The Aleph-X

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#1,803
XA Offset Circuit Addition

I see the circuit as very smart.
Are the diodes introduced for a precise adjustment within about 1.4V?
Is it better than using resistors?
What will happen if we use zener diodes?

JH

PS. Do not shout, be kind pls.
 
#1,806
The stranger had ridden just past the last building on the street and the desert opened before him like a vista of infinite possibilities. Behind him, he could hear other voices joining the argument about the number of ounces in a pound. A passing housewife had been dragged in against her will. And the mayor just had to put in his opinion. Then yet more people had joined in.
The stranger stopped Aleph, turned sideways in the street, and looked back at the growing knot of people. The EE Kid had sidled to the edge of the fracas and was making his way over to stand with the deputy, leaning against the front of the the barber shop. The EE Kid had a sly smile on his face. The deputy appeared to be making a bet with the EE Kid.
The stranger watched for a few minutes as the argument swelled to include still more people.
He then looked the other way, to the mountains. It would be quiet there, peaceful, and there were new things to be found. Better still, there were mountains even beyond those, places he had never been before.
He turned back to the group of people arguing in the street, then looked again at the mountains.
He tugged the reins, turning Aleph, and rode on...

Grey
 
#1,808
Originally posted by super-troll Fred Dickman.
He sure has got quite a "Netlist" of available IP's he can play with, too. Too bad he can't excape from his paranoia and neither can diyaudio.


"By Vv2 I suppose you the pot that adjust the current source for the front end. That pot adjust the absolute DC offset. the circuit shown adjust the differential or relative offset across the speaker. It is only necessary to have the circuit on one side of the diff pair and it can compensate for a positive or negative offset voltage. I think the inputs to the 10K resitors or the actual input signal for the amp should be Ac coupled for this to work best. Looks like a good way to trim the relative offset without changing other parameters in the amp. Kudos Mr. Rollins."
Click to expand...

Fred knowledge is there, no question about it, and it's all nice and dandy, the circuit I mean. What Fred doesn't tell you is that it is completely unncecessary and it's just mental masturbation. Pick mosfet within 30mV, measure the drop on the source resistors before you put them in the circuit, and there will be absolutely NO need for anything besides what's in the most current schematic.
It's the same story as with the HH CCS. Using a ultra low noise CCS and then having 9610 in the differential maybe only cuts the overall noise in half. I made it a point last night to try both CCSs. Could't hear any difference. Fred didn't tell you that either.
By the way, who came up, besides Nelson, with the "MacMillian" resistors, the only useful mod to Grey's original circuit? Ooops!
Also, I forgot that Peter also made his contribution by Ac coupling the input. So don't throw away your AX board just yet. 😉

It seems he has no genuine interest in people succeding in completing their projects. All he wants to do is perpetuate the state of paranoia that there is something wrong in your circuit, something that could be so dramatically improved to the point of changing your overall outlook on life. That is simply not so.

So it comes down to the two proverbial pills. Take the blue pill stay in wonderland, keep believing whatever Fred wants you to believe. Take the red pill, and come to the real world!
 
#1,809
Netlist

quote:

"Originally posted by super-troll Fred Dickman.
He sure has got quite a "Netlist" of available IP's he can play with, too. Too bad he can't excape from his paranoia and neither can diyaudio."

Hi, all, Grataku,

I'm new here. I was lurking on this forum for a few weeks. I registered this morning to help Bricolo with the Spice models. Post #1800, #1801. I can understand that some poeple get a bit paranoia with all the sad things that happened here the last weeks, months...
Please, don't think that "Netlist" is another alias for Fred.
I will post something from myself in the 'Introductions' section later.
Let me tell you that i like this forum very much and i will try to help if i can. 😕 😉
 
#1,810
Netlist,
just as long as you are here to help. 😉 Do you happen to know a guy by the name of Jean-Paul? He should be a neighbor of yours that left the forum awhile ago, he was very knowledgeable, and pretty nice to have around, too. Anyway, Welcome to the forum!
 
#1,815
Pinkmouse has thrown Grey into the sin bin for rude remarks directed towards Fred. You can find this info in "Everything Else".

The cycle continues. We may lose Grey again........
Click to expand...
Guys

I like Grey, he's a very clever bloke. I want him back because I probably be building a Mini A soon, and I am bound to muck it up, and will need his help. His contibution to this board has been, and hopefully will carry on being excellent. He has inspired many projects, and many people are now listening to bits of kit based on his ideas.

I told him that in the email I sent him when I sinbinned him.

If you read his posts in Texas they are a clear and odious personal attack on Fred, and against the rules of the board. He asked for this sentence, and I am not going to apologise for awarding it. One of the things that annoyed me as a member was when justice seemed to be a variable factor, depending on who you knew, like an old boy's network. I think that is wrong, and an insult to all of us, so I am trying not to fall into this trap.
I've about had it with this place.............
Click to expand...
So have I, So have I...🙁
 
#1,816
grataku said:
It seems he has no genuine interest in people succeding in completing their projects. All he wants to do is perpetuate the state of paranoia that there is something wrong in your circuit, something that could be so dramatically improved to the point of changing your overall outlook on life. That is simply not so.
Click to expand...
Paranoia???

It sounds too strong.
Recently, I have heard of people here and there complaining the DC offsets.
What is wrong with the suggestion of a "working" solution?

Mine is not always perfect. :xeye:
Yours is not always perfect either. :xeye:

--Just a thinking--
 
#1,817
Well,

On a happier note I am please to report My X Aleph is up and going 1st pop.

Inital measurements are 500mv across the 0.22 source resisters all round, 66 mv dc offset and after tweeking I got about 27mv absolute Dc offset. (Is this the correct Bias level?)

I have not checked anything else yet but assume all is well.

The diff pair were match to within 5mv Vgs @3.63 volts and the 240's within 100mv @4.33, although this was at 1.00 amp (for the Aleph 5)

So I feel lucky, now to make the other channel and make music.

My speakers mids are being reconed so I cannot play it today but I have a nice pair of puppies (Century L100s) on their way to me.

cheers

Ian
 

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#1,820
GRollins said:
JH,
... I think you'll find that the resistor between the two Sources, unless it's really small (in which case it doesn't really separate the two halves of the differential), will interfere with the signal crossing from the Source of the driven side to the Source of the undriven side. As a result, the front end won't function very well as a phase splitter. ...
Click to expand...
I understand what you mean. However, when I have a balanced source, I expect that the output signal amplitudes of the +/- sides will be virtually the same, and the bridge resistor will act just as a controller of the amplitudes. In this respect, I do not understand the meaning of the interference. The interference is only with respect to the unbalanced source...?

JH
 
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