Motorcycles 
fired up one tranny with first set of caps and bleeders. No explosion, completely mechanically silent tranny. Vdrop as expected after pulling the plug. 0mV ripple / AC (no load though). Iow good so far. Inductors next.
Decided to use alu ground plane only at the load. Too risky on the small caps, one mm wrong=short circuit.
Edit: Andy turned fraidy cat. Or maybe just sensible cat
fired up one tranny with first set of caps and bleeders. No explosion, completely mechanically silent tranny. Vdrop as expected after pulling the plug. 0mV ripple / AC (no load though). Iow good so far. Inductors next.Decided to use alu ground plane only at the load. Too risky on the small caps, one mm wrong=short circuit.
Edit: Andy turned fraidy cat. Or maybe just sensible cat
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Joppepoppo - looks amazing!!! Nice work!
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I want to have dual front-panel LEDs like the ACA. The main reason is so I can see it is on (that might sound dumb, but nice to be able to look over and see if it is powered or not). I have some nice low-output, wide-dispersion blue LEDs that will work perfectly. I will drill out (only about 3-4mm) and hot glue the LEDs in there (partly to fill the hole, partly so I could remove them for whatever reason in the future.
Main question is which of the three (per channel) LED outputs to use. I am thinking the ones off the power supply mainly because they have the highest change of being illuminated (hypothetically the amp boards could be non-functional but the power supply receiving power). Also, they are close and will let me route the wires easier - mainly I could remove the front panel without needing to remove those wires.
Any reason NOT to use the power supply board LED outputs for this?
Thanks!
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I want to have dual front-panel LEDs like the ACA. The main reason is so I can see it is on (that might sound dumb, but nice to be able to look over and see if it is powered or not). I have some nice low-output, wide-dispersion blue LEDs that will work perfectly. I will drill out (only about 3-4mm) and hot glue the LEDs in there (partly to fill the hole, partly so I could remove them for whatever reason in the future.
Main question is which of the three (per channel) LED outputs to use. I am thinking the ones off the power supply mainly because they have the highest change of being illuminated (hypothetically the amp boards could be non-functional but the power supply receiving power). Also, they are close and will let me route the wires easier - mainly I could remove the front panel without needing to remove those wires.
Any reason NOT to use the power supply board LED outputs for this?
Thanks!
No reason not to. I haven’t experienced Bokys remark about pos and neg rails fading differently. But even if they do, at least I wouldn’t care
No reason not to. I haven’t experienced Bokys remark about pos and neg rails fading differently. But even if they do, at least I wouldn’t care
Actually, I did experience this in my Aleph J Zen - neg rails fading slower - and that was a bit unexpected. Indeed, I did not notice this in the beginning - I think both rails were switching off (discharging) equally quickly (almost immediately) when I finished the build, but after a while I noticed the negative side LED fading out a lot more slowly.
What is the reason of negative rail discharging slower?
Note: I left the LEDs next to the bleeding resistors in place (they are red and I see them as precautionary indication if you are going to touch something inside), but I installed another 2 LEDs (blue) on extension wires to the front panel. As I use diyAudio standard PSU boards, pads for the output snubber resistors and capacitors (that I do not use) are perfect places to put the front panel LEDs (LED goes into the capacitor pads).
simple:
as rails are sagging, Aleph CCS is conducting all the way, and positive rail is practically squeezed out through speaker itself ( current is diminutive, no worries), while lower mosfet is shut close somewhat earlier (when LTP is left without enough juice to keep mosfet open) and residual voltage in neg rail caps have no path to go
again, there is no significant current difference between upper and lower rail discharging, or else you'll see it as significant DC offset on speaker (if speaker is connected permanently)
in case that you have loudspeaker protection, disengaging speaker in very moment when you shut amp Off, voltage at rails should stay so-so same , because upper one is left without discharge path (speaker) ........ so you'll have pretty much equal charge residual in upper and lower caps
that is part of things one must take in account when projecting an amp - behavior both during Power On cycle and during Power Off cycle
examples:
- when developing "actual" Babelfish J2 amp, I had task to solve enormous voltage and current spike during Power Off cycle, present in practically penultimate iteration
- LuDEF - when one is using Loudspeaker protection module, there must be placed shunt resistor of some 220R directly across amp output (so at protection module input) , simply because without any load there is 4 to 6V of voltage , enough to confuse protection module to think that amp is Dodo ....... while amp is practically not even yet opening its eyes (time constant of biasing circuit is enormous); it is just potential of 6V, no real current possible, simply because mosfets are not even close to conducting
just few illustrations how projecting a circuit is sometimes more than it is obvious at first glance
as rails are sagging, Aleph CCS is conducting all the way, and positive rail is practically squeezed out through speaker itself ( current is diminutive, no worries), while lower mosfet is shut close somewhat earlier (when LTP is left without enough juice to keep mosfet open) and residual voltage in neg rail caps have no path to go
again, there is no significant current difference between upper and lower rail discharging, or else you'll see it as significant DC offset on speaker (if speaker is connected permanently)
in case that you have loudspeaker protection, disengaging speaker in very moment when you shut amp Off, voltage at rails should stay so-so same , because upper one is left without discharge path (speaker) ........ so you'll have pretty much equal charge residual in upper and lower caps
that is part of things one must take in account when projecting an amp - behavior both during Power On cycle and during Power Off cycle
examples:
- when developing "actual" Babelfish J2 amp, I had task to solve enormous voltage and current spike during Power Off cycle, present in practically penultimate iteration
- LuDEF - when one is using Loudspeaker protection module, there must be placed shunt resistor of some 220R directly across amp output (so at protection module input) , simply because without any load there is 4 to 6V of voltage , enough to confuse protection module to think that amp is Dodo ....... while amp is practically not even yet opening its eyes (time constant of biasing circuit is enormous); it is just potential of 6V, no real current possible, simply because mosfets are not even close to conducting
just few illustrations how projecting a circuit is sometimes more than it is obvious at first glance
Thanks for all the details, ZM!
