The skin depth of copper at 20k Hz is 0.018" (~0.46mm) so by your thinking the pin could be no bigger that 0.036" assuming you don't need to allow for higher bandwidth in which case the pin would be even smaller. <this begs the question of the diameter of the female 'pin'> So, it's impossible per your 'specifications' for an RCA connector to be used for audio as its pin is 0.125" diameter. Copper plating over copper core?? That makes no sense. Unplated copper? Not good either. Surely you don't propose your hypothetical skinny-pin connector for speaker connections.
I'll have to tell my coworkers that we can no longer use the RCA or SMA connectors on our cables and test instruments for amplifier measurements at several GHz.
I'll have to tell my coworkers that we can no longer use the RCA or SMA connectors on our cables and test instruments for amplifier measurements at several GHz.
Ah yes, the line you come up with whenever you are shown to be completely clueless. Your opinions are almost without fail not worth sharing unless you actually want to learn something from the people on this forum who understand the science behind it.
Reminder: THIS IS AN OBJECTIVE THREAD ON AN OBJECTIVE AMPLIFIER. LOONIES SHOULD GO DIRECTLY TO THE LOUNGE
Not trying to beat you up but, what are your opinions based on? It's been proven over and over again the human perception is easily fooled. For me it's more important to adhere to sound engineering practices and measurements, not what we want to believe.
Mike
Why not live with it?
The amp rejects the noise you are concerned with. There is no technical requirement for a quieter power supply used with Modulus.
As an owner of TP Sympatico amps (with PS snubbers) and the Modulus-86 amps, I can say with confidence that it is better to have significantly better amp noise rejection than marginally quieter PS.
Everybody is entitled to an opinion. Everybody is also entitled to ignoring opinions not based on proper evidence.
In my opinion, this is no more and no less than a personal decision: which do you prefer? Which are you willing to pay for? Terrible, better, or best?
The oscillatory ringing waveform on the secondary with NO quieting circuitry at all, is simply terrible. Awful. The slow silicon diodes inside the GBU2510 bridge rectifier of the Power86, have terrible turn-off dI/dt and they produce ENORMOUS ringing in the secondary. The ringing is so big and so ugly that tomchr decided he wouldn't live with it.
So tomchr added a 100nF capacitor across each secondary. This reduced the amplitude of the ringing and also reduced the frequency of the ringing. My measurement of the Power86 ringing (taken on a red epoxy power86-workalike board), was presented in (post#1433) and is copied below. Ringing amplitude has been reduced to ~ 3V and ringing frequency has been reduced to ~ 90 kHz. (I don't think tomchr has published his scope photos of Power86 + AS-2222 transformer ringing; if he has, I haven't seen them.)
Some people say, "That's low enough for me. I can live with that."
Other people say, "That is indeed a welcome improvement. But we know how to improve it even more! Let's reduce the ringing amplitude from 3 volts to ZERO volts!"
It turns out to be very easy to reduce ringing amplitude to zero volts. Just replace tomchr's single-C ringing quieter, with a two-C, one-R quieter (called a CRC snubber). If you want extra, EXTRA (belt-and-suspenders) ringing reduction, install CRC snubber and also replace the terrible GBU2510 diodes, with Soft Recovery diodes. This combination does indeed reduce ringing amplitude to zero volts, shown in the picture below.
But at the bottom line it's still a human decision. What do YOU (the person connecting a power supply to some Modulus-86 amplifier boards) want? Terrible ringing? Better (smaller) ringing? Or best ringing (none whatsoever)?
Nobody disputes that the ringing is real. Nobody disputes that the ringing is easy to measure. Nobody disputes that more ringing is worse and less ringing is preferable. The only area of disagreement is: how much ringing are YOU willing to tolerate? Some people are willing to tolerate 3V peak to peak ringing. Others are not.
(Oh by the way, for those people who find that 3V ringing is acceptable to them, I would venture to ask: what is the largest magnitude of ringing amplitude which is also acceptable? 3.1V? 4V? 10V? 30V? Where's the dividing line between acceptable and unacceptable? Thanks for your reply.)
I doubt SpeakON connectors are weather proof. They have no seal that I can tell. The chassis connectors are air tight so they can be used in speakers.
They're rock solid connectors. The contacts in the Neutrik ones are silver plated bronze. I believe the contacts are self-cleaning - i.e. the mating/un-mating action cleans the contacts.
I agree.
The skin depth in copper at 20 kHz is 0.46 mm.
The skin depth in gold at 20 kHz is 0.53 mm.
At 20 Hz, the skin depths are as follows: 16.7 mm (Au); 14.6 mm (Cu).
Gold has about 30 % lower bulk resistivity than copper.
None of these figures are of any practical significance for line-level audio. With input impedances in the 10-100 kΩ range, does it really matter if the interconnect resistance is 10 mΩ or 20 mΩ? No, it doesn't. Sure, you can simulate a few pico-Bell of difference, but you can't measure the difference even with state-of-the-art gear. Spend your money on a quality connector where the contact geometries and plating materials allow for a low-inductance, low-resistance connection and move on.
Really? Where? In my day job, I work at frequencies in the 1-13 GHz range. We use copper and aluminum wires. The coax cables are typically silver-clad steel. Connectors are typically gold or silver plated. I don't recall the base material. Maybe nickel. The world is moving away from gold wires for cost reasons and is able to do this without taking a performance hit.
Tom
On the Modulus-86 and Parallel-86, there is no effect, audible or measured, of the parasitic ringing caused by the diodes in the power supply. The incredibly high power supply rejection ratio of the PAR/MOD86 ensures this.
This may not be the case for all amplifiers, but is the case for the MOD/PAR86.
Tom
Don't know what your day job is. But generally gold is still used where performance and reliability takes front seat to cost, and generally inside a tightly sealed unit. Not the consumer market. You can avoid using gold for communication because of signal levels you are dealing with, and cost effectiveness. Obviously if the self capacitance effect does not critically degradation performance in you application, you can ignore skin effect. I would consider it to the extent where it is easily achievable in audio., but not of high priority.
BTW, I would recommend thicker wire in the Theile network, make the thickness increase more gradual from the LM3886 legs to the external speaker cables.
If you look at each part of consideration, the effects are going to be small, but when you accumulate the effects conveniently, then you will one day discover that this makes a difference. At lease this is what I found. This includes distortion. Each little care counts.
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