Should I trade SDA1c for RTA15TL?

F1nut

Here's an example of ultra high end amplification. The Musical Fidelity Nu-Vista with 130 peak amperes per channel. It is fully balanced dual mono with chokes and a separate power supply. It use sub-miniature tubes in the output stage. Very cool.

chrispyfur

Definitely ultra-high-end pricing, too!

Sitka

I'm very happy with my Yamaha A-S2200. No it's not up there with the Nu-Vista, but you get a lot of bang for your buck and plenty of high current. Spendy if you pay full MSRP, but big discount for factory refurb (that's how I went).

https://usa.yamaha.com/products/audio_visual/hifi_components/a-s2200/specs.html

ChrisD06

I'll add my 2 cents on this amplifier conversation. I see tons of people who don't fully understand amplifiers and such so I'll try to clear some stuff up.

ChrisD06

The Emotiva BasX A2 and Parasound Halo 23+ both produce 160W/ch into 8 ohms. This means both are going to provide the same level of volume, and same level amperage.

However, they will not have equal damping factor, nor does this indicate how clean the power is, or what the distortion will be like at higher volumes and wattage.

High current amps feel misleading as an amp which is "High current" but only 50W is not really high current. Sure, it might be into 2 ohms, but still, impedance and watts = voltage and amperage, so a 100W 8ohm amp and another 100W 8ohm amp will have the exact same voltage and current. This is due to ohms law and is literally scientifically impossible to change.

The Nu-Vista is going to get less loud than the aforementioned amps and will also provide less amperage at the same impedance. Keep in mind this changes as you go down in impedance.

The biggest difference in amps is the quality of the power. 100 sh*tty watts versus 100 $5000 watts will sound very different. Also remember damping factor prevents overshoot of the cone and is essentially how well the amp can control the cone.

ChrisD06

Another thing I'll say is it depends on the application. I'd personally go for a PA amp for home theater as they can provide tons of current and volume without distorting until you reach immediate hearing damage levels and they have pretty damn good damping factors..

For music I'd pick a "high current" audiophile grade amp. Sure it's not going to reach 130dB, but the quality of the music will be so much better.

ChrisD06

Pretty much this:

Do you want music or home theater?

If you want HT, either stick with an AVR or get quality PA amps. Let's be real, movies are supposed to be this 360° experience with explosions, not a high fidelity listening session.

If you want music, get an amplifier which has a good dampening factor and will provide your speakers quality clean power. Higher wattage is generally better if you're talking about ultra high end amps.

pitdogg2

So I'm going to politely disagree. These amps are 25wpc class A. So you saying they're not really high current? They ran these monster speakers in a larger auditorium at Axpona with such authority and enough current and bass to rattle the fillings out of your teeth.
Approximately 700lbs each and gigafarads of reserve power.

ChrisD06

@pitdogg2

Assuming they are 25W at 8 ohms, this would make their maximum continuous spec 14.1V RMS and 1.8A RMS.

If they are 25W at 4 ohms, this would make their maximum continuous spec 10V RMS and 2.5A RMS

At 2 ohms? Theyre 7.1V RMS and 3.5A RMS

Now the power they provide could very well be far cleaner than any other amplifier out there, and they might have a damping factor of, well for fun, let's say 3000.

Also, 25W can be enough to lose hearing with.

If those are 100dB sensitive, and you drive them with 25W and sit 5 meters away from them, and have them out a few meters from the walls, then at the full 25W you'll have around 103dB of sound, which is more than enough to cause physical pain.

If they were 140dB sensitive, per say, and you drove them at 25W and sat 1 meter away from each speaker and they were both in corners within half a meter from each wall, then the resulting sound is 153dB which is enough to not only immediately cause severe permanent hearing damage, but also actually rupture your eardrum.

So volume and loudness isn't a factor in how much current they provide.

Ohms law also tells you the current and voltage. I don't make the rules, science does. I'm sure back in the day a high current amp was 25-50W, but today we have 15A amplifiers, which is absolutely balls to the wall.

Gardenstater

I think when most people say "high current" they are talking in the time domain as in can the amp meet short term power/current requirements when the music demands it. RMS power/current @ impedance and clipping is a spec. for comparing amps but I think the Dynamic Headroom is better until they come up with something else. Seems that very few manufacturers provide it though. Also very few manufacturers provide @clipping Power ratings and can play games with the ratings at 8 ohms to make the amp seem better at 4 ohms comparatively than it really is. When reviewers do the testing they usually cut through that BS.

