Test 50 Pound 800 Watt Amp vs 17 Pound 6400 Watt Amp
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- Опубліковано 28 чер 2024
- Modern power amps are a fraction of the size and weight of older amps and have much higher power outputs. One of the aspects that has changed significantly is the methods used to specify output wattage as well as the way amplifiers deliver that power. Here is a test where I show and we can hear the differences between older power amp watts and newer power amp watts.
Band : Riarosa
Song: Better Than Nothing
Produced by: J.T. O’Neal
Mixed by : Brian Edwards
Mastered: Voyager Mastering
• Riarosa - Better Than ...
/ @riarosa6083
open.spotify.com/track/2GFUih...
riarosaband?igs...
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www.soundtools.com
00:00 Introduction
01:49 Test Setup
02:43 Crest 4801 Lowest Freq Test
03:27 Crest 4801 Highest Freq Test
04:16 Powersoft T904 Lowest Freq Test
05:40 Powersoft T904 Highest Freq Test
06:44 Crest Power Test
08:14 Powersoft Power Test
09:04 Short Term Power Test
10:39 Hear Power Differences wit Music
12:14 Hear 400 Watts vs 540 Watts
13:39 Outro
I am so glad you did this demonstration! I have been using professional sound equipment for over 40 years and own about 50 Crown amplifiers, all of which are old technology. I suspect that is why my back hurts so much. When Crown came out with their later amplifiers and started to talk "burst power" instead of continuous RMS, I talked to their engineers and was told that in some circumstances where low bass was needed, the old systems were actually better. For example on the Katy Perry song, Dark Horse, there is a very long tone, around 60 Hz. that would send any burst type amplifier into low power mode. In addition to professional sound, I use amplifiers in industrial situations, driving test systems where continuous sine wave power is needed. One great way to determine the real, continuous power of an amplifier is to look at the power cord and the rated input power. You can never put out continuous power greater than what you put in. Recently I was looking at some amplifiers very similar to Powersoft and noticed that the maximum input power was only around 1000 watts despite several thousand watts of "rated" output. My Crown MacroTech 5000 has a 3/4" diameter rubber cord! Thank you so much for the clear explanation of amplifier power! According to Crown engineers, a priority in their designs is weight and size because road crews no longer want sore backs.
Very cool and wise and yes, continuous power out needs a big cord and breaker.
Yes, burst power specs don't translate well to extended low frequency output.
That said, newer amps like the powersoft will run on 120, 208, or 240 single phase or 3 phase, and when run at higher voltages the cable sizes can be thin and the amps tend to have increased duration burst power.
In the amps I tested, the crest put out 400 continuous and the PowerSoft put out 540 watts continuos so even though smaller and lighter, the powersoft still has more output than the crest in continuos measurements as well, so that is another aspect to consider.
@@DaveRat I can see using a high burst power for mids and highs after my RG dynamic expander since it can add up to 20 dB. If I was going mobile again I would also consider running modern amplifiers but I am all but retired and just have a nightclub with a 10,000 watt (Continuous RMS) sound system. In general, sound equipment today is so much better than that of the past. I have a pair of Altec subwoofers that require a fork lift to move and my JBL line array subs blow these away.
Agreed
"You can never put out continuous power greater than what you put in."
Say that again for the kids in the back. It's amazing how many people don't understand this, ultimately continuous power is a simple thing to solve for, and it allows you to cut through the marketing BS to see what an amplifier actually produces, power wise because they might be able to lie on the box, but they cannot lie on the spec sheet and retain UL certs.
Of course, we are way beyond that elementary concept for beginners.
We are looking at the ability of amps to offer peak power profiles that more closely parallel the power needs of the music being reproduced and the ratings of the speakers that amps are connected to.
The video shows 2 amps with similar RMS outputs and one amp that has a peak power 6db above the RMS.
This peak power allows louder playback withoutsignificantly increasing ac power draw.
And I demonstrate and you can hear how much louder the amp capable of processing clean 6 db peaks is. In the video.
Or maybe watch the vid?
There's many people that are advanced in their field but can only explain things to their peers, but there's very few people that are so advanced that they can make very complex subjects easy to understand for people that are not on their level.
Dave absolutely belongs in the latter category.
Thanks you so much for your videos Dave!
Thank you and honored!
Albert Einstein once said: (and i'm paraphrasing) If you can't explain your knowledge to a 10 year old... then you don't truly understand it yourself.
I do find that researching and doing these videos helps me understand things better and I learn something every time
@@DaveRat That is the most amazing and awesome statement, Dave. My pride in my rat tattoo has only grown over the years. Thank you for what you've done and what you continue to do.
Thank you Dave! You rule! Saw a message on FB and will open and read soon.
This is the first time I've noticed the low frequency tones at the end of a video. Really gets the subwoofer going.
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I love that you found a way to accurately record and demonstrate the difference with music, amazing!
🤙👍🤙 ha! Yes I'm glad somebody spotted that. The coolest part of the demo is being able to listen to exactly what the amp is putting out at a reasonable volume and not just look at pictures and graphs.
It's important to note that speakers also handle power in a similar way: they tolerate high bursts but might burn up on long sustained signals, which is why the Powersoft amp makes much more sense in every way. If you hook up an old iron amp to a speaker, you're either giving up headroom for bursts or your amps will be able to put out way too much sustained power for the speakers. This is especially true for modern high density subs, with a lot of power in (relatively) small cabinets and drivers with high Xmax.
True
Dave, thanks for other free MASTER CLASS.
The noise traces in the powersoft for me are inadmissible, looking for hearing healt and technical dignity.
This demonstration stand at same level of your others.
Dont stop!
Cheers from Spain!
Yes it's all about selecting the right tool for the job. And thank you
This is an awesome way to demo burst Vs. continuous power. Thank you Dave !!
