Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

[cakire82]

I have Behringer VT250FX solid state 2x12 100W combo amp in hand. Right now the speaker cab is wired for stereo use. Details pictures are below. The speakers are Bugera Vintage Guitar Series, 50W/8ohms. Detailed specs are also below.

I am a do it yourself kind a guy and I have basic electric and electronics skills. I want to modify this wiring and be able to use these speakers with the solid state combo as they are in stereo, 50W per side and also in mono (100w) with a 100W watt tube amp.

Is this possible? What do I need to get this done. I will need everything I need to know and use for this task and all the the help that I can get is appreciated.

 

[Warheart]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

You can just lay your head on top and just plug the speakers into your head.

Most amps have 2 speaker outputs, paralleled. Just plug both of these into the speaker outputs and set your ohms to 4?

 

[cakire82]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

You can just lay your head on top and just plug the speakers into your head.

Most amps have 2 speaker outputs, paralleled. Just plug both of these into the speaker outputs and set your ohms to 4?

Yes, this is true but these are only 50W speakers. I don't want to ruin them with 100W running in to them.

How should go about re-wiring these speakers?

 

[Jessie Sammler]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

Set the output of the head to 4 ohms, and the power will divide equally between the two speakers. Don't max out the dynamic power of the head, and you should be fine.

 

[cakire82]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

Set the output of the head to 4 ohms, and the power will divide equally between the two speakers. Don't max out the dynamic power of the head, and you should be fine.

Amp has 2 parallel mono outputs. So It will feed 100W(full)/60W(low power) from each speaker output of the amp.

But even in this case the cable attached to speaker are not long enough to be connected to another amp. I will still need to disconnect these and wire longer ones right?

So instead of this temporary/inflexible solution, can I wire a Mono/stereo panel in the back of this combo? If I can so this I can use them as mono or stereo as I want to using external cables. It seems like this would be safest and most flexible way.

 

[Jessie Sammler]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

What amp head is this? Make and model, please.

 

[cakire82]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

What amp head is this? Make and model, please.

It is a Fryette 2/90/2 power amp. I have had another thread where this was discussed and also that was the answer given to me by the Fryette Customer Support.

Could some one please help me with re-wiring combo cab please?

 

[Jessie Sammler]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

So this is a stereo/dual-mono amp. No wonder you're saying that you're getting 100W per side. Still, you're not going to blow your speakers unless you blow your speakers. Speakers don't just magically explode because they somehow sense that they're connected to an amplifier capable of generating more power then the speaker is rated for. Isn't there a 60W mode on it? Try that, if you're worried about it.

As for the wiring thing, I don't know. I don't trust those little tabs to do their job, so I usually wire things up with a switch. A lot of people find the stereo/mono jacks to be really convenient, so:

 

[Warheart]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

Amp has 2 parallel mono outputs. So It will feed 100W(full)/60W(low power) from each speaker output of the amp.

But even in this case the cable attached to speaker are not long enough to be connected to another amp. I will still need to disconnect these and wire longer ones right?

So instead of this temporary/inflexible solution, can I wire a Mono/stereo panel in the back of this combo? If I can so this I can use them as mono or stereo as I want to using external cables. It seems like this would be safest and most flexible way.

To use those speakers in the combo, yes, you would have to disconnect those and use longer wire.

After reading your other thread and looking at the back of the 2 90 2, for Mono plug both speakers into Channel A's speaker outputs 1 & 2, then set ohms to 4.

For Stereo plug 1 Speaker into Channel A, set to 8 Ohms, Plug 1 speaker into Channel B, set to 8 ohms.

That is really the only way to do it with those speakers. I don't understand why you'd want to wire up a switch/jack plate on the back of the combo.

 

[cakire82]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

So this is a stereo/dual-mono amp. No wonder you're saying that you're getting 100W per side. Still, you're not going to blow your speakers unless you blow your speakers. Speakers don't just magically explode because they somehow sense that they're connected to an amplifier capable of generating more power then the speaker is rated for. Isn't there a 60W mode on it? Try that, if you're worried about it.

As for the wiring thing, I don't know. I don't trust those little tabs to do their job, so I usually wire things up with a switch. A lot of people find the stereo/mono jacks to be really convenient, so:

Yes, as I have mentioned above there is 60W mode but customer support told me that it is still risky.

Could you give mode details on the schema you have provided. Is it for mono/stereo panel? Where do I get one of those? How would I go about wiring them with a switch?

 

[cakire82]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

To use those speakers in the combo, yes, you would have to disconnect those and use longer wire.

After reading your other thread and looking at the back of the 2 90 2, for Mono plug both speakers into Channel A's speaker outputs 1 & 2, then set ohms to 4.

For Stereo plug 1 Speaker into Channel A, set to 8 Ohms, Plug 1 speaker into Channel B, set to 8 ohms.

That is really the only way to do it with those speakers. I don't understand why you'd want to wire up a switch/jack plate on the back of the combo.

Where do I get longer wires? Can I simply cur a guitar cable in half and wire them? I have no idea about how to proceed with this?

