Dracule1, Take into consideration that bypassing large inductive electrolytic caps with small non-inductive cap crates parallel resonance circuit that will ring in response to rapid current changes. Designer did not put them for a reason.
I would speculate that you might not like the result but it isn't very expensive to try. |
Dracule1, I don't think so. Looks like you got great stuff there. I second 1% minimum recommendation. |
Dracule1, I speculate that main reason to add bypass caps is to improve frequency response and to lower the noise. To combat ripples you need to increase main capacitor and/or reduce its ESR.
As for self resonance - you want it as high as possible because it is the point where capacitors starts behaving like inductor (inductive reactance larger than capacitive reactance) meaning start of impedance increase with frequency (lowest impedance point). You don't have much control over it unless you use different capacitor type.
Increasing main capacitance will reduce impedance but also reduce self resonance point. It might be necessary step to combat ripple but does nothing to improve frequency response needed to lower the noise or improve load response.
If your main capacitors are film type then you most likely won't have any problems with load response within audio frequencies hence bypass cap will be oriented toward defeating high frequency noise coming from power supply. For that you need much better capacitor with much higher self resonance point. We are not talking about harmonics of rectified AC but about high frequency noise on power line.
I'm not sure what he means by amplifier's "end" |
No, you most likely don't have to worry about ripple.
Film caps of equivalent capacitance have much higher self resonance point and much lower ESR than electrolytics.
Capacitor that has better frequency response offers low impedance at higher frequencies (higher self resonance point) becoming more effective filter for high frequency interference/noise. Also it can respond faster to rapid current demand having lower inductance (inductance resists current change).
Mundorf M-Cap Supreme is high quality metalized polypropylene cap. It might work fine but you can also try metal film polypropylene or Teflon. Metal foil offers lower connection resistance. Try to keep short connections since even straight wire has inductance.
You mentioned 760uF therefore it has to be low power electronics (preamp or DAC?). We might be dealing with regulated power supply greatly reducing ripple. If you have voltage regulators and plan to improve any caps behind them check first what type of regulator it is because some of them don't like low ESR load (oscillate). Give me more info. |
I'm not sure why you need to bypass each capacitor. Why not use just one 1uF cap at the PC board entry. M-Cap like that should be most likely around $20. |
Dracule1, the only purpose of this scheme is to increase wire current delivery since capacitors are charged in narrow current spikes of very high amplitude. You can connect them in series but be sure to use as thick wire as possible and to connect load to the last capacitor in the chain. |
Dave, thanks again. I found nice drawing that shows how rectifier diode behavior introduces EMI:
http://www.powerint.com/en/community/papers-circuit-ideas-puzzlers/circuit-ideas/careful-rectifier-diode-choice-simplifies-and-
Also notice at the "VDC Bus" arrow, that ripple is very big. When ripple gets very small charging current gets very narrow. That's the problem of linear power supplies that in reality are switchers (SMPS) operating at 120Hz but generating a lot of high frequency noise.
Also, SNAP shown at the bottom drawing is not perfectly vertical. Let's imagine that it comes back slowly. If we make vertical line from this small negative peak we can divide it into two times "ta" to the left and "tb" to the right of this vertical line. tb/ta ratio is called "Softness" of the diode. It means that diode pictured here has very little softness. Good diode is fast to switch off (short ta) but slowly snapping back (long tb). |
Thank you Dave for good word but I'm only trying a little to repay all great thing I learn on this forum. Almarg is is the one to be praised for sharing his knowledge and constantly helping people. He is pretty much a guru for all technical things. |
Dracule1, no I would not recommend Mundorf for AC line filter. What I meant is that all your caps are most likely connected in parallel and then to the amp's circuitry. At the input to this circuitry I would put 1uF cap.
When you connect caps in parallel wire going to circuit should be from the very last cap and not the one close to rectifier. |
Dracule1, 1% cap won't do much to reduce ripple but will deliver current when demanded during high frequency transitions where main caps is too slow (inductive).
It will also work to suppress high frequency interference. Imagine that high frequency interference contains 90kHz and 100kHz frequencies. When they appear on non-linear element like output transistor (noting is perfectly linear) sum and difference of them is created (modulation). Sum is inaudible 190kHz but the difference is 10kHz. It gets worse when interference contains a lot of frequencies making a lot of new audible junk. Almarg posted few times on this subject stressing importance of protecting audio system from high frequency interference. |
I would connect 12 capacitors parallel cap #1 to #12 to connect back to #1 (form circle). Now connect rectifier's output to cap #1 and load to cap #7 (opposite side of the circle). High frequency bypass cap should be, in my opinion, at the load to eliminate any wire inductance that can slow down response. If not then at least 1uF cap at main cap #7. Don't spend too much money since you already have very good (film) main caps and might not gain much from Mundorf caps. What kind of wire you use for connection?
Forgot to ask you question about 938s - I found that marked absolute phase doesn't correspond to membrane going forward when connecting battery plus to red and battery minus to black terminal. I tried opposite phase and got worse leaner sound. Is it possible that this phase inversion was done by Hyperion on purpose? |
I'm not sure why you need sequence of capacitors. It would make sense if you got fast and slower caps but your proposed caps vary only by value. I'm not even sure you need any caps. My vote, as I proposed before is just one cap of 1uF at the amplifier. Don't complicate it too much - just wire main caps with good heavy gauge wire and make sure amp is connected to the last cap since it is common mistake people make. |