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Very cool demonstration as always. Thumbs up, keep up the goodwork Dave. Thanks for the knowledge.
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This is fascinating but I also appreciate the amount of editing you did to this video to make it clear and easy to follow.!
Awesome and thank you! Yeah these things do take some time to do. This was actually two separate videos initially and I merge them into one to solidify the concept
I love these unique experiements you do to get to the bottom of what's really going on. Thank you!
Awesome thank you!
Your passion is so refreshing.
Thank you and awesome!
You just answered so many questions I've had for years. Bravo, Maestro!
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Another excellent detailed explanation. Thank you Dave!!
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Impressive comparison test, Dave. Thanks, man.
I also appreciate that you presented it in a way that I understood. There was a lot of information digested and I didn't get any brain gas. 👍😁
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Dave, thank you for taking the time to do this!
Awesome and thank you!
Really great test, Dave!!!! very nice! Thanks for your work! :-)
Thanknyou
Wow, Dave. I can say that this time you honestly schooled me, and I am grateful. Awesome demonstration.
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Dave, I met you years ago at Coachella (I was FOH for OMD) and was absolutely over the moon with your system and your support. Then, recently, your videos came up in my recommended list and I started binge-watching. I love your videos. Just wanted you to know.
So cool! Great to see ya here Charles and thank you!!
Dave, I love the insight you provide to the production community with all of your videos. I remember your early PA systems with Pearl Jam. I was touring with Spin Doctors and met you NYC. Loved your enthusiasm then and how it continues today.
Awesome so cool and yeah I remember doing spin doctor's gigs! Thank you and great to see you still rocking!
So stinking cool! Awesome way to show this data.
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That was a brilliant video Dave! I wish I had your knowledge!
Well you now have some and cool cool David!
Thanks for the demonstration. Nice song!
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Great and interesting video. The low frequencies and short sweep at the end of the video is a nice touch. Subscribed.
Welcome and thank you!
@@DaveRat Thank you for your kind reply!
Thank you for joining and hope you get some cool and useful info here
its crazy seeing this stuff tested. Make sme think deeper in my audio rabbit hole
Awesome video Dave. Been thinking about these sorts of things with my own system. Wicked Demo. Hope to see more creative videos like this. :)
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The sub sweep at the end 😂😂Great video!
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I used to work at a small sound and lighting store. We sold QSC amplifiers, and our bread and butter line was the PLX with its switch-mode power supply and Class H topology. We compared it on a pair of JBL dual-18s to a Crest 8001 and found that, despite similar power spec, the Crest amp had a lot more "girth" in the bass. They both seemed about as loud, but the bass from the Crest seemed more... Powerful? Your demonstration of the Powersoft's peak power may explain what was going on. Perhaps the PLX amp's power supply could not sustain those power output levels, so we got a big punch from the kick drum, but any loud, sustained bass notes fell off, whereas the Crest amp was able to sustain that output.
Despite these sound quality differences, we still only ever took the PLX amps out for shows because they weighed 25 lbs each to the 8001's 80 lbs.
PLX amps always seemed to have a reputation for not being ideal for bass. They were early innovators of SMPSU's and they have come a long way since then!
I had the same experience with the qsc when comparing the Crest 7001 but it wasn't the PLX it was an older amp
We AB compared The sound and the crest was punchy and full on the QSC kind of popped with no follow-through.
I've tested numerous amplifiers over the years using a pulse and a block of four double 18 bins and had a wide variety of results.
The first lightweight amp that performed well was the lab group in 6400
Now when comparing a Crest 7001 to a power soft X4, which of course is rated much higher power, The power soft dominates the 7001 and makes it sound broken.
I think if you compare usable output level of a 1000 Watt Class D app to 1,000 w conventional amp, The conventional amp will win with anything that has low end to it.
But if you compare the amps using metrics like equal weight equal cost, equal power draw from the wall, watts per pound, equal heat dissipation, and even Fidelity per dollar spent if you can measure that, you will find that the class D amp will win in nearly every way.
I would say as a rule of thumb you want two to three times the wattage out of a Class D amp than you would want out of a conventional amp when used for subwoofers.
@@DaveRat It's an interesting topic. Since by design modern switching amps should have a much much lower internal resistance than their analogue counterparts, they should absolutely destroy the older amps in terms of power output. I have always heard however, but never actually seen until now that power soft are clearly limiting the current thought the PSU. What surprises me even more is this is a 4ch amp driving one channel. I was under the (incorrect) assumption that the available PSU power was available for all channels, so for example on a 4ch amp driving 1ch to the rails would be able to do so without current limiting. What's also interesting is it seems there is a recovery period as at @10.22 that power doesn't come back immediately. I wonder how it would behave with 4 ohm or even 4 channels at 4 ohm.
They spec that out and list symmetrical output power with all channels driven the same and asymmetrical output power with two of the channels driven 6db lower level as would happen with bi-amplification.
I believe this symmetrical output is 1600 watts per channel all channels driven and the asymmetrical output is 1800 watts on two of the channels with the other two channels driven at 450 Watts.
For my test I didn't really focus on getting the exact power measurement and I'm sure there was some power drop in the long extension cord I had running the amp reducing its output
I love what you do!!!
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Great job dude.
Thank you 👍🤙🤙
I did not taked my time to learn about decibels, after this video i did a quick read. You have a good video and provides good information. It is allot easier to make + 3dB by adding another speaker if the amp can take higher loads. Building a amplifier with 200 watts in 8 ohms is many times harder and expensive than a amp with 100 w / 8 ohms. Thank you for your video.
That is less true in modern class d amps where watts are cheap and building high voltage amps is not any harder.
But yes, with older amps, it was useful to run lower impedance loads to get maximum amp power.
