A-B-Y Box Questions:

Inspector #20

Inspector #20

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As I am preparing to work my modded Origin 50H back into my setup, I've discovered that the clean tones on my 1999 Marshall MG50 are so good that I may just use it as a clean amp.

I can power the Origin and the MG50 from the same Furhman power conditioner/strip. Would that help ground loop hum issues???

@RobV gave me a really nice A-B-Y box that I've used before in the studio, but never for live work and I had no hum/buzz issues in the studuo.

Any suggestions on how to run it most efficiently live??? I'm assuming I would be totally bypassing my pedalboard, since 1/2 of it goes into the Origin50H's FX loop.

Thoughts???

Shown below is my 1999 MG50 being used front of stage as a keyboard amplifier

received_1331038277241089.jpeg

Gotta love it when people get excited by what your playing.

received_376301637024117.jpeg

The blonde in this photo below came up to me after the show and said, "Your Hotel California solo was perfect. It made me wet..."

received_943664423069134.jpeg
 
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Does the ABY have a phase switch or transformer like the Radial? No hum at all there.
If it has LEDs it would be easier too.
I would think just switch from clean to dirty as required and whatever fx are runnjng through loop in Origin would stay there. I also assume you use clean fairly sparingly so the effects are most useful through Origin.
You can complicate things with a device to take loop effects between both amps bug it gets a bit cumbersome to use. Otherwise pretty straightforward.

twinline-thumb-768x531.png
 
Jethro Rocker said:
Does the ABY have a phase switch or transformer like the Radial? No hum at all there.
If it has LEDs it would be easier too.
I would think just switch from clean to dirty as required and whatever fx are runnjng through loop in Origin would stay there. I also assume you use clean fairly sparingly so the effects are most useful through Origin.
You can complicate things with a device to take loop effects between both amps bug it gets a bit cumbersome to use. Otherwise pretty straightforward.

twinline-thumb-768x531.png
Click to expand...

Good question!!! I will have to take a look...
 
Robert Herndon said:
As I am preparing to work my modded Origin 50H back into my setup, I've discovered that the clean tones on my 1999 Marshall MG50 are so good that I may just use it as a clean amp.

I can power the Origin and the MG50 from the same Furhman power conditioner/strip. Would that help ground loop hum issues???

@RobV gave me a really nice A-B-Y box that I've used before in the studio, but never for live work and I had no hum/buzz issues in the studuo.

Any suggestions on how to run it most efficiently live??? I'm assuming I would be totally bypassing my pedalboard, since 1/2 of it goes into the Origin50H's FX loop.

Thoughts???

Shown below is my 1999 MG50 being used front of stage as a keyboard amplifier

View attachment 73270

Gotta love it when people get excited by what your playing.

View attachment 73271

The blonde in this photo below came up to me after the show and said, "Your Hotel California solo was perfect. It made me wet..."

View attachment 73272
Click to expand...

Basically, both amps are grounded to the wall power.
That (third pin) on the power plug should always be connected to the wall power for safety.
That third pin on the power plug "is" the safety ground.

When you plug a cable to the input of the second amp, the ground (shield or screen) should be disconnected at the end of the guitar cable (disconnected from the one 1/4"plug).
Having guitar cables with one end ground lifted can be handy to stop a ground loop.

The isolated power supply for effects pedals will prevent loops between the effects pedals, but not at the input of the second amp.

As long as the second amp is grounded once, there is no ground loop.
But any time the amp is grounded twice, that's what makes a ground loop.
Being:
the power plug grounds the amp once.
But the guitar cable plugged into the second amp will ground the second amp twice.

There are many gizmos to stop ground loops, but you don't need any of them.
"hum dinger" don't need it at all.
"Hum X" a complete waste of money.
There are lots of vendors who charge you $20 - $50 to lift the ground but it's basically an unneeded adapter.

All you need is a guitar cable that is lifted at one plug end. That's all.

There are lots of vendors, who claim a transformer is needed, but that's a load of BS.
People are gullible.
They don't realize how simple it is to stop a ground loop.....for zero dollars.

Ground loops are quite common in home stereo theater systems also.
In these systems, the ground loop is caused by the cable TV ground.
Lifting the cable TV ground at the theater input (or splitter) will stop the hum.

Yes I have cured many ground loop hums. And it's really easy to do.
 
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Amp Mad Scientist said:
Basically, both amps are grounded to the wall power.
That (third pin) on the power plug should always be connected to the wall power for safety.
That third pin on the power plug "is" the safety ground.

When you plug a cable to the input of the second amp, the ground (shield or screen) should be disconnected at the end of the guitar cable (disconnected from the one 1/4"plug).
Having guitar cables with one end ground lifted can be handy to stop a ground loop.

The isolated power supply for effects pedals will prevent loops between the effects pedals, but not at the input of the second amp.

As long as the second amp is grounded once, there is no ground loop.
But any time the amp is grounded twice, that's what makes a ground loop.
Being:
the power plug grounds the amp once.
But the guitar cable plugged into the second amp will ground the second amp twice.

