2.4KW amp, anyone?

[fas42]

You're right, Frank. I either missed that sentence or it lost its meaning in subsequent references to satisfying Bass Pig, or being comparable to a Krell. No need to quibble over the meaning of continuous, though, we can just go with the meaning of "music power" you quoted from Wikipedia, and now we all know what you're talking about. You're talking about building a 24 watt amp that will totally satisfy Bass Pig and compare favorably to a Krell. You're going to exceed the Phillips by 4 watts per channel. Handy that your existing speakers will be adequate, eh?

I look forward to your progress reports.

Tim

No, it will do 2400W RMS, with excellent distortion figures, for the time that it takes to do the reading from some meter. From then on the output devices and speaker drivers will cook, and the voltage supplies will sag to nothingness: protection circuitry would stop these things happening.

A bit of simple maths tells you what's needed: 400V peak to peak at the speaker terminals, on an 8R unit -- also from the first post:

Of course, this means it will be capable of generating pretty vicious voltage spikes at the speaker terminals, enough to damage someone if precautions aren't taken.

This voltage swing is where it gets tricky, dead easy these days to get amps from SS, the trick is to get volts cleanly. Which is why not everyone is doing it ...

Frank

 

[Phelonious Ponk]

No, it will do 2400W RMS, with excellent distortion figures, for the time that it takes to do the reading from some meter.

Frank, perhaps you need to brush up on your EE degree. If it will only do 2400 watts for an instant, before it goes into meltdown, you're not talking about RMS. Look it up. It's in Wikipedia too.

See the peaks?

That's your 2400 watts. See the dotted line? That's RMS. In any case, we need to get our standards settled. I'm not eating my hat over 24 watts...

Tim

 

[fas42]

Interesting when you go into it, it's not straightforward to get a precise definition. For one thing, there is no such animal as watts RMS. There's volts RMS and amps RMS, but no watts RMS, just watts! The other interesting thing is this weasel word "continuous", it gets thrown around a lot but what does that really mean; refer back to the Krell example. The best I've done so far is the DIN standard, which says that it has to be capable for 10 minutes to meet the requirement. Excellent, I'm sure most speakers out there can handle 2400W for 10 minutes at a pinch ...

So we need to get back to the real word. mbl (lowercase, I note) is one of those rubbishy brands that puts out deceptive ratings, and not very good amplifiers. Silly people, their 9011 reference monoblocks, they claim 5,000W peak pulse power, but there, they finally admit 440W Rated Power, the stuff we're talking about here. Obviously the amp is not worth the metal it's made out of ...

Frank

 

[fas42]

Okay, everyone loses 10 points, for not picking me up on implying that the MC2KW wasn't SS in the first post, which it is, of course. My memory was a little hazy on that ...

So I've had a closer look at that beast. Yes, indeed it claims to be able to output 2000W continuously, which considering a few things seems reasonable enough: each channel requires 3 modules, 6 in total for stereo, for a total weight of about 340Kg. There are 96 output transistors per side, a grand total of 192 output devices; each side to deliver that full output requires 2 normal household spurs each: in Australian terms, two 240V, 10A circuits. So to fully test it you need 4, yes 4, dedicated spurs to check its stereo capabilities.

Slight overkill, anyone?

So I'll pull back slightly from that and aim to do of the order of 600 watts continuously, for just a tad less money, weight and power consumption. Sound reasonable?

Frank

 

[Phelonious Ponk]

Interesting when you go into it, it's not straightforward to get a precise definition.

I'm not an EE, Frank, you are. But I do know that watts, RMS, has long been used as the standard, in everything from midfi up, to help us compare Yamaha to Marantz and match amplifier power to speakers. It has been working fairly well for a few decades now and I haven't heard too many stories of voice coils melting as a result. Maybe someone else can tell us how accurate it is.

The other interesting thing is this weasel word "continuous",

Yes, you applied it to RMS last night, that's not accurate according to your reference, Wkipedia. They call RMS "average" and have published a formula for arriving at it, and the little graph I put in my post last night shows its relationship to peaks (your 2400 watts, I assume?).

Excellent, I'm sure most speakers out there can handle 2400W for 10 minutes at a pinch ...