Reading that, I have another question:
How safe (or dangerous?) in general is to use any FirstWatt (or Papa, or Zen Mod) amps without the speaker protection modules? What are the chances something can go wrong in a way that speakers get enough DC to be damaged?
I reckon, if Papa sells his amps without the protection modules in them, the risk should be minuscule - Papa is blamed enough here already so he should not be taking additional risks, true?
I understand that some people have very dear speakers so that they are ready to go any lengths to keep them absolutely safe. But for all other mortals - should they sleep well without the speaker protection?
Reading that, I have another question:
How safe (or dangerous?) in general is to use any FirstWatt (or Papa, or Zen Mod) amps without the speaker protection modules? What are the chances something can go wrong in a way that speakers get enough DC to be damaged?
I reckon, if Papa sells his amps without the protection modules in them, the risk should be minuscule - Papa is blamed enough here already
so he should not be taking additional risks, true?I understand that some people have very dear speakers so that they are ready to go any lengths to keep them absolutely safe. But for all other mortals - should they sleep well without the speaker protection?
take in account that Papa's amp are made in Papa's organization, so true what you said in "I reckon..."
our DIY amps are in most cases made by Gremlins, so having decent protection for your precious speakers is clever thing
worth saying - if amp is having output cap ( as some recent are having) there is no need for DC speaker protection
our DIY amps are in most cases made by Gremlins, so having decent protection for your precious speakers is clever thing
worth saying - if amp is having output cap ( as some recent are having) there is no need for DC speaker protection
In other words, seeing the LEDs dim differently is a testament to the function of the circuit. Sounds nice if you ask me
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Thanks everyone! I think I will stick to the current plan for the sake of internal wire 'zen' (it will be much cleaner internally).
The more I read about the DC protection question, the more it makes me worry. I don't want to blow up my Sonus Fabers I bought the last two replacement mid-range drivers in the world and guessing the other parts might not be easy to come by!
Or I can buy a paid of KEF LS50 Meta with my employee discount and use those as my guinea pig!
The more I read about the DC protection question, the more it makes me worry. I don't want to blow up my Sonus Fabers
I bought the last two replacement mid-range drivers in the world and guessing the other parts might not be easy to come by!Or I can buy a paid of KEF LS50 Meta with my employee discount and use those as my guinea pig!
Is that because there is something inherently 'dangerous' about this amp build...or because being DIY I might have screwed up?
If the amp worked for, say, 100 hours with 50 power cycles with no issues...would that suggest a failure was almost unthinkable?
I sure as hell would not hook these up to my Sonus Fabers to test after I finished the build...I would use something 'disposable'. But after the amp was proven to work, has some power cycles and hours, how much risk is there of a failure that would pass DC or a otherwise dangerous signal to the speakers?
I also have this hooked up to a McIntosh C53 preamp, which I would hope would also be protected (no current would back-track into the preamp).
The closest replacements to my speakers would be these, if I blew them up: New Compact 3-way Loudspeaker Olympica Nova II | Sonus faber
If the amp worked for, say, 100 hours with 50 power cycles with no issues...would that suggest a failure was almost unthinkable?
I sure as hell would not hook these up to my Sonus Fabers to test after I finished the build...I would use something 'disposable'. But after the amp was proven to work, has some power cycles and hours, how much risk is there of a failure that would pass DC or a otherwise dangerous signal to the speakers?
I also have this hooked up to a McIntosh C53 preamp, which I would hope would also be protected (no current would back-track into the preamp).
The closest replacements to my speakers would be these, if I blew them up: New Compact 3-way Loudspeaker Olympica Nova II | Sonus faber