Well Paul I can tell you an amp being heavy has nothing to do with slam..more dependent on the speakers.I'am using a 60 wpc Dynaco st120 modified more than 10 yrs ago by Van Alstine.It weighs roughly 18 lbs.Has more slam than a 300 wpc Mac I used to own.Me and a friend just refurbed the binding post,input jacks and changed the aluminum wire from the inputs to the pcbs with solid copper 18 awg wire.All for less than $20.00.The sound is weighty with clarity.Not a hint of grain or hardness.Very open and precise without fatigue.Have had to go back and listen to all my cds over again!For $120.00 investment not even my beloved and now parted Music Reference RM9 MK2 could go there! This one I will have for years to come.Price per performance I haven't owned a better amp!
I would go with the standard list of measured performance tests on the model of amplifier you are considering, conducted by knowledgeable technicians (this should eliminate most magazine reviews right there, either they simply don't measure, à la TAS, or else they seem to be a bit inconsistent from test to test and draw rather strange conclusions, à la Stereophile) and then I would go straight to listening to the damn thing with the rest of my associated equipment. Or you could do what some magazines have done in the past and use the price/pound ratio... I fear that no rule of thumb such as those you suggest is applicable. My own prejudice tends to favour heavier amps. The weight must surely come form a healthy power supply. So, I guess, conventional class AB and class A amplifiers would surely win this test. In the final analysis I am afraid you will have to trust your ears, you would be amazed at how little amp may provide great sound to your ears. The amp should never be looked at in and of itself, but as a marriage between it and the speakers it ill drive. No simple solution, I fear.
the bottom line is the current output capability the amplifier can deliver into your speakers, usually specified in amps continuously and peak measurements. A Rowland model 1 is only 60 watts but has nearly 60 amps current output.
Gmood1, I think what you are saying is a valid point, perhaps if we get a super sensitive set up, as in a completely folded horn type of loudspeaker set up, even a 1 watter amp will out do many heavy weight, wattage intense amps which might run a huge, heavy weight and inefficient speaker set up. Nevertheless, I keep hearing about these people who have these inefficient, and yet powerful amp set ups and they keep talking about the slam factor when it is being played. It intrigues me.
Mejames, does it mean that any Rowland amp, like the one you mentioned with out do another amp, with a higher Wattage and weight, with the same speaker? Have you compared this Rowland with other heavyweights such as Krell or Levinson?
Can there be a 20 watter or less than 100 watter amp, which will sound faster, more powerful than a 300 watt set up. Perhaps slam, as listeners perceive it might have more to do with how FAST the amp discharges current, as it is asked by the loudspeaker set up. Does this make sense Mejames?
yes I agree partially with your statement, the speed the current is transferred into the speaker would definitely tend to affect the perceived slam factor [the quicker the better] but if your speaker needs 30 amps for a given transient and your amplifier can only supply 10 amps I don't believe its speed would matter then. example if amplifier 1 deliveries the required 30 amps in 600 microseconds and amplifier 2 also delivered 30 amps but in 300 Microseconds [twice as fast] amplifier 2 would have more perceived slam definitely. I believe the Carver 4.0 has about 22 amps peak output each channel where the Rowland is 55 amps peak per channel and its their smallest amplifier. one listen to a high current amplifier will quickly teach you that watts are really irrelevant.
Thanks for your feedback Mejames. I will check into Rowland amps next time when I am for an upgrade.
Bipolars have more current delivery than Mosfets.
Separate power amp should have more slam since it's power supply is not being shared as in an integrated.
Krells "double down" in power but these type of amps typically loose high end sweetness for some reason.
All other things being equal (and they usually are not), a heavier amp will have more slam than a lighter one. In many cases, my experience is that a heavier amp is also preferred to a higher wattage amp. As an example, a pair of 200W Ampzilla monoblocs (about 58 pounds each) have much more bass controll than a bridged pair of 1200W Carver A760x (39 pounds each?). The reason is mainly the power supplies being used (about half the weight of the Ampzillas is the massive 2.5kVA torroid). The difference is most apparent on speakers that go below 4 ohm. Damping, feedback, etc can also come into play, but any good design has to start with a good (usually meaning heavy) power supply first.
