How about this?

[Kilowatt]

I'm not trying to sturr up any old hard feelings that some of you probably have. I hope I'm not bothering anyone by going on about this, but how would his be? http://homepages.picknowl.com.au/glenk/ Do you think I could do it, eventually anyway? Someone mantioned it on my old thread. I wouldn't get 5kW from them though, only my 1.8kW that I've been after. There are PCB layouts here, but I'm not sure if they are final and funcional designs or still untested. There is other information on the project that I may need that is still under construction on the site, so I may have to wait awhile, but I may not have to completely give up yet. Anyway, I'll still be working on my 400W/channel amp for quite awhile, and I think I'll bi-amp it with a tube amp, so I won't get started again on the big one until I'm done with it, at least. I'm not just going to dive into this.


[Edited by Kilowatt on 12-09-2001 at 10:26 PM]

 

[Kilowatt]

Hope I'm not wasting space on the page

I think it's a neat project. Does anyone else agree, or am I talking to myself in this thread? I've been thinking. I've been planning my 7200W amp for a couple years. 99% of the planning has gone out the window. Originally, it was going to drive a 3-way speaker system with a passive crossover and home made drivers. This and some of the proposed schematics for the amp were so rediculous that I shudder to think of them. Now I'm closer to knowing what I'm doing, but apparently not all the way there yet. Now I want it for a bass amp to bi-amp with some other little amps, and I want to base it on (no, build it just like) a proven design. I've got reasons to forget that I ever thought of the big amp, primarily that the subject seems to bore people on the forum, which is my primary source of audio help. Also, that it's expensive and will be hard and take a long time to complete. Maybe I should spare you all and quit my carrying on, but guess what, I like the idea of the 4 x 1800W, and I desperately want to build it, even though I already have a project going (the 400W amp and the tube amp). But hey, I can work on two projects at once.

Normally, I would have taken your advice and shut the hell up about the big amp, but there's project 20kW, with the voltage amps, drivers and PCBs for it already there, and I thought to myself "My God, Chris, are you just going to screw it and not make the amp?, you've put lots of money into little things that go with it, like the case, heatsinks, effects, preamp, mains wiring, hookups, etc. Damn it, build the thing! How hard could it be if you've got detailed plans for it (project 20kW)?" Anyway, I don't know what I'm getting to, I'm just kinda wondering if I should, or even could really do it. I hope I'm not on anyone's bad side, despite my previous stubborness and apparent ungratefulness. However, I'd still kind of like to build the amp, and I know there are some very knowledgeable people on this forum who might have something to say about it, but if you want to ignore me, go right ahead.

Oh, by the way, especially Geoff, I'm a little curious as to just what it is that I have said in the past that makes it seem like I know practically nothing about electricity/electronics. Were you just saying that to **** me off, or do I always seem far more naive than I really am. Of course I don't know nearly as much as many on this forum, like you, but the idea that I'm a completely ignorant novice is insane, it's simply not true. You say you're suprised I'm even alive, and the way you say it, you don't seem to be exaggerating much. What the hell do you think I'm going to go? Do you think I'm going to get the idea that it's ok to take my 4kVA Jacob's Ladder in the shower with me or what? Come on, just how stupid do you think I am?

[Edited by Kilowatt on 12-09-2001 at 11:31 PM]

 

[AudioFreak]

finish the 400W amp 1st then try something like the 1kW amp available at http://members.optusnet.com.au/~aussieamps/1kwamp.htm then if all things work well and you dont get turned off by the problems you have constructing them then by all means go ahead and try the big project ........

Regards,
AudioFreak.

btw. If you need help with high power amp design and construction i'll help you out.

 

[Damon Hill]

Explain to us again why you >really< need multiple kilowatts
of power to drive home speakers. I can't see how anything over a kilowatt per channel could possibly be justified for
home use.

My >strongest< advice is simply go for a few hundred watts
and get your experience from those designs before attempting
to build something totally ridiculous. You'll spend a lot
less money, more effectively.

What's the largest amplifier you've _actually built_, successfully?

 

[Kilowatt]

Ok, I'm glad someone will. Now, first I'll do the 400W one, then maybe something else, then the big one, but I've got to wait ahwile before I can afford much for the big one. I might have to wait for project 20kW to move ahead a little first too. I'll keep all my progress posted when it starts progressing.

I hope you're not just posting stuff because you think it's what I want to hear. If that's the case, you shouldn't have. If that's not the case, thanks alot

Hey, where can I find plans for that 1kW MOSFET job, I've been wanting to try to build that thing, but haven't seen anything but pictures.

 

[AudioFreak]

I assure you Kilowatt, I am being genuine. It would appear that Anthony has not yet made a pcb available for this project but i would say this will probably change in the near future and anyway, you can probably get a fair idea of what it looks like if you read the construction manual for the symetrical power amp available at the same site.

Damon Hill the amps are for open air use so the power will be useful.

