Two outputs, three/four cabs?????

[FlatEric]

Up to now, I have used all sorts of stuff over the years but never ended
up with what I want to try now.

Over a period of time - trades, swaps, purchases - I have ended up
with three 2 x 10 cabs and a 1 x 15, all Ashdown.
I always use one of the 2 x 10 with a combo or if more power is needed
I have a Hartke 8 x 10, with a 500 watt head.

My heads all have two outputs.

This is what I want to try.

Three 2 x 10 or two 2 x 10 and one 1 x 15 or three 2 x 10 and one 1 x 15!!

All cabs are 8 ohm, all with at least two sockets (one is an ABM with two Jack
and one Speakon)

How is this done and what will be the impedance?

Can anyone help?
It may be simple but I don't want to do any damage to my gear.


Cheers.

[xgsjx]

I believe the Ashdown ABM head has a min load of 4Ω. IIRC, 3 8Ω cabs would be 2.66Ω.
This would heat up the head nicely, allowing you to cook the band's supper before the end of the gig. 4 8Ω cabs should then make the amp hot enough to boil a kettle/pan of water on so you can make cuppas to wash down the supper.

Edited to ask: I've assumed you have an Ashdown head (or another head with a min 4Ω load). If you have a head that runs to 2Ω then plug & play.
Or you could use 2 heads, putting 1-2 cabs on each.

Edited September 5, 2012 by xgsjx

[0175westwood29]

looks like you'd need to grab another amp man.

have two cabs running from the abm and take a line/pre amp out and put that into the power amp in on the second so your just using it as a power amp, or just get a power amp and hook your other two cabs up to that.

andy

[flyfisher]

It's possible but I'm not sure the hassle will be worthwhile and I tend to agree that getting another amp might be the simplest, and probably best, way of driving lots of cabs.

But if you're really keen to give it a try then you'll need to make/buy some suitable cables so that you can connect cabs electrically in series.

Basically, you need to connect the cabs in such a way that the overall load presented to the amp doesn't fall below 4 ohms.

With three 8 ohm cabs, you could wire two of them in series to give 16 ohms into one amp output and then connect the other 8 ohm cab to the other amp output giving 16+8 in parallel, which is a load of 5.3 ohms and is fine for the amp.

BUT - wiring two cabs electrically in series IS NOT the same as connecting a standard cable from one cab to the next. Electrically, that would still be a parallel connection and the two cabs will therefore form a 4 ohm load. If you then add another 8 ohm cab to the amp it will 'see' a 2.6 ohm load and this may damage the amp.

So three 8 ohm cabs can be connected to a 4 ohm amp but it's fiddly and, probably, a little bit pointless.

[JTUK]

Yep..assuming you want this much 'power' and don't mind the load-in..

You need to be running 1 amp at 2ohms as that will be the load of 4x8ohms
or you run the Ashdown into 2 cabs =4ohms and then slave off to another amp that can do 4ohms..which is a pretty default load for all amps, IMO..

Wouldn't mess around rewiring tbh..

Edited September 5, 2012 by JTUK

[Lozz196]

If you want to use all at the same time, why not have:

Combo plus either a 210, or the 115
500 watt head into two of the 210s

And just use a Boss TU2 to connect your bass to both rigs at once. Will be monster sounding - and back-breaking too, I would imagine.

[stingrayPete1977]

And people still ask me why I have a single 4ohm 600watt rated cab simples as that annoying rat thing says.........

[FlatEric]

Ah, I didn't think it was that simple!!

If my 4 x 10 is 8 Ohm in one socket and my 2 x 10 extension is 8 Ohm, out of the other socket,
the amp will run a 4 Ohm, which is what it will do as per manufacturers spec.

So. . . . in the 4 x 10, what impedance is each speaker and how are they wired and in the 2 x 10,
same question.

You [i]may [/i]see where I am going with this.

Cheers.

[xgsjx]

It depends on how they're wired. If wired in parallel, then the drivers are 8Ω. Of wired in series, then the 2x10 has 16Ω drivers & the 4x10 has 32Ω drivers.

Or is it the other way round?

[flyfisher]

Almost.

There are various ways of wiring up such cabs, though I'm not familiar enough with 'standard practice' (if there is one) to give a definitive answer of how that ARE wired, only how they MIGHT be wired.

A 210 cab could be wired as:

2 x 16ohm drivers in parallel to give an 8 ohm cab
2 x 4ohm drivers in series to give an 8 ohm cab

a 410 cab could be wired as:

4 x 32ohm drivers in parallel to give an 8 ohm cab
2 x 8ohm drivers in series to give 16 ohms and these two in parallel with another 2 x 8ohm drivers in series, which gives an 8 ohm cab
4 x 2ohm drivers in series to give 8 ohms

The only way to be sure is to open up the cab and check the actual wiring (and the labels on the drivers!).

[obbm]

By making some special cables 4 x 8-ohm cabs can be wired in series/parallel to give a total 8-ohms although whether the final result gives you what you think you'll get is questionable as it takes no account of the power handling/distribution among the individual drivers. The other thing to consider is whether the cabs are all in-phase.

[xgsjx]

[quote name='flyfisher' timestamp='1346957808' post='1795394']
Almost.

There are various ways of wiring up such cabs, though I'm not familiar enough with 'standard practice' (if there is one) to give a definitive answer of how that ARE wired, only how they MIGHT be wired.

A 210 cab could be wired as:

2 x 16ohm drivers in parallel to give an 8 ohm cab
2 x 4ohm drivers in series to give an 8 ohm cab

a 410 cab could be wired as:

4 x 32ohm drivers in parallel to give an 8 ohm cab
2 x 8ohm drivers in series to give 16 ohms and these two in parallel with another 2 x 8ohm drivers in series, which gives an 8 ohm cab
4 x 2ohm drivers in series to give 8 ohms

The only way to be sure is to open up the cab and check the actual wiring (and the labels on the drivers!).
[/quote]

Thank you

I always get series & parallel mixed up (in name) if I don't check.

I'd just wire red to blue & blue to bits.

[FlatEric]

[quote name='flyfisher' timestamp='1346957808' post='1795394']
Almost.

There are various ways of wiring up such cabs, though I'm not familiar enough with 'standard practice' (if there is one) to give a definitive answer of how that ARE wired, only how they MIGHT be wired.

A 210 cab could be wired as:

2 x 16ohm drivers in parallel to give an 8 ohm cab
2 x 4ohm drivers in series to give an 8 ohm cab

a 410 cab could be wired as:

4 x 32ohm drivers in parallel to give an 8 ohm cab
2 x 8ohm drivers in series to give 16 ohms and these two in parallel with another 2 x 8ohm drivers in series, which gives an 8 ohm cab
4 x 2ohm drivers in series to give 8 ohms

The only way to be sure is to open up the cab and check the actual wiring (and the labels on the drivers!).
[/quote]

Mmm, some food for thought!!
Thanks.

When the night start to draw in and I find myself needing something to do, I shall have a play around.

Cheers.