I bought a Chevin Research A500 power amplifier back in '97. It's only 250W (at 8 ohms) per stereo channel, but while I could pay a LOT less for a large transformer based amplifier, the physical difference in weight of the Chevin Research switch-mode amplifier is what sold me! (Note: I'm aware that Switch Mode amplifiers also have "transformers" as a part of their circuitry)
We have a load of 4 channel Chevin amps that sound great and work well Good amps
Chevin amps have a switch mode power supply with a linear output stage using mosfets instead of bipolar output transistors. Very fast slew rate and extended high-frequency response. Great sounding amps.
been waiting for amp testing, do a whole bunch more
Will do.
Great demo. Real amps, Real figures, A/B switching. Thats what we need. Well done Rat.
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that song is so dope!!!! this is like the best college course
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I had the great pleasure to apprentice under Walter K. Dick (jbl, Alesis, Event, etc.) who has a great story about rated “watts”. There are so many ways to measure wattage output (peak, rms, blah blah). One day he was telling me that everyone originally agreed on a standard until the marketing team at Carver introduced their ratings that everyone tested and found they were inferior, so they started calling them “carver watts”. I don’t know for sure, but I think that was the origin of “peak watts”.
Well car Hi-Fi had a big impact on those super high pequat ratings from small amps that didn't actually deliver more sound. Then cheap PA kind of jumped on the bandwagon. If my memory serves
Thanks Dave
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You should also look at the difference in power draw as well. I think that would be a very valuable metric to consider. Great video!!!
Yeah, I will ponder an efficiency vid
Great video.
🤙👍🤙thank you
The Crest amps just sound great. I used a rig that was all Crest power and it had very musical low end, tight and punchy mids...nice easy to listen highs. Beautiful sounding with a ground stacked EV festival rig. 20 subs and 6 mid hi per side.
Yes, agreed
Ah, that feels good............... 🔈🔉🔊
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i enjoyed this... they have these super small class D for under $50 that run on aprox 40Volts. the other weekend we powered a 400Watts Cerwin-Vega sub for our backyard darts games and it sounded just as loud as with the old and heavy Crown amp. now it makes sense :)
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Current draw is also very interesting to test in a setup like this. Comparing different amps with sine wave signal at different frequencies and then music type signal plotted against AC current. Interesting to know when your venues might not have quite the power source you would like to have.
Very true and that's a test for a different day. Though I can say that when we switched from conventional amps to Class D for a large format sound systems, our current draw from the mains dropped significantly and output volumes increased.
That said the differential between average current draw and peak current draw increased
Very cool video. I can understand why some speaker manufacturers use class-D for the woofers and A/B for the tweeter.
Yes I can understand that and also modern class D amps from top end manufacturers have quite impressive sound. The new L-Acoustics amp that is two rack spaces and 1600 watts per channel and 8 ohms with 16 channels is amazingly impressive in its power output, power density add fidelity
even Logitech did that in the Z-Cinema lol
Hey Dave, Great setup and demonstration!
I remember you did a video demonstrating differences of amp clipping by nulling the signals. Do you think there is anyway to hear the differences in amp types by summing the signals from both the crest and powersoft?
I’m just fascinated by how some genres of music might have different current draw characteristics and how that might change what sort of amp would be suitable. i.e. A class D amp struggling to keep up power with a really thick grungy guitar or a compressed edm track
Love your work!
I would like to do that I would need to find a class D amp that has no digital processing as the digital processor would cause a time offset preventing the null.
I almost recall doing something similar to that with amplifiers I will ponder it
Great video, glad you did this demonstration of the differences between class D and old school amps. I think the old heavy weight amps have suffered badly in recent years due to misinformation about output wattage on the newer class D amps. People see an old amp rated at 400 watts output and think it's no good because they have seen some Chinese-made amp in the local electrical store with a claimed output of 5000+ watts. But if you look round the back of any of these amps you can bet you will find a 2 amp fuse on the mains input. If it's drawing so little current from the mains then where is it finding all this extra power for the 5000 watts output? Meanwhile if they powered-up the old school 400 watts amp, it would blow their ears off.
Having said that I was quite impressed that the Powersoft amp went down to 3 Hz. Certainly a well designed Class D amp with good build quality and decent components would be the one to choose if you needed to power some earthquake inducing subs.
Yes the same issue existed with class A B and older amps, crappy amp sounded bad no matter what they are rated at and good amps performed well.
How many times did I carry Phase Linear 700's and Peavey CS-800's in and out of gigs? Wow. That was a long time ago.
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Yeah, about 1982. And "Daryl Martini the Cosmic Weenie" was on-air for WBCN Boston. My word, yesterday was a long time ago now. 🔈🔉🔊
@@TriAmpHiFi "I was so much older then, I'm much younger than that now."
Incredibly insightfull..... or inearfull.
Brilliant .
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Hey Dave, I'm an audio tech with a background in electrical technology and it was so refreshing to watch this video. I have done tests like this for that exact reason. I have found that class D is better toward the lower frequencies but I much prefer class H for mids and highs. As we saw in your test there is limited frequncy bandwith when amplifining high freqs. and distortion can be quite ear fatiguing as well as damaging to the drivers. A cool load thest is hot water heaters paired to the appropriate impeadance and submerged in water or oil. Starp that to your amp and observe the voltage just under clipping to get a reasonable real world RMS power. Resistive load as opposed to inductive but it will show you what balls the amp really has and what your AC mains needs to be in order to sustain the output.
Keep up the great work. Much appreciated.
Cool, am building a new load with 4x 200 watt and 4 x 250 watt 8 ohm loads on a 1/2" thick aluminum plate. Mat sandwich a second plate on top which should give me the ability to power test in known precision resistive.
Also I have a dead dishwasher that I will pull the heating element out of and see if that will give me a second option.
Looking to do a test of actual power delivered using music.
