Aleph-X source resistors...0.47R?

[h_a]

Hi!

After reading 200 pages of the original Aleph-X monster thread (woah) I still don't know to what extent the source resistors - in hifizen's schematic 4x 0.22 Ohms per channel - can be changed without affecting performance?

I would have a bunch of 0.47 Ohm parts, would they in any way affect the performance?

Of course I could parallel them, but this seems to me just wasting parts.

Thanks for your replies!

Cheers, Hannes

[GRollins]

Now, of all the possible questions about the Aleph-X circuit, I know this one was beaten half to death in the original thread.
Oh well, once more into the breach...
The Source resistors set the bias. You'll see something on the order of .5V across those resistors. By simple application of Ohm's Law (I=E/R) you can determine the quiescent bias current.
I take no responsibility for the schematics that others have posted as variations on the original circuit. Some look okay, some don't. Likewise, I take no responsibility for the other threads, spreadsheets (some of which make no sense at all), etc.
I think it's safe to say that everything that is publicly known about the theory, design, operation, and construction of an Aleph-X is in the original thread.

Grey

[h_a]

Ups. How embarrassing

Man I'm stupid.

Sorry!

Thanks for your reply! Cheers, Hannes

PS: what was really beaten to death was the offset issue. That is definitely #1! Interestingly though solutions came up very quickly, the questions about the offset didn't stop at all.

[GRollins]

Yep, the DC offset questions continue to this day. Shows how many people read the thread before posting. As I recall that was covered early and often. It was the first thing that people who only simulated griped about and some of them never did get over it. The original circuit worked well and Ian's suggestion for the resistors made it better. And still they ask.
You can't please everyone.

Grey

P.S.: Perhaps I'm old-fashioned, but I don't think the thread is all that huge a burden to read. I read 500-1000 page books all the time and think nothing of it. Reading is out of favor. To me that's sad, but clearly I'm out of step with the times.

[Francis_Vaughan]

I've read it nearly twice now.

I think the main trouble with it is that unlike a book, there is no index. Being a single thread there are no additional sub-threads to help traverse it. There are side conversations, controversies, little spats, and sometimes it is quite hard to know that you have arrived at the final understanding of a subject. Thus, unlike a book, you are often well aware that you are reading drivel that is quite unhelpful, but that you must wade through it to find the nugget of good information you need.

Unfortunately the Wiki seems to have fallen by the wayside.

[GRollins]

The lack of an index function here is a bit of a nuisance. To make matters worse, I've found that if I make a note about a particular post in a thread (the post number is pretty much the only rational way to index things), it's not uncommon to go back later and find that the post number has changed. Why? I don't know about all cases, but I've seen instances where one or more posts ahead of the one I was interested in have been deleted, presumably by moderators. There's rarely--if ever--any word as to who did it or why, so I can only speculate. At any rate, the post number changes and I find myself reading something not at all related to what I was interested in.
As for some of the posts in the Aleph-X thread, I learned a new term about a fourth of the way in: Troll. Now, me, being a silly guy, thought that the term troll meant an ogre-like critter who lived in some dark, unsavory place like a dank, dirty cave (preferably with bones and bits of rotting flesh scattered about). The troll would then come out and kill and maim and generally create mayhem sometime after dark. In short, the sort of creature you might expect to find in a tale by the Brothers Grimm or Tolkein.
Well, there are trolls and then there are trolls.
The term appears to have been adopted by the online community to describe someone who has the metaphorical attributes of a troll, regardless of where they live or what they smell like. I didn't know this at the time, but I can kinda see the utility of the term.
Another thing I learned was not so abstract as a new use for an old word. You would think that most people would agree that trolls are bad.
Not so.
****
Brief digression in an attempt to forestall posts from those who were born in other lands. Interestingly enough, some cultures feel that the term 'troll' applies to a benign creature, even a helpful one. What this means in terms of their attitudes towards the online sort of troll, I leave to others to decide.
****
Unfortunately there are those who, for whatever dark personal reasons, feel that trolls are funny. They support the troll either actively (by participating or egging the troll on), or passively (by doing nothing to stop them). The group dynamic is something like the leader of a rough gang swaggering down the street. A few paces back, there are hangers-on who laugh at his every feeble joke, repeat every utterance as though it's Revealed Truth, and just generally create an atmosphere of threat to anyone who doesn't bow down to the head bully.
Bummer.
Worse yet, the police (read: moderators) do nothing. Why? Because at least some members of the police force think the troll is funny. This is in spite of the fact that the head bully is flagrantly breaking some of the very rules that they themselves made. (Another term I learned: Sock Puppet.)
I could go on at length about some of the things that happened behind the scenes, but I won't. Honestly, there's little point. Like some of the politicians we've had to endure here over the last few years, those who are guilty simply, flat-out, don't give a damn. They're proud of their attitudes.
So...where does that leave us? With an artificially inflated thread. But, hey, it's got half a million hits so I guess the old newspaper adage about controversy being good for circulation is still true.
Ironically, the thread was swollen by another sort of post entirely. Those who have read the entire thing will surely have noted that people kept repeating the same half-dozen questions over and over and over and over...
Now, you could blame this--at least in part--on the troll-related stuff, but there's another factor at play here; one stated rather baldly in many of the posts: They're too lazy to read the thread to find their own answers. Our culture has embraced instant gratification to such an extent that folks don't even try to understand things themselves. They want pre-digested answers served up on demand. I'm reminded of the scene in Happy Feet where Norma Jean regurgitates food for young Mumble. Normal for a penguin, perhaps, but for a human...yuk!
Oh well, life is what it is. When I started it, I had no idea that the Aleph-X thread would become what it has become; either the good or the bad.
A word of warning, though...don't ever **** off an author.
Ever.
We have subtle ways of taking our revenge and we have loooong memories.

Grey

[Eric]

I have found the Wiki to be a useful reference, but sometimes it assumes a knowledged that people like me don't have.

I created my own web page for my set of Aleph-X amps, perhaps it might be of some value to you as well. It is far from complete as my amps are still a pile of parts that have not yet been fully assembled. At the bottom, I have tried to pull some of the more useful Q&A and problem solving tidbits from the larger Aleph-X thread.

I did read all of the threads, but the organization is lacking - hence my own effort to organize it all

Eric

[RoboMan]

Originally posted by Eric

I did read all of the threads, but the organization is lacking - hence my own effort to organize it all

Eric

Well done, Eric. Save me time searching around. Keep it up!

[Eric]

Thanks, Robo! I haven't spent much time on this project in the past year, but perhaps will make some additional progress over the summer. I need to find a good source for some heat sinks and actually fabricate a chassis, then I can at least get one channel up and running. When I do, I'll be sure to update my page with additional insights and construction experiences.

There is still a great deal of information to distill from the thread as I have fallen behind in my reading...
Eric

[RoboMan]

Originally posted by Eric

...perhaps will make some additional progress over the summer. I need to find a good source for some heat sinks and actually fabricate a chassis, then I can at least get one channel up and running. When I do, I'll be sure to update my page with additional insights and construction experiences.

That will be great! Keep us informed.