your power amp into its own cabinet and those cabinets are both 16 ohms, they will both be getting 100 watts.

[Ron]

Ok, so basically if I used only 1 speaker out, it is mono?

Yes, @100w if the impedance switch matches the cabinet impedance.

If I use both speaker outs, it would be stereo, regardless if I had 1 or 2 cabs?

Basically yes. You would have 2 mono channels. "Stereo" depends on the input. Since your Engl preamp isn't stereo, and you don't have any stereo effects, you'll always be working with a mono signal chain. For true "stereo" there has to be a difference between the left and right channels, but that's a confusing technicality.

If I split my 1960B cab to 150w@8ohms & used both inputs it would also be stereo, right?

It would be dual mono and use both channels of your amp, so technically it would double the power (2 x 100w) to your single cab vs. using one channel (1 x 100w) and driving the cab at 16 ohms. Still not technically "stereo" though.

*Also one more question:
My Power amp is 100watts and is switchable between 8 and 16ohms
My 1960B cab is rated @300w mono / or 150w stereo

So regardless whether my cab is set to 150w@8ohms or 300w@16ohms, the Poweramp is still pushing it's 100w, right?

In the dual 8 ohm config, you would be pumping 200w into the 1960B since you would be using both output channels of the amp. Each 8 ohm half of the cabinet would be receiving a full 100w.

What are the advantages or disadvantages of either or?

The split 8 ohm setup would allow you to use both channels of the amp, thus doubling the power output of the rig, but do you really need 200w of tube power? If it were me and I was playing live gigs, I would use one channel of the amp with one cab set at 16 ohms and save the second channel of the amp as a spare, or use it to drive a monitor cab in front of me to keep stage level down. (Unless you're a freak with ears in the back of your knees).

I hope I didn't confuse you more, Joe.

[metalchurch]

Actually, no you didn't confuse me, that made perfect sense.

You said that if I used both speaker outputs of my poweramp into my cab, that I'd be pushing 100w from each side. So that would be 200w total.
If I split my cab to 8ohm, it would be rated at 150w@8ohm.
So then 2 speakers from my cab would get a full 100w from the amp, and the other 2 speakers would get the other 100w from the other speaker out.

As long as I'm powering the cab below the speakers max watt rating, I'm safe right?

My Engl preamp has a stereo mode, but I'm running a straight mono signal throughout the rig. That was an excellent catch Ron, I totally forgot that in order to take advantage of true stereo mode, the rest of the rig should be wired as such.

That's also a good idea to run a small monitor off of the #2 speaker out.