Balanced line out to PA vs Direct Out

[Tommy TGrip]

Hi all, I would be very grateful for advice re my Balanced line out (XLR) from my amp. I bought the amp second hand a couple of months ago and I have been very happy with it. I tried lining out to a PA on the weekend and got nothing. When I turned up the volume on the PA, the PA speakers put out a crackling blown speaker kind of sound. To check that it wasn't the PA I tried doing the same with my combo amp (GK MB100). The combo sounded fine. I figured I had bought a dud amp but have just realised the amp out is a Balanced line out, while the combo is described as a Direct out. Ultimately it's annoying either way and I'm still pretty sure there must be a fault with the head. Any advice on how I could fix it? How easy/expensive that might be etc? Thank you

 

[AEVAREX]

https://www.talkbass.com/threads/difference-between-line-out-and-direct-out.920275/#:~:text=Direct Out is a voltage,than mic-level Direct Out.

 

[ThisBass]

With some good luck the issue may be fixed by resoldering the pins ground, signal+ and signal- on the PCB.
I think its a good idea to bring the amp to an authorized service center, or at least to an experienced service tech.
If you don't have experience with working on PCB's you might cause even more issues to the amp than currently present.

 

[JimChjones]

In your place I would want to do a lot more diagnostics before I assumed an amp fault, and I wouldn't go near it with a soldering iron unless I had definitively proved it faulty. In fact, bearing in mind my soldering, perhaps not even then!

Are you completely confident you were running into a balanced line level input on the mixer, and is the cable and everything else tested and good. The symptoms you describe could very easily be outside the amp.

 

[Zbysek]

Make sure the Line Out control is not off when you connect to PA…

 

[InhumanResource]

Hi all, I would be very grateful for advice re my Balanced line out (XLR) from my amp. I bought the amp second hand a couple of months ago and I have been very happy with it. I tried lining out to a PA on the weekend and got nothing. When I turned up the volume on the PA, the PA speakers put out a crackling blown speaker kind of sound. To check that it wasn't the PA I tried doing the same with my combo amp (GK MB100). The combo sounded fine. I figured I had bought a dud amp but have just realised the amp out is a Balanced line out, while the combo is described as a Direct out. Ultimately it's annoying either way and I'm still pretty sure there must be a fault with the head. Any advice on how I could fix it? How easy/expensive that might be etc? Thank youView attachment 4678725 View attachment 4678725

You have a couple of options here. You could just put the amp into a good shop, pay something like $100 just for the price of admission and the tech will tell you how much more it will be to resolve the issue (assuming the amp is indeed the problem).

Your other option would be to grab a cheap passive DI box for like $20 and run that to your PA instead of the amp. If it still gives you that farty blown up sound then you know the amp is not the problem. If it works, you have the choice of bringing the amp to a tech or just moving forward with your $20 DI box solution and forgetting about the problem altogether.

FWIW I have been using one of those cheap boxes for years with no issue. It lives in my gig bag and weighs no more than a typical effects pedal. Even if my amp completely fails, I can still get a good signal to the board and at least get myself into the monitor feed to limp through the night.

 

[Bonafide]

Make sure the Line Out control is not off when you connect to PA…

My first thought also. You did turn up the line out potentiometer on the front?

 

[frankie5string]

Some Markbass amps have a Direct Out/Line Out volume control on the front. If that's down, you'll get no sound.
Turn it up to 12 o'clock, plug into the PA, and have someone slowly bring up the level while you play.

 

[bassmanrocke]

There is a lineout level on the control plate of most Markbass amps. Not being familiar with the amp, You may just not have turned it up

 

[InhumanResource]

Another thought is to verify what the board is expecting (line, mic, instrument level input) and that the amp is dialed in accordingly since it sounds like MarkBass has a control for the XLR out. I wasn’t aware of that

 

[MrLenny1]

Is there a switch on the back to control DI vs balanced ?

 

[john_g]

What version of MB amp is that? LMII, III...? My old LMII, the gain knob controlled the amount of level to the DI. On the LMIII, there is a dedicated knob. Could be a bad head but just checking.

 

[ThisBass]

The OP receives a:
" the PA speakers put out a crackling blown speaker kind of sound."
when he connects the Markbass to the PA.
While everything works fine when he connects the combo amp (GK MB100) to the PA.
I assume the OP has connected both amps with just the same cable to the PA, so I don't think the issue might be caused by the cable that connects the amp to the PA!

So its quite hard to believe the issue of "crackling blown speaker kind of sound" that comes off from the
Markbass may have anything to do with:

My first thought also. You did turn up the line out potentiometer on the front?

You have a couple of options here. You could just put the amp into a good shop, pay something like $100 just for the price of admission and the tech will tell you how much more it will be to resolve the issue (assuming the amp is indeed the problem).

Your other option would be to grab a cheap passive DI box for like $20 and run that to your PA instead of the amp. If it still gives you that farty blown up sound then you know the amp is not the problem. If it works, you have the choice of bringing the amp to a tech or just moving forward with your $20 DI box solution and forgetting about the problem altogether.

