Комментарии •

  • @chrismitlyng1411
    @chrismitlyng1411 3 года назад +8

    Thank you so much Dave! There are likely a lot of “sound guys by need” like me out here that didn’t get this info in school. This helps a lot!

  • @jakesterfiddle
    @jakesterfiddle 3 года назад +7

    I am so excited for this series in power amps!

    • @DaveRat
      @DaveRat 3 года назад +1

      👍

    • @zambotv8150
      @zambotv8150 3 года назад +1

      @@DaveRat ruclips.net/video/tUxsP-792U4/видео.html I booted up a pile of old crowns, after some heat ran through them they sort of booted up, ha ha

    • @DaveRat
      @DaveRat 3 года назад +1

      👍

  • @NiliMoto
    @NiliMoto Год назад +1

    I feel so redeemed by the fact that someone as experienced as you is saying the same things I am saying. I experience a lot of resistance (pun intended) when trying to bring facts and science into audio discussion.
    I would love to hear how you feel about the mighty "watts rms" which I find to be a nonsensical unit in the context it's used.

  • @Toggymok
    @Toggymok 3 месяца назад +1

    Cheers Dave, i feel more validated for my sedimental purchase of an old Perreaux 9000B.

    • @DaveRat
      @DaveRat 3 месяца назад +1

      👍🔧🔧👍

  • @mariodario9033
    @mariodario9033 3 года назад +3

    Thank you for that video. Can't wait for next episodes. All best.

    • @DaveRat
      @DaveRat 3 года назад +1

      Thank you Mario

  • @SuperMcgenius
    @SuperMcgenius Год назад +2

    Yes, I ear told me the same thing when class d amps came along, the old Bryston and Crest amps worked better. With class D I go for 50% more power to keep things safe.

    • @DaveRat
      @DaveRat Год назад

      👍👍👍

  • @dxrocketsurfer34
    @dxrocketsurfer34 3 месяца назад

    Best explanation I have seen of Old tech (AB, H etc) Amps vs New Class D etc. Would be interested to see if there are any newer amps that can sustain the long bass tones e.g. LabGruppen PLM models. The old Crest 7001, 8001s would just keep pumping...

  • @dougaltolan3017
    @dougaltolan3017 3 года назад +4

    What would have been interesting to see is the recovery of the amp. I thought I saw a hint of it when you stopped the signal.
    This would give a good idea of how often you can hit it like that.

  • @markthomas1225
    @markthomas1225 3 года назад +5

    The SQRT(2) = 0.7071 factor works for sine waves only. This would be 1.0 for square waves, and much less for a typical music signal.

    • @DaveRat
      @DaveRat 3 года назад

      True and thank you

  • @michaelrhodes9178
    @michaelrhodes9178 2 года назад +1

    Thanks Dave.

  • @yashvirmahdoo1587
    @yashvirmahdoo1587 3 года назад +1

    Grate video as always. I look forward to your videos. You produce content that I really like.

    • @DaveRat
      @DaveRat 3 года назад

      Thank you Yashvir!

  • @federicogioachini653
    @federicogioachini653 2 года назад

    What a great video series!
    I have just one consideration: when you divide Voltage^2 by R to compute the power you are supposing a purely resisitve load --> In case of a speaker, which is characterized by an impedance figure, it must be considered the frequency of the signal to compute the impedance. Nominal impedance is at 1 kHz. Lower frequencies (like the 225 Hz you had on the example) will lead to lower impedance since the inductance component will behave more more like a short circuit giving you the true resistive part and so, for the same voltage, higher currents (and power)

    • @DaveRat
      @DaveRat 2 года назад

      Hmmm, the resistive load of a typical speaker is closer to 1/2 the rated 8mpedance of most speakers.
      The rated impedance is an average of what to expect over the operating freq range
      The minimum impedance is typically no lower than 80% of the rated impedance but around resonance the actual impedance is much higher.
      Asking as the test methods are the same for various amps being compared we can get a good idea of what is happening.
      The peak power and the amount of time the amp can deliver that peak power is more important in audibly how loud an amp is.
      There is another factor where some amps capture and store back emf and increase their power as well.

    • @federicogioachini653
      @federicogioachini653 2 года назад +1

      @@DaveRat Yes, yes, I totally agree with You!
      I was just pointing out that in order to compute the power "given" by an amplifier by measuring the output voltage it's necessary to divide by the impedance at that frequency (on the Impedance vs Frequency chart) and not by the resistance or the nominal impedance of the speaker.
      The same would occur measuring Voltage and Current --> We need the phase between the two to compute the "actual" power and not just the Apparent one

    • @DaveRat
      @DaveRat 2 года назад

      Agreed.

