The Aleph-X

[Joe Berry]

After a little more digging on this topic, I'm forced to agree that battery operation would be prohibitively expensive here. My initial cost estimate simply multiplied the rate of consumption by the desired playing time to arrive at a total battery capacity requirement.

In reality, this is way off base if you need the battery voltage at the end of play to be within 10% or so of the starting voltage. In that case, according to sources I've read, you have to multiply that basic capacity figure by a factor of 20 or more, at which point cost goes through the roof.

As a side note, this exercise has given me a new respect for the spring motor in my 77-year-old Victrola, from which I can get several minutes of reasonably pitch-stable play from a few turns of the crank.

[GRollins]

And it's class A without the heat, too, in that all driven devices carry all the waveform, all the time...

Grey

[rtirion]

Grey,

Did you check the phase behaviour of your ALEPH-X?.

I am getting some strange results when running sims. But then it could be that I am doing something wrong running the sim.
Running the same sim on a normal ALEPH 3 gives good results. At least what I would expect.
I hope the real world circuit is not plagued by any of this.

regards

[GRollins]

Can you be a little more specific?

Grey

[HarryHaller]

"I am getting some strange results when running sims. But then it could be that I am doing something wrong running the sim." Or it could be that the amp has insufficient phase margin.....

Phase margin perhaps? Remove C104 in your Aelph 3 simulation and see what happens. Also try adding 0.047uF cap from collector to emmiter of Q105 and tell us what happens with and without C104.

http://www.engin.umich.edu/group/ctm/freq/freq.html

H.H.

[rtirion]

Thanks Harry. Yes, phase margin.

It is not always easy to find a correct translation. I could try and post some comparising plots from the sim later this week. Of course I will check if I am not making some stupid mistake.

Regards

[john-china]

hi Grey !
i think , your alphe-x is only based on patent #5,710,522 of nelson pass . i can see nothing based on patent #5,376,899 of pass. the circuit is only a bridge alpeh . if i am wrong , pls correct me.

[GRollins]

John,
That's the sneaky part about X stuff, it doesn't look like much once you strip the cascodes and current sources off. It's nothing more than a feedback strategy for balanced circuits. Pretty simple really. Get out the patent, ignore all the fancy stuff, and trace the signal phase relationships. You have no idea how many times I looked at that patent before the light came on over my head.

Okay, folks, I finally got a chance to play cap games with this circuit. I put caps in here and there and...nothing happened. Zippo. Nada.
So I says to myself,"Self, what's going on here?"
I mean, rtirion has this thing run up in his simulation program and says something looks funny. Harry is being Harry--even to the point of spewing vituperation at me about this in an unrelated thread. And, yes, there are one or two caps (depending on the model) in Nelson's Alephs that I don't have in this circuit. So what's the deal?
I'm sitting here looking at the circuit and most of it's assembled on three of those experimenter boards that you push parts into, and it occurs to me to wonder what the capacitance between the rows of contacts might be. I've always assumed that it's low...on the order of a few pF. But what if it's higher? The total distributed capacitance could add up to a fair amount, depending on whatever the individual numbers might be. If so, that might be a nice--albeit unpredictable--bandwidth limiter.
Short of doing a complete layout, etching a board, and trying that, does anyone have any suggestions for solving this conundrum?

Grey

P.S.: Harry, I'm more than willing to try to work this out to everyone's satisfaction, but your arrogance, condescension, and negativity wears thin. If you have something constructive to add, by all means do so, otherwise please refrain from burning bandwith on the Net. You have alienated members of this site to the point that people are leaving and many others dread your posts in their threads. My e-mail tells me that the ratio is about ten or twenty to one against you.
This is <i>not</i> a good sign.
If you don't intend to help, and I mean <i>real</i> help, not stunts like tossing an admitted newbie with a non-functioning Aleph a URL suited more suited for 2nd year EE students (what the dickens were you thinking, man?), then don't bother posting.
And, yes, I did make an attempt to explain current sources (both standard and Aleph) in layman's terms...more than you could be bothered to do. If this is what getting an EE does to someone's attitude, I'm glad I didn't get one (I considered it briefly before doing geology and psychology instead).
Or, in the vernacular, buzz off.

[janey]

hello.


how much power we get with 20V supply rails on 4 ohm load and
and how much bias current we need for this

i realy do not know how to calculate this.
can somebodi hellp me (Grey)?

thanks

janey

[HarryHaller]

OH PLEASE! I have never gotten an Email complaining about my post and you have gotten enough to discern 10 to one ratios on for and against? I guess we will have to take your word on this one. I have seen you lobby to keep 17 year olds that with unquestionably abusive language on the forum and yet I am driving people away? Isn't there a feature where one can block certain posters? I'm sorry that some what I post is over a few people heads. Guess what, alot of it isn't and some people read it and learn something new. It seems to me that I see more "thank you, Harry"s than "buzz off Harry"s in reponse to my post....

H.H.