Are you? You seemed sure it would cause a meltdown of the Australian grid last night.

So I've had a closer look at that beast. Yes, indeed it claims to be able to output 2000W continuously, which considering a few things seems reasonable enough

So what was not worth the metal it was made of at 10:54, seems reasonable enough at 12:48?

So I'll pull back slightly from that and aim to do of the order of 600 watts continuously, for just a tad less money, weight and power consumption. Sound reasonable?

Not to me. You're still talking about your pretty poorly defined 2400 watts "music power" and an improvisational 600 watts "continuous power," and RMS is still the standard. Again, I'm no EE, but the whole thing reads like you're faking it, Frank. And while it may be an imperfect standard, watts, RMS is the one we've got. If you want to be taken seriously (it's probably too late here, but you mentioned a possible "commercial venture"), you need to figure that one out. And since you've struggled with it so publicly, when you come up with the number, I think you should show your math.

Or not. My culinary hat is out of the ring in any case, and I'm rapidly losing interest in my quest to try to nail you down to specs and/or definitions that are meaningful.

Tim

 

[fas42]

Are you? You seemed sure it would cause a meltdown of the Australian grid last night

Sorry that the sarcasm eluded you ...

So what was not worth the metal it was made of at 10:54, seems reasonable enough at 12:48?

If you can't be bothered following the plot, what's the point of the conversation? I was referring to 2 completely different amplifiers in the 2 posts ...

Not to me. You're still talking about your pretty poorly defined 2400 watts "music power" and an improvisational 600 watts "continuous power," and RMS is still the standard. Again, I'm no EE, but the whole thing reads like you're faking it, Frank. And while it may be an imperfect standard, watts, RMS is the one we've got. If you want to be taken seriously (it's probably too late here, but you mentioned a possible "commercial venture"), you need to figure that one out. And since you've struggled with it so publicly, when you come up with the number, I think you should show your math.

Or not. My culinary hat is out of the ring in any case, and I'm rapidly losing interest in my quest to try to nail you down to specs and/or definitions that are meaningful.

Me too. You jump every which way to suit yourself, including demanding something which is physically impossible within the constraints of my initial proposal. I don't see any value in playing the game you feel comfortable with, and since the interest from others appears to have lapsed I think I'll move on to something else ...

Frank

 

[Phelonious Ponk]

Sorry that the sarcasm eluded you ...

I got the exaggeration for effect, I just was a bit surprised when it was not exaggeration at all, but just fine a few hours later.

If you can't be bothered following the plot, what's the point of the conversation? I was referring to 2 completely different amplifiers in the 2 posts ...

Were you referring to two different amps? Well that was hard to follow, and no, I can't be bothered.

Me too. You jump every which way to suit yourself, including demanding something which is physically impossible within the constraints of my initial proposal. I don't see any value in playing the game you feel comfortable with, and since the interest from others appears to have lapsed I think I'll move on to something else ...

No, Frank, just one jump: A standard of measurement. Peak power, music power, continuous power...2400 watts, 600 watts, who knows how what kind of watts? I'm jumping about? All I'm asking for is a standard, the standard for the most part. That you throw in the towel when someone asks you to define the simple power rating by the common standards says everything else that needs to be said.

Tim

 

[Mark (Basspig) Weiss]

Discussions like this always amuse me. People bandying about dB figures in the sub-120 range and using hundreds or even thousands of watts to do it. Worrying about musicality changing with SPL.. I wish someone invented an ear that didn't lose musicality over 125dB.

Snare drum hits at 127dB. Bass guitar at 137dB.. It feels good, but the ears begin to distort way below those levels. Ear plugs restore the musicality, but I feel that the plugs put a veil on the upper frequencies. The bass feels great though. 137dB is the magic number.. loud enough to feel some firm vibrations, not so loud to make breathing difficult.

Brief excursions into the over 140dB area bring on chest pain and make one feel as though one is drowning. I know of no friend or acquaintance who can stand these levels. However, my fireworks recording (made with the mic cluster about 100' from the launch tubes) seems to gain acceptance by hard-core pyro folks. But then, it's not that loud. I measured only 118dB from my camera position on the tarmac, and the burning fragments were falling all over me, for I was right under the explosions. It's significantly louder there than it is where the public is allowed to go, but the brevity of the sounds belie the loudness, for our ears are average-weighted by the way our brains interpret loudness.

