As it happens, I have a few notes here and there on variations on the Aleph-X theme. I've got 'em stashed in nooks and crannies where they pop out and bite me at intervals. (Cascode is one of them, but I've got some other ideas along those lines that interest me more.) In fact, I came across my notes pertaining to the DC offset problem the other day, including the resistors that I talked myself out of (and Ian [good for him] followed through on), and some other things I never got a chance to try.
At the moment, I'm really pressed for time. Been working the bees (extracting honey--"Yum, yum," as Winnie the Pooh is fond of saying), getting some fall veggies in the ground for my wife (I dasn't eat the things--yuk--gimme steak 'n 'taters...uh, don't forget the wine), getting stories written (and sold!), putting up Sheetrock (then mud and tape, then painting) on the remaining wall in the room where I do my Mad Scientist stuff, etc. etc. etc. Can't find time to breathe. Now, they tell me that the hurry-cane is going to blow high winds all over me tomorrow and tomorrow night, so I gotta get out the Super Glue and fasten my house to the ground so that it doesn't end up like Dorothy's house in The Wizard of Oz. Don't worry, I'm over-dramatizing...my understanding is that we'll only be doing 35 MPH or thereabouts. My main worry is that the gusts will topple some of the trees killed by the drought over the last few years.
As I've said before, I'll do the best I can given the time I've got. One fine day, I'll figure out how to make a penny at this and quit my day job. That'll insert another nine hours per day into my life. In the meantime, I'll muddle along. Be patient. If you can't be patient, run on ahead and I'll toddle on behind, trying to catch up with you.
Grey
At the moment, I'm really pressed for time. Been working the bees (extracting honey--"Yum, yum," as Winnie the Pooh is fond of saying), getting some fall veggies in the ground for my wife (I dasn't eat the things--yuk--gimme steak 'n 'taters...uh, don't forget the wine), getting stories written (and sold!), putting up Sheetrock (then mud and tape, then painting) on the remaining wall in the room where I do my Mad Scientist stuff, etc. etc. etc. Can't find time to breathe. Now, they tell me that the hurry-cane is going to blow high winds all over me tomorrow and tomorrow night, so I gotta get out the Super Glue and fasten my house to the ground so that it doesn't end up like Dorothy's house in The Wizard of Oz. Don't worry, I'm over-dramatizing...my understanding is that we'll only be doing 35 MPH or thereabouts. My main worry is that the gusts will topple some of the trees killed by the drought over the last few years.
As I've said before, I'll do the best I can given the time I've got. One fine day, I'll figure out how to make a penny at this and quit my day job. That'll insert another nine hours per day into my life. In the meantime, I'll muddle along. Be patient. If you can't be patient, run on ahead and I'll toddle on behind, trying to catch up with you.
Grey
Well, that's all very nice Grey, but you get the prize anyway by
popular acclaim. And since you're too busy to build anything
with the parts I would have sent you, I have a nice bottle
of French wine that will depart via UPS as soon as I get
your address.
😎
popular acclaim. And since you're too busy to build anything
with the parts I would have sent you, I have a nice bottle
of French wine that will depart via UPS as soon as I get
your address.
😎
Congrats Grey, you deserve it well. 
Welcome back by the way, glad too see your constructive posts again.
Hope the hurricane doesn't rip you and your bee nests apart.
/Hugo - continuing debugging this monster thread. 😉
Welcome back by the way, glad too see your constructive posts again.
Hope the hurricane doesn't rip you and your bee nests apart.
/Hugo - continuing debugging this monster thread. 😉
Who?
Me?
I didn't do nothin'. Just threw some parts together. It worked. End of story.
Almost...
Grey
Me?
I didn't do nothin'. Just threw some parts together. It worked. End of story.
Almost...
Grey
Congratulations Grey
You deserve the wine Nelson Pass is going to send you.
Thanks for starting this thread, which inspired me to build an aleph-x - and its nice to see you posting again!!
/Hans - who has read this entire thread 2 times
You deserve the wine Nelson Pass is going to send you.
Thanks for starting this thread, which inspired me to build an aleph-x - and its nice to see you posting again!!
/Hans - who has read this entire thread 2 times
Netlist said:
Sounds like a good idea to me. I think I started a framework for Aleph-X stuff in the wiki, but then I was tied up with the bulk order, and then life went off the tracks for a few months... Things are looking a bit better for me lately, so perhaps I'll find some time to pitch in as well. I'm really looking forward to getting back to the A-X project after almost 6 mo. off!