  • @laureanosamuelolmoromero5756
    @laureanosamuelolmoromero5756 2 года назад +1

    can you get hold of a VOID Acoustics Infinite 8 V2, and do the test with that???
    i own such an amp and i think it's a great amp but, i kinda got doubtful about amps now... great videos thanks for each and everyone of them. you really reignited my passion for audio and tech again.

    • @DaveRat
      @DaveRat 2 года назад

      Hmmm, who makes their amps? I don't think void makes amps so finding out the manufacturer would give more insight

  • @JohnKapsis1985
    @JohnKapsis1985 2 года назад +1

    My subwoofer is very happy at the end of every video :)

    • @DaveRat
      @DaveRat 2 года назад +1

      It's cool to have a system that will play the end track!

  • @carlubambi5541
    @carlubambi5541 Год назад

    Fantastic as always

  • @MatbiangShadap
    @MatbiangShadap 3 года назад +1

    Thanks dave...

    • @DaveRat
      @DaveRat 3 года назад

      Awesome and thank you! 👍

  • @giovannimercuri5168
    @giovannimercuri5168 3 года назад +1

    Awesome video Dave; thanks!!

  • @ANATURALDREWSASTER
    @ANATURALDREWSASTER Год назад +1

    I wish amps would have ratings for the internal specs as energy storage/capacitance, rail voltage, and power supply wattage I assume would be better specs to pay attention to nowadays. I try to look at max power draw and efficiency numbers to get an idea of sustained output capacity even though that’s not the whole story for music.

  • @markdavis3629
    @markdavis3629 3 года назад +1

    Thanks for another great video Dave! I like the classic amps. For the most part today's products are BS compared to previous consumer goods from the 60s 70s and 80s. Too much engineered obsolescence now. Your tv's and automobiles forward all ambient sound to a 3rd party for possible future persecution. I drive cool old Fords and will never get rid of my fat stack of Adcom GFA 585's & 565's pushing those 15" and 18" Cerwin Vegas. Old school or no school!

    • @DaveRat
      @DaveRat 3 года назад +6

      I love vintage and also love tech. I don't forget that the vintage gear you live was high tech some day in the past. With someone saying, damn those new fangled cars, horse and buggies are the way to travel.
      I own a Tesla and I can honestly say it is superior in every way to any car I have ever driven
      I laugh at muscle cars trying to hedge me and not let me merge onto the freeway, "ha, you may be loud and smelly but at least you are slow! "
      I then proceed to silently pass the car in front of the car in front of them and make them tiny in my rear view mirror. And smile as I engage auto pilot.
      That is not to say I don't love vintage beautiful machines and cars and sound gear from all decades.

  • @ladjkaoz
    @ladjkaoz Год назад +1

    Great video man, but now days everyone goes for the K watt sticker, dont even bother to look at frequency respond or weight. and power draw.. 👍👍

    • @DaveRat
      @DaveRat Год назад +1

      Power draw is a big deal for us. Power sag is an issue as well as feeder size and length and generator capacity.
      Also thermal issues if hot weather causes amps to shit down.

  • @juwbone
    @juwbone 3 года назад +1

    Wow, that was quite shocking, the rate at which the modern amp fell off surprised me, I have read about sagging but I hadn't imagined it would be that fast. Talk about cliff hanger, ... : )

    • @DaveRat
      @DaveRat 3 года назад +3

      And also it's important to note that not all new amps do that and it varies from model to model and manufacturer to manufacturer.

  • @WestOfBen
    @WestOfBen 3 года назад +1

    Keen to see where this leads. Does this explain the difference we hear between different classes of bass guitar amps? For example, my Gallien-Krueger 700RB-II feels noticeably more alive, responsive, punchy and with more character than similar output digital amps, including GK and Fender. I understand speakers/cab makes a difference but I have played enough different rigs to feel the difference. The tones can be similar and both are great options, but in my experience those MOSFET solid-state amps like the old GK 400/700/800 and old Trace Elliot AH250/AH300 amps simply delivered more of everything. You can push and push them much harder than their digital cousins. Curious to know your thoughts and understand the factors at play.

