Can I run (2) 4x12's and (2) 1x12's from one head safely?

[The Contrast Studio]

I am running a Jcm 2000 TSL 100 with two 4x12 rectifier cabs. I'm about to buy two 1x12's but not sure how they would fit into the equation as far as daisy chaining, etc... All cabs are 8 ohms. Just want to know if there is a safe way to do this.

 

[screamingdaisy]

Do you understand that two 8ohm loads in parallel is 4ohm while two 8ohm loads in series is 16ohm?

I ask because if you do it'll make my explanation a whole lot simpler.

That said... be advised that 50% of the amp's power is going to go through those 1x12s while the other 50% will go through the 4x12s.... so you might not be totally happy with the results for the amount of effort it's going to take as the speakers in the 4x12 will be driven by 6w each while the ones in the 1x12 will be driven by 25w each...

 

[94Tremoverb]

I am running a Jcm 2000 TSL 100 with two 4x12 rectifier cabs. I'm about to buy two 1x12's but not sure how they would fit into the equation as far as daisy chaining, etc... All cabs are 8 ohms. Just want to know if there is a safe way to do this.

Not simply, no. Running all four cabs together will give a total load of 2 ohms, which is too low for the amp even set to 4 ohms. *NB*: "daisy-chaining" from one cab to another does *not* put the cabs in series, no matter what it looks like, it puts them in parallel - so the result is the same as connecting them all to the amp.

You can do it, but you'll need to make a pair of series distribution boxes or cables - or one distribution box with two pairs of series outputs, wired in parallel - this will give you an overall load of 8 ohms.

But also, what screamingdaisy said. The power distribution will be equal between all four cabinets, so firstly the speakers in the 1x12"s will be pushed harder (probably not an issue since each cab will be receiving only 25W), but also the 4x12"s will be much louder unless the speakers in the 1x12"s are really efficient. Stacking them on top of the 4x12"s may help, you'll hear them better if they're up higher.

 

[espboogie123]

I am running a Jcm 2000 TSL 100 with two 4x12 rectifier cabs. I'm about to buy two 1x12's but not sure how they would fit into the equation as far as daisy chaining, etc... All cabs are 8 ohms. Just want to know if there is a safe way to do this.

No. Your amp can run a 16ohm load safely, or a 8ohm load, or a 4ohm load. With two 4x12 rectifier cabs at 8ohms, you are already running a 4ohm load. That is the least load possible. What you need to do is purchase a small power amp and run your emulated line out in back of head to the power amp, then power amp to the 2 1x12s. If the 1x12s are 8ohms, them make sure the power amp can handle a 4ohm load.

 

[The Contrast Studio]

I figured it wasn't doable. The power amp from the emulated line out sparks an interest though. Ultimately, there are two reasons I want to run these 4 cabs.
1) I will have my two 4x12s side by side, head/rack case stacked in the middle, and the two 1x12's at the top corners, to give me a decent looking wall of a rig.
2) I would have the 1x12 mic'ed for gigs, taking advantage of the tighter sound, but now that I type that, I'm thinking it wouldn't make much of a difference live for anyone but myself.

I haven't bought the 1x12's yet so maybe I should look into something a bit more practical and less "good looking"

Thanks guys. All suggestions will be considered.

 

[YellowJacket]

=-o Who are your roadies!?? =-0

Since this is a forum and everyone spouts opinions, have you thought of just running two guitar heads instead? You're running a fullstack already so what is wrong with two halfstacks? You could run a different tone on each one and I bet you could use stereo effects as well!!

If you get 1 x 12s, you could run open back cabs for better clean tone . . .

 

[The Contrast Studio]

I had thought of that. But thinking that my next head purchase might be a triple rec, my bank accept isn't caught up with my gear ideas quite yet. Just picked up a single head/ 6 space rack case. I want to get some use out of that before I upgrade to a dual head case. Although I could get the rack mount version of the triple rec and lose my 2 space drawer.

- no roadies right now. I've just been singing for an established metal band for a couple years that recently decided to call it quits so now I'm getting back into playing guitar and just starting an alt rock band. I'm just addicted to gear and coming up with new ways to set it up. Probably would just use this set up for local shows and take the half stack on the road.

