The cross connection required for "X-ness" would make an
interesting comparator to a couple of reasons.
1) Both halves of a balanced class D system would enjoy
well synchronized switching
2) The low impedance loading of the Sources of the comparator
inputs could enjoy the kind of speed that Seymour Cray had
with emitter coupled logic.
3) Cool idea. You're the first to mention it.
interesting comparator to a couple of reasons.
1) Both halves of a balanced class D system would enjoy
well synchronized switching
2) The low impedance loading of the Sources of the comparator
inputs could enjoy the kind of speed that Seymour Cray had
with emitter coupled logic.
3) Cool idea. You're the first to mention it.
I never undersood how someone could go from building an A75, to an Aleph 2 to An Aleph X, then digress to playing with highly current limited no imagination spec sheet chip amps. They may sound great, but there's no artistry. It's like a master carpenter going from building curved raised panel funiture to installing drawer pulls on melamine kitchen demos at Home Depot.
The problem with large class A amps is my time to dink around with my electrics is after 9:00 PM After I've showered and am settled into my nice air conditioned house, I don't want to go intoo the hot garage and get all dirty at the drill press.
Brian/ missing the excitement of activity in Pass forum
The problem with large class A amps is my time to dink around with my electrics is after 9:00 PM After I've showered and am settled into my nice air conditioned house, I don't want to go intoo the hot garage and get all dirty at the drill press.
Brian/ missing the excitement of activity in Pass forum
You could try the chrome plated knobs or the brushed nickel ones. Three spikes or four.
Add whatever embelishments you want to the case, but it's still a quasi complementary text book three stage amp with current mirrors etc ad nausium.
Do away with the chip and just make art if that's what gets you off.
Who am I to say. There are many worse things we could do with our time.
Add whatever embelishments you want to the case, but it's still a quasi complementary text book three stage amp with current mirrors etc ad nausium.
Do away with the chip and just make art if that's what gets you off.
Who am I to say. There are many worse things we could do with our time.
After following this thread from the beginning, it seems like Uli and Petter were the only ones to get anywhere with this, and I too wonder if there has been any progress..............???
Judging from the comments, the Aleph-X is most probably a fine amplifier, however all the Alephs are somewhaat like "hot-houses" with their SE tchnology. Not that we don't need heat at my latitudes, but still,- it would be intereresting to see the thread get alive again.
The other day, Nelson tipped us off of the original diagram for the X--1000 ( and 600), and there's indeed some topological differences, particularly vs. Uli's design....
Now..............Petter and Uli...???? Still out there..??
Contrary to other posters, I don't mind gettting some dirt from the drill press after 9 PM, but unfortunately I got myself engaged in some other bussiness that still needs a few months to be ended. 24 hrs i just not enough pr.day at these times,-but now finally I do see the light at the end,-- just hope the roof still holds......
Judging from the comments, the Aleph-X is most probably a fine amplifier, however all the Alephs are somewhaat like "hot-houses" with their SE tchnology. Not that we don't need heat at my latitudes, but still,- it would be intereresting to see the thread get alive again.
The other day, Nelson tipped us off of the original diagram for the X--1000 ( and 600), and there's indeed some topological differences, particularly vs. Uli's design....
Now..............Petter and Uli...???? Still out there..??
Contrary to other posters, I don't mind gettting some dirt from the drill press after 9 PM, but unfortunately I got myself engaged in some other bussiness that still needs a few months to be ended. 24 hrs i just not enough pr.day at these times,-but now finally I do see the light at the end,-- just hope the roof still holds......
I'll second that, I am also curious about progress on the "normal" X version. The Aleph-X is hard to scale down for multi amping, because lowering rail voltage below 15 V or so hardly makes sense, and it is then still a bit much for the individual channels of a multi amp setup.
The "normal" X however can be set to a reasonable Class A bias, say 10 W, while running higher rail voltages and thus preserving a nice AB peak capability.
Interestingly NP himself uses Aleph X for the lower end of the Rushmore, and "simple" Alephs for the upper channels in the Rushmore, if I understand the brochure correctly. But there may be a variety of reasons for this, including cost, perceived value of the various amp topologies in the market etc.
The "normal" X however can be set to a reasonable Class A bias, say 10 W, while running higher rail voltages and thus preserving a nice AB peak capability.
Interestingly NP himself uses Aleph X for the lower end of the Rushmore, and "simple" Alephs for the upper channels in the Rushmore, if I understand the brochure correctly. But there may be a variety of reasons for this, including cost, perceived value of the various amp topologies in the market etc.
till said:
I believe I addressed something like that in the
Monolithic SuperSymmetry Thread.
If I do something in this area, I'll try not to boor you
by repeating myself. At the moment we are simply
playing with a variety of chips.
