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Clarification on Amplication Needed

Discussion in 'Amps and Cabs [BG]' started by rickreyn, Jul 16, 2001.


  1. rickreyn

    rickreyn

    Jun 16, 2000
    Lutz, Florida
    I currently use a Carvin R600 with a SWR Goliath 4x10 bottom. I bought the amp after trying out an Eden amp of similar power (but much higher cost) together with an Eden 4x10 cabinet. I noticed a distinct warmness and sweetness in the Eden, which does not appear to be present in the Carvin. What in amps causes the differences in sound. Is it wattage, head room, parts? Further, what amps out there are known for their super warm sound?
     
  2. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    Wattage has noting to do with the final tone of an amplifier. In fact you just found this out yourself trying the two brands.

    Amp design is part science and part art. Good designers try to "voice" an amp to create a sound that is clear but warm, fat but not muddy, etc. Obviously, some do it much better than others. There are so many tradeoffs, all the way from the design of the power supply to the choice of components in the audio path that affect the final sound. Price is very much an issue, a designer may need to compromise sound quality to get the price low enough.

    This is why you can't choose amps just from spec sheets, you do need to go listen to them yourself.
     
  3. Brad Johnson

    Brad Johnson Commercial User

    Mar 8, 2000
    Gaithersburg, Md
    Boom Bass Cabinets, DR strings
    This should be at the top of the Amp FAQ list;)
     
  4. Another factor to consider is cabinet design. The same head may sound very different through different types of cabinets (even with an "identical" speaker configuration). I haven't tried enough different cabinets to speak definitively on the different tonal characteristics of various cabinet brands, though. I have noticed that Eden gear sounds very sweet, round, and warm. If that is what you are after, Eden should be considered.

    If warmth and sweetness are what you're after, I would consider the following amps/combos/preamps, etc.: Mesa Boogie, Ampeg, Aguilar, Kern (preamps), Alembic (preamps), and the new Fender 2x10 combo (very sweet indeed).

    I've been playing through an Aguilar preamp (DB659), a Mackie power amp (1400i), and an Eden 2x10 cab, although I should receive my new Acme 2x10 later this month. I love the warmth, flexibility, and power of the preamp/power amp configuration. it's expensive, but if you choose well, you will have components that will be valuable and useful for a long time to come.
     
  5. rickbass

    rickbass Supporting Member

    rick - I tried to understand this but got lost in the explanations I found. If you want to get ass-deep into this stuff, take a look at this discussion about the influences on amp sound - http://sound.westhost.com/amp-sound.htm . Brianrost and MikeyD may understand it because they know a lot more about amplification than I hope to understand.

    Known for warmth? An old Ampeg B-15 Portaflex is one of the warmest I've ever heard. Motown bass was recorded with it. I've used an Avalon DI in the studio and it is incredibly warm. Plus it is class A amplification.

    But as brianrost mentions, I just let my ear do the judging and leave the spec's/construction details to the techies.
     
  6. MikeyD

    MikeyD

    Sep 9, 2000
    I'm probably confused, but the only comparison I'm seeing is between:
    _ A. Eden head into Eden cabinet, and
    _ B. Carvin head into SWR cabinet.
    I have read generally that people think Eden's cabs give a "warmer" sound than SWR's. If what you're comparing is what I've guessed, then you're probably seeing a much greater effect due to speaker differences than amp differences. I personally think the Carvin head is plenty "warm". But perhaps Eden does a better job getting their SS design to work more like a tube amp. I don't know much about Eden heads, though. Anyway, I apologize if I guessed your comparison wrong.
    - Mike
     
  7. Brad Johnson

    Brad Johnson Commercial User

    Mar 8, 2000
    Gaithersburg, Md
    Boom Bass Cabinets, DR strings
    Guess I should have said this more clearly. I was talking about this post, not the original question, which was a very good one:D. I thought this post would be very useful in an FAQ:


    "Wattage has noting to do with the final tone of an amplifier. In fact you just found this out yourself trying the two brands.

    Amp design is part science and part art. Good designers try to "voice" an amp to create a sound that is clear but warm, fat but not muddy, etc. Obviously, some do it much better than others. There are so many tradeoffs, all the way from the design of the power supply to the choice of components in the audio path that affect the final sound. Price is very much an issue, a designer may need to compromise sound quality to get the price low enough.

    This is why you can't choose amps just from spec sheets, you do need to go listen to them yourself."
     
  8. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA
    Brian, you are only mostly right. Wattage does have something to do with the final tone of an amplifier.

