Complex Speaker Wiring
adam79
currently wired to run at 8ohms, but ideally, I would like to have the
option of either running it at 8 or 16ohms. If I put one of those
mono/stereo (two input) panels on the back of the cab, with some
creative wiring, would it be possible to use the switch that normally
selects mono or stereo to select between 8 or 16 ohms?
Thanks,
-Adam
RichL
> I'm thinking about buying a 2x12 cab w/ two 8 ohm speakers. It's
> currently wired to run at 8ohms, but ideally, I would like to have the
> option of either running it at 8 or 16ohms.
It's impossible to combine two speakers, 8 ohms each, to get 8 ohms
overall. Either you get 16 (connecting them in series) or 4 (connecting
them in parallel).
You may get 8 ohms running "stereo" where one speaker is assigned to
each stereo channel.
> If I put one of those
> mono/stereo (two input) panels on the back of the cab, with some
> creative wiring, would it be possible to use the switch that normally
> selects mono or stereo to select between 8 or 16 ohms?
Only by switching between using a single speaker and using both.
I'd suggest you understand what you have *currently) before modifying
it.
Stephen Cowell
"adam79" <ada...@toast.net> wrote in message
news:IPudneghRYcVzqDW...@posted.toastnet...
If you run at 8, you'll only be using one speaker.
Perhaps the seller is confused?
Most normal folks only get the 4 or 16 option
when presented with two 8ohm speakers.
Do you need all those options? Then I'd
just jack both speakers to the back... and
use different Y-cords to either series (16)
or parallel (8) or just use one at a time.
__
Steve
.
adam79
>
> If you run at 8, you'll only be using one speaker.
> Perhaps the seller is confused?
>
> Most normal folks only get the 4 or 16 option
> when presented with two 8ohm speakers.
>
> Do you need all those options? Then I'd
> just jack both speakers to the back... and
> use different Y-cords to either series (16)
> or parallel (8) or just use one at a time.
> __
> Steve
> .
>
I don't own the speaker cabinet yet.. a guy is selling it to me. I want
the option to switch between 4 or 8 and 16 because I have one amp that
only runs on 4 or 8 ohms, and my only speaker cab at the moment is
running at 16ohms with 16ohm speakers. I want the ability to use both
cabs at once, which would require the 16 ohm load on the cab in question
(making them both run at 8, and also be able to use this cab with my amp
that only can run at 4 or 8 ohms at shows (so I don't have to lug around
a 412).
Can you explain what different Y cords I would need?
Thanks,
-Adam
Stephen Cowell
> Stephen Cowell wrote:
>>
>> If you run at 8, you'll only be using one speaker.
>> Perhaps the seller is confused?
>>
>> Most normal folks only get the 4 or 16 option
>> when presented with two 8ohm speakers.
>>
>> Do you need all those options? Then I'd
>> just jack both speakers to the back... and
>> use different Y-cords to either series (16)
>> or parallel (8) or just use one at a time.
Oops... that should be either (16) or (4)... not (8).
> I don't own the speaker cabinet yet.. a guy is selling it to me. I want
> the option to switch between 4 or 8 and 16 because I have one amp that
> only runs on 4 or 8 ohms, and my only speaker cab at the moment is running
> at 16ohms with 16ohm speakers. I want the ability to use both cabs at
> once, which would require the 16 ohm load on the cab in question (making
> them both run at 8, and also be able to use this cab with my amp that only
> can run at 4 or 8 ohms at shows (so I don't have to lug around a 412).
OK... you want the cab to be able to do *16*, so you
can run it with another 16 and get 8, total. That's easy.
> Can you explain what different Y cords I would need?
OK, first things first. The new cab needs both speakers
connected to jacks in the back, one jack, one speaker.
The jacks have to be isolated from each other, i.e. if
they're not insulated jacks, and the plate they're mounted
to is metal, then you won't be able to series them. Now
you can get 4ohms (both parallel), 8 ohms (one speaker only),
or 16 ohms (both seriesed).
Now you can fabricate the Y-cords. You could probably
buy a parallel Y, but the series Y is definitely a custom
item... and while you're soldering, might as well make both.
The parallel one is very simple... like a 3-legged guitar cord,
all tips connected to all tips, all shields connected to all shields.
This cord will work no matter which one you plug into the amp
and which one you plug into the speakers.