ChrisD06

By dynamic headroom do you mean peak power? Or is dynamic headroom like peak power but for longer than a millisecond?

pitdogg2

@ChrisD06 you really should go to Axpona and have in depth dicussions with some amp designers and builders. If you look at the first picture you see not one but 3 power cords that are needed to run this amp, Two 20 amp 1 for each transformer and one 15 amp for the logic board. Yes it was rated 25 watt mono into 8ohms and doubles down to 1/2 ohm. The designer and I had a long conversation about this amp. I cannot now give exact numbers, this class A amp rated at 25 watts can provide THOUSANDS of watts and HUNDREDS of amps of current due to the GIGAFARADS of capacitance in reserves ( IIRC he threw out number in the millions)

You are making broad definitive statements that in the big world are more fluid. I can show other LARGE less than 100 watt power amps that also provide hundreds of amps on current in one cap than a dozen stereo amps.
My point being your general statement of 50 wpc can't be considered high current is dead wrong.

Those speakers are 90db efficient.

ChrisD06

@pitdogg2 I wouldn't know how that amp works but I could tell you the output itself is going to be limited by the laws of physics.

The gigafareds of capacitance is likely a way of making the amp have a super high peak wattage in the thousands. It most likely charges those capacitors and uses the peak wattage a lot of the time but the actual continuous is still 25W.

THAT would indeed be a high current amp, especially because it goes down to half an ohm meaning that at 0.5 ohm it's continuous rating is ~400W, and chances are the amplifier is designed to compensate for the variability of speaker impedance.

Also, the larger the capacitor in capacitance, the better it smoothes the power and the quicker the drivers will respond to sound. Therefore having these absolutely massive capacitors would provide exceptionally clean and smooth power while also allowing the drivers to respond instantly, and because of that it is providing hundreds of amps.

There's also electrical aspects, such as the fact that current is DRAWN and voltage is PROVIDED. If you have a capacitor rated for say 10 gigafareds, you'd blow a fuse immediately if you didn't have multiple breakers and huge transformers to charge them up every start up. My RT3000p amps blew their fuses when the caps charged up once I repaired them (the fuse was half the size it should have been, never blew in normal operation tho!) because it tried to draw so much current to charge the caps so quickly.

Keep in mind the peak wattage is useless, however the ability to respond (driver wise) is very important, and would indeed use a lot of current.

If you can provide me the exact speakers and amps used there, I'd be more than glad to look them over and see exactly what's going on here.

But remember, ohms law; at a certain impedance, a certain amount of current is required to provide a certain amount of voltage. This can't be changes.

Gardenstater

ChrisD06 wrote: »

@pitdogg2


If those are 100dB sensitive, and you drive them with 25W and sit 5 meters away from them, and have them out a few meters from the walls, then at the full 25W you'll have around 103dB of sound, which is more than enough to cause physical pain.

Actually not so. Even if you played sine wave tones with 0dB dynamic range you would need a 50W amplifier and if you played fairly dynamic music at 15dB dynamic range you would need almost 1600W. If not it is going to distort on the peaks. Now maybe there is some amplifier rated at 25W RMS continuous that might be able to put out 1600W for those short millisecond peaks in the music so that there isn't audible distortion, as hard as that may be to believe. Is it cheaper to go with that or one able to do 1600W RMS continuous.....I don't know. Also, I could very well be wrong, but I think the problem with "Dynamic Headroom" is that it is a non standardized test, therefore up to the whims of the manufacturer. Big problem.

F1nut

The Nu-Vista is going to get less loud than the aforementioned amps and will also provide less amperage at the same impedance. Keep in mind this changes as you go down in impedance.

LMAO....ummm, no.

F1nut

The difference between a damping factor of 50 and 1000 is so infinitesimal it's a non-factor, except for the fact to achieve a high damping factor requires tons of negative feedback, which is never a good thing.

ChrisD06

@Gardenstater Okay so that is where the peak wattage comes into play like I mentioned. I'm POSITIVE the amplifier can provide tons of current when needed for a short period of time, but if you scroll down on the web page you're on, you'll notice that there's an ohms law calculator. Throw in the numbers I gave and give that a try, you'll see I'm correct.