We're just like monkeys in a cage here, throw anything
in and we'll give it serious consideration when were not
playing with ourselves.
It has been a while since I checked into these pages, but I have an X100 running and I am happy with it. I much prefer this design to the hothouse variants of the Aleph ilk which is why I did not participate much in those threads.
The problem with building the X series amp is getting it to "balance". You can easily spend a day thinking it does not work only to realize it actually was OK. Thus, my recommendation is to build a version that auto-calibrates. I started doing that but quit - perhaps I should take it up again
Petter
The problem with building the X series amp is getting it to "balance". You can easily spend a day thinking it does not work only to realize it actually was OK. Thus, my recommendation is to build a version that auto-calibrates. I started doing that but quit - perhaps I should take it up again
Petter
First to mention a class D X amp? Hmmm. Maybe I should go back through my notes and post other ideas. To paraphrase what an older gentleman once said,"I've got more ideas than Carters' got liver pills." It's time and resources to follow through that I lack.
After all, it only took...what...one year? two? for me to go from concept to working prototype on Aleph-X. I'd like to move a lot more quickly than that.
For that matter, I thought of something while I was in the shower yesterday, but I haven't had time to puzzle it through yet. If only the folks here at work would let me bring in a soldering iron and a bunch of parts, I might get something done. Life's a bummer sometimes.
Petter,
Go for it, man. Is it the bias or the DC offset that you're wanting to calibrate?
Grey
After all, it only took...what...one year? two? for me to go from concept to working prototype on Aleph-X. I'd like to move a lot more quickly than that.
For that matter, I thought of something while I was in the shower yesterday, but I haven't had time to puzzle it through yet. If only the folks here at work would let me bring in a soldering iron and a bunch of parts, I might get something done. Life's a bummer sometimes.
Petter,
Go for it, man. Is it the bias or the DC offset that you're wanting to calibrate?
Grey
Sorry for my post earlier which was far to skimpy on the technology
Yes, it is the current sources for the input stage (4 on bottom and 2 on top) that need to "balance" in order for the output of that stage not to go completely bananas. It is not that bad once you have ironed out your design etc, but before that it is painful.
Now that I am at it, I still don't understand why somebody did not just build an X input stage as a ZenX. Using auto-adjust on the current sources and small sense resistors, it should be very easy, and you share the heat over a lot more transistors than for the original Zen. In effect, what one should consider would be a power version of the input stage of the X.
Petter
Yes, it is the current sources for the input stage (4 on bottom and 2 on top) that need to "balance" in order for the output of that stage not to go completely bananas. It is not that bad once you have ironed out your design etc, but before that it is painful.
Now that I am at it, I still don't understand why somebody did not just build an X input stage as a ZenX. Using auto-adjust on the current sources and small sense resistors, it should be very easy, and you share the heat over a lot more transistors than for the original Zen. In effect, what one should consider would be a power version of the input stage of the X.
Petter
Good question.
1. It will change with temperature
2. I fixed it by having a large drop across the current source - I had about 20V on the Zeners at the gates of the FET's so there was CONSIDERABLE degeneration. I assume half that would work as well - still over twice the value of the Vgs
3. The suggestion to use a factory tuned unit works.
4. For a high-power ZenX, you probably won't be able to afford the thermal loss of large degeneration.
5. For those not used to building circuits, the X is far too complicated to set up.
Petter
1. It will change with temperature
2. I fixed it by having a large drop across the current source - I had about 20V on the Zeners at the gates of the FET's so there was CONSIDERABLE degeneration. I assume half that would work as well - still over twice the value of the Vgs
3. The suggestion to use a factory tuned unit works.
4. For a high-power ZenX, you probably won't be able to afford the thermal loss of large degeneration.
5. For those not used to building circuits, the X is far too complicated to set up.
Petter
Few Questions if may
Hi Petter,
I just discovered this thread by luck yesterday. I have spent a good amount of time reading the entire thread. I have a few questions if I may:
1) There was mention of a V2 and V3 in your postings. Is it correct to assume the circuirts and PCB you posed are for V1?
2) It seems you have made some refinements after posting the circuit and PCB re resistor values and added a Vbe. Any chance of posting or eMailing me those updates?
3) I like to see how you implemented the 10W Class A/100W AB and 50W Class A/100W Class AB so you can change via the external case switch you installed. Pic not needed just what points you tapped to, the values you used to switch between or add in parallel or series to enable the bias value change and method of value change as in did you just switch in different value or switched in a series or parallel value?
4) Is there a formula to determine different Class A/Class AB threshold points? If so what or where is this formula?
5) There seemed to be some reference to using output drivers in quadruplets? Is this a fixed requirement of this design that one has to use or can one choose to use 2 or one set of output devices per side of X? I realize this implies less power, that is ok, I am well aware that may be case.