[Edited by AudioFreak on 12-10-2001 at 12:00 AM]

 

[Kilowatt]

Damon Hill, you see, it's not for home use, if it were, It'd blow windows, blow my ear drums, and attract the police very quickly. For home use, I am working on something that's just several hundred watts, and even that may be overkill. As far as my experience, the biggest channel that I've successfully build is a little over 100W. I was working on a 200W one, but gave up because it was for a car, and switching regs are beyond me. I lost the outputs the first time I tested that 200W one. I suspect it either oscillated because my wires to the outputs were too long, and were tangled, or perhaps it saw too much voltage during the test because of my power supply, which was what I happened to have at the time and was actually way too much. All I know for sure is that the outputs were shorted over almost intantly. I had no problems what so ever with the 100W one.

AudioFreak, from looking at the pictures of that 1kW amp, it looks very simple, and seems to have few parts on the PCB. But, uh, what construction mannual, I didn't see one.

[Edited by Kilowatt on 12-10-2001 at 12:06 AM]

 

[Damon Hill]

Yep, I thought so...

Look, you need to build up your experience gradually,
not to mention a decent suite of test equipment so you'll
have at least a prayer of understanding what's actually
going on inside a circuit. I'm dying for an Audio Precision
System One, used (I'll never be able to afford a new one).
Most of my current test bench is geriatric Heathkit.

And you'll need a hefty budget just for the parts you'll
blow up during that learning.

Gotta pay your dues first, boy.

Biggest amplifier I ever built was a SWTPC Tigersaurus,
for a friend who sold it to a band. I concluded then
(around 1980), that the rats nest of wiring for the
required series-paralleled output stage was inviting
trouble and looked terrible.

I stuck with a reliable design (the Leach amplifier),
kept the power levels to a couple of hundred watts, and
went for quality. I'm still looking for a better way
to construct an amplifier chassis so it doesn't look like
a junkbox special.

For your project, go modular. Learn to build reliable, perfected 500 watt monoblocks and use them with speaker arrays that can actually handle the power. Build as many blocks and speakers as you need for the event, in parallel, rather than a Godzilla amplifier that can die spectacularly and maybe take you with it in the early stages of testing.

In practice, you'll find that reliability through modularity
beats a single point of failure shutting down the whole
concert.

Switching supplies are fun; I had a lot of experience testing them for a company that build private branch telephone exchanges. Took our engineer several years to
learn how to build a 300 watt supply that was reasonably
bulletproof. I'd have a steep learning curve learning how
to design my own, to say the least.

 

[AudioFreak]

the construction manual i refer to is for the 400W symetrical power amp http://members.optusnet.com.au/~aussieamps/downloads/symamp.pdf

Though i havent had a good look yet the 1kW amp appears to be based on this amp.

 

[Kilowatt]

Damon Hill, yeah, yeah, I know. I need to build my experience some before I go playing with 1800W amp circuits. But it's not as quite important as it might seem for the big amp, because it will be taken from a proven design, with detailed plans. I do however need (or at least really want) an oscilliscope and a variac. I have neither.

And who said anything about it not being modular. How do you know this thing won't end up being merely a small component itself in an even bigger system? Actually, it probably won't, but I won't be putting on any concerts with it, and I'm not really after extreme reliability, though it would be nice if I could be fairly sure it won't quit on me. I want something that is quick and simple to set up, and also compact, like an ordinary stereo, but bigger. A modular system just isn't what I'm after, sorry. There are big amps out there, and this will be one of them. Also, the speakers can handle the power easily. I'm planning on getting 8 x Audiobahn ALUM12X subs for it.

Well, I'm prepared to lose some transistors either in the big project or something else or both. I guess that's just how the initiation into DIY audio works. I can afford it all, just not very well, and it takes awhile.

I'll try to build up my experience gradually, like you say, but I should soon be good for the big amp (Anyway, what do you mean by gradually? A few projects? 20 years in the repair business?), at least as long as I have a lot to go by (PCB layouts, other details) and won't have to do much designing on my own. I admit that I don't have enough experience to do this on my own. I won't rush into it, I assure you. I've got some other projects to do first anyway, like my 400W thing. Keep in mind that 4 x 1800W is not all that big compared to some amps, it could be worse you know.

Just wondering, how big is that SWTPC Tigersaurus?

[Edited by Kilowatt on 12-10-2001 at 02:11 AM]

 

[Kilowatt]

Oh yeah, I've seen that construction manual before, it is a very simple circuit, you'd expect something like that to be really complicated.

Hey, just disregard all that 4 x 1800W stuff. I think I'm going to make it 8 x 1000W. That will make it easier to build and more reliable. There will be 8 900W into 12 ohm amps in it. I'll probably use that 1kW MOSFET design for them. Every other one will be inverted so I can utilize the both rails all the time. It will be possible then to hook up the speakers for 8 x 900W into 12 ohms, 4 x 1800W into 24 ohms, and many other configs. You've finally talked me into it.

Does anyone know of another amp that uses a transformerless direct line power supply? Nelson Pass once made an amp like that. It was very similar to what I want to do here. Are there (or were there) any mass produced amps with a supply like that? I want to get some info about this type of power supply in audio amps if there's any out there. Where do I look?

[Edited by Kilowatt on 12-10-2001 at 10:09 PM]