The amplifier calculator you're using is essentially for ZERO distortion whatsoever without going into peak wattage. In the Pro audio world, you need to expect to have very dynamic tracks, so the goal is to get amps which don't distort one bit and can actually provide those peaks in the song cleanly for at least a few seconds, as the audio is live and $hit happens.



Here is my exact listening setup with my RT3000p. This image tells me that at a consistent sine wave, I need 31W of power to maintain 100dB. I can indeed confirm I can hit 100dB as I've measured with an SPL meter (and hearing protection), but I was playing music, specifically, resume by bbno$ except I turned off the subwoofers so I wouldn't blow them.

I hadn't heard any clipping through the hearing protection, and I'm pretty damn confident I'd have noticed considering how LOUD I got the music, but the dynamic range of that track isn't nearly as high as you'd expect. I'd say it's maybe 5dB average, meaning that I was using 99W of my Onkyo's total 100W (it was warm as hell after this).

So after looking at the Crown site and throwing in some numbers, I got this:



Essentially meaning to play resume by bbno$ at 100dB without distortion or very minor occasional distortion, I'd need 791W. This is using the listening distance I estimated from those speakers pitdogg sent, along with their sensitivity rating and what I'd consider to be "teeth rattling" bass volume of 100dB.

Can the 25W amps do that? Nah they'd blow up immediately, ohms law remember.

Now I'm more inclined to believe the speakers themselves were lower impedance than the 8 ohms the amp is rated for, but also that the teeth rattling bass pitdogg experienced was probably only around 85dB max.



Wow, would you look at that! Looks about right!

ChrisD06

F1nut wrote: »

The difference between a damping factor of 50 and 1000 is so infinitesimal it's a non-factor, except for the fact to achieve a high damping factor requires tons of negative feedback, which is never a good thing.

I'd disagree, but only at lower volumes, there's less wattage going to the driver so it's moving more 'loosely' so the cone could overshoot easier than at a higher wattage. Most amps nowadays have a high enough damping factor (200+) so it's not a worry anyhow.

ChrisD06

F1nut wrote: »

The Nu-Vista is going to get less loud than the aforementioned amps and will also provide less amperage at the same impedance. Keep in mind this changes as you go down in impedance.

LMAO....ummm, no.

Prove me wrong. A doubling in volume is a doubling in wattage, so to go up 10db from whatever the maximum volume of the Nu-Vista is, you'd need 260Wpc into 8 ohms, but the Nu-Vista is only 130W.

If it has 8000W peak it could probably handle 50dB louder than it's max for a second or two, and longer and you're lucky if that thing still works, once those caps drain you are f*cked.

F1nut

Prove you wrong? Happily.

Nu-Vista specs, greater than 300W into 8 ohms, 500W into 4 ohms, 1000W peaks into 2 ohms.

Amperes, 130 Amps peak to peak.

BTW, the amp I pictured is the PAS version. MF has another Nu-Vista power amp version, the PAM.

Specs:
Greater than 600W into 8 ohms, 1000W into 4 ohms, 1500W peaks into 2 ohms.

Amperes, 150 Amps peak to peak.

MF gear in general sounds sublime.

My suggestion, stop looking at specs and get out to some dealers and shows.

ChrisD06

@F1nut

Okay, you win 😂

I read your "130 peak amperes" as 130 peak watts. It'll absolutely get louder than the parasound.

Also yeah, I agree specs aren't everything, but specs can tell you almost all you need to know about how it drives the speaker. What you don't see listed on the specs is the amps 'voice' - how it handles different frequency ranges, and the detail it can provide.

Gardenstater

ChrisD06 wrote: »

@Gardenstater



Here is my exact listening setup with my RT3000p. This image tells me that at a consistent sine wave, I need 31W of power to maintain 100dB. I can indeed confirm I can hit 100dB as I've measured with an SPL meter (and hearing protection), but I was playing music, specifically, resume by bbno$ except I turned off the subwoofers so I wouldn't blow them.

I hadn't heard any clipping through the hearing protection, and I'm pretty damn confident I'd have noticed considering how LOUD I got the music, but the dynamic range of that track isn't nearly as high as you'd expect. I'd say it's maybe 5dB average, meaning that I was using 99W of my Onkyo's total 100W (it was warm as hell after this).

