Speaker wiring ?

baldy

Yesterday I was given an old non working Line 6 Flextone 111 combi amp, 150 watt I think ?
The person who gave it to me said that the amp part didn"t work & that he had had it looked at by an amp tech who said it would cost more to fix than the amp was worth ?
Looking at it the amp part was just attached to the cab by 8 screws so I undid the screws, removed the amp & now have a 2 x 12, open backed cab.
The cab contains 2 Celestion G12P-80 speakers rated 8 ohms each.
My thought (if the speakers are any good) is to wire up an input & give the cab to my step son who I know is looking for a new gigging amp & cab.
My question is how do I wire the speakers up.
Do I just fit a 1/4" female jack socket to the cab & run 4 wires off that, 2 to each speaker ie parallel ?
If I do do that are the ohms from an amp halved ie if the amp outputs 16 ohms then each speaker receives it"s rated 8 ohms ?
If I wire the speakers in series would they receive the full 16 ohms, assuming the amp head outputs 16 ohms (obviously this would not be the way to do it with 8 ohm speakers but the way to wire the speakers if the amp out put is 8 ohms so each speaker receives it"s rated ohms) ?
I noted that the Line 6 had 2 separate 8 ohm outputs one to each speaker.
Oh & finally are the Celestions any good & what sort of wattage can they handle ?
I am assuming that they are 80 watts each based on the 80 denoted on them ?
Thanks in advance.

ICBM

Those Celestions - also known as Seventy/80s - are not highly regarded as far as Celestions go, but they're OK. They have a rather flat, characterless tone which actually makes them very suitable for modelling amps - but they'll certainly work for anything else too. They are rated at 80W each.

The Line 6 amp is stereo which is why there are two separate connections  - you can just wire it in mono. With two 8-ohm speakers the impedance of the resulting cab will be either 4 ohms connected in parallel, as you describe, or 16 ohms connected in series. The amp needs to be set to (in the case of a valve amp, which usually have either a switch or multiple jacks), or be capable of handling (in the case of a solid-state amp, which will usually run at 4 ohms, but check), either of those impedances. The total cabinet power rating is 160W whichever way you do it.

Does that help?

ecc83

The speaker is also called the "Seventy Eighty" and I cannot recall if they are on ICBM's wish list or hit list! I suspect the latter.

Seems to be liked for cleans but harsh for overdrive sounds?

If the amp can handle 16 Ohms yes, wire them in series. Best to use a twin jack plate and wire the jacks in parallel, that way he could jack in another 16R cab for 8 Ohms and some serious noise!

Right, ready for the flack!

Dave.

baldy

Wow you are like lightening ICBM.
So wired in parallel the speakers will be 4 ohms & the amp output will need to be set at 4 ohms ?
Wired in series the speakers would be 8 ohms impedance ?
I am just thinking that as it will only be a few pounds & the cab & speakers were free that I could wire it up & see if my stepson likes it.
Coincidently it is a modelling amp head he is thinking of getting so it sounds like the speakers may be OK for that ?

baldy

Thanks ecc83.
I am used to working on DC battery systems from another hobby I have & there if you connect batteries in series you double the voltage but the amperage remains the same & if you connect in parallel you double the amperage but the voltage remains the same.
Just trying to get my head round watts & ohms.

ICBM

ecc83 said:

Seems to be liked for cleans but harsh for overdrive sounds?

I would say dull and muddy for both, rather than harsh - but to be fair, they do the job. They just don't sound as lively and characterful as most other speakers.

baldy said:

So wired in parallel the speakers will be 4 ohms & the amp output will need to be set at 4 ohms ?

Yes.

baldy said:

Wired in series the speakers would be 8 ohms impedance ?

No, 16.

baldy said:

I am just thinking that as it will only be a few pounds & the cab & speakers were free that I could wire it up & see if my stepson likes it.

Nothing wrong with this at all - my cabinet is currently a Marshall TSL combo without the amp bit .

baldy said:

Coincidently it is a modelling amp head he is thinking of getting so it sounds like the speakers may be OK for that ?

