It is hard to see all the details of them, but I have wondered if they are pretty legit as it appears possible.
As legit as anything I have ever heard/seen. I talked to the designer for a bit. It's the real deal. I wish I had the time to fully understand the circuit.
I made my mixer from TOA console. It had IEC filter inside from birth. After getting tired of carrying 600W isolation transformer I just cut that Y-caps from the ground, and got rid of noises that otherwise presented when I used RCA outputs to record on a notebook computer that also has Y-caps in it's battery charger.
Don't create dirty currents through ground loops, and you'll be happy.
I can see how that situation would produce noise.
In diy we have less restrictions: what about earthing just one of the components such as the preamp? Everything that is connected to that preamp gets its earth from it through the interconnect (hopefully balanced). Rules out ground loops, but is it hazardous?
In diy we have less restrictions: what about earthing just one of the components such as the preamp? Everything that is connected to that preamp gets its earth from it through the interconnect (hopefully balanced). Rules out ground loops, but is it hazardous?
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In DIY you have a freedom to make grounding properly, without messing with dirty currents through wires that carry fine signal currents. No need to eliminate safety ground in such case, that is indeed dangerous.
Ah, but you use transformers, that makes it easy to keep the safety ground AND eliminate loops!
I remember one product that consisted of a preamp + two monoblock amplifiers, that were sold together, and the manufacturer included a sheet describing the ground loop that is inevitably formed if you use their product per code. At least that is what I read between the lines. They made no explicit suggestion of breaking the safety earth. But they even specified the frequency the loop would be tuned to in a typical installation with each monoblock sitting next to a speaker and the preamp at the center (AM band iirc).
I am not in favour of breaking the safety earth, just discussing this issue with you.
I am not in favour of breaking the safety earth, just discussing this issue with you.
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No, I just think carefully what currents I pass through which wire, and what would happen if something else is connected. If I suspect that some garbage of some boutique brand can be connected, I add transformer balanced interconnects, as a fool-proof measure.
It is just a matter of isolating the signal ground from the protection earth with a resistor // cap - problem solved.
Ground loops from the safety ground being tied to circuit ground in laptop chargers is one of the most common ground loop, noise generators, on the planet. Countless people that make music for fun and professionally with digital stuff experience this pain in the butt.
I got it wrong here. Unless a component is fully floating (battery powered) it needs to be earthed. Parasitic coupling capacitance between primary and secondary of trafo allows an AC current to flow and it wants to return to earth. The interconnects are not the best path for that... Resistance of the interconnects as small as it may be will generate an error voltage.
Adding resistance between signal ground and power ground makes the current return trough the power cord rather than the interconnects and the next grounded component.
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I've not seen a laptop charger with earth connected for years. Thinkpads did but everything I have seem since is double insulated.
Alexandre: Thanks to Jan I am going battery powered for most of my system.
Alexandre: Thanks to Jan I am going battery powered for most of my system.
The EU may be different. In the USA they sell hordes of cheap "student" laptops for $500 and stuff like that. They are flat-out cheaper here I guess. I see a lot of them. Funny, Thinkpads (all I've ever owned) have never had them, that I own/ed in the US.
My Liteon notebook brick has the output isolated from earth. I had to use it with ungrounded outlet once and there was some tingling present! Parasitic capacitance closing the circuit was me 🙂
Almost brand new Dell I have here is earth grounded. My old Thinkpad (t43--man I miss that guy) was double insulated.
Btw, Wavebourn, I have nothing against transformers. On the contrary.
(Ok, maybe I´m against the best units being so expensive.)
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