6) Indication is this design scales well. What PSU or componet value calculations does one use to scale the design? For your implementation I cannot recall the Secondary Vac you used and resulting VRail of your supply design. I have a number of PSU based calculations, but seems the PSU calculations vary widely due to topogogy of the amp. Some topologies need certain key component values recalculated for different PSU rail voltages.
7) Any general thoughts on use of PSU chokes in terms or pros and cons that may be specific to this amplifier design?
I think to have a question or two more, but cannot recall now as my mind tries to review all that I read in thread in my head. Petter, If you have anything to add or is suggested to be commented or added upon due to my questions above, feel most free to do so.
Regards,
John L. Males
Willowdale, Ontario
Canada
13 January 2005 14:52
Regards
Hi Petter,
I just discovered this thread by luck yesterday. I have spent a good amount of time reading the entire thread. I have a few questions if I may:
1) There was mention of a V2 and V3 in your postings. Is it correct to assume the circuirts and PCB you posed are for V1?
2) It seems you have made some refinements after posting the circuit and PCB re resistor values and added a Vbe. Any chance of posting or eMailing me those updates?
3) I like to see how you implemented the 10W Class A/100W AB and 50W Class A/100W Class AB so you can change via the external case switch you installed. Pic not needed just what points you tapped to, the values you used to switch between or add in parallel or series to enable the bias value change and method of value change as in did you just switch in different value or switched in a series or parallel value?
4) Is there a formula to determine different Class A/Class AB threshold points? If so what or where is this formula?
5) There seemed to be some reference to using output drivers in quadruplets? Is this a fixed requirement of this design that one has to use or can one choose to use 2 or one set of output devices per side of X? I realize this implies less power, that is ok, I am well aware that may be case.
6) Indication is this design scales well. What PSU or componet value calculations does one use to scale the design? For your implementation I cannot recall the Secondary Vac you used and resulting VRail of your supply design. I have a number of PSU based calculations, but seems the PSU calculations vary widely due to topogogy of the amp. Some topologies need certain key component values recalculated for different PSU rail voltages.
7) Any general thoughts on use of PSU chokes in terms or pros and cons that may be specific to this amplifier design?
I think to have a question or two more, but cannot recall now as my mind tries to review all that I read in thread in my head. Petter, If you have anything to add or is suggested to be commented or added upon due to my questions above, feel most free to do so.
Regards,
John L. Males
Willowdale, Ontario
Canada
13 January 2005 14:52
Regards
Re: Few Questions if may
A lot of questions - far too detailed to work in the middle of the night. In fact I might not be able to answer most of them but will do my best - probably next week, but some are a bit general. In the meantime: Item 6 - the design is inherently scalable. As long as the power ratings of each component is not exceeded all you have to do is to change the supply voltages. Note that the input stage needs higher voltage than the output voltage in order to be able to drive the output stage to full power. Watch out power dissipation, especially on input FET's.
I am currently on version 3. Considering doing version 4. The basic topology is essentially the same for all - the intial drawing was that good - with the exception of not needing any resistors to ground as per patent, and reduction of the "X" resistor - I have tried short-circuiting it with no issues.
Petter
keypunch said:
A lot of questions - far too detailed to work in the middle of the night. In fact I might not be able to answer most of them but will do my best - probably next week, but some are a bit general. In the meantime: Item 6 - the design is inherently scalable. As long as the power ratings of each component is not exceeded all you have to do is to change the supply voltages. Note that the input stage needs higher voltage than the output voltage in order to be able to drive the output stage to full power. Watch out power dissipation, especially on input FET's.
I am currently on version 3. Considering doing version 4. The basic topology is essentially the same for all - the intial drawing was that good - with the exception of not needing any resistors to ground as per patent, and reduction of the "X" resistor - I have tried short-circuiting it with no issues.
Petter
Re[03]: Few Questions if may
Hi Petter,
Thanks for the reply. No hurry, I know you can be very busy. Some of us think better at night!
There was excellent infomation in this thread, not much diversion as the project proceeded and other inquiries and ideas evolved as progressed.
Excellent that can scale so easy, just what I need as well as not heaing up place in process.
Look forward to your reply when you have time.
Regards,
John L. Males
Willowdale, Ontario
Canada
13 January 2005 22:50
Hi Petter,
Thanks for the reply. No hurry, I know you can be very busy. Some of us think better at night!
There was excellent infomation in this thread, not much diversion
as the project proceeded and other inquiries and ideas evolved as progressed.Excellent that can scale so easy, just what I need as well as not heaing up place in process.
Look forward to your reply when you have time.
Regards,
John L. Males
Willowdale, Ontario
Canada
13 January 2005 22:50