Yes, but check it will support a 4-ohm load. If not - it may be 8-ohm minimum - wire the cab to 16 ohms. With a solid-state output section you can use a higher impedance cab than the amp, but not a lower one.

baldy

Spoke to my stepson last night & he is thinking of getting a Blackstar ID100TVP head ?
Any opinions on that head & that head with the Celestion 2 x G12P-80 cab ?
He needs a cheap head & cab loud enough to gig, playing a variety of music styles.
His present combo, another Flextone 111 XL (150watt I think) is playing up & he thinks it is not really loud enough.
We are led to believe that the Blackstar although 100 watts will be louder ?

baldy

He likes modelling amps. 

ICBM

Yes. For that, you definitely want the cab wired to 4 ohms.

The Blackstar IDs are very loud - they really are almost ‘as loud as valve’, as they claim - at least into a 4-ohm cab. I A/B’d the ID60 with a 50W valve Marshall and it was very close.

They actually do it by being *more* powerful than they claim, unlike almost any other solid-state amp - about double. This is because an overdriven valve amp can put out getting on for double the rated clean power as well.

It should still be fine with a 160W cab though, Celestion ratings are also fairly conservative.

baldy

Thanks ICBM, so the 2 speakers wired in parallel from the cab input jack ?

ICBM

baldy said:

Thanks ICBM, so the 2 speakers wired in parallel from the cab input jack ?

Yes.

baldy

So if I put 2 female inputs on the cab, wired together, then take 4 wires of one of them, 2 to each speaker the speakers will get 50 watts each (assuming 100 watt amp) at 4 ohms.
If he wants to run the other Flextone as a second cab (amp part removed) can he just plug into the second input on the first cab to another female input on the second cab then 2 wires off that input to each speaker ?
Will that give each speaker 25 watts at 4 ohms ?

ICBM

baldy said:

So if I put 2 female inputs on the cab, wired together, then take 4 wires of one of them, 2 to each speaker the speakers will get 50 watts each (assuming 100 watt amp) at 4 ohms.
If he wants to run the other Flextone as a second cab (amp part removed) can he just plug into the second input on the first cab to another female input on the second cab then 2 wires off that input to each speaker ?
Will that give each speaker 25 watts at 4 ohms ?

No.

You must not connect two cabs to the amp if one or both of them is 4 ohms - that will give a 2-ohm load and will probably wreck the amp.

baldy

To do what I am suggesting would the speakers need to be 16 ohm then which would result in a 4 ohm load ?
Please forgive my ignorance

ICBM

baldy said:

To do what I am suggesting would the speakers need to be 16 ohm then which would result in a 4 ohm load ?
Please forgive my ignorance

Yes, that's right.

Or if you really want to use both cabs with the existing speakers, you could wire them to 16 ohms each (speakers in series) and then connect both cabs to the amp which would give a total of 8 ohms - not quite as much power as at 4 ohms, but with four speakers running it would probably be slightly louder because it will move air more efficiently.

The simple rule is that if the speakers are in parallel the impedance is halved, and if they're in series then it's doubled. There are more complicated rules if the speakers aren't the same impedance, but I won't confuse you now! You don't need to apologise for ignorance, we are not born knowing this .

ecc83

Unless the two you look after IC have popped, I have not heard of any ID amps failing.

I did some bad things to them, both by accident and design! They just shut down on me.

Obviously be careful and heed The Book but they are pretty bombproof.  (oh! the 110V version does NOT like 240volts!)

Dave.

ICBM

ecc83 said:

Unless the two you look after IC have popped, I have not heard of any ID amps failing.

I did some bad things to them, both by accident and design! They just shut down on me.

There are more than two now I think. Not a sniff of a problem.

If I could get all the studios to just stick to a mix of these and old Peavey bass amps I would be out of a job...

baldy

Great ICBM & thanks for having the patience to explain to me.
Now to tell him that I now know how to wire the cabs up so that he can run both off a head.

ecc83

ICBM said:

ecc83 said:

Unless the two you look after IC have popped, I have not heard of any ID amps failing.

I did some bad things to them, both by accident and design! They just shut down on me.

There are more than two now I think. Not a sniff of a problem.

If I could get all the studios to just stick to a mix of these and old Peavey bass amps I would be out of a job...

Well, we wouldn't want that! Oh! BTW, remember, B's have entered the BASS amp arena!

Dave.