Say Julian, how did you measure "bass control"? And, btw, you are a dealer of Ampzilla amps, are you not?
The older Carver M series amps, designed by Bob Carver, did not put put a lot of current and weren't as strong as their watt ratings suggested. But, the post-Bob Carver A series were high current amps designed for stability into any load. (I don't have an A-760, but I doubt it would have trouble controlling any speaker made.)
I was always curious about power supply design. For example, I have seen amps that happen to be very light, therefore, I must assume have similar LIGHT power supply design, one of this manufacturers being LINN. Their TWIN KLIMAX is so unbelievably light, and yet it seems to sport a very high wattage. How is this possible? Does this mean that the Linn amps cannot handle tough loads as the impedance drop?
What is the largest single transformer out there? 2.5 KV, is that the largest? If the transformer is too large, does that mean that it might be slow in releasing energy to the speakers? Just wondering....
Yes, I am an Ampzilla dealer as well as a few other brands. Trying to post helpful information on sites like this is somewhat difficult for a dealer like myself. If I say that I am a dealer, I get flamed for "advertising". If I don't say that I am a dealer, I get flamed for "trolling". No-win situation. :-( I used the Ampzillas just because that is the "high weight" amp that I am most familiar with and have had an opportunity to A/B against many others.
My un-scientific measure of bass control is the initial impact and controlled decay of low frequency instruments (i.e., the thump of a kick drum or the initial twang of an upright bass). On a well controlled system, the initial sound should be distinct followed by a resonant decay. On an uncontrolled system, the initial impact is less distinct and the decay is more rumble than resonant. I once tried a 3 watt SET amp with one of my 4 ohm speakers and "bloated" is the word that best comes to mind. In this extreme case, the bass was so "loose" that it was somewhat hard to distinguish individual bass instruments (the mids and tweater sounded fine).
The Ampzilla/Carver comparison was done driving a pair of Martin Logan CLSs (a VERY difficult load). The difference in control was not subtle and something a non-audiophile could easily detect (no golden-ear required). I, as well as my customer, were somewhat surprised at the difference. Had the speakers been an easier load, I do not think the difference would have been nearly as distinct.
Wattage is primarily a marketing term somewhat like an auto manufacturer stating how fast a car will go. If you have an easy to drive speaker (i.e, steady 8 ohms) then it has some realative meaning (think Hona Civic driving 80 down a flat highway). If you have a hard to drive speaker that dips down to the 2-ohm range, then it means little (think Honda Civic trying to pull a 5 ton trailer up a mountain. aaaaugh).
The 2.5kVA torroid in the Ampzilla is very large but is still smaller than the 5kVA+ and dual 4kVA torroids in the higher-end Krell amps. I am sure there are even larger in some of the "specialty" amps. Several of the mega-amps require dedicated 30A circuits (wouldn't want to know what that would do to an electricity bill. ouch).
The released current comes from the capacitors (another part of the equation) so a larger torroid should not result in a slower sound. Since a larger torroid can better feed the capacitor array, the sound should theoretically be faster. I am not an amp designer so I will leave further discussion on this subject to those more knowledgable than myself.
Well, Julian, you did not disclose up front that you are a dealer, and then you made a favorable comparison of something you sell. It isn't as unseemly as it might have been only because the Carver is out of production. And, of course, you didnt measure anything at all. How about the sound pressure level of the speakers driven by the different amps? I assume you matched them by ear, and probably don't realize that a .2 (that's point two) db difference in spl will make the louder of two components sound better.
Not a helpful post. A worthless post except for promoting the amps you sell.
Try Listening to the lastest BelCanto digital 2channel amp.