I would encourage anyone else who has some time, to help out by editing the page. That's what it's there for, and we sure do need it! If we're real organized, perhaps we can split up this thread into digestible chunks for each person...
here's the link: Aleph-X wiki page
Hans B said:Congratulations Grey
You deserve the wine Nelson Pass is going to send you.
Thanks for starting this thread, which inspired me to build an aleph-x - and its nice to see you posting again!!
/Hans - who has read this entire thread 2 times
Here, Here! Three cheers for Grey!
I hadn´t checked this thread for a while and its at 2500 posts. I have alot of reading to do, lol!
Congradulations to all the guys who participated here. And what a great job you guys are doing with the aleph x.
Congradulations to all the guys who participated here. And what a great job you guys are doing with the aleph x.
hifiZen said:
Hi hifiZen, all
I started with transferring the whole thread into a word.doc.
Then I deleted a lot of unnecessary stuff (like non technical and off-topic posts), but there's still too much in it to work in a decent manner.
The basic technical knowledge is already converted into another word document.
So we could say that an original AlephX version could be build with what I extracted.
Give us some ideas to organize something for a group effort. (Preferably not too much people)
/Hugo
The little room where I do my Mad Scientist experiments is in the basement. Things were pretty messy, so I decided to clean up a bit. Well, that was a couple of months ago. One thing led to another, and another, and another...ugh. Anyway, the point is that I had an Aleph-X channel on the bench, running tests on it back last spring. In particular, I measured the distortion, which will be of more interest to some than others, but it's interesting to know, either way.
Then the notes got lost in all the mess.
Why, I don't know. Pieces of paper develop legs and wander off when I'm not watching. So I'm shuffling some paperwork relating to calculations for the active crossover I'm building and what falls out, but part--only part--of the distortion notes.
I'm going to post this before I lose my notes again.
Looks like distortion at 1kHz was .058% with 12V rails.
With 18.3V rails, the distortion dropped to .037%. Note that, at least to a first approximation, nothing else was changed. Just the rail voltage. The front end runs off of a current source, so that's going to remain pretty close to 20mA or so. Yes, you could argue that a Zener fed by a resistor will shift a bit. True. But it'll remain fairly close. The back end is biased by a current source also. So we end up with a more-or-less clear example of increasing voltage reducing distortion. This will be a diminishing returns curve. You can't run the rails up to, say, 100V and expect to get 0% distortion.
Also on this scrap of paper I have the following:
Distortion at 10Hz .041%
At 100 Hz .041%
At 1kHz .043%
At 10kHz .057%
But I don't know what the rails were (probably 15V) or any other test conditions. Perhaps that was on the piece of paper prior to this one. Where that piece of paper is, is a mystery. Probably in with the line stage notes. Maybe with the phono stage notes. Who knows? If I find it, I'll post.
There are also some notes here about various values of mica caps in the NFB loop. Looks like 6pF gave a bit of overshoot on a 10kHz square wave. I believe I settled on 10pF in the end.
Be aware that my amp here runs harder than a lot of the other ones out there. I've got a 2.5 ohm load to push, so I biased the circuit a bit harder than the "stock" version. Your mileage may vary, as the expression goes.
Grey
Then the notes got lost in all the mess.
Why, I don't know. Pieces of paper develop legs and wander off when I'm not watching. So I'm shuffling some paperwork relating to calculations for the active crossover I'm building and what falls out, but part--only part--of the distortion notes.
I'm going to post this before I lose my notes again.
Looks like distortion at 1kHz was .058% with 12V rails.
With 18.3V rails, the distortion dropped to .037%. Note that, at least to a first approximation, nothing else was changed. Just the rail voltage. The front end runs off of a current source, so that's going to remain pretty close to 20mA or so. Yes, you could argue that a Zener fed by a resistor will shift a bit. True. But it'll remain fairly close. The back end is biased by a current source also. So we end up with a more-or-less clear example of increasing voltage reducing distortion. This will be a diminishing returns curve. You can't run the rails up to, say, 100V and expect to get 0% distortion.