    • @DaveRat
      @DaveRat 2 года назад

      Hmmm, I am remiss to jump to conclusions about related gear without testing

  • @mojoemurphy
    @mojoemurphy 3 года назад +1

    I'm curious what the spec sheet rating would be for the new amp that you just showed us. I was hoping to learn if the peak was the rating that manufacturers use as "peak" and if RMS was fairly true to being actually true RMS even during dynamic loading. If the modern amp you tested showed a rated 350 watts at 4 ohm RMS or something similar, then it would appear you only benefit from the peaks creating a large burst of power to follow dynamics of music instead of a more compressed, flat signal.
    I look forward to seeing where this goes

    • @DaveRat
      @DaveRat 3 года назад +1

      You can see the specs, look up a powersoft T904

    • @mojoemurphy
      @mojoemurphy 3 года назад +1

      @@DaveRat I am only able to find one output rating for each impendence, which is, admittedly, laughably high. I would wager their "2000W @ 4 Ohm per channel" is a peak rating and therefore most likely 4x the actual RMS. Luckily, most brands in the price range I can afford list RMS, program, peak output power ratings

    • @DaveRat
      @DaveRat 3 года назад

      Download the actual owners manual and I believe it will clarify the spec

  • @Statist0815
    @Statist0815 2 года назад

    I want to mention Georg Simon Ohm . Great guy.

    • @DaveRat
      @DaveRat 2 года назад

      Yes! Genius!

  • @morleychallenged
    @morleychallenged 3 года назад +2

    Aww Dave! How could you miss that?? P=IE ; as, Watts=Amps x Volts; then returning to Ohms law and derivations. I forgot all this twenty years ago until now!

    • @morleychallenged
      @morleychallenged 3 года назад

      I know I missed lots of things!

    • @morleychallenged
      @morleychallenged 3 года назад +1

      I quit college instead of hurting the dean.

    • @DaveRat
      @DaveRat 3 года назад

      Good stuff

    • @morleychallenged
      @morleychallenged 3 года назад +1

      @@DaveRat I used to rattle that off in my head for paltry u-ground circuits in refitted churches and impromtu art-galleries which couldn't anticipate the requirements. Always an adventure.

    • @DaveRat
      @DaveRat 3 года назад

      👍

  • @guigui5199
    @guigui5199 3 года назад +2

    Waw... sorry Dave , Im not an expert , but with all respect due , you are talking about Efficiency for something called Sensitivity express in dB/1W/1m, efficiency is the ratio of the average acoustical power (in W) radiated by the loud- speaker to the total electrical average power (in W as well) supplied to the loudspeaker its a number without dimension or expressed in % wich is very different things ...

    • @DaveRat
      @DaveRat 3 года назад

      Yes, this is true

  • @bokajllensch661
    @bokajllensch661 3 года назад +3

    My guess is that 90% of music actually has a "loudness signature" simular to the power handling capabilyties of new amps.

    • @DaveRat
      @DaveRat 3 года назад +1

      They do try and design the higher end new amps to match that signature and cheaper amps design for a spec rating.

  • @prefix808
    @prefix808 2 года назад +1

    If you don’t know who Dave Rat is, you should probably look him up…he’s been around for a bit!

    • @DaveRat
      @DaveRat 2 года назад +2

      Hell yes, will do, on it!

    • @prefix808
      @prefix808 2 года назад

      @@DaveRat Hhahahaha thanks Dave for all you do. Had a great time hanging with ya at the sound forums meet up in Wachusett, Massachusetts! This was a while back, I think seven or eight years ago. We got to play around with some new Danley subs.

  • @anandshah71
    @anandshah71 2 года назад +1

    Hi Dave how is your experience with Hypex based class d amps

    • @DaveRat
      @DaveRat 2 года назад

      Hmmm, never used or looked into them

  • @Aio-Project
    @Aio-Project 2 года назад +1

    the average val of the absolute value of the sine function is .637 not .707, I'm a little confused on where that number is coming from

    • @DaveRat
      @DaveRat 2 года назад

      Not sure the vid this was posted about as it only shows the comment on my phone but maybe the info below applies and is helpful?
      RMS Power:
      When measuring a pure sine wave, RMS voltage can be calculated by measuring the peak voltage level and multiplying it by 0.707. This value can then be used to calculate RMS power. In turn, if the RMS power is known, it can be used to calculate the peak power.

    • @Aio-Project
      @Aio-Project 2 года назад +1

      OH! its the root of the average of the squares. In the video you said you wouldn't go into the math and I was trying my hand at the math. I wasn't considering the reality of the situation where we would have to take measurements to find the rms. Typical math nerd... Thank you!

    • @DaveRat
      @DaveRat 2 года назад

      Cool cool!