FWIW I have been using one of those cheap boxes for years with no issue. It lives in my gig bag and weighs no more than a typical effects pedal. Even if my amp completely fails, I can still get a good signal to the board and at least get myself into the monitor feed to limp through the night.

Make sure the Line Out control is not off when you connect to PA…

There is a lineout level on the control plate of most Markbass amps. Not being familiar with the amp, You may just not have turned it up

Some Markbass amps have a Direct Out/Line Out volume control on the front. If that's down, you'll get no sound.
Turn it up to 12 o'clock, plug into the PA, and have someone slowly bring up the level while you play.

Is there a switch on the back to control DI vs balanced ?

Another thought is to verify what the board is expecting (line, mic, instrument level input) and that the amp is dialed in accordingly since it sounds like MarkBass has a control for the XLR out. I wasn’t aware of that

 

[39-Bassist]

Take a pic of full back and full front views. Lets see the controls and model.

 

[Zbysek]

The OP receives a:
" the PA speakers put out a crackling blown speaker kind of sound."
when he connects the Markbass to the PA.
While everything works fine when he connects the combo amp (GK MB100) to the PA.
I assume the OP has connected both amps with just the same cable to the PA, so I don't think the issue might be caused by the cable that connects the amp to the PA!

So its quite hard to believe the issue of "crackling blown speaker kind of sound" that comes off from the
Markbass may have anything to do with:

My understanding is that the primary issue the OP has is this one:

I tried lining out to a PA on the weekend and got nothing.

The fact that PA gets no signal from the amp might be caused by the Line Out being off (CCW).

Then there is the secondary issue of "crackling blown speaker kind of sound" which can be caused by many things including faulty cables, jacks, scratchy pots on the mixer etc.

 

[pbass2]

FWIW I have been using one of those cheap boxes for years with no issue. It lives in my gig bag and weighs no more than a typical effects pedal. Even if my amp completely fails, I can still get a good signal to the board and at least get myself into the monitor feed to limp through the night.

I'm of the school of thought that a bassist should always have a separate DI in their bag, even a cheap one like the basic Whirlwind is foolproof. Spend a little more on something like a JDI and you'll have a bombproof pro-level DI for live or studio use. Mine's been going strong for almost 20 years. I've never used the DI out on my own amp, and when there's backline on tour I've never once seen the tech use the DI out on the amp - they always use their own separate DI or my JDI.

 

[Passinwind]

The OP receives a:
" the PA speakers put out a crackling blown speaker kind of sound."
when he connects the Markbass to the PA.
While everything works fine when he connects the combo amp (GK MB100) to the PA.
I assume the OP has connected both amps with just the same cable to the PA, so I don't think the issue might be caused by the cable that connects the amp to the PA!

So its quite hard to believe the issue of "crackling blown speaker kind of sound" that comes off from the
Markbass may have anything to do with:

It sounds like it might just be a classic case of a DI that doesn't like phantom power, no? I've observed that a number of times over the years, typically with mixers that have a global phantom power switch. Whether it is or isnt that, it's usually a very simple thing to check in any case.

 

[ThisBass]

It sounds like it might just be a classic case of a DI that doesn't like phantom power, no?

yeph, true this might also be an issue.
I think the manual should provide the information if the balanced/DI Out can carry phantom power or if it does not.

But even if the balanced out was not designed to carry savely phantom power, the "crackling sound" how it is described by the OP does let me think about a different issue than that. But, who really knows?

I've observed that a number of times over the years, typically with mixers that have a global phantom power switch. Whether it is or isnt that, it's usually a very simple thing to check in any case.

For the most part of all failermodes I have personally observed with balanced/DI XLR outputs:
damaged outputs cause they were not designed to carry phantom power, and once these are damaged there is (almost always) no more sound coming out of it nothing at all.
Second failermode, issues due to "bad" soldering of pins on the PCB.
Soldering issues had more often become an issue in the very past. Nowadays those issues are quite rare because of better and optimized production processes these days, yet sometimes still appear.

 

[ThisBass]

My understanding is that the primary issue the OP has is this one:



The fact that PA gets no signal from the amp might be caused by the Line Out being off (CCW).

Then there is the secondary issue of "crackling blown speaker kind of sound" which can be caused by many things including faulty cables, jacks, scratchy pots on the mixer etc.

In any case, if the following happens, and it did happen:
"When I turned up the volume on the PA, the PA speakers put out a crackling blown speaker kind of sound. "

then there must be an issue with the output cause this "issue" how it is described must not appear, even must not appear if the volume of the PA was turned up!
If the PA was fine then the issue is caused by the amp.
Furthermore the OP told us that everything was fine when he did use the GK amp.

 

[Zbysek]

In any case, if the following happens, and it did happen:
"When I turned up the volume on the PA, the PA speakers put out a crackling blown speaker kind of sound. "

then there must be an issue with the output cause this "issue" how it is described must not appear, even must not appear if the volume of the PA was turned up!
If the PA was fine then the issue is caused by the amp.
Furthermore the OP told us that everything was fine when he did use the GK amp.

yes, it might have been caused by the amp’s output…