Did I blow my amp?

[Rick Casey]

I am not an electronics guy, but need to ask for some opinions from people who are...and hopefully help me find the right solution to fix my amp.

I have a Roland Cube, which I basically use as an amplifier to play music through, or my guitar. The other night I had my laptop plugged into it, playing some recorded music. I had the music coming out of the laptop turned off, the amp turned off, and plugged into the laptop (via a mini-plug wire connector).

I had accidently touched the volume control on my laptop, however, and didn't see that I set the volume at nearly max output, and started the music playing. There was no sound yet, though, since the amp was off; so when I flipped the power switch on the amp, the sound came blasting out in a huge way, though it was garbled and static since it was overloading the system.

Pulling the plug immediately, when I later tried to play music through the amp again at proper volume, nothing comes out but a steady hum. I hear the same hum if there not even anything connected and playing through it.

So my question is: what damage did I likely do? Can it be fixed? Is there any other testing I can do to determine what was damaged?

TIA,
--Rick

 

[M Philbrook]

In article <2aa872e3-0dcf-48fd-8461-57d05e8eb92f@googlegroups.com>,
caseyrick@gmail.com says...

I am not an electronics guy, but need to ask for some opinions from people who are...and hopefully help me find the right solution to fix my amp.

I have a Roland Cube, which I basically use as an amplifier to play music through, or my guitar. The other night I had my laptop plugged into it, playing some recorded music. I had the music coming out of the laptop turned off, the amp turned off, and plugged into the laptop (via a mini-plug wire connector).

I had accidently touched the volume control on my laptop, however, and didn't see that I set the volume at nearly max output, and started the music playing. There was no sound yet, though, since the amp was off; so when I flipped the power switch on the amp, the sound came blasting out in a huge way, though it was garbled and static since it was overloading the system.

Pulling the plug immediately, when I later tried to play music through the amp again at proper volume, nothing comes out but a steady hum. I hear the same hum if there not even anything connected and playing through it.

So my question is: what damage did I likely do? Can it be fixed? Is there any other testing I can do to determine what was damaged?

TIA,
--Rick

Maybe when yuo yanked the cord you could of broke a wire in the cord
or a solder joint where the plug is inside the unit.

Jamie

 

[Chuck]

On Fri, 13 Nov 2015 13:43:58 -0800 (PST), Rick Casey
<caseyrick@gmail.com> wrote:

I am not an electronics guy, but need to ask for some opinions from people who are...and hopefully help me find the right solution to fix my amp.

I have a Roland Cube, which I basically use as an amplifier to play music through, or my guitar. The other night I had my laptop plugged into it, playing some recorded music. I had the music coming out of the laptop turned off, the amp turned off, and plugged into the laptop (via a mini-plug wire connector).

I had accidently touched the volume control on my laptop, however, and didn't see that I set the volume at nearly max output, and started the music playing. There was no sound yet, though, since the amp was off; so when I flipped the power switch on the amp, the sound came blasting out in a huge way, though it was garbled and static since it was overloading the system.

Pulling the plug immediately, when I later tried to play music through the amp again at proper volume, nothing comes out but a steady hum. I hear the same hum if there not even anything connected and playing through it.

So my question is: what damage did I likely do? Can it be fixed? Is there any other testing I can do to determine what was damaged?

TIA,
--Rick

If it is a loud 120 hz hum, chances are the power amp section is
blown. (Shorted parts)

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[Trevor Wilson]

On 14/11/2015 8:43 AM, Rick Casey wrote:

I am not an electronics guy, but need to ask for some opinions from
people who are...and hopefully help me find the right solution to fix
my amp.

I have a Roland Cube, which I basically use as an amplifier to play
music through, or my guitar. The other night I had my laptop plugged
into it, playing some recorded music. I had the music coming out of
the laptop turned off, the amp turned off, and plugged into the
laptop (via a mini-plug wire connector).

I had accidently touched the volume control on my laptop, however,
and didn't see that I set the volume at nearly max output, and
started the music playing. There was no sound yet, though, since the
amp was off; so when I flipped the power switch on the amp, the sound
came blasting out in a huge way, though it was garbled and static
since it was overloading the system.

