Like most people on earth I own speakers that are made out of MDF with drivers in which the exposed parts are rubber, paper and silk...where exactly would I get shocked?
My future SE amp has no feedback... I don't recall ever seeing secondary connections to gnd in any SE design, maybe it's implied. For feedback designs it's a different story.
My future SE amp has no feedback... I don't recall ever seeing secondary connections to gnd in any SE design, maybe it's implied. For feedback designs it's a different story.
*slaps his head* After all the time I spent calculating what turns ratio I needed on my MC step-up transformer, you'd think I'd remember that.
Thanks, you pretty much answered all my questions.
I'm curious about grounding the speaker frames - some recent threads on speaker forums have been talking about this. If I ground the 0 ohms line of the OPT secondary, that gives me an easy way to experiment with grounding the speaker frame. I can just ground the frames to the -ve speaker terminal (and associated internal wiring), I won't have to run leads back to the amp chassis.
Oh, another question while we're on the topic of RF and instability.
* Do any of you add low pass filters (i.e., input shunt caps) to your amps to roll off at say 100KHz or so (or maybe higher)? This might be relevant for me because I'm considering a non-oversampling DAC, and based on my limited understanding, the output from this kind of DAC has ultrasonic (RF?) noise.
* If you do, is a cap to ground at the input the best way to implement this?
* I already have a series cap at my amp's input to roll off the bass going to my speakers. Is it a good idea to add a shunt cap too? Or should I implement the bass rolloff in a different point in my amp? The driver-output coupling caps are a candidate for this high-pass functionality.
* Do any of you add low pass filters (i.e., input shunt caps) to your amps to roll off at say 100KHz or so (or maybe higher)? This might be relevant for me because I'm considering a non-oversampling DAC, and based on my limited understanding, the output from this kind of DAC has ultrasonic (RF?) noise.
* If you do, is a cap to ground at the input the best way to implement this?
* I already have a series cap at my amp's input to roll off the bass going to my speakers. Is it a good idea to add a shunt cap too? Or should I implement the bass rolloff in a different point in my amp? The driver-output coupling caps are a candidate for this high-pass functionality.
Basket case.
That's true, but remember that earthing is all about where currents flow and where earth connections are made. In your proposed scheme, any RF noise current will be forced to pass down the loudspeaker cable. If the amplifier's 0V isn't at true RF earth, you would now cause it to move up and down in sympathy with the RF. The ideal solution would be to screen the loudspeaker cables, and use the screen as the RF connection from the loudspeaker basket to the amplifier chassis.
As for non-oversampling DACs without output filters, yes, they subject innocent amplifiers to all manner of nasties above 20kHz. There, I've made my position clear, let's see what other people think...
Saurav said:
That's true, but remember that earthing is all about where currents flow and where earth connections are made. In your proposed scheme, any RF noise current will be forced to pass down the loudspeaker cable. If the amplifier's 0V isn't at true RF earth, you would now cause it to move up and down in sympathy with the RF. The ideal solution would be to screen the loudspeaker cables, and use the screen as the RF connection from the loudspeaker basket to the amplifier chassis.
As for non-oversampling DACs without output filters, yes, they subject innocent amplifiers to all manner of nasties above 20kHz. There, I've made my position clear, let's see what other people think...
Hi,
It really is amazing how these threads just keep going on!
And here's my turn
If grounding one speaker wire affects performance, that will mean that performance will change according to:
RH,
Who's sitting near the cable,
Whether the cat's in or out!
In establishing a system, the aim is to reduce the variables, else it becomes art more than science to excel.
Also, we all need to remember that as builders of equipment, we are responsible for it's safety to other parties. That can include partners, children, visitors and even pets. None of whom can fully appreciate the potential dangers.
I've finished...I think
Cheers,
It really is amazing how these threads just keep going on!
And here's my turn
If grounding one speaker wire affects performance, that will mean that performance will change according to:
RH,
Who's sitting near the cable,
Whether the cat's in or out!
In establishing a system, the aim is to reduce the variables, else it becomes art more than science to excel.
Also, we all need to remember that as builders of equipment, we are responsible for it's safety to other parties. That can include partners, children, visitors and even pets. None of whom can fully appreciate the potential dangers.
I've finished...I think
Cheers,
Miserable old g*t mode....
"Visitors" are humans who arrive from time to time and generally get in the way.
They make comments like:
"And HOW much did it cost to make?"
and
"It took HOW long to make"
and
"What's THAT?"
Though not necessarily in that order.
They also talk over the music, and are best avoided.
In my experience children are best avoided too. Especially ones own.
Cheers,
"Visitors" are humans who arrive from time to time and generally get in the way.
They make comments like:
"And HOW much did it cost to make?"
and
"It took HOW long to make"
and
"What's THAT?"
Though not necessarily in that order.
They also talk over the music, and are best avoided.
In my experience children are best avoided too. Especially ones own.
Cheers,
SCREENED?
Hi,
Wow...one day away and look whay's developped...
I assume everyone understands the safety issues involved regarding the OPT grounding so let's skip that one.
LS cables acting as aerials? Yes, Sir.
Several ways exist...when I helped design the Deskadel range of cables we had individually shielded +- runs and shielded twisted pairs.
I prefer the shielded twisted pair...a little shunt capacitance often helps but YMMV.
I've never taken the LS basket in the loop so far but that's worth a try too.
Note that these design are nothing new, they've been around for about ten years now.
At the time though they ewere considered absolutely crazy.
There are other tricks still, equally old...but let's just say that the quality of the screening is of utmost importance.
From reading EC8010's posts, I can only say: I couldn't agree more.
Cheers,
Hi,
Wow...one day away and look whay's developped...
I assume everyone understands the safety issues involved regarding the OPT grounding so let's skip that one.
LS cables acting as aerials? Yes, Sir.
Several ways exist...when I helped design the Deskadel range of cables we had individually shielded +- runs and shielded twisted pairs.
I prefer the shielded twisted pair...a little shunt capacitance often helps but YMMV.
I've never taken the LS basket in the loop so far but that's worth a try too.
Note that these design are nothing new, they've been around for about ten years now.
At the time though they ewere considered absolutely crazy.
There are other tricks still, equally old...but let's just say that the quality of the screening is of utmost importance.
From reading EC8010's posts, I can only say: I couldn't agree more.
Cheers,
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