Paralleled Amplifier Wiring
j r powell
I have a small stereo amplifier which came with two tiny 4ohm 3watt speakers.
I'd like to combine the two channels of the amp in order to drive one, slightly
larger, 8ohm 4watt speaker.
The amp is of the non-bridgeable type, so I assume parallel wiring would be
required - combining the two outputs together. I have read that small resistors
are required in parallel configuration, to enable proper current sharing between
the amplifiers, as without them the two amps would fight each other and
overheat. Can anyone tell me the correct values for these resistors, and where
they should be placed?
thanks,
jamie.
--
PS. If your name is Dave Plowman, do not reply.
Arfa Daily
"j r powell" <nos...@invalid.xy> wrote in message
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How very rude ... d :-\
Arfa
j r powell
"Arfa Daily" <arfa....@ntlworld.com> wrote in message
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Well... he follows me around usenet and trolls me.
Arfa Daily
"j r powell" <nos...@invalid.xy> wrote in message
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How very rude ... d :-\
Arfa
David Nebenzahl
> I have a small stereo amplifier which came with two tiny 4ohm 3watt speakers.
> I'd like to combine the two channels of the amp in order to drive one, slightly
> larger, 8ohm 4watt speaker.
> The amp is of the non-bridgeable type, so I assume parallel wiring would be
> required - combining the two outputs together. I have read that small resistors
> are required in parallel configuration, to enable proper current sharing between
> the amplifiers, as without them the two amps would fight each other and
> overheat. Can anyone tell me the correct values for these resistors, and where
> they should be placed?
Have you tried simply using a pair of 8-ohm speakers with the amp?
Chances are they'd work (less power, but shouldn't harm the amp).
--
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with the flaunting of well-defined muscle, wrapped in flags.
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j r powell
"David Nebenzahl" <nob...@but.us.chickens> wrote in message
news:4c478f88$0$2381$8226...@news.adtechcomputers.com...
>
> Have you tried simply using a pair of 8-ohm speakers with the amp? Chances are
> they'd work (less power, but shouldn't harm the amp).
I have, but then the audio output is too quiet for my requirements.
William Sommerwerck
>> with the amp? Chances are they'd work (less power,
>> but shouldn't harm the amp).
> I have, but then the audio output is too quiet for my requirements.
I'm not being sarcastic -- but how do you know that paralleling the outputs
will produce a significant increase in power? Ignoring the very pertinent
question of how to do this /correctly/, the most you could get is a 3dB
increase, which is plainly audible, but hardly a large increase.
j r powell
"William Sommerwerck" <grizzle...@comcast.net> wrote in message
news:i283ln$l13$1...@news.eternal-september.org...
A small increase is better than nothing.
William Sommerwerck
>>>> with the amp? Chances are they'd work (less power,
>>>> but shouldn't harm the amp).
>>> I have, but then the audio output is too quiet for my requirements.
>> I'm not being sarcastic -- but how do you know that paralleling the
>> outputs will produce a significant increase in power? Ignoring the
>> very pertinent question of how to do this /correctly/, the most you
>> could get is a 3dB increase, which is plainly audible, but hardly
>> a large increase.
> A small increase is better than nothing.
No, it isn't. Not when it requires a lot of work, and will be only slightly
audible.
"Forget about the whole thing." -- The Lady from Philadelphia
j r powell
Fitting resistors is hardly a lot of work. I just need someone who knows their
stuff, to answer my original question.
David Nebenzahl
> "William Sommerwerck" <grizzle...@comcast.net> wrote in message
> news:i285k5$s14$1...@news.eternal-september.org...
>
>>>> I'm not being sarcastic -- but how do you know that paralleling the
>>>> outputs will produce a significant increase in power? Ignoring the
>>>> very pertinent question of how to do this /correctly/, the most you
>>>> could get is a 3dB increase, which is plainly audible, but hardly
>>>> a large increase.
>>
>>> A small increase is better than nothing.
>>
>> No, it isn't. Not when it requires a lot of work, and will be only slightly
>> audible.
>
> Fitting resistors is hardly a lot of work. I just need someone who knows their
> stuff, to answer my original question.
So, William, what is the correct answer here (value of resistors)? I'm
curious now, too.
William Sommerwerck
>>>>> outputs will produce a significant increase in power? Ignoring the
>>>>> very pertinent question of how to do this /correctly/, the most you
>>>>> could get is a 3dB increase, which is plainly audible, but hardly
>>>>> a large increase.
>>>> A small increase is better than nothing.
>>> No, it isn't. Not when it requires a lot of work, and will be only
slightly
>>> audible.
>> Fitting resistors is hardly a lot of work. I just need someone who knows
their
>> stuff, to answer my original question.
> So, William, what is the correct answer here (value of resistors)? I'm
> curious now, too.
I don't see where I'm obliged to provide an answer, but here's what I
believe, to the best of my understanding...
Assuming that both channels have the same output impedance, and the output
levels are closely matched, then (if the outputs are directly paralleled)
there will be /no/ current flow from one channel into the other, and the
total amount of current that /could/ be delivered will be doubled. But if
the load impedance remains the same, there will be no increase in current
flow and no increase in volume level. You would need a speaker of half the
impedance to gain more power.
