Re: Different Ohm Speakers

On Dec 29, 11:51 pm, "Fit E. Cal" <ya...@xxxxxxxxxxxxx> wrote:
On Dec 27, 4:25 pm, "Fit E. Cal" <ya...@xxxxxxxxxxxxx> wrote:





On Dec 27, 2:54 pm, jh <jh-audiop_NOS...@xxxxxxxxxxx> wrote:

Fit E. Cal schrieb:

On Dec 26, 6:14 am, jh <jh-audiop_NOS...@xxxxxxxxxxx> wrote:
Fit E. Cal schrieb:

On Dec 25, 5:50 pm, JD <b24warb...@xxxxxxx> wrote:
Freddie wrote:
Hi,
  I got an amp that can output to 8 or 16 Ohm speakers.  For the same
type of speaker, what would different Ohms do?
   Consider ohms figure the matching component of the system.
   The numbers should match 4 to 4, 8 to 8, 16 to 16, for the
   best performance and meet the power specifications. Mismatches
   are not favorable, results vary. Do your homework.
You do not manditorily have to match;
                                Amp                           Cab
"Hi into lo will go" Ex/ "( 8 ohm into an 4 ohm output jack)"
                                       Amp
Cab
"Lo into high won't fly" Ex/ "(8 ohm into an 16 ohm output jack)
 "Hi into lo will go
 "Lo into high won't fly"
:-) mvm
NO NO NO NO NO NO NO NO

NO

when will you ever learn?- Hide quoted text -

- Show quoted text -

http://www.21frets.com/speakers.html;

"...In the case of solid state amps, there will normally be a "Max
Load" (also called "Minimum Impedance") rating for the amp. The load
plugged into the amp should never go below the minimum impedance or
serious damage may occur to the amplifier. Maximum power will be
obtained when the speaker load matches the minimum impedance. It is
perfectly safe to use a higher impedance speaker load, but there will
be a corresponding drop in output power (i.e. an 8 ohm speaker load
will result in approximately half the output power of a 4 ohm speaker
load).
In the case of tube amps, it is best to match the speaker load as
closely as possible to the amplifier output impedance. In theory,
there is some small amount of mismatch that will not hurt the amp,
however, it is always recommended that you match the speakers as
closely as possible to the rating of the amp to avoid potential
problems. If there is a slight mismatch, it should be at a lower ohm
rating, not higher...."   "Hi into lo will go...Lo into high won't
fly"

marc,
first of all, i wrote my post some days ago from a different provider.
It just appeared today. This was before you made it more clear.
second, your little rhyme is a bit easy to understand - and the example
too. Is the "output jack" the amp or the input of the cabinet?

:-)

jochen- Hide quoted text -

- Show quoted text -

I think the semantics CAN get confusing too Jochen and in fact, many
months ago, Ether clearly pointed out the correct
way to relay this info. I just keep the little rhyme handy. To answer
your question; That's output jack is on the cab
and you are correct, as jacks go, it's actually an INPUT jack.
Laughing. OY! :-) Marc- Hide quoted text -

- Show quoted text -

To close out this issue, I just dug this up from some old posts;

"...QUESTION:

Can I plug a X-ohm cabinet into a Y-ohm head? Several answers are
provided: Rich's short answer, Miles's fairly short answer, LV's long
answer, and StratMatt's non-technical answer.
Rich's answer:

``NO!!!!!!!!!!!!!!!''

Short answer:

In general, you should match impedances. If you must mismatch,
mismatch in the right direction, but stay as close as possible. So
what's the right direction?

With tube gear it's better to have the speaker impedance lower.
Connecting a 4 ohm load to an 8 ohm amp may be OK, but connecting a 16
ohm load to an 8 ohm amp is probably not. Connecting a 16 ohm load to
a 4 ohm or 2 ohm amp is begging to destroy the amp. Running too high
of a load on tube gear can fry anything (and occasionally everything)
in the outputs, including tubes, transformers, resistors and tube
sockets.

With solid state gear it's better to run a higher impedance.
Connecting an 8 ohm load to a 4 ohm amp should be fine. Running too
low of a load with solid state will fry your output transistors, and
possibly more.