There are many gizmos to stop ground loops, but you don't need any of them.
"hum dinger" don't need it at all.
"Hum X" a complete waste of money.
There are lots of vendors who charge you $20 - $50 to lift the ground but it's basically an unneeded adapter.

All you need is a guitar cable that is lifted at one plug end. That's all.

There are lots of vendors, who claim a transformer is needed, but that's a load of BS.
People are gullible.
They don't realize how simple it is to stop a ground loop.....for zero dollars.

Ground loops are quite common in home stereo theater systems also.
In these systems, the ground loop is caused by the cable TV ground.
Lifting the cable TV ground at the theater input (or splitter) will stop the hum.

Yes I have cured many ground loop hums. And it's really easy to do.
Click to expand...

This is what I have on hand..

20210926_220703.jpg
 
Robert Herndon said:
This is what I have on hand..

View attachment 73307
Click to expand...
It has no ground lift switch.
Therefore making a simple guitar cable, with one plug disconnected from ground (no shield connected at one end of the cable) is the easiest solution.

Both amps used will be plugged into power with a 3 prong power plug.
This grounds both amps to the mains power ground.
This is the correct way - for safety.

The ground lift guitar cable goes between the A/B switch and the input of the second amp.
This stops the ground loop.
This stops the second amp from being grounded twice.
You want: the second amp to be grounded only once. (grounded from the mains power 3 prong plug)

Now do you understand how a ground loop is created, when using 2 amps?

Many people think that ground loops are complicated and mysterious. But actually it's really simple.
The problem is solved without any extra purchased "adapters."
The problem is solved for free.
This stops the second amp from being grounded twice.

Do not use this:
1632749363548.png
 
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Amp Mad Scientist said:
It has no ground lift switch.
Therefore making a simple guitar cable, with one plug disconnected from ground (no shield connected at one end of the cable) is the easiest solution.

Both amps used will be plugged into power with a 3 prong power plug.
This grounds both amps to the mains power ground.
This is the correct way - for safety.

The ground lift guitar cable goes between the A/B switch and the input of the second amp.
This stops the ground loop.
This stops the second amp from being grounded twice.
You want: the second amp to be grounded only once. (grounded from the mains power 3 prong plug)

Now do you understand how a ground loop is created, when using 2 amps?

Many people think that ground loops are complicated and mysterious. But actually it's really simple.
The problem is solved without any extra purchased "adapters."
The problem is solved for free.
This stops the second amp from being grounded twice.

Do not use this:
View attachment 73322
Click to expand...

Thanks for that explanation!!! It's like putting together a brand new rig!!!
 
Jethro Rocker said:
Does the ABY have a phase switch or transformer like the Radial? No hum at all there.
If it has LEDs it would be easier too.
I would think just switch from clean to dirty as required and whatever fx are runnjng through loop in Origin would stay there. I also assume you use clean fairly sparingly so the effects are most useful through Origin.
You can complicate things with a device to take loop effects between both amps bug it gets a bit cumbersome to use. Otherwise pretty straightforward.

twinline-thumb-768x531.png
Click to expand...
Radial is good equipment certainly.
It's made in Canada, not China. That alone is the purchasing point!

But you don't need it to solve a ground loop problem.
The transformer "does" solve a ground loop problem but...
you don't need it.

The transformer degrades the signal quality, and degrades the frequency response.
This is why I avoid using transformers in audio signal paths.
There are other methods which work much better and for much less cost.
In fact other methods are basically free, and work just as well or better.
 
Robert Herndon said:
I have several that could be modded for just such a purpose.

Alternatively, could I just make a switchable guitar cable ground lifter device???
Click to expand...
Yes.
Just make a box that disconnects the ground from one plug side of the cable, where it enters the input of the second amp.

In low volume situations you might not notice a ground hum.
But when the loudness is cranked way up, then you hear all the noises.

I always test for noise with everything wide open.
Then I really hear any noise than could be possible.
I don't pretend that there is no noise, by turning the loudness way down.
(many people do this) they turn the master volume way down, and declare that there is no noise. That is a BS test method.

Or they adjust the bias very cold.
This makes the output tubes work like a noise gate.
The tubes shut off when there is no sound going through. Therefore muting the noise.


The truth is: if a Marshall amp has no noise, there is something wrong.
It is normal for a Marshall to have hiss, buzz (filament noise) and hum.
 
Amp Mad Scientist said:
Radial is good equipment certainly.
It's made in Canada, not China. That alone is the purchasing point!

But you don't need it to solve a ground loop problem.
The transformer "does" solve a ground loop problem but...
you don't need it.

The transformer degrades the signal quality, and degrades the frequency response.
This is why I avoid using transformers in audio signal paths.
There are other methods which work much better and for much less cost.
In fact other methods are basically free, and work just as well or better.
Click to expand...
I think the iso was a transformer, could be wrong. All I know is mine has a ground lift as well amd I get no hum when running 2 amps depending how I switch it.
I do not hear any loss of signal at all.
I guess since I already own it, no point in not using it the odd time I do. It also can run 2 guitars or signals in to one out.

BigShot-ABY-thumb-768x844.png
 
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