    The tone of an amplifier changes as you push the power section. That why you typically use different EQ setting depending on the volume you are using. So, in order to get the tone that you want at the volume you want, you have to have enough power. "Warmth" is really subtle harmonic distortion. Different power ratings are going to offer this distortion at different volumes.

    This is noticable in SS amps. It is almost the most important thing to consider with tube amps.

    You are right. In theory, power doesn't effect tone, but the tone isn't worth anything to you unless you can get it to happen at the volume you are looking for. When you say "final" tone, I assume you are talking about usable tone. That's were power comes in.

    I absolutely agree that spec sheets are only a starting point. I wouldn't get too caught up in power. I used a an R600 for about a year and a half, It worked OK, but had to be the softest 600 watts I have ever seen. For portability's sake, I have switched to a Nemesis 210 combo. That 200 watt 210 combo is LOUDER than the R600 bridged into a carvin R410T. (it is supposed to be 500 watts bridged at 8 ohms) Perhaps this idea of Carvin cabs being inefficient was a factor, but it is noticably cleanly louder with half the speakers and less than half the power. Real Eden stuff is very powerful for its rating.

    Chas
     
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  10. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Hey Chas, regarding the first point, I think I have to disagree, at least for SS amps. I haven't found that a good SS amp, when used within its limits, sounds all that different at various points in its volume, *if you take the "loudness" effect* into account. It's well known that we don't hear the same way at lower volumes that we do at higher ones. That's the reason for those "loudness" switches on home stereos. I think the real reason you change your EQ at different volumes is that you hear the signal differently as it gets louder or softer. Thus it doesn't have anything to do with power per se but rather with volume. The situation is of course different with amps that are designed to distort relatively easily, like many tube amps.

    Regarding the R600 and volume, it's funny how experiences can differ. I posted elsewhere about how I directly compared an R600 with an Eden WT-400 through the same cab in the same space at the same time with the same EQ settings. The Carvin was *not*, in fact, quieter: it was noticeably louder than the Eden.

    Mileage varies indeed.
     
  11. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA
    I agree. But your qualifier of "used within its limits" supports both my point as well as yours. If you are basically leaving all things equal and rolling up the master volume, yep it sounds fairly even until you get close to max output, then things start muddying up on the bottom.

    The whole point of utility is to get your tone at the volume you want. So if you have to have the power to get the volume you need and still drive the amp "within it's limits."


    This isn't completely true. Power and volume are too closely related. When amplifying a signal, different frequencies consume power in different ways. It requires less power to amplify higher frequences. More for bass frenquencies. As you increase the output of a power amp, different frequencies consume the power differently. Sound is not measured in linear progression, but logrythmic progression. So, as the output is increased the frequency relationships change.

    Loudness on a stereo is simply an EQ preset that jacks the bass. It isn't that your ears can't hear bass, it is that the amp isn't pulling hard enough to reproduce it.



    I can believe this without question. I mentioned that my experiences could have easily been related to Carvin's cabinets. The more I read about them, the more I gather that they are quite inefficient. I have also gathered from this board and others that the Nemesis 210 is designed to be loud. It is a selling point for it.
     
  12. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    As I understand it, loudness is more often actually attenuation of the midrange (though I could be wrong), so that both lows and highs are exaggerated. And yeah, AFAIK it actually is a hearing thing: you really don't hear extreme lows or highs as well at lower volumes.

    It can't be that the amp isn't "pulling" hard enough. I'm not sure what that would even mean. At lower volume settings, the amp would actually have *more* power in reserve and thus in theory would be able to reproduce those power-hungry lows *better* than it does at high volume settings. (This BTW is the main reason bassists should use big amps--when you don't have to turn the amp up high, it has plenty of reserve for lows.) If hearing anomalies didn't play a role, the fact that an amp has more power reserve at lower settings would result in our hearing more bass at low volumes, not less. Which just isn't what happens.

    The reason your lows clip at high volumes is that the amp comes to the end of its ability to reproduce them correctly. It just can't give them any more oomph. That, if anywhere, is where your amp can't "pull" hard enough any more. At lower volumes, the situation, if anything, would be the opposite: your amp has much more power, relatively speaking, to spend on reproducing bass. So why don't we hear more bass at lower volumes? It's our ears, not our amps.
     
  13. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    I don't see how this follows. Sure, highs take less power than lows. But that in no way implies that frequency relationships *have* to change as output increases. Why wouldn't they simply remain proportional? (E.g., 50/300, 100/600, 200/1200.)

