Author Topic: Hooked audio amplifier to my scope and amp died  (Read 1026 times)

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Offline ghinckley68Topic starter

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Hooked audio amplifier to my scope and amp died
« on: February 02, 2020, 01:50:03 am »
I got the ground to earth part. But how does one hook an amp up to a scope?
« Last Edit: February 02, 2020, 02:06:54 am by ghinckley68 »
 

Offline oPossum

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Re: Hooked audio amplifier to my scope and amp died
« Reply #1 on: February 02, 2020, 02:21:21 am »
It is a bridged (BTL) amp? That would require a differential probe or using two probes and the math feature of the scope.
 

Offline ataradov

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Re: Hooked audio amplifier to my scope and amp died
« Reply #2 on: February 02, 2020, 02:22:42 am »
What exactly did you hook up?  It is pretty easy to kill the scope with incorrect probing. But killing the device under test is much harder. So we'll need a detailed explanation of what you did.
Alex
 

Offline IanB

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Re: Hooked audio amplifier to my scope and amp died
« Reply #3 on: February 02, 2020, 02:27:23 am »
I believe a few audio amplifiers used to have a problem being operated without a load, although I think modern designs have protection against this. If you connect an unprotected amplifier to the high impedance inputs of a scope then you are effectively operating the amp with no load, and this may damage it.

Also, it may be that the outputs of a mains powered audio amplifier are not meant to be connected to mains ground, and this will happen if you connect to the ground terminal of a scope.
 

Offline supperman

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Re: Hooked audio amplifier to my scope and amp died
« Reply #4 on: February 02, 2020, 02:30:14 am »
Either you got the polarity wrong.. or the amp does not use a ground (i.e. both wires swing).

Basically you shorted the amp out by connecting it to the ground terminal on the Scope. As mentioned above you needed to hook the one wire to one port and the other to another scope cannel. (or use a differential probe)
 

Offline ghinckley68Topic starter

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Re: Hooked audio amplifier to my scope and amp died
« Reply #5 on: February 02, 2020, 02:53:27 am »
yeap it was running in BTL
 

Offline ghinckley68Topic starter

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Re: Hooked audio amplifier to my scope and amp died
« Reply #6 on: February 02, 2020, 02:55:28 am »
I have 50watt test load. those Al block not inductive loads
 

Offline ghinckley68Topic starter

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Re: Hooked audio amplifier to my scope and amp died
« Reply #7 on: February 02, 2020, 02:57:01 am »
So hook one probe to the negative and one to the positive? a
 

Offline supperman

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Re: Hooked audio amplifier to my scope and amp died
« Reply #8 on: February 02, 2020, 05:00:30 pm »
So hook one probe to the negative and one to the positive? a

yes, and you can see if there is a ground (or use the case) for the ground on both.

Then go to the math function to combine them into one signal if you want to actual values.. or just know what you are looking at when you see the two waves.. since they should just be mirrored / opposite.
 

Offline ghinckley68Topic starter

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Re: Hooked audio amplifier to my scope and amp died
« Reply #9 on: February 02, 2020, 05:22:12 pm »
thanks i have a few throw aways to practice with
 


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