Snipping it down a bit to respond a little. One thing we need to keep in mind is that there is a difference between dynamic range and peak dB vs avg. dB. Dynamic range is the ratio of the very loudest sounds to the very quietest, which will be those that are just above the noise floor. In your example say that is, in fact, 5dB. When you set the volume on your system that you want to listen at on average, there will be peaks in the music that are above that and those will be less than 5dB (maybe 2dB or something) because it is referenced to the avg. dB. That's what your amp has to be able to create without distortion, whether it's a pro amp or audiophile amp. Yeah live music can have louder peaks relative to avg. though. Music isn't an exact science. The amplitude varies throughout and the frequencies vary also. Impedance of a speaker varies with frequency. You could play two completely different pieces of music that might have the same dynamic range, say 20dB and you could have the same average dB in your listening room but one could make your amp run a lot hotter than the other.




Also, sPL meters probably vary a LOT in their ability to measure very short term dB peaks and very low frequencies. The most expensive one for sale at parts express can read down to 31Hz and has a fast setting of 125ms and a slow setting of 1s. That's 8x faster. That's probably not even close to a pro model. pitdoggs ears + brain (and teeth?) are probably a pretty fast response.

That's all I got for now. I'm still learning about this stuff

ChrisD06

@Gardenstater

I'll add this: The small short peaks are handled by the amp in peak power, so no worries there.

The SPL meter was ~100dB average so take that as you will. Never playing my speakers that loud again because the tri-lams can't handle those volumes for more than a few minutes.

If you're still learning, I highly advise learning about Continuous power (wrongly labeled RMS), musical power (2x RMS), and peak power (4x RMS). It's important stuff.

F1nut

I advise you unlearn that stuff as it's not as important as you seem to think it is.

Gardenstater

ChrisD06 wrote: »

@Gardenstater

I'll add this: The small short peaks are handled by the amp in peak power, so no worries there.

The SPL meter was ~100dB average so take that as you will. Never playing my speakers that loud again because the tri-lams can't handle those volumes for more than a few minutes.

If you're still learning, I highly advise learning about Continuous power (wrongly labeled RMS), musical power (2x RMS), and peak power (4x RMS). It's important stuff.

Those are all the bogus ways that amplifier manufacturers have misled people by. Continuous is not bogus and RMS is just the mathematical way that it is expressed with a sine wave source.

audioluvr

As Bob Carver used to say " it takes 1.44 jigawatts to accurately reproduce the snip of a pair of scissors" or something like that. Ivan is dead on balls accurate when saying reserve capacity is the key to accurate sound reproduction and that's not the tequila talking either!

Specs are meant to sell. Like F1nut says, get out and listen to some high end equipment at a audio dealer or audio club meeting. Find out what sounds best to you and start saving up. Once you have a big wad of cash, let us know and we will be more than happy to help you spend it.

ChrisD06

F1nut wrote: »

I advise you unlearn that stuff as it's not as important as you seem to think it is.

Well, its important, because if you don't understand it you might think peak power is actually a useful measurement lol.

Continuous is what you should focus on, musical is more of a "could handle this uncomfortably for a few minutes" level, so the actually usable peak power, and the peak power is "1 millisecond burst before explosion" level.

ChrisD06

audioluvr wrote: »

As Bob Carver used to say " it takes 1.44 jigawatts to accurately reproduce the snip of a pair of scissors" or something like that. Ivan is dead on balls accurate when saying reserve capacity is the key to accurate sound reproduction and that's not the tequila talking either!

Specs are meant to sell. Like F1nut says, get out and listen to some high end equipment at a audio dealer or audio club meeting. Find out what sounds best to you and start saving up. Once you have a big wad of cash, let us know and we will be more than happy to help you spend it.

Oh yeah I have plans to go to tons of audio conventions and whatnot, I found a local audiophile group with 10,000 members which I joined a month or two back.

I'd be more than glad to ask for advice here. You guys can help me spend my money any time you'd want lol... except for the next month, as I just bought a CS1000p and TV.

invalid

@ChrisD06 some amps can double the power output when the impedance is halved and some can't, even though the rated RMS power is the same.

ChrisD06

@invalid Yeah I'm aware. A good quality amp generally can double the continuous wattage when the impedance is halved.

High current amps do generally go to lower impedance than a "regular" amp, but that's about it really. They do also draw tons of current on startup, but the actual continuous current draw is very small during operation due to the use of filter caps.