Thanks to everybody who have contributed so far, and especially thanks to Bill who started this thread. He has yet to finish his amp but has grown his family exponentially instead.Bill! This the year! No pressure...
hey that gives me 2.5 yrs of extra margin... got mine last summer
I like the idea of support for a CRC snubber network. Even if the snubber doesn't benefit the Modulus amplifiers measurably, it would make the power supply have broader appeal for usage in other amplifiers that might not be so forgiving with their power supply.
I agree that a 12 V trigger input is a nice addition.
What about an option to use discrete diodes vs bridge rectifiers? Would that be getting to complicated?
Also, for the +5 V always on auxiliary output, would this be powered from a separate transformer?
, and especially thanks to Bill who started this thread. He has yet to finish his amp but has grown his family exponentially instead.
Thanks all!
Tom
Every morning when I leave for work I see a board against the headsink and think I should start the swarf and sawdust making. Making progress with sleep training youngest one so I am hopeful of news soon...Honest
That's basically my thought.
To support a stereo Modulus-686, the diodes will very likely need to be discrete anyway. Discrete with heat sinks. So either a TO-220 or TO-247 package kind of deal.
I'm thinking a Mean Well switcher. They cost about a quarter of what a transformer-based supply would cost, are dead quiet, and take international mains in.
True. But so does the single cap across the transformer secondary - and that, in contrast to the RC snubber, does not need to be sized to the transformer. I can certainly include instructions for how to determine the RC snubber should anyone desire to pursue that angle, but optimizing the snubber to the transformer (and its wiring harness!) will be up to the end user.
Tom
My two cents to the Power 686.
I also like the CRC snubber option, the 12v trigger and of course the soft start.
To further increase flexibility and appeal to non Mod users I could imagine to leave some room for the capacitor diameter so people can use even larger caps than the two 22000uF per rail.
I also like the CRC snubber option, the 12v trigger and of course the soft start.
To further increase flexibility and appeal to non Mod users I could imagine to leave some room for the capacitor diameter so people can use even larger caps than the two 22000uF per rail.
No changes to the transformer.
The board will probably be twice as long as the discrete diodes + heat sinks take up quite a bit of room and allowing for twice the capacitance will take up some space. Add 1.0-1.5" to the width to accommodate the Mean Well switcher and associated bits. Fitting the board within 5x6 to 5x7 inches would be pretty nice. The current Power-86 is 3.3x3.6 inches.
No promises on the board size. I'm familiar with the various constraints of shoehorning an amp into an enclosure and will keep those constraints in mind when deciding the board size. The board will be large enough to accommodate the features but no larger than that. Smaller is better when it comes to board size.
I hear ya. The Power-86 supports two 40 mm diameter caps. The two caps I specify are actually 35 mm in diameter. So there's room to grow. 40 mm gets up to 27000 uF (27 mF) per cap for 50-63 V snap-in types. The next sizes up are 50 mm and 63 mm diameter. Mouser shows exactly one (1) non-stocked 33 mF 50 mm cap in the 50-63 V range. The two (2) 63 mm caps are both 22 mF (and non-stock as well). The difference between 27 mF and 33 mF is negligible in this context, honestly.
This is how I landed on the 40 mm footprint in the first place. There are quite a few options to choose from in the 35-40 mm range.
So I'll stick with the 40 mm footprint. I did take into account when designing that footprint that a "40 mm" specified cap may be a tad larger due to production tolerances and the footprint can accommodate that too. If the resulting 4x27 mF = 108 mF isn't enough capacitance for you, you'll probably want to go with the chassis-mounted screw terminal caps rather than board mounted caps.
I use 10 mm pin pitch on the caps, so you have tons of options to choose from.
Tom
Oh, I suppose I can design it to be either level triggered or edge triggered on the power-on switch. This would allow you to use either a momentary switch (doorbell switch) or a toggle switch for the power-on. You may have to move a jumper or something to change the switch type.
A standby LED is easily added. Should the standby LED then turn off when the supply turns on? I guess that would make the most sense. One could even design it to use one of the two-colour LEDs.
Tom
A standby LED is easily added. Should the standby LED then turn off when the supply turns on? I guess that would make the most sense. One could even design it to use one of the two-colour LEDs.
Tom
I am human, yes.
That is the danger in asking for opinions!
Yep. Careful what you ask for, because you just might get it. On the other hand, I am not necessarily obligated to implement all the requested features. If the features seem handy and don't require a lot to implement, I'm for their inclusion.
I did receive a request via email about the inclusion of an audio detect circuit that would turn the supply on when the music started playing and automatically turn the supply off some time after the music stopped. That's a great feature (thanks for the mention), but also one that takes quite a bit of circuitry. That feature is better served as a separate circuit that'll plug into the supply board.
