Hi Destroyer OS,
Really good test gear is encased in a double shield. The outer one goes to safety ground. The inner one is the system ground. So there is a start for you. Some audio equipment does follow this convention for low level signals. Example, the Marantz SC-9 / 3650 for the MC stage. It has its own little shielded environment. I'm pretty certain that other makes and models also follow this practice.
-Chris
Yes, and when you involve different designers, I strongly doubt you will achieve that perfection in shielding.
Really good test gear is encased in a double shield. The outer one goes to safety ground. The inner one is the system ground. So there is a start for you. Some audio equipment does follow this convention for low level signals. Example, the Marantz SC-9 / 3650 for the MC stage. It has its own little shielded environment. I'm pretty certain that other makes and models also follow this practice.
-Chris
Congratulations!
How much is it to advertise in a magazine?
Mono and Stereo High-End Audio Magazine: NEW MARSH ULTRA HIGH END POWER AMPLIFIER
I figured they got it from a 1950s Popular Mechanics article...
A/C can be pretty nasty and be considered normal, kind of like water.
I tried a ham radio trick, a small filament-type bulb close to the device, actually helped to greatly reduce a low level noise when my laptop is charging or consuming more power.
Seems like most everything I have tried just begins to remove the top layer (of any serious noise issue).
A/C can be pretty nasty and be considered normal, kind of like water.
I tried a ham radio trick, a small filament-type bulb close to the device, actually helped to greatly reduce a low level noise when my laptop is charging or consuming more power.
Seems like most everything I have tried just begins to remove the top layer (of any serious noise issue).
Obviously jan.didden misunderstood Bonsai´s post (Nice example of confirmation bias at work......); imo he didn´t quit due to "semi-guru-bsing" or "snake oil peddlers" but due to the reaction of some people to Waly´s sin bin time, as he was in the past often the target of that sad mobbing approach by Waly.
Nice example of confirmation bias at work......
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From my experience i agree with 1audio´s post. Even in a simple/basic system with just a signal source (let´s assume a cd-player/digital device) preamplifier and amplifier and all units have a connection (somehow
) between audio ground and PE and are connected via rca interconnects, then there are quite extended loop areas possible. I think 1audio mentioned it already, it is usually a really good advice to connect all devices at one point to the mains/protective earth.Simon7000´s advice is well worth the attention, coupling of mains noise can be reduced in that way; even better might be to consider some shield windings.
Of course it could be a matter of definition to say any equipment is only then competently designed if a power cord change does not make an audible difference (any place of the world), but i´d assume that the number of competently designed equipment is much smaller than expected.....
(Btw, i´ve seen a lot of tweaking in measurement labs doing compliance certification despite their use of equipment from the majors costing more than a fortune)
The garbage out of standard lab supplies is shocking. TeK scopes were notorious for power transformer leakage, the lab had a good stock of 3 to 2 plugs.
Hi Scott,
I only have two pieces of Tek equipment. The rest is HP / Agilent / Keysight, and it's all a fair bit better built than the Tek is. My oldest usable piece of gear is an ancient HP 1722A oscilloscope. Its actually a very good scope even today and it hails from about 1974.
Depending on the lab, they might go through hell trying to reduce noise. I don't see lifting the safety ground as being allowed in the labs I've worked in. But I guess if you're chasing really low noise levels, anything that works will be done.
-Chris
I only have two pieces of Tek equipment. The rest is HP / Agilent / Keysight, and it's all a fair bit better built than the Tek is. My oldest usable piece of gear is an ancient HP 1722A oscilloscope. Its actually a very good scope even today and it hails from about 1974.
Depending on the lab, they might go through hell trying to reduce noise. I don't see lifting the safety ground as being allowed in the labs I've worked in. But I guess if you're chasing really low noise levels, anything that works will be done.
-Chris
From my experience i agree with 1audio´s post. Even in a simple/basic system with just a signal source (let´s assume a cd-player/digital device) preamplifier and amplifier and all units have a connection (somehow
Unless you use Schurter DENO's, then there is no loop.
We went too far when we asked the electricians to stop alternating the phases of the 220 from bench to bench because someone brought in an old piece of hot chassis gear and the obvious happened.
I think the VFA/CFA thing got way out of hand (again) and frankly on some technical points Waly was right and some others here were in fact wrong. I was made aware later that Waly might have had some offending posts removed so I am sorry, I only wanted to defend what I thought were valid technical points.
Honestly for years I've seen posts on this debate that literally make smoke come out of my ears.
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Hi Scott,
Me too (smoke coming out of ears). What can you do? Sometimes you have to just let it slide. Sometimes the true meaning of a post comes out later and its best to see where things go.
I use an HP 5087A on my bench. Know of any isolated ones that need a home?
-Chris
Me too (smoke coming out of ears). What can you do? Sometimes you have to just let it slide. Sometimes the true meaning of a post comes out later and its best to see where things go.
I can see why. I generally try to run separate circuits on the same phase with the lights on the other phase (along with the lunch room and small warehouse). The leakage currents with recent equipment would be enough to disturb low noise measurements. It also helps to have the lab frequency references running on transformer coupled outputs. That means no HP 5087A distribution amps allowed! I wonder if they fixed that with the 5087B?
I use an HP 5087A on my bench. Know of any isolated ones that need a home?
-Chris
Obviously asking to disable your account makes a statement.
I have it on good authority that eventually, Mr. B *could* be back...
Jan
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