OK, this is an update on the "unified" PCB design / purchase effort (separate from Carpenter's PCB fab run) from the Aleph-X thread.
Grataku has graciously offered his layout as the starting point for this design, and BrianGT has also offered to help with layout work. Grataku's layout is similar to tvi's (see previous posts in main Aleph-X thread to get an idea of what grataku's boards look like). The design at present includes most of the following features:
- absolute DC offset nulling resistors added (output to diff pair sources ala Ian)
- Local rail decoupling
- options for either Fred's current source, or Grey's (option for R17 to either ground or negative rail)
- footprints for stability capacitors will be included (may not be necessary, but they'll be there in case they're needed)
- maximum symmetry
- back-to-back diff pair for thermal coupling
- optimized grounding scheme
- two transistors on each end of the board (like tvi's layout), all facing up so they can be mounted to a non-flanged heatsink as well as the Conrad Engineering double-flanged MF30 series heatsinks
These were the list of features members have requested so far. If you have anything else you'd like to add to the "wish list" please post or email me soon!
The plan at this point is to start by prototyping (rev. Beta) grataku's design at expresspcb.com. These boards will be available very soon, probably in about a week or so. After the proto boards are fabbed, then we will have some time to build and test while I copy the design into Protel, and do a the Gerber/NCD file generation for the professional fab house. Once rev Beta is tested and refinements are made, rev. 1.0 will go out for the main order.
The large order will probably go to Advanced Circuits for fab. They are a professional fab house, with excellent equipment and tight tolerances. The boards which emerge will be production quality, with the following features:
- Double sided
- extra-heavy 2oz. copper (heavier available, up to 4oz at greater cost)
- plated through-holes
- high quality LPI (photo-printed) solder mask, both sides
- single side silkscreen
- 3 x 4.5 inch dimensions (based on tvi's compact board layout)
- routered edges, not sheared or sawn
These will be top-of-the-line cadillac boards!
Pricing is roughly:
20pcs: $24 each
30pcs: $16 each
40pcs: $12 each
50pcs: $10 each
Shipping costs are additional. The current order count I have is about 26 boards. This number should increase as more people come on board (pun fully intended
). Tentative timeline for delivery of the rev. 1.0 boards is pre- Christmas. We'll see how it goes and take it one step at a time - I hope we can get there sooner.
Grataku has graciously offered his layout as the starting point for this design, and BrianGT has also offered to help with layout work. Grataku's layout is similar to tvi's (see previous posts in main Aleph-X thread to get an idea of what grataku's boards look like). The design at present includes most of the following features:
- absolute DC offset nulling resistors added (output to diff pair sources ala Ian)
- Local rail decoupling
- options for either Fred's current source, or Grey's (option for R17 to either ground or negative rail)
- footprints for stability capacitors will be included (may not be necessary, but they'll be there in case they're needed)
- maximum symmetry
- back-to-back diff pair for thermal coupling
- optimized grounding scheme
- two transistors on each end of the board (like tvi's layout), all facing up so they can be mounted to a non-flanged heatsink as well as the Conrad Engineering double-flanged MF30 series heatsinks
These were the list of features members have requested so far. If you have anything else you'd like to add to the "wish list" please post or email me soon!
The plan at this point is to start by prototyping (rev. Beta) grataku's design at expresspcb.com. These boards will be available very soon, probably in about a week or so. After the proto boards are fabbed, then we will have some time to build and test while I copy the design into Protel, and do a the Gerber/NCD file generation for the professional fab house. Once rev Beta is tested and refinements are made, rev. 1.0 will go out for the main order.
The large order will probably go to Advanced Circuits for fab. They are a professional fab house, with excellent equipment and tight tolerances. The boards which emerge will be production quality, with the following features:
- Double sided
- extra-heavy 2oz. copper (heavier available, up to 4oz at greater cost)
- plated through-holes
- high quality LPI (photo-printed) solder mask, both sides
- single side silkscreen
- 3 x 4.5 inch dimensions (based on tvi's compact board layout)
- routered edges, not sheared or sawn
These will be top-of-the-line cadillac boards!
