Atmaspere ;
In your statement above...
"If the speaker has a low impedance at low frequencies, you are going to have to provide the current that making power into that load demands by law (Ohm's Law- no pun intended)."
Is this opposed to providing voltage , which will also increase the power ?
|
Something quite basic , that has not been touched upon here , is the configuration of those added watts .
Watts are a result of the amount of volts and amps going through a device . Amps are the driving force of the volts which do the work . It is the amps that will drive the volts through a tough crossover network and into a power hungry woofer .
You can have the same amount of watts with 2 amps (with higher voltage) or 20 amps (with lower voltage). But the 20 amp watts have the ability to do much more with a tough load . This is why some amplifiers will double down as the ohms decrease within a speaker , such as 100 watts into 8 ohms , 200 watts into 4 ohms , 400 watts into 2 ohms and so forth . Where as a low amperage amplifier may do 100 watts into 8 ohms and 125 watts into 4 ohms etc.
And yes , it usually costs more to make high amperage watts than high voltage watts .
Just a though . |
I was not addressing the speaker characteristics . Neither was the original poster ! He was asking about watts .
Of course the speaker will make a big difference in the final output . You can't get 20hz. out of a speaker designed to only put out 80hz. I consider that a different topic for discussion !
I was merely trying to show that there are different watts capable of doing different things .
Bob;
We have a control over the configuration by our purchasing decisions . When one has a tough load to power , doesn't one seek out the amps that will power that load ? There are amps that have a high current output and there are amps that don't ! This is why some amps will power that tough load and others will not , even though they 'seem' to have the same amount of power.
By your way of thinking one could assume that a 100w HT
receiver , such as HK , Pioneer , Onkyo , Denon and etc.(high voltage watts) would have the ability to drive a 1 ohm bass load with a 4th order crossover network of an 80db. speaker . I think that you probably know better than that .
As to your example with Bryston and Parasound , some companies list there ratings conservatively and others exaggerate . Which makes it even tougher to pick the right amp for the job ! That is why we do not use generalities and company spec sheets but specific brands and models . |
Let me try , I could be all wet here , it's been a very long time !
Volts X Amps = Watts , the basic electrical power formula if I remember correctly .
Now you can get 100 watts with 20 volts and 5 amps - 20v X 5a = 100w , high voltage watts .
And you can get 100 watts with 5 volts and 20 amps - 5v X 20a = 100w , high amperage watts .
Correct ?
Further , really going out on a limb here ... I believe that the differences in these two examples is achieved within the power supply , ie. the output transformer , and the way that it is constructed .
I believe that the transformers' size and configuration will govern how much amperage is produced with a given amount of voltage . It takes a larger/heavier transformer to make big amperage as opposed to a smaller/lighter transformer to make small amperage .
Isn't this the reason that a 5.1 A/V receiver , with its smaller transformers , can weigh in at 25lbs. and a 2 channel amp , with larger transformers , can weigh in at 50lbs. while both putting out 100 watts/channel ? The A/V receiver will give you anemic sound under a tough load whereas the 2ch. amp is capable of giving sound with much more drive and authority .
These transformer primary and secondary windings , and their proportions , are the reason that when you cross the speaker cables on that receiver you get a light show and probably trip a breaker or blow a fuse . Do it on a welder and you can melt metal together . Both driven by a 120v/20a circuit .
Now I understand that the speaker will require X number of watts to operate that tough load . But it is the configuration of those watts that determines how that tough load is handled .
Am I making any sense here ? Kindness counts !
|
Atmaspere ;
First off...I would like echo Bob's accolades and offer our thanks to you for your patience and diligence in this thread ! You are one of a very few gentlemen that would not only offer some input but also stick it out for a myriad of questions as we try to learn a thing or two . A true industry leader !!!
I understand that it takes both voltage and amperage to make watts (E x I = W). And that you can have different kinds of watts ie. "voltage source" and "current source" depending on the impedence of the amp .
Can you tell us if the 'ratio' of volts to amps is the same for both types ? IOW do the watts from a "voltage source" amp generally contain more volts , than the watts from a "current source" amp ? And conversely do the watts from a "current source" amp generally contain more amps , than the watts from a "voltage source" amp ?
Or...
As you stated , "It is true that some constant voltage amplifiers can deliver lots of current." Would this be an example of a ratio difference ?
Thank you . |
"Bob_reynolds, we *do* have some control over that 'configuration' of voltage vs. current. It has to do with the output impedance of the amp."
The rest of the story !
Ya , that is the part that I was eluding to but missing in my feable attempt !
Thanks Atmaspere . |
Atmaspere ;
Do these characteristics ,
"the amplifier ideally is low or zero loop feedback and class A"
apply to all types of amplification ie. tubes , SS and digital ?
What gives tubes the "punch and body" at lower volumes ? |
Atmaspere ;
One more answer , please , to Mapman's last response !
Thank you . |
"The fact of the matter is no transistor amplifier sounds right on 4 ohms, nor does any tube amp. If you want to really see what either one is really capable of, you need a higher impedance -16 ohms is nice- to do that."
Given this , why don't we see many 16 ohm speakers ? |
Atmasphere ;
So synergy is the only constant and wattage takes a backseat to circuit design for both amp and speaker . Is this a correct summation ?
Up for some more questions ?
Are global feedback , negative feedback , loop feedback , and zonal feedback all names for the same thing ?
How close to zero should we get ? I noticed that you offer up to 2? of feedback adjustability on your amps .
And what is your opinion of the use of 'autoformers' to achieve the higher speaker resistance that the amplifier will see ?
Thank you . |
Yes , compatible may be a better term to use .
Not necessarily using the autoformer for problem solving ...
"The fact of the matter is no transistor amplifier sounds right on 4 ohms, nor does any tube amp. If you want to really see what either one is really capable of, you need a higher impedance -16 ohms is nice- to do that."
but trying to achieve maximum potential within a present 4 or 8 ohm setup , inexspensivly..."Its all about money". Could we hear an improvement with this usage ? And how would a 16ohm speaker operate on an amp that has 4 & 8 ohm speaker taps ?
We all have read where a higher db. rated speaker is an easier load to drive for lower powered amps such as SET's .
Where does the decibel rating figure into the rest of this discussion ? For instance would the higher resistance of a 16ohm speaker be able to counter the detriment of an 85db. rating ?
One heck of an informative thread here !
Thank you . |
Atmasphere ;
Yes we are off topic but there is sooo much info here I would hate to break it up into two threads !!!
If you would address the db rating issue , that I asked about , I would consider this discussion closed .
I would also consider this thread one of the best primers here for the budding hobbiest ! You have dispelled some myths and misinformation for me and probably others as well . I would like to think of this thread as a "one-stop-shopping" area for those who want to learn how to do it right thus saving a lot of time , aggravation and money !
Sort of "System Building 101" !
I was planning on sending others to this thread when they had questions that were addressed here .
So , please can I coax just a little more out of you here ?
Thank you . |
OUTSTANDING !!!
Thank you so much for your time and expertise ! |
