I would take the output R||L off the PCB and insert it in the cable route to the speaker terminals.
It is not necessary to change the layout, just insert a jumper instead the inductor for those who want it remote from the PCB.
A few Designers have suggested that the field produced by the coil should not be in the susceptible amplifier.
Some further recommend that the coil should not be near metalwork, probably meaning steel panels.
I just pass on these as my observations to the many Builders who seem to generally ignore what the Designers tell them.
So, in answering the question, yes there are technical reasons why the coil should not be near the amplifier. And it follows the same logic as applied to:
low loop area close coupled pair for carrying any and every current around the equipment.
If it ain't a low loop area pair, then it must not be near any other circuit.
Some further recommend that the coil should not be near metalwork, probably meaning steel panels.
I just pass on these as my observations to the many Builders who seem to generally ignore what the Designers tell them.
So, in answering the question, yes there are technical reasons why the coil should not be near the amplifier. And it follows the same logic as applied to:
low loop area close coupled pair for carrying any and every current around the equipment.
If it ain't a low loop area pair, then it must not be near any other circuit.
So you should remove all printed circuit on the board.😀
D. Self write about crosstalk provoked by the inductors proximity between two channels, don't know if he added more about in his sixth edition.
What is the minimum trace width and what is the distance that trace should be from an adjoining trace to prevent interference? This is just for the input and driver stages of course. Also ideal pad size for devices. Transistors, diodes, resistors and capacitors. All in the IPS or driver stages.
Chris, don't wary about, your layout is very good for audio. Tere is no ideal pad size to accommodate all device type, use that from macros.
Dadod, I am putting Eagle together, and looking at the smt and thru hole stuff and some of the SMT is very small and I want to make the circuit smaller. The width of the traces is just part of my equation, and I just wanted to know how small is too small. I got some 2240's and 970 on order and I have all the others in house. So I am going to build something. I might redo the board to make a single sided one. But who knows I might do a double in house.
Managed some hours around the layout of the V-MOSFET version and here is the result. There have been a couple of additions to the previous design, a cap multiplier to the front end rails, and a short circuit protection that turns off and hold off the solid state speaker relay when tripped.
Attachments
Chris, I never built enything with SMT, to small for my fingers(and age), so no help from me here. I used ones SMT mosfet as CCS in my TT amp and I burned two out of eight(I made six amp boards) during soldering process.
You and me both do not want to go to SMT.
I am just trying to figure out an acceptable trace width to make the boards as small as possible and minimize inductive interference, crosstalk and such.
Nattawa Board is great, but I do not think it will be done, I wish it could be as a proof of concept. But practically it is not inclined to be done for the DIYers here. A thru hole board done to prove the schematic needs to be done first. But that is just my thought.
The one thing about the board I did is that you can or can not add any components you like. Then you can MUNTZ the board to see if it still performs well.
I want to use something other than wire inductor types on the emitter resistors, I think that there are some non inductive types out there, just have to find them or go with LARGE SMT ones.
I waiting with baited breath for OS to get done. I think he is on to something.
In the OLD days we did not have the luxury of sims and such, we built and modified tested and modded some more till we got something that worked. Then we built other complete circuits and compared them. That at least is what I did at National Semi. We had little parts of actual IC's that we bread boarded. Chips. Then we baked and shook them and use Liquid Nitrogen to freeze um. testing all the while. I worked in Linear IC on the Ford ignition systems.
I am just trying to figure out an acceptable trace width to make the boards as small as possible and minimize inductive interference, crosstalk and such.
Nattawa Board is great, but I do not think it will be done, I wish it could be as a proof of concept. But practically it is not inclined to be done for the DIYers here. A thru hole board done to prove the schematic needs to be done first. But that is just my thought.
The one thing about the board I did is that you can or can not add any components you like. Then you can MUNTZ the board to see if it still performs well.
I want to use something other than wire inductor types on the emitter resistors, I think that there are some non inductive types out there, just have to find them or go with LARGE SMT ones.
I waiting with baited breath for OS to get done. I think he is on to something.
In the OLD days we did not have the luxury of sims and such, we built and modified tested and modded some more till we got something that worked. Then we built other complete circuits and compared them. That at least is what I did at National Semi. We had little parts of actual IC's that we bread boarded. Chips. Then we baked and shook them and use Liquid Nitrogen to freeze um. testing all the while. I worked in Linear IC on the Ford ignition systems.
This still seems to be the best way IMO to learn and develop circuits. Finding myself simulating, building, testing, simulating mods, building mods, testing again. Then going round that loop continuously until I blow the circuit up by pushing things too far. Then starting on a new development on the theme.
Dadod et al, I'm looking forward to someone building this amp and reporting on the result.
Chris you are loosing the fate in this amp. Don't wait for OS to do something, his amp is something quite different. I am quite confident in this amp, all simulation I did beffore and built the amps after, worked at first try, some fine tuning could be done latter.
Damir
PS. the layout is not so critical, only if it is done completely against accepted rules
Dadod, I will definitely build this amp, possibly along with a 200W VFA that I'm in the middle of putting together a schematic and simulating for.
Kris you could have put "But practically it is not inclined to be done for the DIYers here who are unable to do and unwilling to learn SMT" and it would've been much more precise. If you zoom my layout to its life size, you'll realize the SMD parts I used are not that small, and that the smallest 2-pin SMT parts, in 0805 size, have in fact larger pads than that of the TO-92 footprint. In my particular layout, most decals have over-sized pads that are specifically designed for being hand soldering and rework friendly.
Modern design and simulating tools have long made "proof of concept" integrated part of schematic design. Member OS has demonstrated in the CFA thread how simulation resembles the real world product measurements as closely as within a few percentage points. When we design PCBs we most often design final products.
Kris you could have put "But practically it is not inclined to be done for the DIYers here who are unable to do and unwilling to learn SMT" and it would've been much more precise. If you zoom my layout to its life size, you'll realize the SMD parts I used are not that small, and that the smallest 2-pin SMT parts, in 0805 size, have in fact larger pads than that of the TO-92 footprint. In my particular layout, most decals have over-sized pads that are specifically designed for being hand soldering and rework friendly.
Modern design and simulating tools have long made "proof of concept" integrated part of schematic design. Member OS has demonstrated in the CFA thread how simulation resembles the real world product measurements as closely as within a few percentage points. When we design PCBs we most often design final products.
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Nattawa, I see that you are using 80V mosfets for your SSLR. You need to make sure your mosfets are at least rated for the total +- supply voltage, otherwise you run the risk of them failing (actually, its not a risk, its a certianty!). I use NXP PSMN4R4-100 for +-50V rail, and Fairschild 150V types for up to +-75V rails (I forget the part number). The pinouts are the same - TO-220. Both of these types can switch 10's of amps if you do it quickly. There are two articles on my website with the details to help you select the SSLR mosfets.
Nice board by the way - complex circuit though!
🙂
Nice board by the way - complex circuit though!
🙂