The series one is very different: the amp plug is always the
amp plug. Come out from the amp plug's tip... connect this to
the first speaker tip. Come out of the first speaker shield...
connect this to the second speaker's tip. Come out the second
speaker's shield... connect this to the amp plug's shield.
Do you see how this works? If your speakers are wired
in-phase, this will result in series in-phase.
Materials: 6feet of lamp cord, six 1/4" plugs, solder, etc.
You'll probably have to do the speaker cab wiring as well.
Some folks would rather try to do this with complex jack
switching... I'd rather do it this way. Of course, you also
have the stereo option available as well, although if the
cab is not internally baffled your separation will suffer.
__
Steve
.
jh
you are looking for the impossible. A Cab with 4 16ohm speakers can at
no time have 8 ohms, assuming all 4 speakers are running. It' either 4
ohms or 16 ohms. Period
But there might be a solution for your problem.
IMHO you only need a cab that can be switched from 4 to 16 ohms with a
parallel slaving jack.
I assume the mm still to have the series wiring at the outputs.
MM with single cab:
switch cab and amp to 4 ohms.
MM with two cabs:
switch amp to 8 ohms use one output jack only!,
use the 16 ohms setting and connect the second 16 ohms cab to the slave
jack ( = 8ohms total)
Peavey:
both cabs at 16 ohms; amp setting 8ohms; assuming the peavey has its
output jacks wired in parallel.
HTH
Jochen
adam79
here's the link:
http://s273.photobucket.com/albums/jj209/adam_l79/Cabinets/. He said
that there are two inputs on the back, but couldn't recall whether it
was a mono/stereo panel, or something else. He said that he took the cab
to a tech, and that the tech said it was an 8ohm cab. The seller said
that he's been running it at 8 ohms, with just one speaker cable. In the
pictures, the two speakers are connected, so he's been mismatching the
impedance between the amp and cab (which can't be good for the
speakers). I posted the pictures is so someone could tell me which
impedance the cabs are wired for, and if there's any way the it could be
8 ohms (in total) depending how the wires are connected to the jacks.
adam79
>
> you are looking for the impossible. A Cab with 4 16ohm speakers can at
> no time have 8 ohms, assuming all 4 speakers are running. It' either 4
> ohms or 16 ohms. Period
>
I wrote that the reason I wanted the 16ohm option was to match it with
my other 16ohm cabinet. Running two 16 ohm cabs turn the total impedance
to 8 ohms.
jh
now that's something completely different. I obviously did not
understand correctly what you wrote.
Lord Valve
> The seller just sent me some pictures of the speakers in the cabinet,
> here's the link:
> http://s273.photobucket.com/albums/jj209/adam_l79/Cabinets/. He said
> that there are two inputs on the back, but couldn't recall whether it
> was a mono/stereo panel, or something else. He said that he took the cab
> to a tech, and that the tech said it was an 8ohm cab.
The "tech" is an idiot.
> The seller said
> that he's been running it at 8 ohms, with just one speaker cable. In the
> pictures, the two speakers are connected, so he's been mismatching the
> impedance between the amp and cab (which can't be good for the
> speakers).
Doesn't matter a rat's ass to the speakers. Won't hurt anything but your
feelings.
> I posted the pictures is so someone could tell me which
> impedance the cabs are wired for,
16, although it's obvious that one of the wires has become disconnected from
the terminal on one speaker.
> and if there's any way the it could be
> 8 ohms (in total) depending how the wires are connected to the jacks.
No. Period.
Look - this is turning into a cluster-fuck. You don't need any
magic Y-cords or rocket-scientist wiring schemes. The 212
cab is wired for 16ohms. Put it in parallel with your 412 box
and you have an 8-ohm load. Set your amp's impedance selector
to 8 ohms. Game over.
If you decide to make the impedance of the 212 box switchable,
you can switch between 4 and 16 ohms. You *cannot* get
an 8-ohm load from two 8-ohm speakers. However - you
can use one of these:
https://taweber.powweb.com/store/zmatch.htm
Not cheap, at $100, but a problem solver that
will do "impossible" matches.
I use one on my bench, for matching the outputs of all
the various amps I work on to my 8-ohm bench speaker.
Lord Valve
Expert (please obsess)
Stephen Cowell
> The seller just sent me some pictures of the speakers in the cabinet,
> here's the link:
> http://s273.photobucket.com/albums/jj209/adam_l79/Cabinets/.
Obviously worth more than 1000 words, in this case.
> He said that there are two inputs on the back, but couldn't recall whether
> it was a mono/stereo panel, or something else.