I'm mostly asking to make sure that I don't miss anything obvious. It sucks to get 100 boards made only to go "*face-palm* why didn't I think of that" after the boards arrive.
Tom
A couple of thoughts:
1. If there's space to add optional holes for a screw terminal block within the IEC connector footprint, that would give the option of using either connector. (Well I suppose you could still run wire from the IEC connector holes but an optional screw terminal block would make it neater.) Personally I wouldn't use the IEC block as I've become a convert to Neutrik Powercon connectors: they're much more secure than IEC and dead easy to mount on a panel (1 x 24mm hole, 2 x 3.2mm holes).
2. If you're intending to have the board mounted right up against a chassis panel, could you set the mounting holes on the panel edge further back from the board edge? The only minor gripe I have with my Modulus boards is that the holes on the 3886 side of the board are so close to the edge that it has made it difficult to use them, as the part of the mounting plate underneath them is directly over a connecting rod (I'm using one of the Hifi2000 Dissipante cases in the end).
3. If you're using a MOV for the 120J surge protection, circuitry to prevent thermal runaway causing a fire when it fails. I know I'm probably teaching you to suck eggs but a friend of mine narrowly averted a fire when the MOV in a cheap surge protected mains extension cord failed recently.
4. How are you planning to implement the standby LED - on the PCB, or on a header that can be taken to a panel-mount component?
5. How about an input for a second "power on" logic line, e.g. from a remote control PCB? This would be XORed with the input from the momentary switch so that you could turn the supply on or off either from remote control (powered from the always on supply (if it's intended for powering auxiliary boards, might 12V be a better choice?) or from the front panel switch.
1. If there's space to add optional holes for a screw terminal block within the IEC connector footprint, that would give the option of using either connector. (Well I suppose you could still run wire from the IEC connector holes but an optional screw terminal block would make it neater.) Personally I wouldn't use the IEC block as I've become a convert to Neutrik Powercon connectors: they're much more secure than IEC and dead easy to mount on a panel (1 x 24mm hole, 2 x 3.2mm holes).
2. If you're intending to have the board mounted right up against a chassis panel, could you set the mounting holes on the panel edge further back from the board edge? The only minor gripe I have with my Modulus boards is that the holes on the 3886 side of the board are so close to the edge that it has made it difficult to use them, as the part of the mounting plate underneath them is directly over a connecting rod (I'm using one of the Hifi2000 Dissipante cases in the end).
3. If you're using a MOV for the 120J surge protection, circuitry to prevent thermal runaway causing a fire when it fails. I know I'm probably teaching you to suck eggs but a friend of mine narrowly averted a fire when the MOV in a cheap surge protected mains extension cord failed recently.
4. How are you planning to implement the standby LED - on the PCB, or on a header that can be taken to a panel-mount component?
5. How about an input for a second "power on" logic line, e.g. from a remote control PCB? This would be XORed with the input from the momentary switch so that you could turn the supply on or off either from remote control (powered from the always on supply (if it's intended for powering auxiliary boards, might 12V be a better choice?) or from the front panel switch.
That's indeed my plan. I'll have the footprints overlap so you populate either the terminal block or the IEC connector.
I agree (x2).
Certainly. Is 0.3" (7.62 mm) enough? Or would you prefer 0.4" (10.16 mm)?
I'll put it on the 'inside' of the fuse for that exact reason.
When it comes to safety stuff, it's better to over-communicate.
Probably the same EURO-style connector I used on the Power-86 for the LED.
XORs now... Man. This power supply will have more compute power than the space shuttle.
I think an edge triggered power supply on/off will work both for a remote function and a momentary switch (requested earlier). You can just OR one with the other.
Tom
Power 686 Suggestions for consideration:
1. Specify iTMOV integrated MOV and Fuse, if the MOVs are not protected by a fuse. I believe that this is required by some Code. Relying on a mains fuse to protect against thermal runaway of the MOV is not supposed to be safe (I understand).
2. Include an optional ground loop breaker, that places a heavy-duty diode bridge between the ground from the line cord and everything else. In some areas, this apparently is illegal so it has to be an option that could be jumpered out.
1. Specify iTMOV integrated MOV and Fuse, if the MOVs are not protected by a fuse. I believe that this is required by some Code. Relying on a mains fuse to protect against thermal runaway of the MOV is not supposed to be safe (I understand).
2. Include an optional ground loop breaker, that places a heavy-duty diode bridge between the ground from the line cord and everything else. In some areas, this apparently is illegal so it has to be an option that could be jumpered out.