As for the 2/90/2, I will use Channel A in mono with only one of the speakers out connected to the cab. Thats why I need to wire these speakers in mono.
I would like to use the cab in stereo whenever I use it with the VT250FX combo amp.

 

[Warheart]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

Where do I get longer wires? Can I simply cur a guitar cable in half and wire them? I have no idea about how to proceed with this?

As for the 2/90/2, I will use Channel A in mono with only one of the speakers out connected to the cab. Thats why I need to wire these speakers in mono.
I would like to use the cab in stereo whenever I use it with the VT250FX combo amp.

You should use Speaker cable, not guitar cable.

Guitar cable is a wire and shield, while a speaker cable is 2 wires, no shield.

You can make a speaker cable from lamp wire, as long as you have two bigger wires in the one plastic sheath.

I understand, but you get the same result if you wire the 2 speakers together and then plug into channel A, or if you just plug both speakers into channel A. Its the exact same thing, but the latter is less fooling around with it.

If you wire the speakers together in parallel, or if you just plug the two speakers into paralleled outputs, its the same thing. The jacks on the 2 90 2 are merely connected to each other on the inside.

 

[cakire82]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

You should use Speaker cable, not guitar cable.

Guitar cable is a wire and shield, while a speaker cable is 2 wires, no shield.

You can make a speaker cable from lamp wire, as long as you have two bigger wires in the one plastic sheath.

There speakers cables out there (MF, GC, etc...)with different gauges from 12-18? What is the difference? Which ones should I use and why?

Where can i purchase the panels that goes in the back of the speaker cabs. I would like to wire them in a similar way as below (2x12) if possible so I can use them in mono/stereo options.

I understand, but you get the same result if you wire the 2 speakers together and then plug into channel A, or if you just plug both speakers into channel A. Its the exact same thing, but the latter is less fooling around with it.

If you wire the speakers together in parallel, or if you just plug the two speakers into paralleled outputs, its the same thing. The jacks on the 2 90 2 are merely connected to each other on the inside.

Even in low power mode Channel A will feed 60W from each of the parallel mono speaker outs but the speakers are rated at 50W. Even though it is a low risk I don't to damage them using the speaker in stereo. I believe when I wire the speakers in mono (series) cab will be rated 100W and amp will have no chance of damaging them. Am I wrong?

 

[Warheart]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

There speakers cables out there (MF, GC, etc...)with different gauges from 12-18? What is the difference? Which ones should I use and why?

Where can i purchase the panels that goes in the back of the speaker cabs. I would like to wire them in a similar way as below (2x12) if possible so I can use them in mono/stereo options.

Even in low power mode Channel A will feed 60W from each of the parallel mono speaker outs but the speakers are rated at 50W. Even though it is a low risk I don't to damage them using the speaker in stereo. I believe when I wire the speakers in mono (series) cab will be rated 100W and amp will have no chance of damaging them. Am I wrong?

The thicker the speaker cable the better, you want the least resistance from amp to speaker, which means a thicker cable. Good 1/4" plugs are the only other requirement. 12 gauge is bigger than 18 gauge.

Think of electricity as water, it flows more easily through a large pipe than a small.

There is no difference in wattage if it is wired series or parallel, but the Ohms would be different.

When you plug both speakers into channel A using both outputs, the amp is dividing 60W into 100W (50w +50w speakers), using 4 ohms.

If you wire those two speakers together and then plug into channel A using one output, the amp would be running 60 watts into 100W, using 4 ohms (parallel) or 16 ohms (series).

That is the only difference.

 

[cakire82]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

The thicker the speaker cable the better, you want the least resistance from amp to speaker, which means a thicker cable. Good 1/4" plugs are the only other requirement. 12 gauge is bigger than 18 gauge.

Think of electricity as water, it flows more easily through a large pipe than a small.

Thank you for the advices on the speaker cables. gauge logic makes perfect sense.

There is no difference in wattage if it is wired series or parallel, but the Ohms would be different.

When you plug both speakers into channel A using both outputs, the amp is dividing 60W into 100W (50w +50w speakers), using 4 ohms.

If you wire those two speakers together and then plug into channel A using one output, the amp would be running 60 watts into 100W, using 4 ohms (parallel) or 16 ohms (series).

That is the only difference.

I think this is where we fall apart. This was how I understood it in the first place also. I thought if I were to connect both speakers out from Channel A
to speakers in parallel the power would be dividing. I thought I would be feeding 30W each output (30Wx2=60W) to each speaker (50W) in parallel. But the customer support and the another member from he other thread explained to me that each Channel in this amp has parallel mono. So the power does NOT get divided. It feed 60W from both outputs of the Channel A.

 

[Warheart]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

I think this is where we fall apart. This was how I understood it in the first place also. I thought if I were to connect both speakers out from Channel A to speakers in parallel the power would be dividing. I thought I would be feeding 30W each output (30Wx2=60W) to each speaker (50W) in parallel. But the customer support and the another member from he other thread explained to me that each Channel in this amp has parallel mono. So the power does NOT get divided. It feed 60W from both outputs of the Channel A.

I disagree.

If I have a 100 watt head, with 2 speaker outputs, its not going to put out 200 watts if I plug 2 cabs into it. The 100 watts is divided amongst the 2 cabs.