Pulling the plug immediately, when I later tried to play music
through the amp again at proper volume, nothing comes out but a
steady hum. I hear the same hum if there not even anything connected
and playing through it.

So my question is: what damage did I likely do? Can it be fixed? Is
there any other testing I can do to determine what was damaged?

**Unknown.
Probably.
Not really.

--
Trevor Wilson
www.rageaudio.com.au

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[pfjw@aol.com]

Look for internal fuses. Generally what you did will not damage most amps.... But it may well pop internal fuses or links. But not always. Next would be the output devices.

 

[Rick Casey]

On Saturday, November 14, 2015 at 7:37:34 AM UTC-7, pf...@aol.com wrote:
> Look for internal fuses. Generally what you did will not damage most amps.... But it may well pop internal fuses or links. But not always. Next would be the output devices.

Thanks for the tip! Will see if I can find that...

 

[Phil Allison]

Rick Casey wrote:

I am not an electronics guy, but need to ask for some
opinions from people who are...and hopefully help me find
the right solution to fix my amp.

I have a Roland Cube, which I basically use as an amplifier
to play music through, or my guitar.

** The first Roland cube was the "Cube 40" released in 1978, then followed Cubes 20 and 60 and then too many new models to count. Roland claim to have sold over 1,000,000 Cubes of all the various sorts.

Which one have you got?



> Pulling the plug immediately, when I later tried to play music through the amp again at proper volume, nothing comes out but a steady hum.

** Was that the power plug ?

So my question is: what damage did I likely do?
Can it be fixed? Is there any other testing I can
do to determine what was damaged?

** Answer the first question and maybe we can make an educated guess.

One possibility is the input jack ( or the PCB it is mounted on) has broken.

All depends on which model Cube you have.


.... Phil

 

[John Robertson]

On 11/13/2015 2:35 PM, M Philbrook wrote:

In article <2aa872e3-0dcf-48fd-8461-57d05e8eb92f@googlegroups.com>,
caseyrick@gmail.com says...

I am not an electronics guy, but need to ask for some opinions from people who are...and hopefully help me find the right solution to fix my amp.

I have a Roland Cube, which I basically use as an amplifier to play music through, or my guitar. The other night I had my laptop plugged into it, playing some recorded music. I had the music coming out of the laptop turned off, the amp turned off, and plugged into the laptop (via a mini-plug wire connector).

I had accidently touched the volume control on my laptop, however, and didn't see that I set the volume at nearly max output, and started the music playing. There was no sound yet, though, since the amp was off; so when I flipped the power switch on the amp, the sound came blasting out in a huge way, though it was garbled and static since it was overloading the system.

Pulling the plug immediately, when I later tried to play music through the amp again at proper volume, nothing comes out but a steady hum. I hear the same hum if there not even anything connected and playing through it.

So my question is: what damage did I likely do? Can it be fixed? Is there any other testing I can do to determine what was damaged?

TIA,
--Rick

Maybe when yuo yanked the cord you could of broke a wire in the cord
or a solder joint where the plug is inside the unit.

Jamie

I'm with Jamie here. Have you powered up the amp with ONLY the speakers
hooked up? No other cables going to the inputs.

If still hums, does the hum volume go up/down with the volume control?
This could indicate a problem in the pre-amp section.

If the hum level is steady, then the problem could be a blown fuse on
one of the power amp rails (B+ or B-).

John :-#)#
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www.flippers.com
"Old pinballers never die, they just flip out."

 

[Phil Allison]

John Robertson wrote:

I'm with Jamie here. Have you powered up the amp with ONLY the speakers
hooked up? No other cables going to the inputs.

** Roland Cubes are combo amps with the speaker internally wired.

If the hum level is steady, then the problem could be a blown fuse on
one of the power amp rails (B+ or B-).

** None that I have seen use DC rail fuses, they normally have fuses in the two AC lines coming from the transformer. If one of them fails, the amp continues to work. When both fail, it goes silent.



.... Phil