I think that's correct. Anybody want to agree or disagree?
tm
Well, you sure don't want to use resistors to match it. Any gain would just
be
converted to heat.
ASSuming the impedance's were the same and you paralleled the outputs, you
would need a 1.5 to 8 ohm transformer to match the speaker.
But I agree with the first premise, it's hardly worth the 3 dB you might
gain.
T
--- news://freenews.netfront.net/ - complaints: ne...@netfront.net ---
stra...@yahoo.com
> "William Sommerwerck" <grizzledgee...@comcast.net> wrote in message
The increase will be 0. Changing from 4 ohms to 8 will cut the power
in half because the voltage stayed the same and the current cut in
half because of the impedance change. Paralleling the amps raises
current capacity - which you don't need - and does nothing to increase
the voltage. In fact, your resistors will reduce it slightly. You need
a bigger amp.
G²
Phil Allison
"j r powell"
>
> I have a small stereo amplifier which came with two tiny 4ohm 3watt
> speakers.
> I'd like to combine the two channels of the amp in order to drive one,
> slightly larger, 8ohm 4watt speaker.
> The amp is of the non-bridgeable type, so I assume parallel wiring would
> be required - combining the two outputs together.
** The only way to go here is to use "bridge mode".
Parallel wiring of the outputs is not only 100% useless it will almost
certainly destroy both amplifier channels.
> I have read that small resistors are required in parallel configuration,
> to enable proper current sharing between the amplifiers,
** Complete crap.
There is such of lot of it on the net you know.
.... Phil
William Sommerwerck
know why.)
Regardless, if the output levels are closely matched, one amp /will not/
pump current into the other. But to gain any increase in power, you'd have
to use a lower-impedance speaker.
There is also the possibility that, even with the levels matched, the amps
might not "like" looking at each other.
"Buy a decent amplifier that delivers the power you need." -- The Lady from
Philadelphia
stra...@yahoo.com
wrote:
> I made a mistake -- for some reason I assumed this was a tube amp.
(I don't
> know why.)
>
> Regardless, if the output levels are closely matched, one amp /will
not/
> pump current into the other. But to gain any increase in power,
you'd have
> to use a lower-impedance speaker.
You are VERY WRONG on this.
> There is also the possibility that, even with the levels matched,
the amps
> might not "like" looking at each other.
Virtually a certainty.
> "Buy a decent amplifier that delivers the power you need." -- The
Lady from
> Philadelphia
This is good advice.
G²
William Sommerwerck
>> not/ pump current into the other. But to gain any increase in power,
>> you'd have to use a lower-impedance speaker.
> You are VERY WRONG on this.
Why? You haven't changed the output voltage. If the amps are solid state,
their source impedance is much lower than that of the load, so there
wouldn't be any significant increase in current flow (that I know).
Allodoxaphobia
<- snippage->
>
> Assuming that both channels have the same output impedance, and the output
> levels are closely matched,
.. and, assuming both outputs are _exactly_ in phase,
> then (if the outputs are directly paralleled)
> there will be /no/ current flow from one channel into the other, ....
Jonesy
whit3rd
> I have a small stereo amplifier which came with two tiny 4ohm 3watt speakers.
> I'd like to combine the two channels of the amp in order to drive one, slightly
> larger, 8ohm 4watt speaker.
> The amp is of the non-bridgeable type,
The power limit might not be the amplifier output stages,
but the common power supply. So, you'd just connect
to the left channel and ignore the other.
Alternately, you could transformer-couple and put the
left and right channel outputs in series (not parallel), to
get good drive into an 8 ohm speaker. Transformers,
though, aren't cheap. Doing this only gains you 3 dB,
it's scarcely worth the effort.
More efficient speakers (two of 'em, not one) is the
preferred solution if you don't like what you've got.
stra...@yahoo.com
wrote:
If the output voltage is _slightly_ not matched, each amp will attempt
to correct it and push large currents into each other. HEAT. BANG.
G²
GregS
You forgot to give the power.
From quick reading of posts, to get more sound you can put 2- 8 ohm
speakers in parallel which will give 6 db increase over one
8 ohm.
You can bridge, say put 1-2 ohm resistors in series
with the speaker and use a bridge transformer on the input.
If you gave the minimum ohm spec of the amp, I could be more specific.
You also did not specify the output
type if the amplifier. Are the channels allready bridged ?
greg
Phil Allison
"Greg Shithead"
> You forgot to give the power.
** It in the very first line of the original post.
You pathetic imbecile.
... Phil
GregS
Reading.........
I have a small stereo amplifier which came with two tiny 4ohm 3watt speakers
Still reading.........................................
How tiny?
What color ??
greg
Phil Allison
>>
>>>>> You forgot to give the power.
>>
>>
>>** It in the very first line of the original post.
>>
>> You pathetic imbecile.
>>
>
> I have a small stereo amplifier which came with two tiny 4ohm 3watt
> speakers
** Wot a pathetic moron....
... Phil
Michael A. Terrell
Phil Allison wrote:
>
> ** Wot a pathetic moron....
...and you'll never change.
--
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have a DD214, and a honorable discharge.