Netlist said:
As the Wicked Witch of the West remarked, "These things must be
done delicately".
I have continued to work on the design, but the details are not
yet complete. I expect significant improvement on several
fronts.
I will plan to start a new thread when this surpasses 500,000, but
this will still take about 3 months, so don't start punching F5 yet.
moe29 said:Grey,
For this thread to reach .5M hits it needs some controversy.
Like...
The US Government is responsible for this thread!!!
There's no way that Grey could have been the lone poster!!
Everyone knows an Aleph-X will melt at 2,750 degrees F....
etc. etc.
1) This site's policy prohibiting political discussion prevents me from coming clean. I can neither confirm nor deny that mistakes were made in the voting required for this circuit to become law. I promise to veto any appropriations bill that includes a withdrawal date for this schematic unless it includes provisions for single malt Scotch, gratuitous sex, red wine, and gratuitous sex.
(Always loved that scene in Blazing Saddles where they're interviewing villains and one states his qualifications as "Rape, murder, arson, and rape." When the interviewer points out that he said rape twice, the bad guy replies, "I like rape!")
2) I wake up in a sweat some nights, having had a nightmare that the moderators went through and removed Fred's (and all his various sock puppets') posts. Were that to happen, the thread would implode. There might be as many as five posts remaining, all mine.
3) Given that 2750 degrees F is more than double the melting point of aluminum, I hereby officially declare that if you run your Aleph-X that hard it will indeed melt your heatsinks.
Tomorrow morning I will initiate a Group Buy for titanium heatsinks. If I recall correctly, Ti's melting point is somewhere north of 3k degrees F.
On second thought, perhaps I'd better get out my CRC Handbook and check that. My memory ain't what it used to be. It'd be a shame to have molten puddles of titanium on your living room floor--bad for the carpet, not to mention pet hamsters.
Grey
P.S.: Breadcrumbs are not as reliable as one might wish. Bear in mind the difficulties faced by Hansel & Gretel.
P.P.S.: Them what does computers for a living might derive a bit of amusement from the thought of someone named Julian calculating dates...
P.P.S.: Nelson, do you have intentions of posting such a circuit or should I?
Nelson Pass said:I will plan to start a new thread when this surpasses 500,000, but
this will still take about 3 months, so don't start punching F5 yet.
Suppose the AlephX could do with just a few nifty mods…
Suppose I could take the new design to the DiyAudio meeting in England this summer...
Suppose it would beat its competitor, the Krell KSA100…
Just suppose...
/Hugo
graphite foam heatsinks
Regards
James
An externally hosted image should be here but it was not working when we last tested it.
Regards
James
The graphite foam thing is interesting, but it's going to get really complicated if you have to have a bunch of plumbing. If you're going that route, water cooling is safer, cheaper, easier, and looks pretty cool. I'm currently weighing air vs. water cooling for a circuit I have in mind. At the moment I'm leaning towards water.
As for why it takes time to design a circuit...try it. I believe you'll find that there's a bit of work to be done. It took me four or five months to go from concept to working prototype for the original Aleph-X. Granted, I was only able to put in an hour or two per day, but it does take a bit of fiddle-factor to get the job done. Nelson gets to do this eight hours a day, and has more experience, not to mention scads of parts right at his elbow. He'll get where he's going a lot faster than I will, I imagine.
For the record, I have no idea what Nelson has in mind regarding Aleph-X updates. It's highly unlikely that my ideas are the same as his ideas, so the circuits will likely be rather different. I have some notes detailing a few areas in the circuit that I'd like to change (...perhaps even for the better...). I've already done some work on the most radical of the departures from the original circuit.
As most folks know, I insist on real-world parts doing real-world things. I put a circuit together, played with it for a while, decided that it wasn't doing quite what I wanted it to do, and dismantled it. Went to bed. Got up and had to rebuild the damned thing from scratch because I had a sneaky suspicion that I'd overlooked something. Yep. I had. Adjusted one thing and the li'l booger jumped right up and started dancing just the way I'd wanted it to in the beginning. I suspect that it will transfer into an Aleph/Aleph-X circuit fairly readily, but will need to try it first. I'm not much fond of the taste of foot.
Then I'll look at the other things on my list.