Those on the quest for loudness and musicality need look no further than using quality drivers with high sensitivity (over 100dB/1W/1M), split the energy spectrum into various bands and send to separate amplifiers, with the largest for the low frequencies. Bridge mono for the MF/HF, since the crest factor of music can work to advantage here. Careful design and driver matching can net you the listening experience you want, in spades.

 

[fas42]

Mark, as mentioned or implied in earlier posts, there are several reasons for this exercise. Firstly to be to able to drive very low sensitivity, 80-85dB, speakers to decent listening levels. Secondly, to have sufficient headroom to deal with the crest factor of the music being replayed at live levels without any limitations being due to the amplifier. Thirdly, to be able to do this in a reasonable, not outrageously expensive, heavy, or energy consuming package using relatively conventional, linear technology. The main thrust is that of a design exercise, as a demonstration of what's possible using reasonable techniques, from the electronics side.

Of course it is possible to generate devastatingly loud, decent quality systems using the right blend of speaker and amplifier technologies, but that is definitely not the point of this thread.

As a side note, two experiences stick with me of personally experienced intense sound that would be a good goal for an ambitious, all out loudness system: close to the runway, air force jet came down it slowly, sitting on its tail so to speak using the raw power of its engines to hold the position and just as it passed hit the accelerator and seemingly almost vertically climbed away; and then, at a Chinese New Year celebration, a massive vertically hanging string of what we call bungers, crackers, set alight about 20 feet away. This went on for the order of minutes, it seemed, and the level of treble energy was in every sense deafening ...

Frank

 

[JackD201]

Less typing, more building

 

[fas42]

Jack, if I build it, will you come ...?

And, can I put you down for 10, at the special Costco inspired price?

Frank

 

[Whatmore]

Jack, if I build it, will you come ...?

And, can I put you down for 10, at the special Costco inspired price?

Frank

I'll take a couple... oh alright I'll take a dozen if you'd just build the wretched thing and stop talking about it

 

[Phelonious Ponk]

Twelve pages and I'm still waiting for you to tell us what it is.

Tim

 

[Whatmore]

It's this, perhaps (I'm sick of Waitsing too **groans**)

How do we do it? how do we do it? volume, volume, turn up the volume
Now you've heard it advertised, don't hesitate
Don't be caught with your drawers down
Don't be caught with your drawers down
You can step right up, step right up
That's right, it filets, it chops, it dices, slices
Never stops, lasts a lifetime, mows your lawn
And it mows your lawn and it picks up the kids from school
It gets rid of unwanted facial hair
it gets rid of embarrassing age spots
It delivers a pizza, and it lengthens, and it strengthens
And it finds that slipper that's been at large under the chaise lounge(2) for several weeks
And it plays a mean Rhythm Master
It makes excuses for unwanted lipstick on your collar
And it's only a dollar, step right up, it's only a dollar, step right up
'Cause it forges your signature
If not completely satisfied, mail back unused portion of product
For complete refund of price of purchase
Step right up

 

[fas42]

Twelve pages and I'm still waiting for you to tell us what it is.

Tim

Well, the last time I was considering it, it was a power amplifier: if you really want it to be a CD player, or a pair of headphones, or a silver encrusted 5 inch thick mains cable you'd better let me know fast, before I run down to the shop and buy some bits ...

Oh, if you really mean you're still worrying about power figures, read this article a few dozen times until it all sinks in: http://www.hifi-writer.com/he/misc/rmspower.htm. As I've already stated several times, 600W average watts is the aim, and I'll nominate the old standard of 5 minutes for doing the test (huh? ... read the article!). But it will have headroom of 6dB, 2400W peak. For how long sustained? ... How expensive do you want your amplifier? If you want it sustained "continuously", go and start putting some coins in the piggy bank for the 340Kg McIntosh MC2KW ...

Frank

 

[Phelonious Ponk]

Well, the last time I was considering it, it was a power amplifier: if you really want it to be a CD player, or a pair of headphones, or a silver encrusted 5 inch thick mains cable you'd better let me know fast, before I run down to the shop and buy some bits ...