The relative weight of the amp in lbs now has very little
to do with its impact or weight in the bass.Whether the industry knows it or not producers of conventional analogue amplifiers
should now realise that their days may be numbered. While the current examples of digital amplifiers now available
are not perfect they do exhibit some characteristics that
conventional analogue amps are hard pressed to equal.An astonishingly large and transparent sound stage with very good focus in addition near matchless bass impact and definition.As with any other amplifier design if you go cheap on the power supply the bass and all other aspects
of the the reproduced sound will suffer.The first generation BelCanto had this mistake,maybe bean counters at work. In regards to the Clayton S-40,I belive it has a Class AB region that goes on up to 180 watts and doubles into 4 ohms.It is also a bipolar output design which gives it the ability to have a voltage swing nearly rail to rail.
It can use more of its total power supply voltage to reproduce music than a conventionally designed mosfet output based amplifier.One of the digital amplifiers' greatest
strengths comes from its typically 90% efficient utilization
of its power supply.At any given moment 90% of the stored energy in the power supply is available to accurately reproduce a musical waveform.Contrast this with an average
40% power supply efficiency for conventional amp.A digital
amp has another advantage over conventional amplfiers. Its output transistors are either all the way turned on or they are off.In the case of the high speed Mosfet outputs typically used they are turned all the way on and in their most linear operating region instantly.They are also exhibiting their lowest real world output impedence[ie.,before feedback] at all times.The analogue amp only
approaches this ideal when at full rated power,a conditon
that is rarely seen during actual use.Usually the listeners ears and speakers are in a region of non-lineariy when it occurs. In conclusion,it would appear that we live in a brave new Digital world and can expect a closer approach
reality in music reproduction in our listening room if we desire it. Happy Listening, _scotty_
Amplifiers that continue to increase their output with decreasing impedance loads will have more "slam" or "low frequency dynamic contrast" than those that employ current limiting in the output stage.
ie: 200wpc into 8ohms, 400wpc into 4ohms, etc...
This is especially true with loudspeakers that drop below 4ohms in the bass.
This almost always translates into a very large, heavy power supply and many high-power output devices per channel.($)
The "speed" of current delivery has nothing to do with slam or dynamic contrast.
Electrical current travels at virtually the same speed in all electronics.
In any event, the electrical rise time of a low frequency waveform is going to vastly outrun a massive mechanical device like a loudspeaker driver.
You can pretty much judge the quality of an amplifer by two criteria; the weight and the price.
Dear Snickelfritz,I have to agree that generally speaking
a higher price tag will insure a heavier box and a possibly
a more pleasing exterior appearance.Price and weight
however are completely unrelated to the accuracy of reproduction the amplifier can deliver.This is perhaps
one of the few hobbies where spending more money will not automatically guarantee a superior end result.What we are attempting to purchase is someones intelligence applied to solving problems related to successfully reproducing music accurately in our listening room.By spending more money
on a prettier and heavier box we may have accomplished nothing more than to line the pockets of someone smart enough to build the aforementioned box and convince us we need it. There are a limited number of geniuses in the world and all of them cannot be working in this field.The trick is to find one with some insight into the problem.
The urge to spend more money to insure a more satisfactory
outcome isn't to hard to understand it usually works.
Spend enough money and you can graduate from a leaky rowboat
to a X millon dollar carbon-fiber hulled racing yacht.
In this hobby money doesn't equal brains it usually means
you helped pay for an expensive marketing campaign in Stereophile or Absolute Sound.
Regarding Slam or dynamic contrast, a lower power supply
impedence is a key component in helping an amp to deliver
more accurate waveform reproduction at all frequencies but
taken by itself is no guarantee of anything.An amplifier
is the sum of its parts.Ignoring slewrate,settling time,and
symmetry when discussing amplifier design will lead to false conclusions. I hope this post will help clarify certain aspects of this discussion.Happy listening,_scotty_
Hehe, my tongue was firmly placed in my cheek when I made that comment regarding price and weight.
You're absolutely right; the best way to choose any high performance audio component is through extensive auditioning and research.
Bring a scale and a fat wallet with you just to be safe though.
AH HA Snickfritz, I'am on to you now.I guess we will have to discuss the relative merits of Digital vs Analogue scales now. Of course I like digital scales because they don't "weigh" so much and are easier for a lazy man to pack around to various "highend salons".