    What it does mean is that your lows will clip before your highs. But if you're not clipping, then I see no reason to think that that frequency relationship (and hence tonal balance) is affected. However, as I said, humans do hear differently at different volumes; my understanding is that this is pretty well agreed on in the audio world.
     
  14. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    Actually "warmth" can be best had when you have ZERO distortion. To me warmth is more the lack of shrillness or brittleness than something in and of itself. Think about it...if I have a very warm toned acoustic instrument and then mike it and feed it through a PA system, do I need the PA to DISTORT in order to capture that warmth? No, in fact a lack of distortion will convey the warmth better.

    Let me put it a better way, as long as the amp can deliver the volume you want without straining (i.e. you have sufficient headroom), wattage is irrelevant to tone.

    You could have a really awful sounding 1000 watt amp and a great sounding 100 watt amp and as long as the 100 watter will get loud enough for you, you can have great tone. Best exmaple I can think of is the Amepg B-15, it's well known for great tone...with only 30 watts of power! I can think of plenty of higher powered amps that can't match the beauty of a B-15, but they can get a heck of a lot louder :)

    Another good example is a pair of amps I own, they are the same brand and have similar features. One is rated at 250 watts, the other at 400 watts. I can't really tell the difference between the two on a gig because I don't play loud enough for the extra headroom of the 400 watter (about 2 dB) to make an audible difference.

    Anyway, back to the original question, looking at wattage as an INDICATOR of the tone an amp will have is quite useless.
     
  15. MikeyD

    MikeyD

    Sep 9, 2000
    Gotta step in here for a bit. The spectrum of audio passing through a good amplifier will not change much from one volume level to another, if it is kept within the amp's linear operating range (i.e., not clipping) and the amp's circuits are in good alignment.

    As Richard correctly points out, it is human hearing that determines how the balance winds up. Look up the Fletcher-Munson hearing sensitivity curves. Our hearing is least sensitive at the lowest and highest frequencies. Not only that, but the sensitivity curves themselves vary with sound pressure level at the ear! This means that the very same spectrum emitted by a loudspeaker sounds different to us in its tonal balance depending on the loudness at our ears.

    Sound is essentially linear. The sound pressure level we measure is a linear phenomenon (small-signal acoustic perturbations of the air). The reason we use a logarithmic scale to quantify sound pressure level is because the range of human hearing is astounding: a factor of 10 to the 12th power (!!) from softest to loudest intensity. We can hear vibrations of air one-trillionth as strong as the level that would hurt our ears. That is amazing. So instead of expressing sound measurements in straight numbers (lots of decimals), we use a logarithm (base 10) and call the result a "Bel". Then we call one tenth of a Bel a decibel. It is our ears that are nonlinear, not sound itself.

    Regarding tone changing by "pushing" an amp, this is a well-known phenomenon once the amp starts to go out of its linear operation range. For rock guitarists, this effect is valuable - which is why dummy loads are sometimes added to heavily burden the amp to achieve the desired tone.

    And my take on the issue of "warmth" is that a purely clean reproduction could be additionally "warmed" by *certain* kinds of distortion. Even-order harmonics, if at low enough levels, sound natural (like the overtones in a musical instrument), and probably fool our brain into thinking the sound is warmer. These are more typical of tube amps that are slightly overdriven. Overdriven SS amps, on the other hand, give odd-order harmonics which sound harsh and unpleasant.

    - Mike
     
  16. Brad Johnson

    Brad Johnson Commercial User

    Mar 8, 2000
    Gaithersburg, Md
    Boom Bass Cabinets, DR strings
    Hey Mikey, nice to see someone else into Nathaniel Phillips of "Pleasure"
     
  17. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Actually, I read something recently that suggested that that old even-odd distinction might not be quite the gospel truth that so many of us (me certainly included) always assumed it was. This guy Jon Blackstone, who makes a booteek overdrive pedal, claims that the tube amp distortion guitarists love contains a healthy dose of odd-order harmonics and these odd-order harmonics are essential to the sound:

    http://www.mindspring.com/~j.blackstone/dist101.htm
     
  18. MikeyD

    MikeyD

    Sep 9, 2000
    Well, if you mean you're a fan, too, then I feel the same! :) He is a really awesome and versatile funk bassist. He captures the best. Not that this is on-topic, but I really dig his slap in "Glide" (coved it myself in a band I was in recently) as well as fantastic muted BAD fingerstyle in "Take A Chance". Anyway - back to amplifiers... Thanks for the message!
    - Mike