Pricing is roughly:
20pcs: $24 each
30pcs: $16 each
40pcs: $12 each
50pcs: $10 each
Shipping costs are additional. The current order count I have is about 26 boards. This number should increase as more people come on board (pun fully intended
). Tentative timeline for delivery of the rev. 1.0 boards is pre- Christmas. We'll see how it goes and take it one step at a time - I hope we can get there sooner.When stops the ordering?
I don't know yet which board I need, this one or the carpenter board. I haven't the other parts yet, so time is not an issue. Also I am not sure what to build the Aleph 30 or the Aleph-X. I think the Aleph-X is better. I looked at the orginal circuit of Grollins, and the complexity of both circuits is of the same order to construct (O ).
Some advice on what board to choose?
I don't know yet which board I need, this one or the carpenter board. I haven't the other parts yet, so time is not an issue. Also I am not sure what to build the Aleph 30 or the Aleph-X. I think the Aleph-X is better. I looked at the orginal circuit of Grollins, and the complexity of both circuits is of the same order to construct (O
).Some advice on what board to choose?
- single side silkscreen
Just the opposite! The silkscreen shows the location, outline, polarity,and refererence designators for stuffing the parts. For parts mounted on only one side of the board it is the standard approach. The only double silkscreens I recall seeing were for mounting SMT parts to both sides of the PCB.
Fred
Just the opposite! The silkscreen shows the location, outline, polarity,and refererence designators for stuffing the parts. For parts mounted on only one side of the board it is the standard approach. The only double silkscreens I recall seeing were for mounting SMT parts to both sides of the PCB.
Fred
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I was wondering about the same thing: scalability. Will the board feature a specific number of mosfets, or will it more like an Aleph design where the input stage and output stage are not part of the same board. In this manner, it seems that, like an Aleph, I could build an amp to suit my specific power needs and heat concerns.
Hi,
To Whoever requested the mother-daugther boards let me clarify how I see this effort, maybe HiFiZen and John would like to add or subtract from what I am saying: we are shooting for an alephX between aleph3 and 5 in terms of power. The times are not mature yet for a universal, high power AlephX. This is not a 'kit' either, it's just a non-profit (people that don't believe that should call Nelson lawyers for more in depth explanation) effort between a group of friends making something beautiful for a reasonable price and having a lot of fun in the process.
What we need to do right now is prototype, that includes testing the layout correctness, Fred CCS, DC offset, turn on-off transient, GROUNDS-trafo flux noises ETC, ETC. Adding outboard wiring and little boards flying all over the place is not going to help at this stage of the game.
If all goes well with prototyping the project may go on to higher powers and bigger and better things, but the foundations need to be solid for that to happen.
We are looking for is at least 10 volunteers willing to jump into prototyping for about $20? dollars a board or less. We have about 3 to 4 at this point, I think. After 15 production boards (to be used as prototypes) may become more convenient than prototypes at least with expresspcb.
Interested parties should send an email to Chad (HiFZen) which is the coordinator.
thank you
To Whoever requested the mother-daugther boards let me clarify how I see this effort, maybe HiFiZen and John would like to add or subtract from what I am saying: we are shooting for an alephX between aleph3 and 5 in terms of power. The times are not mature yet for a universal, high power AlephX. This is not a 'kit' either, it's just a non-profit (people that don't believe that should call Nelson lawyers for more in depth explanation) effort between a group of friends making something beautiful for a reasonable price and having a lot of fun in the process.
What we need to do right now is prototype, that includes testing the layout correctness, Fred CCS, DC offset, turn on-off transient, GROUNDS-trafo flux noises ETC, ETC. Adding outboard wiring and little boards flying all over the place is not going to help at this stage of the game.
If all goes well with prototyping the project may go on to higher powers and bigger and better things, but the foundations need to be solid for that to happen.
We are looking for is at least 10 volunteers willing to jump into prototyping for about $20? dollars a board or less. We have about 3 to 4 at this point, I think. After 15 production boards (to be used as prototypes) may become more convenient than prototypes at least with expresspcb.
Interested parties should send an email to Chad (HiFZen) which is the coordinator.
thank you
I think it might be a good idea to design one board with 4 output devices (like Grey's version). It should be able to provide around 40-50W which is plenty for bi-amping or tri-amping, or for home theatre purposes. More output devices on a single board will complicate the layout. Now, if somebody wants still to use this board with more power and more output FETs, all he has to do is to use separate output board or p2p technique and use the universal board only for front end without output FETs.