So I'm thinking of a combination of the loads plus a playlist and scope to right before clip while monitoring load temps over time with a thermal camera.
Also monitoring input current to the amp
Determine which amp heats the load faster.
See if I can gain visible insight into various amp efficiencies and capabilities.
That should provide interseting results...I'm looking forward to the thermal cam images!@@DaveRat
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Thanks!
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It's nice being able to hear the relative maximum loudness differences between the amplifiers, and that the 300 millisecond duration of full power is plenty for most music (apart from ghetto rap and some EDM, but then it may protect the speakers not having that sustained sine wave potential anyway). Cranking them up through speakers would be in most cases too loud to notice much difference unless in a field and the speakers are tough enough to handle both without power compression.
Agreed.
Smashing
Man i wish someone demo'd that for me when i was a student, that was great
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Great Video. 😃👍♥️
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GREAT VIDEO. tq
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Dave is the Most Reliable, Fact Based Audiophole Reviewer out there Some people whoe Review amplifiers and preamplifier, and Speakers are Ghost hunters and Alien Hunters, who hires 3 Writers to make their channel sounds good. DAVE knows the Physics of Audio Stuff, Speakers , HIfi Amplifiers , Dave is the real Golden 👂 Ear. Always delivers Facts , not hype
Epic and thank you! I do try very hard to share info I think will be useful that is unbiased
COOL!
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Class D amps are amazing. Especially for subs where you really need the power.
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Hey, @DaveRat ,
I'd love to duplicate this kind of testing to look at my QSC amp, and compare it to some of the receivers and AVRs I have laying around, in the hopes of finding the one that's best as an amp for speaker testing (so I can avoid impedance dependent frequency response).
Where do you have your oscilloscope probe attached? I'm assuming you just have the probe running in parallel with the 8ohm load (ground to negative on the amp output, probe on the positive on the amp output).
And same goes for your multimeter measuring the voltage (and after a calculation, power). Is that also in parallel with your 8ohm load?
Thanks, and fantastic videos man!
PS. The QSC RMX1450 I have is driving a DIY sub in my home theater. Good for the long, deep rumbles, but you've definitely got me thinking about getting a smaller class H or class D for some burst power!
Hey Dave! Thanks for the demonstration. so due to the more linear continuous output of this older analogue gear could one say, that it is better suited to drive subwoofers for dance/soundsystem music with long standing basslines like dub or dub influenced music? In my imagination this powersoft amp would basically build a kind of long transient.
For that to be true you would want to have equal amounts of usable output capability. For the amps I tested the old app was 400 Watts and the new amp was 540 Watts, so the new app was louder for continuous power which would benefit the dance systems and it was louder for peak power which would benefit the dance systems and all systems. And it was smaller lighter and more efficient generating less heat.
That said if you were to get aClass D amp rated at 400 Watts and compare it to an older app also rated at 400 Watts
The older app would be preferable but cost more, be larger, generate more heat, use more power from the wall, and weigh more
Cool cool... I still have a pile of old school amps, they sound great but, my back gets sore just looking at them.... Shame there's no Vz5000,s anymore, they were terrifying beasties
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It's amazing how much more efficient the new amps are. I'm a big fan of the new light amps, with a mobile rig, the old iron just doesn't make much sense for me
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🤘😉👍great video... I love my old crowns power base 1 and 2 but I rather use the digital ones still crown. K2 Itech and Mtech.
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Great video,
might be worth comparing the costs of these amplifiers, crest produced much more powerful amps than this back in the day for probably the same or less cost than a powersoft will cost you now? I would be interested in seeing a crest 8001 of another seriously heavyweight old amp 5000vz vs powersoft T602. Are we getting better value vs power / listening quality from newer amps ?(of course they are much more practical and have more features) but in a situation such as an install where weight is less of an issue what advantage would upgrading to a more modern amp be if we are just concerned with quality and output power.
Not as extreme as the cost of hard drives and computer memory, The dollar per watt cost of audio power amps has dropped tremendously over the years.
As has dollar per pound. What has increased is dollar per rack space.
Switching to modern high quality amplifiers can add new life to an older sound system by increasing available power to the speakers as well as enhanced protection of the speakers utilizing the multiple programmable limiters and compressors available in many of the top amps.
This will also increase reliability and reduce power draw from the grid as well as lower the heat dissipation and reduce overall size.
I have done several upgrades to clubs where I replaced full racks of older amps with just a few new class D apps and made those older sound systems sound better than new.
48kHz internal processing in the Powersoft, hence filtering at Nyquist.
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That’s what some very enterprising manufacturers liked to call “music power.” It’s perfectly valid in almost all cases. Almost. EDM subwoofers beg to differ.
Agreed and the question is, would an EDM subwoofer perform better on a Class AB amp rated at 1,000 Watts RMS that can do 1200 watt peaks or perform better on the Class D amp also rated at a 1000 watts RMS but can offer 4,000 w peaks?
The class D could be lighter, smaller and draw less power from the wall due to efficiency and deliver the same power to the speakers RMS and offer the peaks as well.
I don't disagree that having longer duration power delivery is important for more consistent signals.
What I debate is whether Class A B amp is actually beneficial or just a larger more powerful yet smaller and lighter class D amp would do equally well or better
@@DaveRat The last question is the pondering point. Doing a dubstep gig a dozen years ago on JBL 4880a with I Tech 8K power we could smell the VC heat at ~500W/ch continuous. Peaks on dub are mostly a matter of performer fader position choices, so from a genre standpoint the smaller, lighter, tastes great, less filling Class D amp *should* suffice in my example. For a rock show with lead kick drum, the time it takes the output power of the class D to taper down isn't an issue until the double kicks; having that 6dB of extra output for 250ms is just right. Big stiff power supplies are big, heavy, and expensive making that extra transient headroom even more resource consuming. Your demo of the Crest just on the edge of clip sounds very compressed compared to the PowerSoft at the same long term (clip) point. That makes me think the folks who advocate for the Crests have rosier memories and less painful backs than myself.