Grey
As for why it takes time to design a circuit...try it. I believe you'll find that there's a bit of work to be done. It took me four or five months to go from concept to working prototype for the original Aleph-X. Granted, I was only able to put in an hour or two per day, but it does take a bit of fiddle-factor to get the job done. Nelson gets to do this eight hours a day, and has more experience, not to mention scads of parts right at his elbow. He'll get where he's going a lot faster than I will, I imagine.
For the record, I have no idea what Nelson has in mind regarding Aleph-X updates. It's highly unlikely that my ideas are the same as his ideas, so the circuits will likely be rather different. I have some notes detailing a few areas in the circuit that I'd like to change (...perhaps even for the better...). I've already done some work on the most radical of the departures from the original circuit.
As most folks know, I insist on real-world parts doing real-world things. I put a circuit together, played with it for a while, decided that it wasn't doing quite what I wanted it to do, and dismantled it. Went to bed. Got up and had to rebuild the damned thing from scratch because I had a sneaky suspicion that I'd overlooked something. Yep. I had. Adjusted one thing and the li'l booger jumped right up and started dancing just the way I'd wanted it to in the beginning. I suspect that it will transfer into an Aleph/Aleph-X circuit fairly readily, but will need to try it first. I'm not much fond of the taste of foot.
Then I'll look at the other things on my list.
Grey
I'll second that! Despite the fact that Nelson gave out the entire circuit topology for the GC Susy amp excepting only the parts values, it took me about 4 months to get a real version working without uncontrolled oscillation (which the SPICE sims were completely unable to predict). Even then, it still required another few months of refining to get the best out of it.
Grey's right. This stuff doesn't happen overnight.
Cheers, Terry
At the moment it's quiet at work, so I'm scratching out PCB artwork on a scrap of paper. I've never been entirely comfortable with computer programs for this stage of the game (don't confuse this with my distaste for simulation programs), so I sit and scribble various layouts on a piece of paper until I'm satisfied, then transcribe the whole mess into the computer. Yes, it's a clumsy way to go about it, but it's easier for me to visualize what's going on if it's on paper. Why, I don't know...it just is.
PCB artwork is largely unappreciated. People like the finished product, but don't want to think about what went into it; not unlike the making of sausage.
Once, and only once, have I posted PCB artwork. Don't plan on doing so again. Everybody wants parts changes. Those parts inevitably have vastly different footprints, which leads to a complete redo.
I look at the a lot of the artwork posted here on the site and cringe for any number of reasons:
1) The boards have parts scattered higgledy-piggledy here and there as though thrown at flypaper from across the room. This is the PCB equivalent of "spaghetti code" in computer parlance. It's the result of those self-same computer programs.
2) The artwork was designed by committee...and looks like it. Instead of keeping a few inevitable parts substitutions to a reasonable minimum, the fellas responsible try to satisfy anyone who has some oddball part they want to use. As a result, the board has three or four places to put a device depending on the pinout. Yuck.
3) Wires entering the middle of the board. This kind of nonsense needs to be kept to an absolute minimum. Why? Because one of these days, the circuit will need service, and you'll discover the hard way that it's a nightmare to work around all those wires. To the extent possible, all wires should attach at the edges of the board. Period. The only decent exceptions I can think of are when the board is designed to be mounted directly on the screw terminals of the power supply caps--properly done, this can reduce the point-to-point wiring in the amp--and when the circuit is quite deliberately laid out so that it can piggy-back against another circuit board in the manner used by John Curl and Jonathan Carr. Mind you, this is still a pain in the behumpus to service, but it's a good way to get a lot of work done without having to resort to four layer boards.
4) Jumpers. Hate 'em. Almost never necessary. If you're patient you can almost always find a way to get the job done without resorting to jumpers. It's been ages since I've used one. If I see a board with more than one or two, I start thinking the designer was a tad lazy. A buddy of mine brings me dead stuff for parts. Looked inside an Audio Source amp. YIKES! It's a rogue's gallery of bad ideas, but I will content myself with one item: Bipolar output device. Trace from the emitter (if I recall correctly) leads away from the pin, through a jumper across the trace carrying the rail, then back through another jumper right next to the original trace whereupon it went through a resistor back across the same rail trace...etc. Ugh. They could easily have used the resistor to jump the rail and been done with it. Instead, the bloody thing is full of jumpers. Probably a hundred of them. It's a wonder the blasted things work at all. (But their power amp transformers make marvellous preamp/crossover/etc. transformers!)
