Safety capacitor / Ground loop breaker
Audio Component Grounding and Interconnection
You mentioned you've not seen it in other circuits, but the concept has been around for some time. Here it is in AMB's M3 headphone amp from 2004:
More information: Audio Component Grounding and Interconnection
I've been using this nifty little board from Glassware that implements what you show above (resistor and cap + a diode bridge). Its neat and tidy.
House GND Kit
Yes, that's pretty much what I meant. I was curious HOW it worked, not just what it does. Granted, I'm a bit of newbie, so it's no surprise to me that it's been elsewhere. Just not in anything I've seen.
PS I use they, etc, as pronouns. I should add that to my sig.
The cap in question does not seem to be in the BOM, though it is of course in the kit. What precisely are the specs? Anyone can help with a Mouser #? I ordered everything else from various suppliers with the intention of building a high-end-parts version to compare to the stock version. (Hard to see the kit part now....) Mostly that means Takman resistors and Jentzen caps for the series film caps. (I thought about doing this with Vishay naked foil resistors, but the resistors alone are $300+!!!)
So, to continue from above, is it worth doing the resistor paralleled?
So, to continue from above, is it worth doing the resistor paralleled?
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Yeah, Papa uses the thermistor all the time, right? Though I'm not sure I understand how that works exactly, either.
Mostly, I am with electronics as I for many years was with cooking: I can follow a recipe but I don't always understand WHY things are put together the way they are. I'm better with cooking now, but I still need help with electronics. Thanks to you for the help you've provided!
PS I've always loved the quip in your signature.
How do you get a signature here? I can't seem to figure that out....
Mostly, I am with electronics as I for many years was with cooking: I can follow a recipe but I don't always understand WHY things are put together the way they are. I'm better with cooking now, but I still need help with electronics. Thanks to you for the help you've provided!
PS I've always loved the quip in your signature.
How do you get a signature here? I can't seem to figure that out....
When you have interconnected equipment eg cd player, preamp, amp.
If more than one piece of equipment has a direct path to the earth pin, you can end up with earth loops which will end up as hum at your speakers.
The thermistor provides resistance to break a earth loop from forming, but if there is a fault condition on the circuit the thermistor will draw current, the resistance will drop further and hopefully the fuse will blow.
If more than one piece of equipment has a direct path to the earth pin, you can end up with earth loops which will end up as hum at your speakers.
The thermistor provides resistance to break a earth loop from forming, but if there is a fault condition on the circuit the thermistor will draw current, the resistance will drop further and hopefully the fuse will blow.
Please read through the article referred to above on diyaudio; it does a fantastic job explaining how the 3 different paths to ground work (with a bunch of other relevant information about ground loops etc...).
In the case of the CL-xxs used on the amplifiers, remember that they are used in two places: 1) connecting the system ground to the chassis ground and 2) only as inrush current limiters placed in series across the transformer secondaries. In the case of the former, that acts as effectively the resistor in the discussion/approach to ground. My understanding is that they will not perform the other functions that the diode bridge/cap perform and that it is a good idea to incorporate this approach there too.
There isn't a specific chassis for the kit version of the project with pre-punched holes/custom faceplate, etc... I will caution you to look at the various options and get the largest one you are happy with. While the project fits into the small Hammond chassis Wayne's original article shows, its quite tight. I personally have built 2 Whammys now and used the Galaxy 2U w/Steel Covers in the 230mm x 280mm / 10mm size. That gives you enough room to comfortably run wires/etc... and also not have the IEC inlet bump into the transformer, and also gives you more options on where to mount the headphone jack and volume control. And that box isn't too too big to fit on a desk - mine sits right here with me all day long.
I also personally dig the look of the silver faceplate over the black chassis with silver control knobs myself.
I also personally dig the look of the silver faceplate over the black chassis with silver control knobs myself.
Does the bypass cap for the optocoupler affect the noise floor? I just built a 2nd whammy and it has a loud white hiss. The only deviation from the schematic is c13 and here i used a 2.2uf elcap (correct polarity) instead of 0.1uf film. well, also the gain resistor values are slightly lower- 2.2k and 800ohm but i dont think that should cause any issue?
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