 

[YellowJacket]

You've come to the right forum. We're all gear addicts here and we are quick to come up with creative ways to drain the bank account. Since I discovered my father in law is a carpenter, I have forced him to build three 2 x 12s, 2 of which were for me. I also found out about Bare Knuckle Pickups here and I did a complete pickup and electronics upgrade on my Les Paul this summer. You'll most certainly hear talk of everyone's favourite boost pedal, tube cocktails, and even the best patch cables and speaker leads to run. The big thing I am always on about is how important speaker cabs are for tone. I'm always trying different blends of guitar loudspeakers. Incidentally, I was suitably impressed by WGS Reaper 50watt speakers. Stinking amazing rock speaker.

 

[94Tremoverb]

I figured it wasn't doable.

It's definitely doable, you just need a non-standard way of connecting the cabs in order to give the correct impedance.

The power amp from the emulated line out sparks an interest though.

The real advantage of getting a power amp as well - which by the way you *don't* want to run from the Emulated output, if it's going back into guitar cabs... that's for DI'ing through a full-range system eg PA - is that you will have not only independent level control for the two 1x12"s, but you could also use them for stereo effects, by putting the FX processor between the main amp and the power amp. You could set the mix anywhere from normal to 100% wet on the 1x12"s, and get a really full sound with the bulk of your straight-ahead rock-god tone coming out of the 4x12"s and only the 'shimmery' stuff (chorus, ping-pong delays etc) from the little cabs. This is exactly how a lot of pros do it because it means no compromise on the main tone. But, you will then need to mic three cabs to get the full effect through the PA... which isn't going to make you very popular with most small-gig soundmen. On the other hand, with that much on stage it may not matter if you're really going through the PA or not...

 

[The Contrast Studio]

I'm glad I posted here. Tons of great responses. So I'm seriously considering the separate power amp to run the 1x12s. Would you mind breaking down how I'd run everything without using the line out? I figured that would have been the best way...

 

[screamingdaisy]

I'm glad I posted here. Tons of great responses. So I'm seriously considering the separate power amp to run the 1x12s. Would you mind breaking down how I'd run everything without using the line out? I figured that would have been the best way...

Run the FX loop send off the head into the effects processor(s). Run those into the left/right inputs of the power amp.

 

[The Contrast Studio]

Okay so specifically, why would I not want to run it straight from the line out? I understand the potential for stereo effects and separate cabs for clean tones by going through the loop, but in the meantime - is there a damage risk by running from the line out to a power amp, to the cabs? Or are as just talking bad quality?

PS - there's an A and a B fx loop, both run through my dbx 166xl, with a gate on my gain channels and compression on the clean.... Which gives me side chains for both channels on the dbx. Could those be used in the equation somewhere?

 

[screamingdaisy]

Okay so specifically, why would I not want to run it straight from the line out? I understand the potential for stereo effects and separate cabs for clean tones by going through the loop, but in the meantime - is there a damage risk by running from the line out to a power amp, to the cabs? Or are as just talking bad quality?

Emulated line outs are typically take a post-power amp signal and emulate the tone shaping that'll happen at the speaker stage so that it can be fed into some processors and sent direct to a PA/Recording console.

If you run an emulated line out into another power amp and speaker cabs you're doubling up the processing.

Using the effects loop send allows you to run a pure preamp signal into the second power amp/speakers, so you're not doubling up on the processing.

A line out signal would be ideal if you wanted to run your signal into a processor and a couple of powered Mackie monitors.

The preamp out would be ideal if you wanted to run your signal into a processor, power amp, and a couple of V30 loaded 1x12s.

PS - there's an A and a B fx loop, both run through my dbx 166xl, with a gate on my gain channels and compression on the clean.... Which gives me side chains for both channels on the dbx. Could those be used in the equation somewhere?

You'll have to figure that one out for yourself. Two possible solutions are to run both effects loop sends into an parallel line mixer, or using a midi switcher that can switch each half of your DBX in and out of the signal path.

 

[The Contrast Studio]

So as for a power amp, something like this should do?

http://m.guitarcenter.com/Rocktron-Velocity-100-Power-Amp-480118-i1171328.gc#overview