5) Don't get me wrong. I believe in short signal paths. But...some misguided people go a little overboard, shall we say? You see some really bizarre layouts perpetrated in the name of a "one inch signal path." Uh, guys, get real. An extra tenth of an inch of trace isn't going to kill you. Egad, live a little...maybe even two extra tenths. Why? Again, service. One, it's a nightmare to get probes down among parts that are too tightly packed; you're almost sure to short something out and do more harm than good. Two, it's helpful if the parts are laid out in some logical sequence so their function is apparent. Put all the parts of the current source together. Put the differential stuff in one place. Put the bias circuit together. Since some people feel that some of these things "aren't in the signal path" they scatter the parts all over the board in an effort to get other "in the circuit path" parts closer to one another. Harrumph! Penny wise, pound foolish, I say.
6) Inconsistent spacing. Why on Earth would any rational person use, say, .4" spacing for their 1/8W resistors, then suddenly use .5" or .6" for one where it's completely unnecessary to do so? What possessed them? Yes, the circuit works. Yes, it's purely esthetic when you get right down to it. But, jeez, don't these people take any pride in their work? Grumble, grumble. If I ever show artwork with that sort of inconsistency, bonk me on the head.
There's an art to this. That's why they call it "artwork." A really well-executed board is a wonder to behold. It's easier to populate. It's easier to service. It's just plain nice to look at.
Most people here are content if their board works--and yes, that really is the most important thing. But there are levels of excellence beyond the simple function of the circuit. Unfortunately, I keep seeing boards that look as though people aren't improving their board making skills.
Bummer.
The PCB aspect of this is all a behind-the-scenes thing as far as I'm concerned. It helps me get the circuit tidy and working so that I can post a schematic. It's all part of the game.
Glad to hear that the sausage is appreciated.
Grey
P.S.: Quite some while ago in this very thread, Nelson went to great pains to point out that if you put the + and - traces of a balanced signal on opposite sides of the board (or side-by-side) the two phases will be subject to the same magnetic/RF/whatever fields and thus the induced signal will cancel. I don't recall anyone "getting it." The boards I've seen certainly don't use the principle.
PCB artwork is largely unappreciated. People like the finished product, but don't want to think about what went into it; not unlike the making of sausage.
Once, and only once, have I posted PCB artwork. Don't plan on doing so again. Everybody wants parts changes. Those parts inevitably have vastly different footprints, which leads to a complete redo.
I look at the a lot of the artwork posted here on the site and cringe for any number of reasons:
1) The boards have parts scattered higgledy-piggledy here and there as though thrown at flypaper from across the room. This is the PCB equivalent of "spaghetti code" in computer parlance. It's the result of those self-same computer programs.
2) The artwork was designed by committee...and looks like it. Instead of keeping a few inevitable parts substitutions to a reasonable minimum, the fellas responsible try to satisfy anyone who has some oddball part they want to use. As a result, the board has three or four places to put a device depending on the pinout. Yuck.
3) Wires entering the middle of the board. This kind of nonsense needs to be kept to an absolute minimum. Why? Because one of these days, the circuit will need service, and you'll discover the hard way that it's a nightmare to work around all those wires. To the extent possible, all wires should attach at the edges of the board. Period. The only decent exceptions I can think of are when the board is designed to be mounted directly on the screw terminals of the power supply caps--properly done, this can reduce the point-to-point wiring in the amp--and when the circuit is quite deliberately laid out so that it can piggy-back against another circuit board in the manner used by John Curl and Jonathan Carr. Mind you, this is still a pain in the behumpus to service, but it's a good way to get a lot of work done without having to resort to four layer boards.
4) Jumpers. Hate 'em. Almost never necessary. If you're patient you can almost always find a way to get the job done without resorting to jumpers. It's been ages since I've used one. If I see a board with more than one or two, I start thinking the designer was a tad lazy. A buddy of mine brings me dead stuff for parts. Looked inside an Audio Source amp. YIKES! It's a rogue's gallery of bad ideas, but I will content myself with one item: Bipolar output device. Trace from the emitter (if I recall correctly) leads away from the pin, through a jumper across the trace carrying the rail, then back through another jumper right next to the original trace whereupon it went through a resistor back across the same rail trace...etc. Ugh. They could easily have used the resistor to jump the rail and been done with it. Instead, the bloody thing is full of jumpers. Probably a hundred of them. It's a wonder the blasted things work at all. (But their power amp transformers make marvellous preamp/crossover/etc. transformers!)
