Can you have too much power ?

[DaveVoorhis]

I'm having trouble getting this; so you're saying there was not a reduction in power going from 70wpc to 25wpc?

Given two hypothetical amplifiers, one of nominal 70wpc capacity and the other of nominal 25wpc capacity and both driven by relatively low level 0.5v signal, they might both send nominally 1 watt to their respective speakers.

The difference is that when driven to maximum volume -- which typically requires 2 volts on the input for consumer gear -- the 70wpc amp will put 70 watts into its speakers, whilst the 25wpc amp will put 25 watts into its speakers.

 

[Bodyblue]

 

[4-2-7]

Too many wpc was the root cause of the problem I had and I solved it by an easy combination. I lowered the wpc which then allowed me to increase the gain on the MR80 pretty simple I thought.

Actually the best thing for sound quality would be to have lower input gain and high output power. While with some components you can do either or and end up with the same output SPL for the over all system it's not wise. Boosting gain prior to the power amp can add distortion that the power amp simply amplifies out the speakers.

 

[motorstereo]

Does your preamp have line level settings for all your inputs?

I wasn't using the C100 I was using the C33.

To increase overall performance of the system with both digital and turntable inputs I decided to boost gain of the phono input instead of reducing the digital sources.

I do the same thing on my C100. There's still a gap but it gets things closer

Actually the best thing for sound quality would be to have lower input gain and high output power.

I needed the extra gain from the source to give the Erath enough drive to accomplish it's purpose. The most straightforward way for me to accomplish that was to lower the wpc woops I mean remove one amp which reduces the gain and had no effect on the wpc

 

[4-2-7]

I needed the extra gain from the source to give the Erath enough drive to accomplish it's purpose. The most straightforward way for me to accomplish that was to lower the wpc woops I mean remove one amp which reduces the gain and had no effect on the wpc

I understand one has to do what works for them with their equipment.

 

[SoCal Sam]

Actually the best thing for sound quality would be to have lower input gain and high output power. While with some components you can do either or and end up with the same output SPL for the over all system it's not wise. Boosting gain prior to the power amp can add distortion that the power amp simply amplifies out the speakers.

Especially true with digital players such as cell phones and i-whatevers that have miniaturized output stages which are analog signal amplifiers that have the same constraints as power amplifiers. Analog output stages can compress and clip just like power amplifiers. Lowering the gain in mini sources allows for greater signal swing in the line signal to which a powerful amp can apply more than enough speaker gain. I have also found that running my variable output CDP's at 50% gain yields the best dynamics. IME and IMO.

 

[whoaru99]

Ok then we'll just leave it at that. I did not reduce the power output by removing one amp I reduced the overall gain which in turn allowed me to increase the gain. There are zero situations where excess wpc would ever cause a problem........... anywhere
...

The sarcasm is only a hinderance to furthering your understanding of gain vs. power.

 

[I LIKE MUSIC]

To keep this simple.

For an 8 Ohm load, if we have 2 amplifiers with the same input sensitivity 0.5 volts and one is 10 watts and the other is 100 watts the 100 watt amplifier must have more gain.

Leaving power out of this for a moment, we are just going to look at the output voltage of each power amplifier.

The output voltage of the smaller amplifier will be about 8.9 volts and the output of the larger amplifier will be about 28.3 volts.
The only way that the larger amplifier can have a larger output voltage is if it has more gain. Remember we are only looking at the voltage.

What I see in this thread is that some believe that you can have more power without more gain and that is not the case because to increase the power for any given load, more voltage must be applied to the load or so says our friend Ohm's law.

One must understand the difference between gain and power. In the above example the larger amplifier has and remember that we are talking about voltage, about 9.5 dB more gain. Remember the input sensitivity for full power is the same.

So if there is a problem with the relative position of a volume control with respect to listening levels (the larger amplifier is too loud) for a higher power amplifier versus a lower power amplifier (all other things being equal) it is because there is more over all system gain (the higher power amplifier has more gain).

It seems that some that have posted do not understand that you can't have more power (more voltage output from the amplifier) without more gain, given the same input voltage.

Of course changing the load impedance will change the power for a given applied voltage but that is not the discussion here, just to prevent more strawman arguments.

Of course the gain of the power amplifier is just one part of the over all gain structure.

The output of a power amplifier does not turn into power until its output voltage is applied to a load.

This is all basic electronics 101.

 

[unie01]

Loving this! sub'd

 

[MannyE]

IMO no, just use it wisely and enjoy the headroom. I have 1000 watts per channel, it is dead silent and a audio agent of destruction in the wrong hands. If you treat your ears, speakers and neighbors with respect a high powered amplifier can be a prefect partner on the road to audio nirvana

Totally agree. I don't have the time and mostly the inclination to look up all the technical data which I don't do for a few reasons. The first is because I'm lazy. The second is because I don't want to be biased by information when I do a practical test and the third is because I don't want to form any opinions on data. Ever. Anything I comment on is because I have heard it and done it. And I have always liked how my systems sound when there is a big fat powerful amp in the chain.

This is not a slight on anyone that likes looking at data. I'm sure my methods are formed because I am personally bored to tears by taking measurements unless I'm setting levels and the thought of reading about them just zzzzzzzzzzzzzzzzzzzzzzzzz wait what was I talking about?