Oh, if you really mean you're still worrying about power figures, read this article a few dozen times until it all sinks in: http://www.hifi-writer.com/he/misc/rmspower.htm. As I've already stated several times, 600W average watts is the aim, and I'll nominate the old standard of 5 minutes for doing the test (huh? ... read the article!). But it will have headroom of 6dB, 2400W peak. For how long sustained? ... How expensive do you want your amplifier? If you want it sustained "continuously", go and start putting some coins in the piggy bank for the 340Kg McIntosh MC2KW ...

Frank

A? A/B? D? Stereo? Mono blocks? Dual mono? Rating at RMS? You did say 600 watts average power. That's not a rating I'm familiar with. I was at an online audio store just yesterday, can't say I saw a single amp rated at "average power." Commit to a standard, talk about design. Set yourself some goals for specifications. Or do what you did yesterday and back out. It doesn't matter to me much one way or the other. Like Mark, I'd never trust the thing plugged into my wall, much less any of my equipment.

Tim

 

[fas42]

A? A/B? D? Stereo? Mono blocks? Dual mono? Rating at RMS? You did say 600 watts average power. That's not a rating I'm familiar with. I was at an online audio store just yesterday, can't say I saw a single amp rated at "average power." Commit to a standard, talk about design. Set yourself some goals for specifications. Or do what you did yesterday and back out. It doesn't matter to me much one way or the other. Like Mark, I'd never trust the thing plugged into my wall, much less any of my equipment.

Tim

Dear me, talk about running hot and cold! With you, Tim, I never know from one post to the next how it's going to come out, I would hate to have you as a boss ...

So you obviously didn't follow that link in my last post: until you do that, and read it at least once you won't understand what my specs mean. My rating will be "average", read the link! To answer the other points, I have already said linear, which must mean some type of A/B, not A, otherwise the unit would burn a hole in the floor from the heat generated. And, yes, I intend it to be a single stereo chassis, and to test at 600W "average" with both channels running. Depending on how things turn out I might throw in a preamp as well, make it a true integrated. Why? Because then I have total control on at least how this part of the system works, people can't muck it up by putting on dumb interconnects and suchlike ...

Why I backed out, Tim, is that, to be honest, you are an extremely frustrating individual to interact with. I need a little consistency in the level and tone of the conversation ...

Frank

 

[steve williams]

I took the liberty of moving this thread to our DIY Forum.

 

[fas42]

Thanks, Steve, that makes sense: I didn't know where this thread would go, and the tone of it now makes it more relevant to be there ...

Frank

 

[Phelonious Ponk]

Dear me, talk about running hot and cold! With you, Tim, I never know from one post to the next how it's going to come out, I would hate to have you as a boss ...

So you obviously didn't follow that link in my last post: until you do that, and read it at least once you won't understand what my specs mean. My rating will be "average", read the link! To answer the other points, I have already said linear, which must mean some type of A/B, not A, otherwise the unit would burn a hole in the floor from the heat generated. And, yes, I intend it to be a single stereo chassis, and to test at 600W "average" with both channels running. Depending on how things turn out I might throw in a preamp as well, make it a true integrated. Why? Because then I have total control on at least how this part of the system works, people can't muck it up by putting on dumb interconnects and suchlike ...

Why I backed out, Tim, is that, to be honest, you are an extremely frustrating individual to interact with. I need a little consistency in the level and tone of the conversation ...

Frank

I'm not trying to be frustrating, Frank, it just comes naturally to me.

I've been many people's boss over the years and have always been told I was fair, supportive and pretty easy to work for. But I can get hard when someone I don't fully trust fails to clearly state the objectives and commit to the deliverables of his project. Even worse is when they avoid the standards that are common and well-understood within the organization and expect, instead, everyone to follow their own, much more vague standard. Unless they have clearly articulated a reason for that behavior, I find myself suspecting that they are just trying to avoid being held to a standard at all. You've made a lot of very wild claims around here, Frank. Did you expect to try to demonstrate them without scrutiny?

I'm glad you don't work for me too. Enjoy your project. Since I've taken my edible hat out of play, I'll watch it all unfold with no personal investment and a lot less commentary going forward.

Tim