5) Don't get me wrong. I believe in short signal paths. But...some misguided people go a little overboard, shall we say? You see some really bizarre layouts perpetrated in the name of a "one inch signal path." Uh, guys, get real. An extra tenth of an inch of trace isn't going to kill you. Egad, live a little...maybe even two extra tenths. Why? Again, service. One, it's a nightmare to get probes down among parts that are too tightly packed; you're almost sure to short something out and do more harm than good. Two, it's helpful if the parts are laid out in some logical sequence so their function is apparent. Put all the parts of the current source together. Put the differential stuff in one place. Put the bias circuit together. Since some people feel that some of these things "aren't in the signal path" they scatter the parts all over the board in an effort to get other "in the circuit path" parts closer to one another. Harrumph! Penny wise, pound foolish, I say.
6) Inconsistent spacing. Why on Earth would any rational person use, say, .4" spacing for their 1/8W resistors, then suddenly use .5" or .6" for one where it's completely unnecessary to do so? What possessed them? Yes, the circuit works. Yes, it's purely esthetic when you get right down to it. But, jeez, don't these people take any pride in their work? Grumble, grumble. If I ever show artwork with that sort of inconsistency, bonk me on the head.
There's an art to this. That's why they call it "artwork." A really well-executed board is a wonder to behold. It's easier to populate. It's easier to service. It's just plain nice to look at.
Most people here are content if their board works--and yes, that really is the most important thing. But there are levels of excellence beyond the simple function of the circuit. Unfortunately, I keep seeing boards that look as though people aren't improving their board making skills.
Bummer.
The PCB aspect of this is all a behind-the-scenes thing as far as I'm concerned. It helps me get the circuit tidy and working so that I can post a schematic. It's all part of the game.
Glad to hear that the sausage is appreciated.
Grey
P.S.: Quite some while ago in this very thread, Nelson went to great pains to point out that if you put the + and - traces of a balanced signal on opposite sides of the board (or side-by-side) the two phases will be subject to the same magnetic/RF/whatever fields and thus the induced signal will cancel. I don't recall anyone "getting it." The boards I've seen certainly don't use the principle.
GRollins said:
with all respect,you can't be hippie and exclusive in same time..........
on the other side,I agree with some things,but with other don't.
besides, you didn't see everything...........
I know zilch in pcb making area (like with most other things I just didn't tried) ,but I have that luck to have friend who's damn guru with pcbs.
just look at Oly's Babelfish or little symetric amp pcbs and you'll see what is pure engineering approach ,even with few shorties and few wires nested in middle of it...........
broader perspective.......life is too funny and why is so damn needed to have attitude about everything.........for me just opinion is more than enough. ( having attitude often dictate that man must cover every inch of object , and that's not the case with opinion)........
ps. you know that you have my respect
that's why I wrote this
Quote by Grey:
I appreciate you pointing this little tid-bit out of the matrix of information in this thread. It has occurred to me that two traces may affect one another; my concern has always been, do we want cancellation, will this affect the primary signal as well as that of the induced? I'm certainly aware that a degree of inductance cancellation is a benefit in my ZV7-T choke experiments--no saturation.
Thanks, Grey.
I appreciate you pointing this little tid-bit out of the matrix of information in this thread. It has occurred to me that two traces may affect one another; my concern has always been, do we want cancellation, will this affect the primary signal as well as that of the induced? I'm certainly aware that a degree of inductance cancellation is a benefit in my ZV7-T choke experiments--no saturation.
Thanks, Grey.
Zen Mod said:
I'm not sure what the hippe/exclusive part means.
As far as the rest, the fault is mine. I didn't express myself clearly.
I'll get the hang of this writing thing one of these years.
Let me outline my train of thought and see if I can identify where it derailed. (Yes, that's a crude pun.)
Starting with carpenter's comment, my thinking went thusly: He expressed appreciation, presumed in context to be for the Aleph-X circuit. The way I go at circuits is that I pretty much have a fully functioning prototype before I post. Others do all their development out in public with input from a hundred people. I do mine in the Dungeon, pretty much solo. Part of that process is the making of a circuit board. At that moment, I happened to be working on a PCB layout, my eyes got tired, so I looked in on the DIY site to see what was going on and take a break.
