Shocking

[islandamp]

I have a Budda SD45 that's 240 volt. I use a 120v to 240v transformer and it works great, but before hooking up my hd500x effects box I started wondering if the 120 volt Hd500x and the 240 volt Budda will be compatible. Seems like there will be either a 120 or a 360 volt potential difference on the chassis's. I'm wondering if touching the amp, guitar and effects chassis, at the same time won't shock the hell out of me.

[PaulD]

Unless either of those units has a serious fault (if they have they should blow fuses) and they both have mains safety grounds then there is no potential difference, both chassis will be at 0V,

[pdf64]

Hence the benefit of solidly connecting equipment chassis to ground, ie rather than a mains current conductor. You verified that you step up transformer maintained the ground circuit?
If not grounded, your fx chassis should be double insulated.

[SoulFetish]

Hence the benefit of solidly connecting equipment chassis to ground, ie rather than a mains current conductor. You verified that you step up transformer maintained the ground circuit?
If not grounded, your fx chassis should be double insulated.

if you run quarter cables to connect your all your effects and amplifier, you cannot have double insulation. By nature, you are electrically coupled via the grounding conductor in your instrument cables. Right?
You would have to have some physical decoupling via audio transformer, RF, or ADC to optical transmission.

[PaulD]

if you run quarter cables to connect your all your effects and amplifier, you cannot have double insulation. By nature, you are electrically coupled via the grounding conductor in your instrument cables. Right?
You would have to have some physical decoupling via audio transformer, RF, or ADC to optical transmission.

In the UK the term "double insulated" or more correctly a class II device refers to electrical equipment that is constructed in such a way that no single failure could result in any live parts being accessible to the user therefore a mains safety ground connection is not mandated. The fact that a device may or may not be connected to ground via interconnect cables is irrelevant, if it meets the necessary safety standards it is still a class 2 device. (Not sure if this is the same in other territories?)

[xtian]

if you run quarter cables to connect your all your effects and amplifier, you cannot have double insulation. By nature, you are electrically coupled via the grounding conductor in your instrument cables. Right?
You would have to have some physical decoupling via audio transformer, RF, or ADC to optical transmission.

In the UK the term "double insulated" or more correctly a class II device refers to electrical equipment that is constructed in such a way that no single failure could result in any live parts being accessible to the user therefore a mains safety ground connection is not mandated. The fact that a device may or may not be connected to ground via interconnect cables is irrelevant, if it meets the necessary safety standards it is still a class 2 device. (Not sure if this is the same in other territories?)

Yes, in the US, vacuum cleaners are a good example of this.

[SoulFetish]

if you run quarter cables to connect your all your effects and amplifier, you cannot have double insulation. By nature, you are electrically coupled via the grounding conductor in your instrument cables. Right?
You would have to have some physical decoupling via audio transformer, RF, or ADC to optical transmission.

In the UK the term "double insulated" or more correctly a class II device refers to electrical equipment that is constructed in such a way that no single failure could result in any live parts being accessible to the user therefore a mains safety ground connection is not mandated. The fact that a device may or may not be connected to ground via interconnect cables is irrelevant, if it meets the necessary safety standards it is still a class 2 device. (Not sure if this is the same in other territories?)

A class II device cannot have any exposed conductor, grounded or otherwise. Guitarist are grounded via the strings-bridge-sheilded audio interconnect.

[pdf64]

Dunno the current chapter and verse of it all, but it certainly used to be the case that mains powered guitar gear, eg multi fx, could be ungrounded / double insulated, maybe use figure of 8 mains inlets, as used in other portable audio gear, eg radio cd players.

[PaulD]

A class II device cannot have any exposed conductor, grounded or otherwise. Guitarist are grounded via the strings-bridge-sheilded audio interconnect.

Nope. Plenty of class II devices around with metal cases. The IEC definition of class II is here (see note 3 about continuity of protective circuits) http://std.iec.ch/terms/terms.nsf/3385f ... enDocument

[SoulFetish]

A class II device cannot have any exposed conductor, grounded or otherwise. Guitarist are grounded via the strings-bridge-sheilded audio interconnect.

Nope. Plenty of class II devices around with metal cases. The IEC definition of class II is here (see note 3 about continuity of protective circuits) http://std.iec.ch/terms/terms.nsf/3385f ... enDocument

To clarify, I mean exposed conductor constituting part of the electrical circuit. A metal enclosure according to the document you posted would have to be either reinforced insulation or double insulated from the electrical circuit

[PaulD]

Yes, and it also makes it clear that it is perfectly feasible to design a class II device that could be used between a guitar and and an amplifier that would meet all the requirements whilst still maintaining a direct ground connection between the guitar and amp without needing any decoupling or transformers.

[SoulFetish]

Yes, and it also makes it clear that it is perfectly feasible to design a class II device that could be used between a guitar and and an amplifier that would meet all the requirements whilst still maintaining a direct ground connection between the guitar and amp without needing any decoupling or transformers.

See, this is an interesting point. For instance, obviously many of us use effects powered via wall wart or pedal supply, which is not earthed. However I'm curious about how they maintain insulation rated for class II. Perhaps it is by maintaining a separate power supply keeping mains power separate from the enclosure.
I'm just not seeing how the document allows for that provision. Can you elaborate?

[PaulD]

When a device is powered from a wall wart or external low voltage power supply the device itself is not regarded as a class II appliance, it is a low voltage class III appliance that does not require any of the safety features that apply to class I or class II appliances. The power supply itself of course which plugs into the mains is covered by the relevant regulations. https://en.wikipedia.org/wiki/Appliance_classes

[pdf64]

... I started wondering if the 120 volt Hd500x...

It looks to have an external power supply, so no 120Vac connection to the unit.


Did you verify that your step up transformer for the amp maintained the ground circuit?