For more information, and to see when you might be able to get away
with impedance mismatching in the wrong direction, see LV's
explanation ("Long Answer") below and the AGA Technical FAQ.

-Miles
------------------------------------------------
Long Answer:

Actually, this thread pops up every month or so. It always winds up
the same way, too... the guys who know their stuff tell everyone that
it's not a good idea to run a tube amp at a higher load impedance than
it's looking for, and a bunch of other dudes chime in with "Oh Yeah? I
ran my (whatever) into a 16-ohm cabinet for years and it was rated for
8 ohms. What about that?"

Well, this is what about it: sometimes it'll be OK. Things are
different from amp to amp; playing style and signal type factor into
the equation, too. A player who plays loud, with lots of treble,
through an amp with high plate voltage (old Marshall, Orange, Music
Man, older Ampegs, etc.) is much more likely to wind up with arced
sockets (or worse) than a dude who plays jazz, with bassy tone,
through a Fender amp with 430V on the plates. The type of mismatch
matters, too... running an 8-ohm amp into a 16-ohm cabinet is less
likely to cause problems than running a 4-ohm amp into a 16-ohm box.
Running a downward mismatch will eat your tubes up a bit faster, but
if your amp has a good output tranny that's probably the only thing
that will happen.

Older Fenders have an extension speaker jack that's wired in parallel
with the main one; if you plug an extension cab into a Twin Reverb
(for instance) the load will be lower than 4 ohms, no matter what the
box is rated at. If the amp was going to be damaged by running a load
that was lower than the rated impedance, it stands to reason that
Fender would have wired the jacks in series. They didn't, though.

A downward mismatch is usually OK, or at least it's better than the
upward variety. I see a few Super Reverbs every year that have been re-
speakered by their owners; they go to a lot of trouble to find out how
to do a series-parallel hookup for the speakers because they "know"
that the amp should be running an 8-ohm load. All of a sudden, the amp
starts sounding like crap and blowing fuses. A Super Reverb wants a 2-
ohm load; running it at 8 ohms pretty well guarantees you'll be making
a substantial contribution to the Lord Valve Home for Lord Valve. (My
favorite charity.) Of course, there will be a few "experts" who are
convinced that SS amps and tube amps respond to improper loading in
the same way. They're wrong, no matter how loudly they may screech.

As far as solid state amps go, it's a lot more straightforward... if
you go below the rated impedance, you're going to smoke something
unless the amp has really good current limiting in the output stage.
Running a higher-than-rated impedance is just fine... you get less
power output, of course, but the amp will run cooler and last longer.
You can run a SS amp into an open circuit 'til the cows come home, and
it won't do jack to it. Run a tube amp into an open, and you'll
probably arc a socket (or worse) with the first note you play. It's a
really common failure; I do three or four a week, year in, year out.

-Lord Valve
---------------------------------------------

StratMatt's non-technical explantion:

I wanted to know the facts on this so I asked Mike Soldano when I
picked up my amp. After explaining it to me in detail (as he does with
all my tube amp newbie questions) I asked if this was an accurate way
to put it (in simple non-tech terms).... If the amp is designed for 8
ohm load and you are running it with an 8 ohm speaker load the
speakers are using 100% of the power that the primary winding of the
transformer is refilling to the secondary winding of the transformer.
Now if you run a higher speaker load like 16 ohms or more (or no
speaker load), since the resistance is higher than the transformer
expects to see the power leaving the transformer can't get out as fast
because its path is restricted by the higher resistance/impedance. So
now only 60% (for example- I'm just making up this number) of the
power has been able to leave the secondary wiring of the transformer
and there is 40% left in there. The primary winding of the transformer
now refills the 100% it always refills to the secondary that still has
40% in it. Obviously the transformer was not designed to cope with
140% of it's design load. Over and over this repeats with power
remaining in the secondary- and it keeps stacking hihgher and higher
until it gets so overloaded and hot that the insulation melts and you
get arcing and all that fun stuff.

Mike said this was a somewhat accurate way to put it in simple non-
tech terms.

So that is my understanding of it. And I am definitely not a tech!

-StratMatt...."- Hide quoted text -

- Show quoted text -
--------------------------------------------------------------
Shortest non-tech answer on record?

"Hi into lo will go
"Lo into high won't fly"
:-) mvm
.

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