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#1
Posted to rec.audio.tubes
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Isolating bench test equipment
I am setting up my test bench.
I have a variac with an iron vane ammeter and volt meter to serve the DUT. (usually tube amp). some older live chassis stuff too. My question is how to deal with my other mains powered test equipment, these include: HP sine generator Distortion analyzer VTVM Old tube Tek scopes Newer Philips scope If these units are all converted to three wire polarized plugs should just the scope sit on an Isolation transformer? Should the device under test chassis ground bypass the variac and go directly to the mains outlet? All this equipment will be connected to the same ckt on the service panel providing a single point of ground. The service panel has been overhauled, neutral/ground bus renewed and a new earth rod installed down into the water table, (I live on a barrier beach and hit water at about six feet). any help appreciated, JVC |
#2
Posted to rec.audio.tubes
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Isolating bench test equipment
On Sep 20, 6:50*pm, "Trailboss" wrote:
I am setting up my test bench. I have a variac with an iron vane ammeter and volt meter to serve the DUT.. (usually tube amp). some older live chassis stuff too. My question is how to deal with my other mains powered test equipment, these include: HP sine generator Distortion analyzer VTVM Old tube Tek scopes Newer Philips scope If these units are all converted to three wire polarized plugs should just the scope sit on an Isolation transformer? Should the device under test chassis ground bypass the variac and go directly to the mains outlet? All this equipment will be connected to the same ckt on the service panel providing a single point of ground. The service panel has been overhauled, neutral/ground bus renewed and a new earth rod installed down into the water table, (I live on a barrier beach and hit water at about six feet). any help appreciated, JVC Makes a lot more sense to run the DUT off the iso imho. If/when you need the scope unearthed, an RCD can deal with the resulting risk, albeit imperfectly. A 2nd iso-tf is better. A pocket scope is another option. A final option is an opamp based voltage difference level shifter. With a hi z input chain, measuring mains is relatively easy, and A-B is trivial with an opamp. NT |
#3
Posted to rec.audio.tubes
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Isolating bench test equipment
"Trailboss" I am setting up my test bench. I have a variac with an iron vane ammeter and volt meter to serve the DUT. (usually tube amp). some older live chassis stuff too. ** Live chassis tube amps or something else like TV sets ? My question is how to deal with my other mains powered test equipment, these include: HP sine generator Distortion analyzer VTVM Old tube Tek scopes Newer Philips scope If these units are all converted to three wire polarized plugs should just the scope sit on an Isolation transformer? ** Never earth isolate ( ie float) your scope, that is very dangerous. No need exists for an isolation tranny, with the exception of servicing modern SMPSs and a few TV sets. Should the device under test chassis ground bypass the variac and go directly to the mains outlet? ** Huh ? The variac should have a 3 pin outlet fitted with mains ground. .... Phil |
#4
Posted to rec.audio.tubes
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Isolating bench test equipment
On Sep 21, 1:56*am, "Phil Allison" wrote:
"Trailboss" I am setting up my test bench. I have a variac with an iron vane ammeter and volt meter to serve the DUT. (usually tube amp). some older live chassis stuff too. ** Live chassis tube amps or something else like TV sets ? My question is how to deal with my other mains powered test equipment, these include: HP sine generator Distortion analyzer VTVM Old tube Tek scopes Newer Philips scope If these units are all converted to three wire polarized plugs should just the scope sit on an Isolation transformer? ** Never earth isolate ( ie float) your scope, that is very dangerous. Hardly. Deaths per annum from electrocution: typ 21 a year in UK. Deaths per annum from unearthed scopes: about zero. You have something to back up your claim? No need exists for an isolation tranny, with the exception of servicing modern SMPSs and a few TV sets. Servicing live chassis radios with no iso is far riskier than using an unearthed scope with no iso or rcd. Should the device under test chassis ground bypass the variac and go directly to the mains outlet? ** Huh ? The variac should have a 3 pin outlet fitted with mains ground. ... *Phil |
#5
Posted to rec.audio.tubes
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Isolating bench test equipment
"Nutcase Turd." , "Phil Allison" : "Trailboss" I am setting up my test bench. I have a variac with an iron vane ammeter and volt meter to serve the DUT. (usually tube amp). some older live chassis stuff too. ** Live chassis tube amps or something else like TV sets ? My question is how to deal with my other mains powered test equipment, these include: HP sine generator Distortion analyzer VTVM Old tube Tek scopes Newer Philips scope If these units are all converted to three wire polarized plugs should just the scope sit on an Isolation transformer? ** Never earth isolate ( ie float) your scope, that is very dangerous. Hardly. ** It is - you ****ing nut case. No need exists for an isolation tranny, with the exception of servicing modern SMPSs and a few TV sets. Servicing live chassis radios ** Same risks as live chassis TV sets. **** off you retarded jerk. .... Phil |
#6
Posted to rec.audio.tubes
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Isolating bench test equipment
On Sep 21, 8:25*am, "Phil Allison" wrote:
"Nutcase Turd." , "Phil Allison" : "Trailboss" I am setting up my test bench. I have a variac with an iron vane ammeter and volt meter to serve the DUT. (usually tube amp). some older live chassis stuff too. ** Live chassis tube amps or something else like TV sets ? My question is how to deal with my other mains powered test equipment, these include: HP sine generator Distortion analyzer VTVM Old tube Tek scopes Newer Philips scope If these units are all converted to three wire polarized plugs should just the scope sit on an Isolation transformer? ** Never earth isolate ( ie float) your scope, that is very dangerous. Hardly. ** It is - *you ****ing nut case. No need exists for an isolation tranny, with the exception of servicing modern SMPSs and a few TV sets. Servicing live chassis radios ** Same risks as live chassis TV sets. * * **** off you retarded jerk. ... *Phil I ddint think you could back up your bs |
#7
Posted to rec.audio.tubes
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Isolating bench test equipment
"Nutcase Troll" ** **** off, you retarded ****ing jerk. .... Phil |
#8
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For off ground measurements I use a Picoscope TA041 Differential Probe in front of the scope. OK to 700 volts common mode.
http://accessories.picotech.com/acti...bes.html#TA041 These daze my scoping is done with one of the other of Pico Scopes PC Scopes- http://www.picotech.com/oscilloscope.html That way results can be transferred direct to the PC for later use. The 2-channel, 100 MHz analogue scope sits on the shelf gathering dust. Gotta get on the bike now. Cheers, John |
#9
Posted to rec.audio.tubes
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Isolating bench test equipment
ARTA, Visual Analyser
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#10
Posted to rec.audio.tubes
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Isolating bench test equipment
Patrick, I have sitting around here with an analyser program and sound card. Well, the big question will be in what dynamics you like the measure... The HW brand (soundcard) has some band limited spec's (usuall for tube stuff good enough) and good things are not free.. as you may not like to work for free O Cheers hp http://www.hpw-works.com |
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