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Please don't get me wrong
, an earlier post asked for suggestions, I was just naming one that occurred to me 
. Granted, now may not be the best time, but it may be an item worty of a future wish list 
Peter: I had this thought at the same time as you. It seems adding more output devices would be a relatively easy point-to-point addition.
Please don't get me wrong, an earlier post asked for suggestions, I was just naming one that occurred to me .
Eric,
my aim was to simply clarify the situation, so no problem here!
Granted, now may not be the best time, but it may be an item worty of a future wish list
Absolutely, once the concept is developed the whole thing can be passed down to the EE dept. to squeeze the last watt out of the design.
Eric,
my aim was to simply clarify the situation, so no problem here!
Granted, now may not be the best time, but it may be an item worty of a future wish list
Absolutely, once the concept is developed the whole thing can be passed down to the EE dept. to squeeze the last watt out of the design.
Yeah, I think Peter got it right. Extra output devices can be added to a standard board with a little P2P wiring.
I've had several requests for more output devices, but I don't think it's appropriate to include them in this design, in light of the above... What I am going to do, however, is try and facilitate the addition of more output devices by making the board friendly to this kind of wiring.
I think carpenter is interested in doing some sort of extensible design for the addition of more output devices. My suggestion for this is a separate step-and-repeat style layout, such that one long board can be fabbed with many copies of this pattern repeated down it's length. Then, just cut to length depending on the number of transistor pairs desired. These separate boards could simply be tacked on to the existing design for more power. The P2P wiring is another option too. But, I should reiterate that at this point, we're concentrating on getting the basic design finished, tested, and refined before moving on to other things.
One step at a time...
I've had several requests for more output devices, but I don't think it's appropriate to include them in this design, in light of the above... What I am going to do, however, is try and facilitate the addition of more output devices by making the board friendly to this kind of wiring.
I think carpenter is interested in doing some sort of extensible design for the addition of more output devices. My suggestion for this is a separate step-and-repeat style layout, such that one long board can be fabbed with many copies of this pattern repeated down it's length. Then, just cut to length depending on the number of transistor pairs desired. These separate boards could simply be tacked on to the existing design for more power. The P2P wiring is another option too. But, I should reiterate that at this point, we're concentrating on getting the basic design finished, tested, and refined before moving on to other things.
One step at a time...
...and one last thing:
Although we may not get to it in the Beta revision, rev. 1.0 boards will include multi-geometry footprints for common component variations (trimpots, power resistors, large caps etc.), in addition to the circuit option footprints. That way, there should be a set of holes which fit the particular parts you have on hand, or at least make it possible to get the part in without too much trouble.
The key word is: flexibility.
Although we may not get to it in the Beta revision, rev. 1.0 boards will include multi-geometry footprints for common component variations (trimpots, power resistors, large caps etc.), in addition to the circuit option footprints. That way, there should be a set of holes which fit the particular parts you have on hand, or at least make it possible to get the part in without too much trouble.
The key word is: flexibility.
AMPMAN:
The pricing estimates are in the first post of this thread. The dollar figures listed are for <i>one</i> board, at the order quantity shown. Exact cost is not yet available, as it depends on the total quantity ordered, among other things. The more people order, the cheaper the boards will be. At present, I'm guessing we'll be doing an order for 40 boards, so pricing is extremely affordable. Sorry this is the best I can do for now...
The pricing estimates are in the first post of this thread. The dollar figures listed are for <i>one</i> board, at the order quantity shown. Exact cost is not yet available, as it depends on the total quantity ordered, among other things. The more people order, the cheaper the boards will be. At present, I'm guessing we'll be doing an order for 40 boards, so pricing is extremely affordable. Sorry this is the best I can do for now...
till:
Carpenter and I are discussing this. However, there are some people who do not want to wait. The idea was to have carpenter's boards fabbed right away, since the design was ready to go. It will take much longer for us to finish the Beta design, prototype and test, then make changes for rev 1.0, and get that fabbed... However, I guess carpenter is waiting to gather more orders anyway, so it may just work out better if we combine efforts. I'm leaving this decision to carpenter, and the vote of those who have requested boards based on his design. Whatever the outcome, the Beta/v1.0 effort will be pressing on to arrive at a well tested design for general use. I'm sure we'll be posting more about this possibility soon.
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