Also on this scrap of paper I have the following:
Distortion at 10Hz .041%
At 100 Hz .041%
At 1kHz .043%
At 10kHz .057%
But I don't know what the rails were (probably 15V) or any other test conditions. Perhaps that was on the piece of paper prior to this one. Where that piece of paper is, is a mystery. Probably in with the line stage notes. Maybe with the phono stage notes. Who knows? If I find it, I'll post.
There are also some notes here about various values of mica caps in the NFB loop. Looks like 6pF gave a bit of overshoot on a 10kHz square wave. I believe I settled on 10pF in the end.
Be aware that my amp here runs harder than a lot of the other ones out there. I've got a 2.5 ohm load to push, so I biased the circuit a bit harder than the "stock" version. Your mileage may vary, as the expression goes.
Grey
Hi Grey, what do you use to measure THD? A HP339? Just curious.
It looks like a large drop in distortion for a very low voltage increase. I am assuming all the dc were set back to 0 and that the AC current gain was readjusted, when varying the voltage I notice things change quite a bit.
At what power did you make the measurements?
It looks like a large drop in distortion for a very low voltage increase. I am assuming all the dc were set back to 0 and that the AC current gain was readjusted, when varying the voltage I notice things change quite a bit.
At what power did you make the measurements?
HP339. Those of us who can't afford an Audio Precision have to make do with more mundane hardware.
As far as power, I think that was at 1W. Possibly, but not probably, at 10W. I tend to think in terms of ones in cases like that, but it's either written somewhere else or I didn't get it written down at all.
Grey
As far as power, I think that was at 1W. Possibly, but not probably, at 10W. I tend to think in terms of ones in cases like that, but it's either written somewhere else or I didn't get it written down at all.
Grey
Mosfet distortion becomes more sensitive to voltage at thegrataku said:
lower rail voltages.
Hi,
If you allow me, this is a nice paralel that applies to tubes just the same...mossies and tubes share a lot of characteristics.
Cheers,😉
If you allow me, this is a nice paralel that applies to tubes just the same...mossies and tubes share a lot of characteristics.
Cheers,😉
Frank,
One of these days you are going to come over to our side...............😀
Regards,
Jam
P.S. Do you have any curves that show distortion vs plate voltage?
One of these days you are going to come over to our side...............😀
Regards,
Jam
P.S. Do you have any curves that show distortion vs plate voltage?
Hi,
Just trying to help you guys...
When it comes to reproducing music consider me a very stubborn tube lover...I know exactly how magical they CAN sound.
I also know how expensive this hobby can be...
I'm also a vinyl addict...does that put me into Jurassic Park?
Prejudice reigns in both camps, I made a choice...maybe it's time for you to make yours?
Both technologies can live together, Jam...My ears tell me tubes.
Yours may well be different.
We're all different in the end.
Thing is, most SS and tube ideas aren't that innovative as people seem to think they are...
Tubes are fascinating, they do anything related to music and much, much more...
Study industrial industry and you may soon share my fascination...
and fascinating it is.
Cheers,😉
Just trying to help you guys...
When it comes to reproducing music consider me a very stubborn tube lover...I know exactly how magical they CAN sound.
I also know how expensive this hobby can be...
I'm also a vinyl addict...does that put me into Jurassic Park?
Prejudice reigns in both camps, I made a choice...maybe it's time for you to make yours?
Both technologies can live together, Jam...My ears tell me tubes.
Yours may well be different.
We're all different in the end.
Thing is, most SS and tube ideas aren't that innovative as people seem to think they are...
Tubes are fascinating, they do anything related to music and much, much more...
Study industrial industry and you may soon share my fascination...
and fascinating it is.
Cheers,😉
Well I like all sorts of wine, and I like all sorts of
people (I started to say women), cars, etc, etc, ....
All these things are fun and deserve appreciation.
people (I started to say women), cars, etc, etc, ....
All these things are fun and deserve appreciation.
sounds good
The Aleph-X is back in the work shop. The mini-a is getting the torture test. Listening to Sponge Bob and Rugrats daily. Turned on and off fifteen times a day. It has made it through the first week. Back to the X. I was listening to it tonight and thinking this really sounds nice. Thanks Mr. Pass and Pass DIY. .😀
The Aleph-X is back in the work shop. The mini-a is getting the torture test. Listening to Sponge Bob and Rugrats daily. Turned on and off fifteen times a day. It has made it through the first week. Back to the X. I was listening to it tonight and thinking this really sounds nice. Thanks Mr. Pass and Pass DIY. .😀