(Whether the particular circuit I'm working on ever gets posted here remains to be seen.)
Since I regard the making of PCBs as part of the R&D for a circuit, my post was a long-winded way of saying "you're welcome" to carpenter.
And, of course, you guys have never known me to be long-winded...right?
Then my thoughts went on to other PCBs I've seen here.
Let me address that in a slightly different way and see if I can clarify what I was saying.
Pick out a new member here at DIY. Make sure it's someone who's got the fire, the passion, and the commitment to do what it takes. They start with something that looks kinda silly, like a post saying, "What amp should I build?" or "Can I substitute MOSFET xxx into this circuit?" Posts like that are a dime a dozen. But fast forward a year, and if you're watching the right person, they'll be helping others choose projects, and suggesting what MOSFETs might or might not work. Two years on, they're able to make non-trivial alterations to posted circuits and fix their own problems. In short, they learn, they improve, they grow. Their skills develop. This is good. It's how things should be.
But...
For some reason, I don't see peoples' PCB skills developing. Why, I'm not sure. Am I saying that everyone should be able to do their own boards? Not necessarily. But those who attempt it should attempt to improve their PBC abilities the same way that they put effort into learning the electronics angle. And yet, time after time after time, I see boards that are no better than the last board I saw from the same member. They're not improving. I'd like to see raised standards for circuit boards. Don't just go "Ooooh! Aaaah!" every time someone posts a picture of a board. Look at the confounded thing. No...really...I mean look at it. Does it look like it was made by a drunken monkey or a master at his craft? I see clever circuits here that make me think. I see pictures of metalwork that are models of competence. Then they pop the top and the bubble bursts. Ohmigod! You mean that marvelous chassis was built to contain that? Yuck! It's criminal...or should be.
Nelson has said that you should build a chassis as though it's a temple to contain your circuit.
I say, apply that same ethic to your circuit boards. Do not settle for "Well, it works, so I guess it's okay." Goad yourself. Make each circuit board better than its predecessor. Don't pat yourself on the back just because some other member went "Ooooh! Aaaah!" Their standards might not be high enough. Make yours higher. Do not accept mediocrity. We've got some pretty bright people here and there's no reason that they can't master the art of making printed circuit boards.
Excel, dammit!
Grey
Nelson,
Niven has a much more flexible imagination than I do. I could never have written The Integral Trees, for instance. As for the actual writing part of the equation, I'll be content if I can approach his work w/Pournelle...which of course is a direct derivative from Heinlein's writing style (something they've pretty much explicitly acknowledged elsewhere [also note their character Robert Anson in Footfall--Heinlein's full name being Robert Anson Heinlein]).
I make no claim to being on their level, only that's it's something to aspire to.
All of which being my long-winded way of saying thanks.
Grey
P.S.: I have no earthly idea if you've ever read any of my stories--you may be judging purely from my yik-yak here. But in the interests of full disclosure, I must also point out that I also count Alistair MacLean as an influence.
Yes, The Guns of Navarone, Where Eagles Dare, Puppet On a Chain...etc. Him. And, yes, to me MacLean (like Heinlein) gets a capital "H" in the spelling of Him. The tagline on his covers always said Master Storyteller. That's all I want to do...tell stories that entertain people. I leave the artsy-fartsy writing to others.
Niven has a much more flexible imagination than I do. I could never have written The Integral Trees, for instance. As for the actual writing part of the equation, I'll be content if I can approach his work w/Pournelle...which of course is a direct derivative from Heinlein's writing style (something they've pretty much explicitly acknowledged elsewhere [also note their character Robert Anson in Footfall--Heinlein's full name being Robert Anson Heinlein]).
I make no claim to being on their level, only that's it's something to aspire to.
All of which being my long-winded way of saying thanks.
Grey
P.S.: I have no earthly idea if you've ever read any of my stories--you may be judging purely from my yik-yak here. But in the interests of full disclosure, I must also point out that I also count Alistair MacLean as an influence.
Yes, The Guns of Navarone, Where Eagles Dare, Puppet On a Chain...etc. Him. And, yes, to me MacLean (like Heinlein) gets a capital "H" in the spelling of Him. The tagline on his covers always said Master Storyteller. That's all I want to do...tell stories that entertain people. I leave the artsy-fartsy writing to others.