I can fully relate to the skepticism of the claims from many amplifier manufacturers.
Clearly audible issues will often not show up in specifications.
At rat sound we used to do tests when any amplifier company came to the shop by running their amp bridge mono into four 16 ohm rat subs wired in parallel.
Then we would use a pulse test and compare their amp to the amplifiers we were using which were Crest 7001 at the time.
This test would clearly divulge any issues with the various amplifiers.
I remember a QSC amp rated at 4000 Watts sounded like a wet tire compared to the 1800 watt Crest 7001.
The lab group in FP6400 was comparable but only with three subs in parallel bridge mono. Adding the fourth sub sent the amp unstable.
Putting a PowerSoft X4 on the subs clearly was more powerful and clear than the crest 7001.
Developing a test that allows you to easily hear the difference is wise and I probably take that for granted more than I should as I have much experience in that realm.
I will try and do a video down that line of testing so people can develop tests that work for them
One of the best demos I've seen online! Ironically, modern EDM music (trap, dubstep, and drum & bass especially) has much more sine wave content, especially in the subwoofer range, compared to a live band. Burst power ratings should be almost meaningless for that type of sine wave bass music. With sine waves having a 3db crest factor, I imagine modern DJ music has a crest factor closer to 6db at most whereas a live band is easily closer to 12db+... Getting the rights to play music on UA-cam is not the easiest thing in the world, but I wonder how this exact experiment would look/sound with an actual EDM bass music song vs just a raw 50hz sine wave... I imagine the Powersoft amp may be a hair louder but I would expect the difference to be less than it was in this experiment using a track that was recorded with live musical instruments... So cool to see this either way!
If you do the math there a 6DB crest factor would mean that a 500 watt amp would need a 2000 w peak because 6dB is four times the power.
The apps that I measured show the class D having more continuous power and more peak power and fully capable of meeting the specs you propose
@@DaveRat Yes, I use all Class D. The weight savings and efficiency is a must in the modern era. I remember when I had boat anchor QSC RMX and Crown CE2000s amps as a kid when first getting into audio. My how time flies when you're having fun! Thanks as always, Dave!
Awesome thank you Josiah!
Funny thing about crest factor is that it's affected by bandpass filtering. Guess what every loudspeaker on earth is, even before you add extra processing? A simple sealed box is a second order high pass filter, and that alone can make your 6 dB CF content suddenly look like 9 dB... What actually hits the speaker is rarely quite so dense. That is of course, unless you've not brought enough rig for the gig or don't have amps with sufficient peak voltage swing to handle the 12 dB CF side-chained kickdrums that sit on top of the rolling sub...
Interesting
I would love to see you test the Admark K30 (which is what we use on our subs) They claim 3000W @ 8 ohms. They are killer little amps, but I'd like to see them benched to know the exact numbers. I'd be willing to send one to you, if you'd be interested.
So on the new one is like the signal is passing through some sort of expander, that's a form of distortion. The old one on the other hand was very impressive to me, staying almost flat for that wide range. Also the new one has not a good reconstruction filter, the noise may be outside the audible range but it's not guaranteed to be inaudible as it can be distorted back into the audible spectrum, by the speakers for example.
The new one is not an expander.
It's more like a limiter where it lets all of the peaks through but the longer duration signals get compressed
That said with normal music nothing gets compressed it just is louder lighter smaller and more powerful
The powersoft t904 is a class D type amp. They do not have any heatsinks on the transistors because they are switched on and off entirely. Therefore don't need much space, and make more use of the power coming from the supply. If you put 1000 watts in you get 998 watts out !
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nice video - Crest all the way for me. Quality over Quantity.
I do love the old crests and also when we switched from Crest to the modern class D amps our sound systems sounded dramatically better.
That said when we first started switching to lighter weight amps many years ago, we tested everything and found some amps were rated very high wattage and sounded like crap and other ones sounded much better and there was no consistency. I believe that's still the case as it is with the older style amps as well.
What a well thought out test rig.
I was surprised you could see the switching power bleed thru so much on the Powersoft.
Agreed
Personally, I like the Class AB amps better, BUT I can understand why the Class D amps are popular. If you've got a BIG rig, it's much less mass to move around.
Efficiency as well I think. Large class D amplifier clusters can get louder for the same power consumed vs class AB.
They each have their advantages. Crusty amps can deliver really beautiful fast transience at very high levels and can also struggle with long extended bass notes. Class a B can sound smoother but they tend to fart and you need a lot of back muscle to move them around, they generate a lot of heat and use up a lot of power from the wall
Dave is the bomb! I love watching his stuff!
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I had to take out the IEC power connectors and hardwired cords of the proper guage into all my amplifiers. I haven't had an amplifier failure since then. The IEC power connectors are THE number one cause of amplifier failures as they are only meant to carry 10 amps. The 20 amp IEC only carries 15 amps. The power lights don't dim on my amplifiers any more. If you don't believe me, put a volt meter between one of the lines and the corresponding connector in the amplifier and drive it at full power - 20 to 30 volt difference and drop between wall receptacle and power switch inside the amplifier!. I have 3 dozen Cerwin Vega CV-5000 amplifiers rated for 5,000 watts each. They came with 20 amp IEC's - i could not get the amplifiers to put out anything past 2,925 watts bridged at 4 ohms. When I hardwired 8 guage power cords into each of them - 6,600 watts bridged at 4 ohms, pulling 60 amps peak each amplifier.
Cool experiment! I'd love to know what internal voltage these amps are running.