Your 2 90 2 in low power will feed 60 watts from each CHANNEL, not 120.

Both outputs on channel A are connected in parallel, your speakers would still be 100W.

 

[cakire82]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

I disagree.

If I have a 100 watt head, with 2 speaker outputs, its not going to put out 200 watts if I plug 2 cabs into it. The 100 watts is divided amongst the 2 cabs.

Your 2 90 2 in low power will feed 60 watts from each CHANNEL, not 120.

Both outputs on channel A are connected in parallel, your speakers would still be 100W.

I don't know man. Thats what I have been told. Did you read what was posted on the other thread. It was posting #26. The customer support also confirmed what he said So right now I am lost.


BTW, CAN ANY ONE HELP ME WITH THE WIRING? Where do I get those panels?

 

[Warheart]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

In the other thread Joelap in post #28 said:

"NOW: if you wanted to use 2 cabinets but only 1 channel, thats easy. If you have two 16ohm cabinets, connect one to each output but put the selector switch at 8ohms instead of 16ohms. You are still getting 65W output, but you've got 8 speakers instead of 4 moving the air. So it is effectively "louder" but no more or no less wattage is coming out of the amp."

The key here is NO MORE OR LESS WATTAGE IS COMING OUT OF THE AMP.
you quoted this yourself in a later response.

In post #26, J Moose is clarifying the stereo mono thing.

If you wanted to use your 2 90 2 in stereo, you must use both channels.

If you plug the 2 speakers into channel A, it will be MONO, 4 ohms, and 100 watts.

If you wire the 2 speakers together then plug them into channel A it will be MONO, 4 OR 16 ohms, and 100 watts.

The only way to do what you're talking about is to have the speakers wired up separately.

If you wire the speakers together, you would have to rewire them every time to use them with your combo again. There is no REASONABLE explanation to add a jack plate, it is a LOT simpler to keep the speakers wired the way they are so you can just plug them in the Fryette or the combo as they are.

 

[cakire82]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

In the other thread Joelap in post #28 said:

"NOW: if you wanted to use 2 cabinets but only 1 channel, thats easy. If you have two 16ohm cabinets, connect one to each output but put the selector switch at 8ohms instead of 16ohms. You are still getting 65W output, but you've got 8 speakers instead of 4 moving the air. So it is effectively "louder" but no more or no less wattage is coming out of the amp."

The key here is NO MORE OR LESS WATTAGE IS COMING OUT OF THE AMP.
you quoted this yourself in a later response.

It was my understanding that he meant that I will be same full wattage from the each of the speaker outs of Channel A. Impedance will be 4. And it will sound louder only because number of speakers are more.

In post #26, J Moose is clarifying the stereo mono thing.

If you wanted to use your 2 90 2 in stereo, you must use both channels.

If you plug the 2 speakers into channel A, it will be MONO, 4 ohms, and 100 watts.

This is correct. Only Channel A will give dual mono not stereo. I was wrong at that point.

If you wire the 2 speakers together then plug them into channel A it will be MONO, 4 OR 16 ohms, and 100 watts.

The only way to do what you're talking about is to have the speakers wired up separately.

If you wire the speakers together, you would have to rewire them every time to use them with your combo again. There is no REASONABLE explanation to add a jack plate, it is a LOT simpler to keep the speakers wired the way they are so you can just plug them in the Fryette or the combo as they are.

This was the thing I want to find out. I thought If I can wire a jack plate in some certain way I can use the cab as both mono (100W) and stereo (2x50W)
For example when you plug in only into the mono speaker in it works as mono. If you plug in into the both speaker ins it performs as stereo. Just like the marshall 2X12 jack plate I have posted above. isn't it how that works?

 

[cakire82]

Re: Modding a Combo 2X12 Cab for Stereo/Mono (Speaker Rewiring)?

Thanks to Jessie I think I have found the diagram that I was looking for.

Explanation from the web site
"Here we have another two-speaker stereo cabinet; this time loaded with 8-ohm speakers. Your options are: dual singles @ 8-ohms each, or combined in series @ 16-ohm total load.
Input A or B will give you that speaker @ 8 ohms. Using both A & B is fine; it's 8 ohms each.
Input C combines the two speakers in series giving us a 16-ohm total load.

In other words,
Plugging into either Input A or Input B would give you that speaker.
When either of these two (A&B) inputs are used, they are not connected, which means you could use two different amps, or a true stereo amp (Line6), or just both outputs from a mono amp (Marshall, Fender, Egnater).
Plugging into Input C will give you both speakers combined in series.

And again: If you're plugged into Input C, you cannot also be plugged into either A or B and have this work!
1. A @ 8 ohms
2. B @ 8 ohms
3. A + B (8 ohms each)
4. C (but not A or B!) @ 16 ohms total load"

I think this should work perfect for me.

I can still plug both speaker outs from behringer combo into INPUTS A and B of the cabinet. This way combo will work as it does today. (50Ws per side)
And for the 2/90/2, I will only use left speaker out from Channel A and plug it into INPUT C of the cabinet. Channel A will be set to 16 ohms. (100w series)

What do you guys think?