  • @dam55ian
    @dam55ian 2 года назад

    interesting video been trying to put together a small pa on battery running 50w a channel on 4 ohms with a 92db/1w speaker but curious if upgrading to a 99db/1w at 8 ohms would be worth the upgrade as it then gives 25w from the amp

    • @DaveRat
      @DaveRat 2 года назад +1

      A speaker that is 7 DB more efficient should be the same volume at less than 1/4 the power. That said speaker efficiencies need to be measured in the same range as you're using them and often manufacturers will use differing ways to measure efficiency. Oh for battery operated systems high efficiency speakers are the way to go

  • @NealMiskinMusic
    @NealMiskinMusic 3 года назад +1

    So this test is with the amps set just a hair below clipping, correct? How do the amplifiers behave when you have more headroom to work with, if the amps are running at, say 75% of their maximum capacity?

    • @DaveRat
      @DaveRat 3 года назад +2

      At lower outputs they are linear all good. On the member side i am doing a series of vids comparing the sound of various amps in overload as well as impacts of wall voltage coming soon

    • @NealMiskinMusic
      @NealMiskinMusic 3 года назад +2

      @@DaveRat So then I guess the best approach is to always try to get a slightly more powerful PA than you actually need so that you can run it with some headroom. As interesting as amplifier behaviour is when they're right on the edge, in practical terms a little headroom goes a long way.

    • @DaveRat
      @DaveRat 3 года назад

      And using limiters that allow you to hit the system hard when needed without bad sounds

    • @mojoemurphy
      @mojoemurphy 3 года назад +2

      @@NealMiskinMusic a lot of loudspeakers are killed from folks running amps at or under speaker rating, then running those amps into clipping. I was brought up to run 1.5 or 2x speaker rating for headroom and set limiters and listen to the speakers for any distortion they get from being ran too hard

    • @DaveRat
      @DaveRat 3 года назад

      👍

  • @pearldrumsets
    @pearldrumsets 3 года назад +1

    What if some amps use 30a/220 and break it down to a lower v does it still reduce the performance of the amp. Or 30a twist plug to a 110

    • @DaveRat
      @DaveRat 3 года назад

      Would need to test but I believe most amps put out rated power with rated input ac. And with lower supply the output derated

  • @JohnnyGuitar1
    @JohnnyGuitar1 3 года назад +3

    Dave at 11:30 you say that it needs 4000W to get as loud, yet it is a 6dB difference, so it should be 8000W.
    Am I missing something?

    • @DaveRat
      @DaveRat 3 года назад +1

      Yes the video math is correct.
      Speaker 1
      94db 1 watts
      104 10 watts
      114 100 wats
      124 1000 watts
      127 2000 wats
      Speaker 2
      100 1 watt
      110 10 watts
      120 100 watts
      130 1000 watts
      Speaker 1 max is 127db at 2000 watts. Would need to handle 4000 watts to hit 130db that speaker 1 hits at 1000 watts.

    • @JohnnyGuitar1
      @JohnnyGuitar1 3 года назад +2

      @@DaveRat the 2000W text above the 4000W threw me off completely because it is a 6dB difference, not 3dB.
      I stand corrected.
      Thank you for being kind and helpful Dave.

    • @DaveRat
      @DaveRat 3 года назад +2

      👍 cool cool! I appreciate the double check! Keep me on my toes, all good!

    • @JohnnyGuitar1
      @JohnnyGuitar1 3 года назад

      @@DaveRat great! But would you like to be a real audio nerd’s hero?
      Most things you talk about in this video is already on RUclips on one form or another.
      But here is what is not so common:
      Why don’t manufactures make most drivers’ efficiency 101dB or above?
      What are the cons and pros of a higher efficiency above 101dB, besides the basic “heat” and price answer?
      What are the phase issues (related to Impedance) by becoming more efficient?
      These answers I am yet to find on RUclips.

    • @erikbritz8095
      @erikbritz8095 3 года назад +1

      @@DaveRat so in short for pro audio i should get the more efficient drivers? And what bout car audio subs that are so inneficient but can get so loud are they still the better option for car audio specifically or should a more efficient driver in car be louder IF the mechanical limits allow for it?

  • @Not-Only-Reaper-Tutorials
    @Not-Only-Reaper-Tutorials 3 года назад +1

    11:32 4 times more power out 2kW = 8kW not 4kW ... or did I missed something?

    • @DaveRat
      @DaveRat 3 года назад +2

      I believe the calc is correct in the video.
      Speaker 1
      94db 1 watts
      104 10 watts
      114 100 wats
      124 1000 watts
      127 2000 wats
      Speaker 2
      100 1 watt
      110 10 watts
      120 100 watts
      130 1000 watts
      Speaker 1 max is 127db at 2000 watts. Would need to handle 4000 watts to hit 130db that speaker 1 hits at 1000 watts.