I.E. is the powersoft/crown voltage or current limited? Id guess the powersoft is running very high voltage internally but relies on capacitors to provide the current. When the capacitors empty out after a second the amp clips.
The powersoft has built in processing that is set to protect the amp and prevent clipping from ever occuring
Nice job. I would like to know how long those typical spikes in music are. A 250 ms burst is 25 cycles at 100 Hz. Did the class-D amp meet its peak power rating in those short bursts?
A full 1/4 second is pretty long for a kick or snare spike. Also, it's important to know that the duration of the burst power rating increases when the amps has better input power.
I was running it in worst case scenario with it on a longish 16 ga ac power cord plugged into a wall outlet. The amp can power from 120, 208, 240v on single phase or 3 phase ac. Better Ac will increase the pulse power durations.
Also the amp harvests back EMF from reactive loads like speakers, so there's even more energy available in real world use.
The amp works great in real world but I would not use this tiny singe rack space 4 channel amp as the optimal subwoofer amp.
I would get it's beg brother, the X4 that does 5000 watts per channel x 4 in a single rack space
Wow that powersoft has a pretty funky & fuzzy waveform - as you said; likely switching frequency psu doing what they do - It’s supposedly out of hearing range…
But can it be accumulative ? Can it be compounded under certain conditions ?
It's not ideal and be better if it wasn't there. You look closely there's actually two frequencies floating around on those waveforms. One appears to be in the 48K region and the other is maybe 500k or something.
Being that the amp is the last thing in the signal chain and nearly all audio high frequency drivers are incapable of reproducing anything over 30k, and the audio cabling we use does not transmit those high frequencies very well, and the impedance of the voice coils tends to go very high for high frequencies pretty much blocking those out completely anyway.
Additionally class D amps have pretty strict low pass filters at 22k or so so they won't regenerate those frequencies if they get back into the input somehow.
And yes it'd be cool if they weren't there and also the amount of electronics and filtering needed to make sure they're not on the output is probably more detrimental than leaving them
I am such a geek. thank you for your content, Rat!
🤙👍🤙 as we should be
Super cool 😎 and extremely well presented. I do wonder if the old tech "sounds" better when staying within its limits. Any thoughts on that part? Forgive me if you've answered this in the comments, I didn't have time read them all! And that sine wave on the new amp sure looked funky.
I've been trying to do tests and get more clarity on that. And even if I do gain headway the variations between manufacturers blur the outcome.
What I found so far is that class D amps can sound really good and all things being equal in cost size weight, including the fidelity, you'd be hard pressed to find a class AB amp that outperforms Class D amps.
I guess the question is with an unlimited budget buying the most expensive class A or Class A B amp, would you end up with something that sounds better than the most expensive Class D amp. And for that I would say yes.
But as soon as you add in any other metric like size, weight, cost, efficiency, output power, or fidelity per dollar spent, everything seems to point to Class D being the winner
Add in things like cool factor, aesthetics, and simplicity, and the outcome tilts more towards Class A or Class A B
@@DaveRat Thanks, and totally agree on all points. The "sounds better" thing is just so subjective to begin with, but wanted to hear your thoughts regardless. I've kind of come down to the conclusion that when the differences are small, I can't really tell what sounds better by a quick a/b. But I think I can tell something when I've lived with it for time, like say an hour, do I still think it sounds good, or is there something bugging me and I don't want to listen anymore. If I'm happy with something after say an hour, it sort of becomes a clear winner to me, but that is so subjective to any subconscious impulse, you can't really quantify why it's better or if it even is better. That's what I've arrived at these days, and obviously you've experienced a huge gamut of experience with not only different gear, but just time and different situations. So I pick your brain because I trust it. 😎 And thanks again. It's really interesting how you use your knowledge and imagination to teach and prove or disprove concepts. You should probably be the whacky professor that everyone loves. Anyway, really appreciated. 🙏
Agreed on the "over time, awareness to subtle differences can increase" these are the aspects I love to test!
@AdamGotheridge My experience is that the old-tech linear amps sound better in the upper mids and highs, but modern amps can sound better on the bass. Unless the bass is composed of sine waves... Perhaps oversampling will help class D amps rival linear amps high-frequency sound quality.
Will the powersoft push more watts on average without themal throttle/protect? It was driving the fans pretty fast with single channel loaded, thats a lot of power density to keep cool.
The fans were ramping up not because of the load as much as the pure high frequency I was driving into it. The class D amps have a hard time with long-term high power high frequency energy. Which is rarely a real world scenario as the high frequencies tend to be the least continuous and most transient.
We've been using the smaller t604s on monitor rigs like the EAW microwedge systems we have and they perform very well for that.
Classy amps tend to be very efficient and don't normally run much hotter when under full load than they are with no load.
Cool video , but as far as I remeber either the 4601 or the 4801, it's optimized to run high mid frequencies rather than fullrange.
It was the 4601 that was designed and optimized for high frequency applications.
The 4801 was the small brother to the 7001. The 8001 is the three rack space version with even more power and weight
I miss my 60 pound qsc isa300ti's. They were a bitch to lug around to smaller gigs but frankly they outshone my 2kw peak power amps while retaining more quality from less distortion, and never ever broke, even though they were 15 years old and absolutely covered in dust rust and grime. This however is not to say all new amplifiers suck, I am particularly interested in the rise of the ultra tiny class D amplifiers as they seem to be doing some crazy stuff for the size, but as of now, and maybe wont be for too long, if you want that clean reliable power, the heavier that transformer the better it's been.
I we saw the opposite. We had louds of issues with the Crest amps. We now deploy literally 100s of L-acoustics LA48 and LA12x amps with very low failure rates, improved sound quality and volume levels that make the Crests sound broken
Super interesting how much the instantaneous power headroom helps with preserving transient info. I wonder how the Class D Powersoft would compare with a class G or H amplifier. Idk if those are even made as pro audio amps though.