Especially true with digital players such as cell phones and i-whatevers that have miniaturized output stages which are analog signal amplifiers that have the same constraints as power amplifiers. Analog output stages can compress and clip just like power amplifiers. Lowering the gain in mini sources allows for greater signal swing in the line signal to which a powerful amp can apply more than enough speaker gain. I have also found that running my variable output CDP's at 50% gain yields the best dynamics. IME and IMO.

Yes! Depending on the device anywhere from 1/2 to 3/4 on the source volume gets me the best and clearest sound.

 

[I LIKE MUSIC]

All I'm trying to say is there's several members that believe one cannot have too many wpc. I disagree with that blanket statement. Yesterday's little gear swap showed that yes it is possible to have a problem with too many wpc just as easily as there can be too much gain

.
Gain and power go hand in hand. In terms of this discussion you can't have power without gain, source to speaker output.

The system with more power maximum power will have more gain, source to speaker output.

Trying to separate gain and power in the manner that you are is not correct.

This is basic electronics 101. If it is not, show me the math.

 

[GYMusic]

Yes, there is always a limit as to how much power speakers will handle. Most manufacturers state what that maximum power is. Speaker efficiency.

I was in a dinner conversation a while back where one person was bragging about how he was using a 1500 watt amp for his home stereo and was going to get a "bigger" amp. I said your speakers must not be very efficient if they need that much power. I mentioned the "3 dB rule" (which he had never heard of) where if he was going to get 3 decibels louder, he would need a 3000 watt amplifier. To this day, he still doesn't get it.

 

[motorstereo]

The sarcasm really only serves to reinforce your misunderstanding of the subject gain vs. power.

Correct and I edited it. My frustration is showing

 

[I LIKE MUSIC]

BTW, if a person has a 500 WPC amplifier that they to drive to full power connected to speakers that can only safely handle 25 watts of power it is it is very likely that the speakers will be damaged. The power handling capacity of the speakers in use (often somewhat in doubt) is the issue along with the correct operation of the system by the user, taking into account the capability of all parts of the system.

To protect the speaker the user could use a lower power amplifier with in it capability. But guess what...

This reduces the overall system gain in terms of input to output.

Again, it is just not about there being too much power. The over all gain structure comes into play in terms of the possible position of the volume control and its convenience of use and so on.

 

[motorstereo]

Thanks for the education guys; no doubt about it I was wrong on this subject and I'll admit it now. Hopefully there's some others that have benefited from my misunderstanding on gain vs. power to.

 

[4-2-7]

Thanks for the education guys; no doubt about it I was wrong on this subject and I'll admit it now. Hopefully there's some others that have benefited from my misunderstanding on gain vs. power to.

And that’s all it’s about, learning, not being right or wrong.

 

[Ken Boyd]

Having more devices in the chain does add the increased odds of introducing unwanted noise. I am referring to additional amplification such as extra phono amps, head amps, SUT's and such, at least I would thing that would be the case.

 

[E-Stat]

To increase overall performance of the system with both digital and turntable inputs I decided to boost gain of the phono input instead of reducing the digital sources. I am using HOMC cartridges with a SOTA Phono Head Amp, this is similar to a SUT but is adjustable. By adding gain prior to the signal going into the C100 preamps phono stage, the overall system output playing records is much louder, because the power amps can only do so much with a low signal.

As a student of the art, I've found it interesting to track changes in preamplifier design over the years and one area is with gain structures. In the pre-digital era, most line stages had at least 20 db of gain like Moto's C33. Then you typically added another 40 db for phono. Your C100 is a later design with the line stage lowered to 15 db, but retaining the 40 db for phono with a staggering 70 db for MC (almost too much). With the SOTA, I presume you are using the lower 18 db setting giving you a total of 58. Current Mac designs are like yours but lower the MC down to a similar 60 db. 75 db total should be enough for most applications!

Coincidentally, your combination is almost identical to that of my ARC SP20 with 14/58 which I find works great with my mid output Dynavector MC. In a sense, I have chosen my preamps over the past twenty years by finding good two stage designs with a total in the 70 db ballpark. My older SP9 MKIII was similar, but split the difference in a "more traditional" 21/46 way. Which didn't work as effectively with CD players and now, DACs.

As you are likely aware the SOTA is a John Curl discrete class A design. One of my all time favorites was his original Mark Levinson JC-2.

 

[restorer-john]

The lunchbox amp. Wow. Supposedly 200watts (100+100w?). So it has one Class AB 100w amplifier that maybe doubles its power into a paralleled additional speaker.

Even with a switch mode 200watt supply (which it must have for a total 4.7kg weight and judging by the distinctly Chinese look of the rear panel plate and voltage selector slide switch), pushing a class AB amp, they'll need a lot more heatsink area than a flat back plate. I see no ability to get rid of 40-60watts of heat on a continuous basis, letalone the 100w+ from the driver itself. Now if it was a PWM amp, maybe, but they state Class AB.

I smell an overly specified rat.

 

[I LIKE MUSIC]

Having more devices in the chain does add the increased odds of introducing unwanted noise. I am referring to additional amplification such as extra phono amps, head amps, SUT's and such, at least I would thing that would be the case.

And remember that the S+N to N (signal plus noise to noise ratio) can not be better than the first device in the chain.

We deal with this in the world of RF. In RF it is called the cascaded noise figure or signal chain noise figure.