    • @Not-Only-Reaper-Tutorials
      @Not-Only-Reaper-Tutorials 3 года назад +1

      @@DaveRat well in the video it seems you are talking about the 2kW speaker then telling 4 times the power, written under th 2k speaker, it should be 4x2=8k … I will re-watch it again

    • @DaveRat
      @DaveRat 3 года назад

      So where is the error in the db to watts conersions shown in the post above?

    • @Not-Only-Reaper-Tutorials
      @Not-Only-Reaper-Tutorials 3 года назад

      @@DaveRat no no I never told an error in dB calculation. Just having umder the eyes 2000W, sayong 4times thata value, it’8000w. Not 4000.

    • @DaveRat
      @DaveRat 3 года назад +1

      Ahh, I could see the confusion with the text, should have made it more clear. I think what I say in the vid should be correct

  • @michaelhenshaw258
    @michaelhenshaw258 2 года назад +1

    👍

    • @DaveRat
      @DaveRat 2 года назад

      👍🤙👍

  • @stevean77
    @stevean77 Месяц назад +1

    I've tried learning how to calculate my power amps so I have perfect match power going to my cabinets but Bro this is over my head haaaaa

    • @DaveRat
      @DaveRat Месяц назад +1

      👍🔧👍

  • @jonathancook4022
    @jonathancook4022 3 года назад +1

    Was this made with my comment in mind?

    • @DaveRat
      @DaveRat 3 года назад

      Probably a factor as I got several comments guiding me in this direction

    • @Newschoolcovers
      @Newschoolcovers 3 года назад +1

      @@DaveRat Still waiting for X4 vs K20 :D

    • @DaveRat
      @DaveRat 3 года назад

      I started doing the X4 on the member side of the channel with a video with my daughter Sammy and I won't be doing a K20 cuz I don't own one but I do have some other powersoft amps I'll look at

  • @timothyhassett5344
    @timothyhassett5344 3 года назад +1

    thumbs down? really? congrats to "that guy"

    • @DaveRat
      @DaveRat 3 года назад +3

      Ha! My guess is the every once in a while someone comes along bullying people or trying to propagate incorrect info. I try and resolve things cordially and with respect but sometimes it runs amuck and pretty sure these butt hurt knuckleheads hide in the shawdows like cowards and find joy in down thumbing.
      That said, what they don't know is that it makes me smile to think they spend their time thinking of me and that I have had such an impact on their life.
      Over the past 10 years or so I recall about 5 such humans, so overall, I think we are ok.

    • @johnmcquay82
      @johnmcquay82 3 года назад

      @@DaveRat Saw that on another video a few weeks ago from a different content creator. Some guy came into the chat dumping on everything that was said basically saying "you're wrong, I'm right". Not ashamed to admit, I bit and he soon departed the conversation with his tail between his legs... :D

    • @DaveRat
      @DaveRat 3 года назад

      👍

  • @EdPin_
    @EdPin_ 2 года назад +1

    "Old" tube amp at full power/overdrive may sound "awesome", the "new" digital amp may not ;-)

    • @DaveRat
      @DaveRat 2 года назад

      👍👍

  • @RAILWAY_FILMS
    @RAILWAY_FILMS 2 года назад +1

    so basically I sold all my passive speakers because I couldn't afford the amps I needed. I should just quit all together

    • @DaveRat
      @DaveRat 2 года назад

      well, either that or rock on and bump it up a notch

  • @JohnnyGuitar1
    @JohnnyGuitar1 3 года назад +1

    Dave you can just skip an extra step by multiplying Peak to Peak times 1.14.

    • @DaveRat
      @DaveRat 3 года назад +1

      Are you referring to covering peak to peak by dividing by 2 and the multiplying times .707 to get RMS?
      If so, yes you can skip a step but not by multiplying 2x .707
      The correct math is to multiply
      .707 x .5 to get .3535
      Multiplying peak to peak by .3535 will give RMS voltage.

    • @JohnnyGuitar1
      @JohnnyGuitar1 3 года назад +2

      @@DaveRat I stand corrected Dave. This is rust from my electronics engineering course from 1983 plus not enough coffee, but I do live on stages with equipment, full time for a living.
      0.3535 times ppV it is, of course, but still, you save an extra step.

    • @DaveRat
      @DaveRat 3 года назад +1

      Yes, agreed and in future vids I switched.