From the wiring, it's a parallel panel.
> He said that he took the cab to a tech, and that the tech said it was an
> 8ohm cab.
That was not a tech... thatt was a moron. They charge less.
> The seller said that he's been running it at 8 ohms, with just one speaker
> cable.
Then he's been running a low-to-high mismatch.
> In the pictures, the two speakers are connected, so he's been mismatching
> the impedance between the amp and cab (which can't be good for the
> speakers).
On the contrary, it's probably the reason you're getting the
speaker cab cheap... he's probably fried his amp, and now
thinks the speakers are the problem. World is full of these
folks... make sure that the speakers work before you buy
them, of course.
> I posted the pictures is so someone could tell me which impedance the cabs
> are wired for, and if there's any way the it could be 8 ohms (in total)
> depending how the wires are connected to the jacks.
No chance in hell. It's wired 16 ohms... you'll have to get
creative if you want different impedances out of it... I've
already given you the way to get all three.
__
Steve
.
The Repair Guy
>> He said that he took the cab to a tech, and that the
>> tech said it was an 8ohm cab.
>
>That was not a tech... thatt was a moron. They charge
>less.
Not always :-)
The Repair Guy
http://repairguy1993.netfirms.com/
adam79
>
> If you decide to make the impedance of the 212 box switchable,
> you can switch between 4 and 16 ohms. You *cannot* get
> an 8-ohm load from two 8-ohm speakers. However - you
> can use one of these:
>
> https://taweber.powweb.com/store/zmatch.htm
>
> Not cheap, at $100, but a problem solver that
> will do "impossible" matches.
>
I would buy that unit, but it only can handle 100 watts; my amps are 120
and 130.
If the guy never connected the wire to the terminal that's disconnected,
would it only power the one speaker, or would the circuit be incomplete?
Thanks for all the help,
-Adam
RickH
I wouldnt use a switch at all, just wire up two jacks where one is in
parallel and the other in series, then only use jack at a time. But
it will be either 4 ohms or 16 ohms (not 8 ohms). You could add 2
more jacks for each speaker separately, but to get 8 ohms only one
speaker would be used, or use as stereo with 2 amps. Switches are
noisy and dangerous in that it can be flipped while the speaker is
connected and running, jacks force you to be explicite and prevent
accidental mismatches.
adam79
speakers, and then a wire from each speaker to each of the jacks.. and
ten he only plugs the amp in one of the jacks. Does that make any sense?
Stephen Cowell
> He said that there are three wires. The one that connects the two
> speakers, and then a wire from each speaker to each of the jacks.. and ten
> he only plugs the amp in one of the jacks. Does that make any sense?
No. The speakers are wired series. We are not sure how
the jacks are wired, but there's no possible way to get
anything except 16ohms from the speakers the way they're
wired.
Get a picture of the jack plate and we'll have the whole
story. I'm betting they're paralleled.
You can plug in a speaker cord and use an ohmmeter to
measure the ohms of the cabinet... add 20% since this
is DC instead of AC. The 16ohm cab will measure around
12-14ohms. An 8ohm cab will measure 5-7 ohms.
A 4ohm cab will measure 2-4ohms.
__
Steve
.
adam79
> "adam79" <ada...@toast.net> wrote in message
> news:p7-dnVuQCIc6-qPW...@posted.toastnet...
>> He said that there are three wires. The one that connects the two
>> speakers, and then a wire from each speaker to each of the jacks.. and ten
>> he only plugs the amp in one of the jacks. Does that make any sense?
>
> No. The speakers are wired series. We are not sure how
> the jacks are wired, but there's no possible way to get
> anything except 16ohms from the speakers the way they're
> wired.
>
I tried asking him to take a picture of the wiring including the inputs,
but haven't heard back from him. Like I was saying in my last post, he
said that there is that one wire that connects the two speakers, another
that connects one speaker to one jack, and another wire that connects
the other speaker to the other jack. Then he just plugs his amp into one
of the jacks, and runs it at 8ohms. If he does send me the picture, I'll
post a link.
>
> You can plug in a speaker cord and use an ohmmeter to
> measure the ohms of the cabinet... add 20% since this
> is DC instead of AC. The 16ohm cab will measure around
> 12-14ohms. An 8ohm cab will measure 5-7 ohms.
> A 4ohm cab will measure 2-4ohms.
>
Unfortunately, I don't have an ohmmeter.
Greasehorse
Harbor Freight ... >$5