That 4801 is a Class h
@@DaveRat I had no idea. Thanks for letting me know.
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Hey Dave, Would if those class D amps were driving a sub or a bass cabinet? I have class A/B GK bass head and an Acoustic Image class D amp. I have run them through the same 8 ohm cabinet. It seems the GK has tons more headroom, especially when I am playing on the Low B. Any thoughts? Thanks for the cool video. I purchased the Riarosa tune after watching one of your other videos. Great song and performance!
For bass you want more continuous power so class ab performs well. But, getting big class D can still out perform the class ab for less weight and size.
You just need a bigger class D amp if you're going to go that way but one that's still lighter than the class a B
@@DaveRat Thanks Dave. Good information. Despite the weight of the GK, I still like it’s tone shaping qualities more than the Acoustic Image amp. Modern Technology is a good thing!
So many variables and yeas, for a bass amp I would thing conventional would be more desirable. Better overload character as well
I wonder if the extra dynamic range helps or hurts heavily electronic material as compared to acoustic. Clearly, it enhances vocal and instrumental music.
Having enough dynamic range is important. Anything that exceeds the capability of an older amp tends to manifest as clipping which is undesirable.
That said having an amp that too much exceeds the speaker capabilities can result in damage to the speaker or undesirable sounds from the speaker.
In general a class D app can offer more power, less weight, generate less heat, draw less power from the wall, while being smaller and outputting the same or more energy than conventional older amps
The small rig I used to run used all class D amps. I'd always get people telling me how inferior they were and they couldn't keep up with the old tin... True in very specific circumstances, but I had to move these things around so I did not care.
Yes it's difficult to buy any gear at this point that doesn't have class D amps. All the self-powered gear and all the top end professional gear is based on Class D
You would think with the Powersoft Amp that what was represented as a bit of fuzz on the scope would be heard when the music was played, but apart from the output volume changing, it sounded ok. If anything is to be "considered", would it be a fair call to say that the Powersoft Amp would be a better choice (according to the scope) for bottom end sound? As the Crest Amp was far cleaner at the top end? Thanks Dave.
That high frequency fuzz is in the 50 kilohertz region I believe so it's neither audible nor can speakers reproduce it
cool
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The waveform of crest amp is nice, I'm still a fan of old topology amp like Class AB or Class H. I built a DIY Class D amp before with infineon chip but the high frequency response is very harsh unlike the old school class AB the response is very clear.
For home hifi, the fan less class ab is the way to go. If you need to move or transport it, or it needs to be small ao draw less power, class D all the way
@@DaveRat true, class d is for outdoor use for its efficiency and weight.
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It’s amazing the technology that has brought us these lightweight but powerful amplifiers. In the old days, amplifier manufacturers built huge power supplies so that the output devices had ample clean power available on their power rails. Then along came switching power supplies and their fast, clean, and efficient ICs that made huge heavy transformers and capacitors unnecessary. Finally, someone made the intellectual leap to in effect just modulate the power supply and the modern amplifier was born. I don’t think they sound as good for critical listening but hell a lot of modern music sounds like bad distortion and audio processing artifacts to begin with. So, I’ll still be over here with a nice warm sounding tube amp with the kinds of distortion I like and the kids can use the type they like and we will all be happy. All kidding aside, having humped more than a few old Flame Linear, Crown, and “modern” QSCs, the new amps are awesome. Not only are they lighter and much more dense, they take a fraction of the power supply. Add in the swap to modern lighting with moving effects, color swaps , and LEDs, you don’t need to run the massive cables to a couple thousand amps of 208 for lighting and a 100 plus amps for sound in an arena gig. Much less hang thousand of par cans. Vari-light won.
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It would be interesting with your demo music to measure dB in the room at the edge of clipping with the 2 amps (with your dummy load setup, running into another amp/speaker).
The dummy load was running directly into a speaker and there wasn't really a need for an amp. You can just put a speaker across part of the load and the speaker will play the voltage drop that's showing on that load. So that's pretty much what you heard in the video
Ok I grabbed 2 sections of audio from the video with music playing through the 2 amps (not ideal with UA-cam but worth a shot). Looks like about 7dB difference over the sections. Does that sound about right?
Yes that sounds about right. The Crest amp puts out 400 watts and I was running it right near clip and the power soft amp puts out around 1600 Watts which is 4 times the power which is 60b.
Thanks for this great A/B comparison. Can you comment how the different amps handle the load of a real crossover + modern drivers vs the resistive voltage divider for this video? Maybe no one uses passive crossovers in pro audio anymore 😂
Powersoft can do energy recycling from reactive loads (idk if all amps but the only I ordered does), so you'll get more power out of the amp than on a purely resistive load. Keep in mind that real power delivered to the speakers will be lower than apparent power (V*I).
Some amps might get unstable at various low impedance/weird angle loads, but idk much about that since nobody really tests that and I haven't seen much data on that.
Yes, I will ponder a test for that
A/B comparison lol
Could you share some more details regarding the load you are using?
How did you achieve an 8Ohm load that can't handle all this power?
Also, is the lamp just a standard AC LED lamp? Won't the lamp add also resistance to the output?
Lastly, is it dangerous to measure the amp output voltage while driving a speaker if the speaker is rated for at least the same as the amp?
Based on what your saying about peak power (not average power) the peak power will help a kick drum to thump better. I guess you can factor this into how you purchase a sub speaker power amp. I’ve always ignored it, but considering how a kick drum is only 50 to 60ms in duration. If the peak power is 2k watts, that would be something that should be considered when purchasing a sub speaker power amp.
Yes the peak power rating if it lasts long enough duration is the rating that matters. That said, if it only lasts 100 milliseconds it's not going to work as well as an amp that has a peak power rating that lasts 250 to 350 milliseconds.
