Hi there, 2 questions using my Seaward Apollo 500:
1- my radio connection between guitar and amplifier has a separate PSU, so is class 3? Should I simply PAT this as class 2?
2- my bass combo amp is a pretty new Ashdown Studio 15 which does not have any class marking (apart from RoHS CE) so has to be class 1? But this device fails earth continuity and I don't believe it is manufactured to earth the exposed metal parts. Can I ignore this test? If so, for what reason?
Thank you.
I would test the power supply of your radio link unit as class II, assuming it is marked as such. Note that under the latest COP electrical testing of class II may no longer be required depending on your risk assessment and a formal visual inspection may suffice.
For the bass amp I would approach the manufacturer for confirmation of the class, and if they say class II then ask them why it is not marked as such. They don't provide any information in the manual either. The only other point of inference on this is there is no statement on the unit or in the manual that ‘This appliance must be earthed’ - so maybe not class I but if they messed up the markings then what else have they messed up?
Edited to add - Class II marking is not mandatory - but is jolly helpful in these situations!
Related. All venues that provide electrical supplies for musicians and entertainers etc. should have 30mA R.C.D. protected sockets for that purpose. For your additional safety or if in doubt, you can run your gear through an R.C.D. adaptor.
Power & Electrical Safety On Stage (soundonsound.com)
Z.
ashdown studio 15 wiring diagram - Bing images
It might be the case, although I am not certain, as info. is limited, that the internals are all powered from a double wound mains isolating transformer. So the maximum Voltage on the amplifier circuit board may not exceed approx. 50/60 Volts.
Z.
Contact Ashdown
The Old Maltings Ind. Est.
Hall Road
Heybridge
Essex
CM9 4NJ
UK
Tel. 01621 857853
info@ashdownmusic.co.uk
They should know what is in the box, if not ask for the internal schematic and we can tell you.
Either exposed metal should be earthed, or able to hold off a 500volt DC test to L and N shorted together with the mains switch in the on position. If it is not earthed, you verify it cannot come live instead.
Mike.
Many thanks for your replies. I also put in a query to the amp manufacturer, Ashdown, at the point of posting here. I've now had 2 replies from them.
The first reply said that the combo is class D with a switchmode supply
The second reply said that the device should be tested at Test 102 and it is a Class I device
Am I right in thinking that class D with a switchmode supply has no impact on PAT?
Following the second reply, I revisited the amp with a multimeter and found continuity between the earth pin on the kettle power lead socket and the edge of the metal facia, so think amp now has clearly passed it's PAT (it previously passed the Seagate 500 auto CLII sequence)
Does anyone know what “Test 102” refers to?
Not something I have experience of, though I have PAT testers and the C&G qualification.
There doesn’t appear to be any helpful information online, I suspect the amp is Class I without any exposed conductive parts on the case other than possibly the input and output connection plugs.
A question to ask the manufacturer for guidance on. You could possibly unscrew the mains inlet IEC panel connector to see if the earth is connected, but then you could confuse the issue if it has fell off ?
https://cdn.shopify.com/s/files/1/2397/1117/files/AAA_Manual.pdf?6983232278938802724l
I was typing that while you were posting your last post, so have not taken that into consideration.
Class I equipment may have no obvious exposed-conductive-parts.
However, in the case of a guitar amplifier with mains input the [accessible] exposed-conductive-parts could include instrument jacks etc. …. the circuits they are connected to are often supplied by PELV to reduce noise and static “pops”. Things like the jacks are an exposed-conductive-part simply because they are connected to PE (anything accessible on the ELV side could become live in a fault if the PE conductor were broken).
There are some Class II (or Class III) guitar amplifiers, for example if I remember correctly, some of the Roland Cubes, but they are suitably labelled with the appropriate safety class markings. Some smaller practice amps are intended to operate from external SELV “power packs”, or batteries.
I have a Vox VT40X which has a separate PELV-output “power pack” and this is becoming more common for electronically-loaded lower-power amps as far as I can see … so you “PAT Test” (apologies for the tautology, I hate it too) the power pack not the amp.
RichMcGill:
Many thanks for your replies. I also put in a query to the amp manufacturer, Ashdown, at the point of posting here. I've now had 2 replies from them.
The first reply said that the combo is class D with a switchmode supply
The second reply said that the device should be tested at Test 102 and it is a Class I device
Am I right in thinking that class D with a switchmode supply has no impact on PAT?
Following the second reply, I revisited the amp with a multimeter and found continuity between the earth pin on the kettle power lead socket and the edge of the metal facia, so think amp now has clearly passed it's PAT (it previously passed the Seagate 500 auto CLII sequence)
Does anyone know what “Test 102” refers to?
Is this related?
Electrical Safety Testing 102 - Bing video
z.
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