Also for long extended bass notes the continuous power rating of a higher level can be useful
Fun test!
IIRC Powersoft amps also have supply power sharing between channels. Would that mean that to get the most total output from them you would send each amp's four channels material that didn't peak at the same time? So maybe mids/highs and subs or differently delayed fills/subs on individual channels of one amp? Instead of putting multiple identical subwoofers on one amp. Maybe even just pairing a more power hungry output (subwoofer) with a less demanding output (monitor/fill) could enable more power to be continuously allocated to the demanding output?
Does this jive?
Also (at least sone) Powersoft amps can run on 240V mains, and the manual says they run a bit cooler at higher input voltage. Have you seen benefits in this arena?
I did one installation with Powersoft amps and used 208V power, cause it was readily available, and "why not?" It only cost some NEMA L6 cables.
Yes we run amps on 208 or 240 regularly. We run three phase to all our amp racks.
Power sharing and harvesting back EMF into the power supply is common amongst power soft amps.
In this demo since I only used one channel it demonstrated the maximum power. I do know that the limiting factor on the T-Series amplifiers is the power supply and with a bigger power supply it would be able to supply even more output.
If memory serves, I recall powersoft telling me that the duration of the peak power is increased with a higher AC input voltage
that's exactly how these amps and other modern 4ch amps (e.g. lab fp10000q) are made to be used ;)
their individual channel capability far exeeds that of their psu for all channels. But it's the ideal solution for small setups (e.g. 2 subs, 2 tops) or larger active multiway systems per side (e.g. sub/mid/hi/fill).
also no one is playing pure sines, average crest factor for music is 12db+, so it becomes all about pumping out the peaks, not sustained load (except maybe subs in heavily compressed eectronic music)
for full throttle sub uses there are beasts like the x4l
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It's really fun when you use the Powersoft X series in the EU, where they hook directly to 415V 3ph mains 😎
Yes!
I use electrostatic speakers, which can have very demanding impedance loads, both high and low. Is there a difference between these amps with, let's say, a 2 Ohm load or a 60 Ohm load? (Yes, I have one pair of speakers that have these impedance extremes, depending upon frequency)
It'd be interesting to try a class D app on those. I know the PowerSoft amps can run loads as low as 1/2 ohms and have the voltage swing to run high impedance loads and still deliver a good amount of power more so then class A B apps.
It would seem the class D would be better suited for those complex loads but would we worth testing
Thanks for the video Dave. So, since it takes 10dB to double volume, but you only get 3dB per doubling of watts, then it’s sort of a logarithmic scale? 3 1/3 X watts is 2X volume?
3db double watts, 6db 4x watts 10 db is 10 x the watts and 20 db is 100x the watts
10db is said to 2x the perceived volume level. Or 10x the watts to double the perceived Volume
@@DaveRat ohhhhh. I missed that detail. I would be really interested to learn how we measure perceived volume.
Yeah, I am not convinced it is as simple as they say. Adding 3 db to a system running 115db sounds significant and adding 3 db to a system running 90 db sounds irrelevant
@@DaveRat also frequency. Going from background dinner levels to cleaning levels I notice a significant increase in bass, so at least initially the bass grows louder first, though it levels off at very high volumes and is overtaken by the rest of the sound. Perhaps it's the level of tactile feel increases faster than the loudness of the tone due to the increased energy beyond the rate of increasing loudness. Although I tend to think those frequencies around 3kHz get louder the fastest. Adding 10dB to a 3kHz note sounds a much bigger change than adding it to 150Hz. The fletcher munson loudness curves are an interesting look up.
The modern amplifiers use a principle similar to a photo flash where in the store of a tremendous amount of power and capacitors and then they can release enormous amount of power for a very short duration. Not much good though if you need continuous sine wave for several seconds. You're going to be limited by the wall socket.
Also modern amps can recycle back EMF from the speaker as well as they are significantly more efficient than older amps.
These factors combine to offer quite a bit more usable energy delivered to the loud speaker from the same wall outlet than older amps.
Crest amp's extended high frequency explains cooking horn drivers. Digital amps have to have a low pass filter on the output (to get rid of digital switching noise), so it is not going to give you much if anything above 20kHz.
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WTF?
if you burn a horn driver the problem is the amp? Please, seriously, search in AI the next: technical dignity
@@AragonDubs If you BURN it, as in voice coil failure, then yes it can be an amp issue unless you have chosen the wrong compression driver. The HP-filter on class-D amps cuts out the overtones above the audible range which just heat up the voice coil without any audible sound. If you don't have a passive filter on the Crest it will heat the voice coil of a compression driver more at the same audible acoustical output, especially when driven hard.
Also watch your tone, even if you think you're right doesn't mean you have to be a dick about it.
Yes, excess energy outside of audible bandwidth can create additional heat and increase failures.
And yes, this is all about sharing info and learning
I wonder how that would compare to my Carvin DCM 2004L amp?
I believe that amp is rated at 300 Watts per channel into 8 ohms so that would be a much smaller amp compared to the power soft rated at 1600 Watts per channel or the crest rated at 400 Watts per channel.
Your a lot of fun Dave….
Awesome thank you
I understand the peak power and music duration. Question asking is how, dose the two work together? I’m thinking about a driver. The response of peak power handling. Is the powersoft continuous in control of the two or the driver?
The signal tells the amp what to do, the amp then tries to send it and the speaker then tried to do it. All is good until the signal exceeds the amp's capability to deliver.
And amp with more peak capability will deliver the peaks, and amp without the peak capability will clip/distort.
Same thing sort of with continuos except the powersoft amp has built in protection so it will never clip or distort, it just turns down things that are too much to deliver
Thanks.
Didn’t know the body of the 3 paragraphs. That’s an ah ha moment. 🔊😁
Awesome!!